Three groups of arteries found in the eye which supply the iris, pupil, sclera, conjunctiva, and the muscles of the iris.
Artery originating from the internal carotid artery and distributing to the eye, orbit and adjacent facial structures.
Central retinal artery and its branches. It arises from the ophthalmic artery, pierces the optic nerve and runs through its center, enters the eye through the porus opticus and branches to supply the retina.
A ring of tissue extending from the scleral spur to the ora serrata of the RETINA. It consists of the uveal portion and the epithelial portion. The ciliary muscle is in the uveal portion and the ciliary processes are in the epithelial portion.
The vessels carrying blood away from the heart.
Ultrasonography applying the Doppler effect, with the superposition of flow information as colors on a gray scale in a real-time image. This type of ultrasonography is well-suited to identifying the location of high-velocity flow (such as in a stenosis) or of mapping the extent of flow in a certain region.
The L-Isomer of bunolol.
A direct acting sympathomimetic used as a vasoconstrictor to relieve nasal congestion. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1251)
The recording of muscular movements. The apparatus is called a myograph, the record or tracing, a myogram. (From Stedman, 25th ed)
A tissue preparation technique that involves the injecting of plastic (acrylates) into blood vessels or other hollow viscera and treating the tissue with a caustic substance. This results in a negative copy or a solid replica of the enclosed space of the tissue that is ready for viewing under a scanning electron microscope.
Central retinal vein and its tributaries. It runs a short course within the optic nerve and then leaves and empties into the superior ophthalmic vein or cavernous sinus.
The thin, highly vascular membrane covering most of the posterior of the eye between the RETINA and SCLERA.
The organ of sight constituting a pair of globular organs made up of a three-layered roughly spherical structure specialized for receiving and responding to light.
Drugs that bind to and activate adrenergic receptors.
The short wide vessel arising from the conus arteriosus of the right ventricle and conveying unaerated blood to the lungs.
An alkaloid found in opium but not closely related to the other opium alkaloids in its structure or pharmacological actions. It is a direct-acting smooth muscle relaxant used in the treatment of impotence and as a vasodilator, especially for cerebral vasodilation. The mechanism of its pharmacological actions is not clear, but it apparently can inhibit phosphodiesterases and it may have direct actions on calcium channels.
The 2nd cranial nerve which conveys visual information from the RETINA to the brain. The nerve carries the axons of the RETINAL GANGLION CELLS which sort at the OPTIC CHIASM and continue via the OPTIC TRACTS to the brain. The largest projection is to the lateral geniculate nuclei; other targets include the SUPERIOR COLLICULI and the SUPRACHIASMATIC NUCLEI. Though known as the second cranial nerve, it is considered part of the CENTRAL NERVOUS SYSTEM.
Either of the two principal arteries on both sides of the neck that supply blood to the head and neck; each divides into two branches, the internal carotid artery and the external carotid artery.
The nonstriated involuntary muscle tissue of blood vessels.
The arterial blood vessels supplying the CEREBRUM.
A branch of the abdominal aorta which supplies the kidneys, adrenal glands and ureters.
The main artery of the thigh, a continuation of the external iliac artery.
A stable prostaglandin endoperoxide analog which serves as a thromboxane mimetic. Its actions include mimicking the hydro-osmotic effect of VASOPRESSIN and activation of TYPE C PHOSPHOLIPASES. (From J Pharmacol Exp Ther 1983;224(1): 108-117; Biochem J 1984;222(1):103-110)
A value equal to the total volume flow divided by the cross-sectional area of the vascular bed.
Muscular contractions characterized by increase in tension without change in length.
Drugs used to cause constriction of the blood vessels.
Arteries which arise from the abdominal aorta and distribute to most of the intestines.
The physiological widening of BLOOD VESSELS by relaxing the underlying VASCULAR SMOOTH MUSCLE.
The artery formed by the union of the right and left vertebral arteries; it runs from the lower to the upper border of the pons, where it bifurcates into the two posterior cerebral arteries.
The flow of BLOOD through or around an organ or region of the body.
That phase of a muscle twitch during which a muscle returns to a resting position.
Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).
The pressure of the fluids in the eye.
Either of two large arteries originating from the abdominal aorta; they supply blood to the pelvis, abdominal wall and legs.
The first branch of the SUBCLAVIAN ARTERY with distribution to muscles of the NECK; VERTEBRAE; SPINAL CORD; CEREBELLUM; and interior of the CEREBRUM.
Surgical therapy of ischemic coronary artery disease achieved by grafting a section of saphenous vein, internal mammary artery, or other substitute between the aorta and the obstructed coronary artery distal to the obstructive lesion.
Visualization of a vascular system after intravenous injection of a fluorescein solution. The images may be photographed or televised. It is used especially in studying the retinal and uveal vasculature.
Single pavement layer of cells which line the luminal surface of the entire vascular system and regulate the transport of macromolecules and blood components.
The direct continuation of the brachial trunk, originating at the bifurcation of the brachial artery opposite the neck of the radius. Its branches may be divided into three groups corresponding to the three regions in which the vessel is situated, the forearm, wrist, and hand.
Arteries originating from the subclavian or axillary arteries and distributing to the anterior thoracic wall, mediastinal structures, diaphragm, pectoral muscles and mammary gland.
A free radical gas produced endogenously by a variety of mammalian cells, synthesized from ARGININE by NITRIC OXIDE SYNTHASE. Nitric oxide is one of the ENDOTHELIUM-DEPENDENT RELAXING FACTORS released by the vascular endothelium and mediates VASODILATION. It also inhibits platelet aggregation, induces disaggregation of aggregated platelets, and inhibits platelet adhesion to the vascular endothelium. Nitric oxide activates cytosolic GUANYLATE CYCLASE and thus elevates intracellular levels of CYCLIC GMP.
Branch of the common carotid artery which supplies the anterior part of the brain, the eye and its appendages, the forehead and nose.
Artery arising from the brachiocephalic trunk on the right side and from the arch of the aorta on the left side. It distributes to the neck, thoracic wall, spinal cord, brain, meninges, and upper limb.
Pathological conditions involving the CAROTID ARTERIES, including the common, internal, and external carotid arteries. ATHEROSCLEROSIS and TRAUMA are relatively frequent causes of carotid artery pathology.
The mucous membrane that covers the posterior surface of the eyelids and the anterior pericorneal surface of the eyeball.
Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)
The recording of images in three-dimensional form on a photographic film by exposing it to a laser beam reflected from the object under study.
The circulation of the BLOOD through the MICROVASCULAR NETWORK.
Pieces of glass or other transparent materials used for magnification or increased visual acuity.
The determination of oxygen-hemoglobin saturation of blood either by withdrawing a sample and passing it through a classical photoelectric oximeter or by electrodes attached to some translucent part of the body like finger, earlobe, or skin fold. It includes non-invasive oxygen monitoring by pulse oximetry.
Conjunctival diseases refer to a broad range of disorders that affect the conjunctiva, the mucous membrane covering the inner surface of the eyelids and the outer layer of the eyeball, causing symptoms such as redness, itching, irritation, discharge, and/or inflammation.

Analysis of blood flow in the long posterior ciliary artery of the cat. (1/68)

PURPOSE: Experiments were undertaken to use a new technique for direct on-line measurement of blood flow in the long posterior ciliary artery (LPCA) in cats and to evaluate possible physiological mechanisms controlling blood flow in the vascular beds perfused by this artery. METHODS: Blood flow in the temporal LPCA was measured on a continuous basis using ultrasonic flowmetry in anesthetized cats. Effects of acute sectioning of the sympathetic nerve and changes in LPCA and cerebral blood flows in response to altered levels of inspired CO2 and O2 were tested in some animals. In others, the presence of vascular autoregulatory mechanisms in response to stepwise elevations of intraocular pressure was studied. RESULTS: Blood flow in the temporal LPCA averaged 0.58+/-0.03 ml/min in 45 cats anesthetized with pentobarbital. Basal LPCA blood flow was not altered by acute sectioning of the sympathetic nerve or by changes in low levels of inspired CO2 and O2, although 10% CO2 caused a modest increase. Stepwise elevations of intraocular pressure resulted in comparable stepwise decreases of LPCA blood flow, with perfusion pressure declining in a linear manner throughout the perfusion-pressure range. CONCLUSIONS: Ultrasonic flowmetry seems to be a useful tool for continuous on-line measurement of LPCA blood flow in the cat eye. Blood flow to vascular beds perfused by this artery does not seem to be under sympathetic neural control and is refractory to modest alterations of blood gas levels of CO2 and O2. Blood vessels perfused by the LPCA show no clear autoregulatory mechanisms.  (+info)

Effect of Ox-LDL on endothelium-dependent response in pig ciliary artery: prevention by an ET(A) antagonist. (2/68)

PURPOSE: To investigate whether oxidized low-density lipoprotein (Ox-LDL) affects endothelium-dependent responses in isolated porcine ciliary arteries. METHODS: In a myograph system for isometric force measurements, quiescent vessels were incubated with 50 microg/ml, 100 microg/ml, or 200 microg/ml Ox-LDL; 100 microg/ml native LDL (n-LDL); 1 microM of the ET(A)- endothelin receptor antagonist BQ 123; 100 microg/ml Ox-LDL coadministered with 1 microM BQ 123; or 100 microg/ml Ox-LDL coadministered with 50 microM of the protein synthesis inhibitor cycloheximide. Vessels with nonfunctional endothelium (intentionally and mechanically damaged) were also exposed to 100 microg/ml Ox-LDL. Two hours later, vessels were washed, precontracted with the thromboxane A2 analog U 46619 (approximately 0.1 microM), and exposed to bradykinin (0.1 nM to 3 microM), an endothelium-dependent relaxing agent. RESULTS: In quiescent vessels, Ox-LDL evoked delayed contractions. In contrast, no contractions were observed after exposure to n-LDL, BQ 123, Ox-LDL with BQ 123, or Ox-LDL with cycloheximide. In vessels with nonfunctional endothelium, Ox-LDL did not evoke contraction. Bradykinin-induced relaxations were inhibited in a dose-dependent manner by Ox-LDL, but not by n-LDL, BQ 123 alone, Ox-LDL with BQ 123, or Ox-LDL with cycloheximide. CONCLUSIONS: In porcine ciliary arteries, Ox-LDL affects endothelium-dependent responses through the activation of ET(A)- endothelin receptors. As Ox-LDL can accumulate in atherosclerotic plaques, such a mechanism might be involved in the occlusion of the ophthalmic circulation observed in patients with hypercholesterolemia and atherosclerosis.  (+info)

Effect of acute intraocular pressure changes on short posterior ciliary artery haemodynamics. (3/68)

BACKGROUND/AIMS: Vascular insufficiency due to abnormal autoregulation has been proposed as a major factor in the development of glaucoma. The anterior optic nerve is primarily perfused by the short posterior ciliary arteries. The autoregulatory capacity of these vessels in response to acutely elevated intraocular pressure (IOP) was examined in normal human subjects. METHODS: Colour Doppler imaging was performed on the short posterior ciliary arteries of 10 normal subjects at baseline and during four incremental IOP elevations. Using a scleral suction cup placed temporally, IOP was elevated to approximately 25, 30, 40, and 50 mm Hg. Additional measurements were performed immediately after pressure release. Systolic and diastolic flow velocities were measured and Pourcelot's resistivity index was calculated. RESULTS: Systolic and diastolic flow velocities decreased linearly with each incremental increase in IOP (p < 0.001). Pourcelot's resistivity index increased linearly with each incremental increase in IOP (p < 0.001). Changes in end diastolic velocity, peak systolic velocity, and Pourcelot's resistivity index were linearly related to changes in IOP. CONCLUSION: The normal healthy eye is not able to autoregulate to maintain PCA blood flow velocities in response to acute large elevations in IOP.  (+info)

Morphological variations of the peripapillary circle of Zinn-Haller by flat section. (4/68)

AIMS: To evaluate the morphometric and morphological variations of the circle of Zinn-Haller (CZH) in the human eye. METHODS: 42 human enucleated eyes were used in this study. After transverse flat thick sections were cut through the optic nerve and adjacent sclera, tissue sections were stained with haematoxylin and eosin or examined immediately by wet preparation under a light microscope. The average vessel diameter of the arterial circle and the average distance between the optic nerve head (ONH) and the arterial circle were determined. Various branching patterns of the CZH were also evaluated. RESULTS: The vessel diameter of the arterial circle was 123 (SD 75) microm (range 20-230 microm). The distance of the CZH from the ONH margin was 403 (352) microm (0-1050 microm). The CZH gave off branches to the optic nerve and to the peripapillary choroid (PPC) with various branching patterns especially at the entry point of paraoptic short posterior ciliary artery. CONCLUSIONS: The CZH exists within a variable distance from the ONH and its average diameter is similar to that of the central retinal vessels though it shows marked variation even in the same circle. The CZH also shows variable configurations in branching patterns. These variations may act as contributing factors that are responsible for the individual susceptibility of the anterior optic nerve and the PPC to circulatory disturbances.  (+info)

Microvasculature of the rat optic nerve head. (5/68)

PURPOSE: To describe the arterial blood supply, capillary bed, and venous drainage of the rat optic nerve head. METHODS: Ocular microvascular castings from 6 Wistar rats were prepared by injection of epoxy resin through the common carotid arteries. After polymerization, tissues were digested with 6 M KOH, and the castings washed, dried, and coated for scanning electron microscopy. RESULTS: Immediately posterior to the globe, the ophthalmic artery trifurcates into the central retinal artery and two posterior ciliary arteries. The central retinal artery directly provides capillaries to the nerve fiber layer and only contributes to capillary beds in the neck of the nerve head. The remainder is supplied by branches of the posterior ciliary arteries that are analogous to the primate circle of Zinn-Haller. Arterioles arising from these branches supply the capillaries of the transitional, or laminar, region of the optic nerve head. These capillaries are continuous with those of the neck and retrobulbar optic nerve head. All optic nerve head capillaries drain into the central retinal vein and veins of the optic nerve sheath. A flat choroidal sinus communicates with the central retinal vein, the choriocapillaris, and with large veins of the optic nerve sheath. CONCLUSIONS: The microvasculature of the rat optic nerve head bears several similarities to that of the primate, with a centripetal blood supply from posterior ciliary arteries and drainage into the central retinal and optic nerve sheath veins. Association of nerve sheath veins with the choroid represents an important difference from the primate.  (+info)

Neurogenic vasoconstriction as affected by cholinergic and nitroxidergic nerves in dog ciliary and ophthalmic arteries. (6/68)

PURPOSE: To determine the involvement of noradrenergic and other vasoconstrictor nerves in the contraction of ocular arteries and the modification by cholinergic and nitroxidergic nerves of vasoconstrictor nerve function. METHODS: Changes in isometric tension were recorded in helical strips of the canine posterior ciliary and external ophthalmic arteries denuded of the endothelium, which were stimulated by transmurally applied electrical pulses (5 Hz). Vasoconstrictor mediators were analyzed by pharmacological antagonists, such as prazosin, alpha,beta-methylene ATP, a P2alpha-purinoceptor antagonist, and BIBP3226, a neuropeptide Y receptor antagonist. RESULTS: Transmural electrical stimulation produced contractions that were potentiated by N(G)-nitro-L-arginine (L-NA), a nitric oxide (NO) synthase inhibitor. The contraction was partially inhibited by prazosin and abolished by combined treatment with alpha,beta-methylene ATP but was not influenced by BIBP3226. Stimulation-induced contraction was attenuated by physostigmine and potentiated by atropine. Contractions induced by exogenous ATP were reversed to relaxations by alpha,beta-methylene ATP. In the strips treated with L-NA, prazosin, and alpha,beta-methylene ATP, the addition of L-arginine elicited relaxations by nerve stimulation. The ATP-induced relaxation was attenuated by aminophylline, whereas neurogenic relaxation was unaffected. CONCLUSIONS: Ciliary and ophthalmic arterial contractions by nerve stimulation are mediated by norepinephrine and ATP, which stimulate alpha1-adrenoceptor and P2X purinoceptor, respectively. ATP from the nerve is unlikely involved in vasodilatation. Acetylcholine derived from the nerve impairs the neurogenic contraction, possibly by interfering with the release of vasoconstrictor transmitters, and neurogenic NO also inhibits the contraction postjunctionally by physiological antagonism.  (+info)

Specialised sympathetic neuroeffector associations in immature rat iris arterioles. (7/68)

Sympathetic nerve-mediated vasoconstriction in iris arterioles of mature rats occurs via the activation of alpha(1B)-adrenoceptors alone, while in immature rat iris arterioles, vasoconstriction occurs via activation of both alpha1- and alpha2-adrenoceptors. In mature rats the vast majority of sympathetic varicosities form close neuroeffector junctions. Serial section electron microscopy of 14 d iris arterioles has been used to determine whether restriction in physiological receptor types with age may result from the establishment of these close neuroeffector junctions. Ninety varicosities which lay within 4 microm of arteriolar smooth muscle were followed for their entire length. Varicosities rarely contained dense cored vesicles even after treatment with 5-hydroxydopamine. 47 % of varicosities formed close associations with muscle cells and 88 % formed close associations with muscle cells or melanocytes. Varicosities in bundles were as likely as single varicosities to form close associations with vascular smooth muscle cells, although the distribution of synaptic vesicles in single varicosities did not show the asymmetric accumulation towards the smooth muscle cells seen in the varicosities in bundles which were frequently clustered together. We conclude that restriction of physiological receptor types during development does not appear to correlate with the establishment of close neuroeffector junctions, although changes in presynaptic structures may contribute to the refinement of postsynaptic responses.  (+info)

Optic nerve and peripapillary choroidal microvasculature of the rat eye. (8/68)

PURPOSE: To investigate the three-dimensional microvascular anatomy of the optic nerve and peripapillary choroid in the rat eye. METHODS: Gross vascular anatomy of the posterior eye segment of Wistar rats was studied in serial microsections with a light microscope. The optic nerve and peripapillary choroidal vessels were sequentially microdissected, using methylmethacrylate corrosion microvascular castings, and were examined with a scanning electron microscope to determine the three-dimensional relationships of the vessels. RESULTS: The posterior ciliary artery traveled along the inferior side of the optic nerve sheath, directly entered the optic nerve head, and divided into three branches: the central retinal artery and medial and lateral long posterior ciliary arteries, which provided several short branches to the choroid. The optic nerve head vasculature was consistently nourished by a recurrent arteriole from the central retinal artery and an arteriole from the choroidal artery at the peripapillary choroid. The central retinal vein flowed into a venous anastomosis along the optic disc border of the peripapillary choroid. Capillaries within the optic nerve drained into the central retinal vein, the marginal venous anastomosis of the peripapillary choroid, and the pial veins, all of which flowed into the posterior ciliary veins along the optic nerve sheath. CONCLUSIONS: The findings illustrate vascular anatomic differences in optic nerve and peripapillary choroidal microcirculation between rat and human. In rats, the peripapillary choroid plays a significant role in both blood supply and venous drainage of the optic nerve head. The central retinal artery also contributes to the optic nerve head circulation.  (+info)

Ciliary arteries are a type of ocular (eye) artery that originate from the posterior ciliary and muscular arteries. They supply blood to the ciliary body, choroid, and iris of the eye. The ciliary body is a part of the eye that contains muscles responsible for accommodation (the ability to focus on objects at different distances). The choroid is a layer of blood vessels that provides oxygen and nutrients to the outer layers of the retina. The iris is the colored part of the eye that controls the amount of light reaching the retina by adjusting the size of the pupil.

The ophthalmic artery is the first branch of the internal carotid artery, which supplies blood to the eye and its adnexa. It divides into several branches that provide oxygenated blood to various structures within the eye, including the retina, optic nerve, choroid, iris, ciliary body, and cornea. Any blockage or damage to the ophthalmic artery can lead to serious vision problems or even blindness.

A retinal artery is a small branch of the ophthalmic artery that supplies oxygenated blood to the inner layers of the retina, which is the light-sensitive tissue located at the back of the eye. There are two main retinal arteries - the central retinal artery and the cilioretinal artery. The central retinal artery enters the eye through the optic nerve and divides into smaller branches to supply blood to the entire retina, while the cilioretinal artery is a smaller artery that supplies blood to a small portion of the retina near the optic nerve. Any damage or blockage to these arteries can lead to serious vision problems, such as retinal artery occlusion or retinal artery embolism.

The ciliary body is a part of the eye's internal structure that is located between the choroid and the iris. It is composed of muscle tissue and is responsible for adjusting the shape of the lens through a process called accommodation, which allows the eye to focus on objects at varying distances. Additionally, the ciliary body produces aqueous humor, the clear fluid that fills the anterior chamber of the eye and helps to nourish the eye's internal structures. The ciliary body is also responsible for maintaining the shape and position of the lens within the eye.

Arteries are blood vessels that carry oxygenated blood away from the heart to the rest of the body. They have thick, muscular walls that can withstand the high pressure of blood being pumped out of the heart. Arteries branch off into smaller vessels called arterioles, which further divide into a vast network of tiny capillaries where the exchange of oxygen, nutrients, and waste occurs between the blood and the body's cells. After passing through the capillary network, deoxygenated blood collects in venules, then merges into veins, which return the blood back to the heart.

Ultrasonography, Doppler, color is a type of diagnostic ultrasound technique that uses the Doppler effect to produce visual images of blood flow in vessels and the heart. The Doppler effect is the change in frequency or wavelength of a wave in relation to an observer who is moving relative to the source of the wave. In this context, it refers to the change in frequency of the ultrasound waves as they reflect off moving red blood cells.

In color Doppler ultrasonography, different colors are used to represent the direction and speed of blood flow. Red typically represents blood flowing toward the transducer (the device that sends and receives sound waves), while blue represents blood flowing away from the transducer. The intensity or brightness of the color is proportional to the velocity of blood flow.

Color Doppler ultrasonography is often used in conjunction with grayscale ultrasound imaging, which provides information about the structure and composition of tissues. Together, these techniques can help diagnose a wide range of conditions, including heart disease, blood clots, and abnormalities in blood flow.

Levobunolol is a non-selective beta blocker used in the treatment of glaucoma and high blood pressure. It works by reducing the production of aqueous humor within the eye, thereby decreasing intraocular pressure (IOP). Levobunolol is available as an ophthalmic solution for topical application.

The medical definition of Levobunolol is:

A synthetic, non-selective beta-adrenergic antagonist with membrane-stabilizing activity and a vasodilating effect. It is used in the form of its hydrochloride salt as an ophthalmic solution for the treatment of glaucoma, reducing intraocular pressure by decreasing aqueous humor production. The drug has a prolonged action due to its poor solubility and slow absorption through the cornea.

Oxymetazoline is a direct-acting mainly α1-adrenergic receptor agonist, which is primarily used as a nasal decongestant and an ophthalmic vasoconstrictor. It constricts blood vessels, reducing swelling and fluid accumulation in the lining of the nose, thereby providing relief from nasal congestion due to allergies or colds. Oxymetazoline is available over-the-counter in various forms, such as nasal sprays, drops, and creams. It's important to follow the recommended usage guidelines, as prolonged use of oxymetazoline can lead to a rebound effect, causing further congestion.

I'm sorry for any confusion, but "myography" is not a recognized term in the field of medicine or medical terminology. It may be possible that you have misspelled or misremembered a related term. If you meant "myology," that refers to the study of muscles, their structure, function, and disorders. If you had a different term in mind, please provide it so I can give you a more accurate response.

Corrosion casting is a specialized technique used in anatomy and pathology to create detailed casts or molds of biological specimens, particularly vascular systems. This method is also known as "acid etching" or "corrosive casting." Here's the medical definition:

Corrosion casting is a process that involves injecting a special resin or plastic material into the vasculature or other hollow structures of a biological specimen, such as an organ or tissue. The injected material thoroughly fills the cavity and then hardens once it has set. After hardening, the surrounding tissues are corroded or dissolved using strong acids or bases, leaving behind only the cast or mold of the internal structures.

This technique results in a detailed three-dimensional representation of the complex internal networks, like blood vessels, which can be used for further study, research, and education. Corrosion casting is particularly useful in visualizing the intricate branching patterns and structural relationships within these systems.

A Retinal Vein is a vessel that carries oxygen-depleted blood away from the retina, a light-sensitive layer at the back of the eye. The retinal veins originate from a network of smaller vessels called venules and ultimately merge to form the central retinal vein, which exits the eye through the optic nerve.

Retinal veins are crucial for maintaining the health and function of the retina, as they facilitate the removal of waste products and help regulate the ocular environment. However, they can also be susceptible to various pathological conditions such as retinal vein occlusions, which can lead to vision loss or damage to the eye.

The choroid is a layer of the eye that contains blood vessels that supply oxygen and nutrients to the outer layers of the retina. It lies between the sclera (the white, protective coat of the eye) and the retina (the light-sensitive tissue at the back of the eye). The choroid is essential for maintaining the health and function of the retina, particularly the photoreceptor cells that detect light and transmit visual signals to the brain. Damage to the choroid can lead to vision loss or impairment.

The eye is the organ of sight, primarily responsible for detecting and focusing on visual stimuli. It is a complex structure composed of various parts that work together to enable vision. Here are some of the main components of the eye:

1. Cornea: The clear front part of the eye that refracts light entering the eye and protects the eye from harmful particles and microorganisms.
2. Iris: The colored part of the eye that controls the amount of light reaching the retina by adjusting the size of the pupil.
3. Pupil: The opening in the center of the iris that allows light to enter the eye.
4. Lens: A biconvex structure located behind the iris that further refracts light and focuses it onto the retina.
5. Retina: A layer of light-sensitive cells (rods and cones) at the back of the eye that convert light into electrical signals, which are then transmitted to the brain via the optic nerve.
6. Optic Nerve: The nerve that carries visual information from the retina to the brain.
7. Vitreous: A clear, gel-like substance that fills the space between the lens and the retina, providing structural support to the eye.
8. Conjunctiva: A thin, transparent membrane that covers the front of the eye and the inner surface of the eyelids.
9. Extraocular Muscles: Six muscles that control the movement of the eye, allowing for proper alignment and focus.

The eye is a remarkable organ that allows us to perceive and interact with our surroundings. Various medical specialties, such as ophthalmology and optometry, are dedicated to the diagnosis, treatment, and management of various eye conditions and diseases.

Adrenergic agonists are medications or substances that bind to and activate adrenergic receptors, which are a type of receptor in the body that respond to neurotransmitters such as norepinephrine and epinephrine (also known as adrenaline).

There are two main types of adrenergic receptors: alpha and beta receptors. Alpha-adrenergic agonists activate alpha receptors, while beta-adrenergic agonists activate beta receptors. These medications can have a variety of effects on the body, depending on which type of receptor they act on.

Alpha-adrenergic agonists are often used to treat conditions such as nasal congestion, glaucoma, and low blood pressure. Examples include phenylephrine, oxymetazoline, and clonidine.

Beta-adrenergic agonists are commonly used to treat respiratory conditions such as asthma and COPD (chronic obstructive pulmonary disease). They work by relaxing the smooth muscle in the airways, which makes it easier to breathe. Examples include albuterol, salmeterol, and formoterol.

It's important to note that adrenergic agonists can have both desired and undesired effects on the body. They should be used under the guidance of a healthcare professional, who can monitor their effectiveness and potential side effects.

The pulmonary artery is a large blood vessel that carries deoxygenated blood from the right ventricle of the heart to the lungs for oxygenation. It divides into two main branches, the right and left pulmonary arteries, which further divide into smaller vessels called arterioles, and then into a vast network of capillaries in the lungs where gas exchange occurs. The thin walls of these capillaries allow oxygen to diffuse into the blood and carbon dioxide to diffuse out, making the blood oxygen-rich before it is pumped back to the left side of the heart through the pulmonary veins. This process is crucial for maintaining proper oxygenation of the body's tissues and organs.

Papaverine is defined as a smooth muscle relaxant and a non-narcotic alkaloid derived from the opium poppy. It works by blocking the phosphodiesterase enzyme, leading to an increase in cyclic adenosine monophosphate (cAMP) levels within the cells, which in turn results in muscle relaxation.

It is used medically for its vasodilatory effects to treat conditions such as cerebral or peripheral vascular spasms and occlusive diseases, Raynaud's phenomenon, and priapism. Papaverine can also be used as an anti-arrhythmic agent in the management of certain types of cardiac arrhythmias.

It is important to note that papaverine has a narrow therapeutic index, and its use should be closely monitored due to the potential for adverse effects such as hypotension, reflex tachycardia, and gastrointestinal disturbances.

The optic nerve, also known as the second cranial nerve, is the nerve that transmits visual information from the retina to the brain. It is composed of approximately one million nerve fibers that carry signals related to vision, such as light intensity and color, from the eye's photoreceptor cells (rods and cones) to the visual cortex in the brain. The optic nerve is responsible for carrying this visual information so that it can be processed and interpreted by the brain, allowing us to see and perceive our surroundings. Damage to the optic nerve can result in vision loss or impairment.

The carotid arteries are a pair of vital blood vessels in the human body that supply oxygenated blood to the head and neck. Each person has two common carotid arteries, one on each side of the neck, which branch off from the aorta, the largest artery in the body.

The right common carotid artery originates from the brachiocephalic trunk, while the left common carotid artery arises directly from the aortic arch. As they ascend through the neck, they split into two main branches: the internal and external carotid arteries.

The internal carotid artery supplies oxygenated blood to the brain, eyes, and other structures within the skull, while the external carotid artery provides blood to the face, scalp, and various regions of the neck.

Maintaining healthy carotid arteries is crucial for overall cardiovascular health and preventing serious conditions like stroke, which can occur when the arteries become narrowed or blocked due to the buildup of plaque or fatty deposits (atherosclerosis). Regular check-ups with healthcare professionals may include monitoring carotid artery health through ultrasound or other imaging techniques.

A smooth muscle within the vascular system refers to the involuntary, innervated muscle that is found in the walls of blood vessels. These muscles are responsible for controlling the diameter of the blood vessels, which in turn regulates blood flow and blood pressure. They are called "smooth" muscles because their individual muscle cells do not have the striations, or cross-striped patterns, that are observed in skeletal and cardiac muscle cells. Smooth muscle in the vascular system is controlled by the autonomic nervous system and by hormones, and can contract or relax slowly over a period of time.

Cerebral arteries refer to the blood vessels that supply oxygenated blood to the brain. These arteries branch off from the internal carotid arteries and the vertebral arteries, which combine to form the basilar artery. The major cerebral arteries include:

1. Anterior cerebral artery (ACA): This artery supplies blood to the frontal lobes of the brain, including the motor and sensory cortices responsible for movement and sensation in the lower limbs.
2. Middle cerebral artery (MCA): The MCA is the largest of the cerebral arteries and supplies blood to the lateral surface of the brain, including the temporal, parietal, and frontal lobes. It is responsible for providing blood to areas involved in motor function, sensory perception, speech, memory, and vision.
3. Posterior cerebral artery (PCA): The PCA supplies blood to the occipital lobe, which is responsible for visual processing, as well as parts of the temporal and parietal lobes.
4. Anterior communicating artery (ACoA) and posterior communicating arteries (PComAs): These are small arteries that connect the major cerebral arteries, forming an important circulatory network called the Circle of Willis. The ACoA connects the two ACAs, while the PComAs connect the ICA with the PCA and the basilar artery.

These cerebral arteries play a crucial role in maintaining proper brain function by delivering oxygenated blood to various regions of the brain. Any damage or obstruction to these arteries can lead to serious neurological conditions, such as strokes or transient ischemic attacks (TIAs).

The renal artery is a pair of blood vessels that originate from the abdominal aorta and supply oxygenated blood to each kidney. These arteries branch into several smaller vessels that provide blood to the various parts of the kidneys, including the renal cortex and medulla. The renal arteries also carry nutrients and other essential components needed for the normal functioning of the kidneys. Any damage or blockage to the renal artery can lead to serious consequences, such as reduced kidney function or even kidney failure.

The femoral artery is the major blood vessel that supplies oxygenated blood to the lower extremity of the human body. It is a continuation of the external iliac artery and becomes the popliteal artery as it passes through the adductor hiatus in the adductor magnus muscle of the thigh.

The femoral artery is located in the femoral triangle, which is bound by the sartorius muscle anteriorly, the adductor longus muscle medially, and the biceps femoris muscle posteriorly. It can be easily palpated in the groin region, making it a common site for taking blood samples, measuring blood pressure, and performing surgical procedures such as femoral artery catheterization and bypass grafting.

The femoral artery gives off several branches that supply blood to the lower limb, including the deep femoral artery, the superficial femoral artery, and the profunda femoris artery. These branches provide blood to the muscles, bones, skin, and other tissues of the leg, ankle, and foot.

Blood flow velocity is the speed at which blood travels through a specific part of the vascular system. It is typically measured in units of distance per time, such as centimeters per second (cm/s) or meters per second (m/s). Blood flow velocity can be affected by various factors, including cardiac output, vessel diameter, and viscosity of the blood. Measuring blood flow velocity is important in diagnosing and monitoring various medical conditions, such as heart disease, stroke, and peripheral vascular disease.

Isometric contraction is a type of muscle activation where the muscle contracts without any change in the length of the muscle or movement at the joint. This occurs when the force generated by the muscle matches the external force opposing it, resulting in a balanced state with no visible movement. It is commonly experienced during activities such as holding a heavy object in static position or trying to push against an immovable object. Isometric contractions are important in maintaining posture and providing stability to joints.

Vasoconstrictor agents are substances that cause the narrowing of blood vessels by constricting the smooth muscle in their walls. This leads to an increase in blood pressure and a decrease in blood flow. They work by activating the sympathetic nervous system, which triggers the release of neurotransmitters such as norepinephrine and epinephrine that bind to alpha-adrenergic receptors on the smooth muscle cells of the blood vessel walls, causing them to contract.

Vasoconstrictor agents are used medically for a variety of purposes, including:

* Treating hypotension (low blood pressure)
* Controlling bleeding during surgery or childbirth
* Relieving symptoms of nasal congestion in conditions such as the common cold or allergies

Examples of vasoconstrictor agents include phenylephrine, oxymetazoline, and epinephrine. It's important to note that prolonged use or excessive doses of vasoconstrictor agents can lead to rebound congestion and other adverse effects, so they should be used with caution and under the guidance of a healthcare professional.

The mesenteric arteries are the arteries that supply oxygenated blood to the intestines. There are three main mesenteric arteries: the superior mesenteric artery, which supplies blood to the small intestine (duodenum to two-thirds of the transverse colon) and large intestine (cecum, ascending colon, and the first part of the transverse colon); the inferior mesenteric artery, which supplies blood to the distal third of the transverse colon, descending colon, sigmoid colon, and rectum; and the middle colic artery, which is a branch of the superior mesenteric artery that supplies blood to the transverse colon. These arteries are important in maintaining adequate blood flow to the intestines to support digestion and absorption of nutrients.

Vasodilation is the widening or increase in diameter of blood vessels, particularly the involuntary relaxation of the smooth muscle in the tunica media (middle layer) of the arteriole walls. This results in an increase in blood flow and a decrease in vascular resistance. Vasodilation can occur due to various physiological and pathophysiological stimuli, such as local metabolic demands, neural signals, or pharmacological agents. It plays a crucial role in regulating blood pressure, tissue perfusion, and thermoregulation.

The basilar artery is a major blood vessel that supplies oxygenated blood to the brainstem and cerebellum. It is formed by the union of two vertebral arteries at the lower part of the brainstem, near the junction of the medulla oblongata and pons.

The basilar artery runs upward through the center of the brainstem and divides into two posterior cerebral arteries at the upper part of the brainstem, near the midbrain. The basilar artery gives off several branches that supply blood to various parts of the brainstem, including the pons, medulla oblongata, and midbrain, as well as to the cerebellum.

The basilar artery is an important part of the circle of Willis, a network of arteries at the base of the brain that ensures continuous blood flow to the brain even if one of the arteries becomes blocked or narrowed.

Regional blood flow (RBF) refers to the rate at which blood flows through a specific region or organ in the body, typically expressed in milliliters per minute per 100 grams of tissue (ml/min/100g). It is an essential physiological parameter that reflects the delivery of oxygen and nutrients to tissues while removing waste products. RBF can be affected by various factors such as metabolic demands, neural regulation, hormonal influences, and changes in blood pressure or vascular resistance. Measuring RBF is crucial for understanding organ function, diagnosing diseases, and evaluating the effectiveness of treatments.

Muscle relaxation, in a medical context, refers to the process of reducing tension and promoting relaxation in the skeletal muscles. This can be achieved through various techniques, including progressive muscle relaxation (PMR), where individuals consciously tense and then release specific muscle groups in a systematic manner.

PMR has been shown to help reduce anxiety, stress, and muscle tightness, and improve overall well-being. It is often used as a complementary therapy in conjunction with other treatments for conditions such as chronic pain, headaches, and insomnia.

Additionally, muscle relaxation can also be facilitated through pharmacological interventions, such as the use of muscle relaxant medications. These drugs work by inhibiting the transmission of signals between nerves and muscles, leading to a reduction in muscle tone and spasticity. They are commonly used to treat conditions such as multiple sclerosis, cerebral palsy, and spinal cord injuries.

"Swine" is a common term used to refer to even-toed ungulates of the family Suidae, including domestic pigs and wild boars. However, in a medical context, "swine" often appears in the phrase "swine flu," which is a strain of influenza virus that typically infects pigs but can also cause illness in humans. The 2009 H1N1 pandemic was caused by a new strain of swine-origin influenza A virus, which was commonly referred to as "swine flu." It's important to note that this virus is not transmitted through eating cooked pork products; it spreads from person to person, mainly through respiratory droplets produced when an infected person coughs or sneezes.

Intraocular pressure (IOP) is the fluid pressure within the eye, specifically within the anterior chamber, which is the space between the cornea and the iris. It is measured in millimeters of mercury (mmHg). The aqueous humor, a clear fluid that fills the anterior chamber, is constantly produced and drained, maintaining a balance that determines the IOP. Normal IOP ranges from 10-21 mmHg, with average values around 15-16 mmHg. Elevated IOP is a key risk factor for glaucoma, a group of eye conditions that can lead to optic nerve damage and vision loss if not treated promptly and effectively. Regular monitoring of IOP is essential in diagnosing and managing glaucoma and other ocular health issues.

The iliac arteries are major branches of the abdominal aorta, the large artery that carries oxygen-rich blood from the heart to the rest of the body. The iliac arteries divide into two branches, the common iliac arteries, which further bifurcate into the internal and external iliac arteries.

The internal iliac artery supplies blood to the lower abdomen, pelvis, and the reproductive organs, while the external iliac artery provides blood to the lower extremities, including the legs and feet. Together, the iliac arteries play a crucial role in circulating blood throughout the body, ensuring that all tissues and organs receive the oxygen and nutrients they need to function properly.

The vertebral artery is a major blood vessel that supplies oxygenated blood to the brain and upper spinal cord. It arises from the subclavian artery, then ascends through the transverse processes of several cervical vertebrae before entering the skull through the foramen magnum. Inside the skull, it joins with the opposite vertebral artery to form the basilar artery, which supplies blood to the brainstem and cerebellum. The vertebral artery also gives off several important branches that supply blood to various regions of the brainstem and upper spinal cord.

Coronary artery bypass surgery, also known as coronary artery bypass grafting (CABG), is a surgical procedure used to improve blood flow to the heart in patients with severe coronary artery disease. This condition occurs when the coronary arteries, which supply oxygen-rich blood to the heart muscle, become narrowed or blocked due to the buildup of fatty deposits, called plaques.

During CABG surgery, a healthy blood vessel from another part of the body is grafted, or attached, to the coronary artery, creating a new pathway for oxygen-rich blood to flow around the blocked or narrowed portion of the artery and reach the heart muscle. This bypass helps to restore normal blood flow and reduce the risk of angina (chest pain), shortness of breath, and other symptoms associated with coronary artery disease.

There are different types of CABG surgery, including traditional on-pump CABG, off-pump CABG, and minimally invasive CABG. The choice of procedure depends on various factors, such as the patient's overall health, the number and location of blocked arteries, and the presence of other medical conditions.

It is important to note that while CABG surgery can significantly improve symptoms and quality of life in patients with severe coronary artery disease, it does not cure the underlying condition. Lifestyle modifications, such as regular exercise, a healthy diet, smoking cessation, and medication therapy, are essential for long-term management and prevention of further progression of the disease.

Fluorescein angiography is a medical diagnostic procedure used in ophthalmology to examine the blood flow in the retina and choroid, which are the inner layers of the eye. This test involves injecting a fluorescent dye, Fluorescein, into a patient's arm vein. As the dye reaches the blood vessels in the eye, a specialized camera takes rapid sequences of photographs to capture the dye's circulation through the retina and choroid.

The images produced by fluorescein angiography can help doctors identify any damage to the blood vessels, leakage, or abnormal growth of new blood vessels. This information is crucial in diagnosing and managing various eye conditions such as age-related macular degeneration, diabetic retinopathy, retinal vein occlusions, and inflammatory eye diseases.

It's important to note that while fluorescein angiography is a valuable diagnostic tool, it does carry some risks, including temporary side effects like nausea, vomiting, or allergic reactions to the dye. In rare cases, severe adverse reactions can occur, so patients should discuss these potential risks with their healthcare provider before undergoing the procedure.

The endothelium is a thin layer of simple squamous epithelial cells that lines the interior surface of blood vessels, lymphatic vessels, and heart chambers. The vascular endothelium, specifically, refers to the endothelial cells that line the blood vessels. These cells play a crucial role in maintaining vascular homeostasis by regulating vasomotor tone, coagulation, platelet activation, inflammation, and permeability of the vessel wall. They also contribute to the growth and repair of the vascular system and are involved in various pathological processes such as atherosclerosis, hypertension, and diabetes.

The radial artery is a key blood vessel in the human body, specifically a part of the peripheral arterial system. Originating from the brachial artery in the upper arm, the radial artery travels down the arm and crosses over the wrist, where it can be palpated easily. It then continues into the hand, dividing into several branches to supply blood to the hand's tissues and digits.

The radial artery is often used for taking pulse readings due to its easy accessibility at the wrist. Additionally, in medical procedures such as coronary angiography or bypass surgery, the radial artery can be utilized as a site for catheter insertion. This allows healthcare professionals to examine the heart's blood vessels and assess cardiovascular health.

The mammary arteries are a set of blood vessels that supply oxygenated blood to the mammary glands, which are the structures in female breasts responsible for milk production during lactation. The largest mammary artery, also known as the internal thoracic or internal mammary artery, originates from the subclavian artery and descends along the inner side of the chest wall. It then branches into several smaller arteries that supply blood to the breast tissue. These include the anterior and posterior intercostal arteries, lateral thoracic artery, and pectoral branches. The mammary arteries are crucial in maintaining the health and function of the breast tissue, and any damage or blockage to these vessels can lead to various breast-related conditions or diseases.

Nitric oxide (NO) is a molecule made up of one nitrogen atom and one oxygen atom. In the body, it is a crucial signaling molecule involved in various physiological processes such as vasodilation, immune response, neurotransmission, and inhibition of platelet aggregation. It is produced naturally by the enzyme nitric oxide synthase (NOS) from the amino acid L-arginine. Inhaled nitric oxide is used medically to treat pulmonary hypertension in newborns and adults, as it helps to relax and widen blood vessels, improving oxygenation and blood flow.

The internal carotid artery is a major blood vessel that supplies oxygenated blood to the brain. It originates from the common carotid artery and passes through the neck, entering the skull via the carotid canal in the temporal bone. Once inside the skull, it branches into several smaller vessels that supply different parts of the brain with blood.

The internal carotid artery is divided into several segments: cervical, petrous, cavernous, clinoid, and supraclinoid. Each segment has distinct clinical significance in terms of potential injury or disease. The most common conditions affecting the internal carotid artery include atherosclerosis, which can lead to stroke or transient ischemic attack (TIA), and dissection, which can cause severe headache, neck pain, and neurological symptoms.

It's important to note that any blockage or damage to the internal carotid artery can have serious consequences, as it can significantly reduce blood flow to the brain and lead to permanent neurological damage or even death. Therefore, regular check-ups and screening tests are recommended for individuals at high risk of developing vascular diseases.

The subclavian artery is a major blood vessel that supplies the upper limb and important structures in the neck and head. It arises from the brachiocephalic trunk (in the case of the right subclavian artery) or directly from the aortic arch (in the case of the left subclavian artery).

The subclavian artery has several branches, including:

1. The vertebral artery, which supplies blood to the brainstem and cerebellum.
2. The internal thoracic artery (also known as the mammary artery), which supplies blood to the chest wall, breast, and anterior mediastinum.
3. The thyrocervical trunk, which gives rise to several branches that supply the neck, including the inferior thyroid artery, the suprascapular artery, and the transverse cervical artery.
4. The costocervical trunk, which supplies blood to the neck and upper back, including the posterior chest wall and the lower neck muscles.

The subclavian artery is a critical vessel in maintaining adequate blood flow to the upper limb, and any blockage or damage to this vessel can lead to significant morbidity, including arm pain, numbness, weakness, or even loss of function.

Carotid artery diseases refer to conditions that affect the carotid arteries, which are the major blood vessels that supply oxygen-rich blood to the head and neck. The most common type of carotid artery disease is atherosclerosis, which occurs when fatty deposits called plaques build up in the inner lining of the arteries.

These plaques can cause the arteries to narrow or become blocked, reducing blood flow to the brain and increasing the risk of stroke. Other carotid artery diseases include carotid artery dissection, which occurs when there is a tear in the inner lining of the artery, and fibromuscular dysplasia, which is a condition that affects the muscle and tissue in the walls of the artery.

Symptoms of carotid artery disease may include neck pain or pulsations, transient ischemic attacks (TIAs) or "mini-strokes," and strokes. Treatment options for carotid artery disease depend on the severity and type of the condition but may include lifestyle changes, medications, endarterectomy (a surgical procedure to remove plaque from the artery), or angioplasty and stenting (procedures to open blocked arteries using a balloon and stent).

The conjunctiva is the mucous membrane that lines the inner surface of the eyelids and covers the front part of the eye, also known as the sclera. It helps to keep the eye moist and protected from irritants. The conjunctiva can become inflamed or infected, leading to conditions such as conjunctivitis (pink eye).

An encyclopedia is a comprehensive reference work containing articles on various topics, usually arranged in alphabetical order. In the context of medicine, a medical encyclopedia is a collection of articles that provide information about a wide range of medical topics, including diseases and conditions, treatments, tests, procedures, and anatomy and physiology. Medical encyclopedias may be published in print or electronic formats and are often used as a starting point for researching medical topics. They can provide reliable and accurate information on medical subjects, making them useful resources for healthcare professionals, students, and patients alike. Some well-known examples of medical encyclopedias include the Merck Manual and the Stedman's Medical Dictionary.

I'm sorry for any confusion, but "holography" is not a term that has a medical definition. Holography is a technique used to create 3D images, typically using laser light. It is commonly used in non-medical fields such as data storage, art, and security features on credit cards and banknotes. I'm here to help with medical information, so please feel free to ask me about any medical topics or questions you might have!

Microcirculation is the circulation of blood in the smallest blood vessels, including arterioles, venules, and capillaries. It's responsible for the delivery of oxygen and nutrients to the tissues and the removal of waste products. The microcirculation plays a crucial role in maintaining tissue homeostasis and is regulated by various physiological mechanisms such as autonomic nervous system activity, local metabolic factors, and hormones.

Impairment of microcirculation can lead to tissue hypoxia, inflammation, and organ dysfunction, which are common features in several diseases, including diabetes, hypertension, sepsis, and ischemia-reperfusion injury. Therefore, understanding the structure and function of the microcirculation is essential for developing new therapeutic strategies to treat these conditions.

In the context of medical terminology, "lenses" generally refers to optical lenses used in various medical devices and instruments. These lenses are typically made of glass or plastic and are designed to refract (bend) light in specific ways to help magnify, focus, or redirect images. Here are some examples:

1. In ophthalmology and optometry, lenses are used in eyeglasses, contact lenses, and ophthalmic instruments to correct vision problems like myopia (nearsightedness), hypermetropia (farsightedness), astigmatism, or presbyopia.
2. In surgical microscopes, lenses are used to provide a magnified and clear view of the operating field during microsurgical procedures like ophthalmic, neurosurgical, or ENT (Ear, Nose, Throat) surgeries.
3. In endoscopes and laparoscopes, lenses are used to transmit light and images from inside the body during minimally invasive surgical procedures.
4. In ophthalmic diagnostic instruments like slit lamps, lenses are used to examine various structures of the eye in detail.

In summary, "lenses" in medical terminology refer to optical components that help manipulate light to aid in diagnosis, treatment, or visual correction.

Pulse oximetry is a noninvasive method for monitoring a person's oxygen saturation (SO2) and pulse rate. It uses a device called a pulse oximeter, which measures the amount of oxygen-carrying hemoglobin in the blood compared to the amount of hemoglobin that is not carrying oxygen. This measurement is expressed as a percentage, known as oxygen saturation (SpO2). Normal oxygen saturation levels are generally 95% or above at sea level. Lower levels may indicate hypoxemia, a condition where there is not enough oxygen in the blood to meet the body's needs. Pulse oximetry is commonly used in hospitals and other healthcare settings to monitor patients during surgery, in intensive care units, and in sleep studies to detect conditions such as sleep apnea. It can also be used by individuals with certain medical conditions, such as chronic obstructive pulmonary disease (COPD), to monitor their oxygen levels at home.

Conjunctival diseases refer to a group of medical conditions that affect the conjunctiva, which is the thin, clear mucous membrane that covers the inner surface of the eyelids and the white part of the eye (known as the sclera). The conjunctiva helps to keep the eye moist and protected from irritants.

Conjunctival diseases can cause a range of symptoms, including redness, itching, burning, discharge, grittiness, and pain. Some common conjunctival diseases include:

1. Conjunctivitis (pink eye): This is an inflammation or infection of the conjunctiva that can be caused by viruses, bacteria, or allergies. Symptoms may include redness, itching, discharge, and watery eyes.
2. Pinguecula: This is a yellowish, raised bump that forms on the conjunctiva, usually near the corner of the eye. It is caused by an overgrowth of connective tissue and may be related to sun exposure or dry eye.
3. Pterygium: This is a fleshy growth that extends from the conjunctiva onto the cornea (the clear front part of the eye). It can cause redness, irritation, and vision problems if it grows large enough to cover the pupil.
4. Allergic conjunctivitis: This is an inflammation of the conjunctiva caused by an allergic reaction to substances such as pollen, dust mites, or pet dander. Symptoms may include redness, itching, watery eyes, and swelling.
5. Chemical conjunctivitis: This is an irritation or inflammation of the conjunctiva caused by exposure to chemicals such as chlorine, smoke, or fumes. Symptoms may include redness, burning, and tearing.
6. Giant papillary conjunctivitis (GPC): This is a type of allergic reaction that occurs in response to the presence of a foreign body in the eye, such as a contact lens. Symptoms may include itching, mucus discharge, and a gritty feeling in the eye.

Treatment for conjunctival diseases depends on the underlying cause. In some cases, over-the-counter medications or home remedies may be sufficient to relieve symptoms. However, more severe cases may require prescription medication or medical intervention. It is important to consult with a healthcare provider if you experience persistent or worsening symptoms of conjunctival disease.

The anterior ciliary arteries are derived from the muscular branches of the ophthalmic artery. The ophthalmic artery and its ... The short posterior ciliary arteries from six to twelve in number, arise from the ophthalmic artery as it crosses the optic ... The long posterior ciliary arteries, two for each eye, pierce the posterior part of the sclera at some little distance from the ... The ciliary arteries are divisible into three groups, the long posterior, short posterior, and the anterior. ...
Within the ciliary body, the anterior ciliary arteries anastomose with branches of the long posterior ciliary arteries to form ... The anterior ciliary arteries are seven arteries in each eye-socket that arise from muscular branches of the ophthalmic artery ... There are seven anterior ciliary arteries on each side of the body; two anterior ciliary arteries are associated with the ... whereas the lateral rectus muscle is associated with only a single anterior ciliary artery. The anterior ciliary arteries arise ...
... may refer to: Long posterior ciliary arteries Short posterior ciliary arteries This disambiguation ... page lists articles associated with the title Posterior ciliary arteries. If an internal link led you here, you may wish to ...
The long posterior ciliary arteries are arteries of the orbit. There are long posterior ciliary arteries two on each side of ... There are two long ciliary arteries. They are branches of the ophthalmic artery. The long posterior ciliary arteries first run ... Non-terminal branches of the long posterior ciliary arteries anastomose with branches of the short posterior ciliary arteries. ... The long posterior ciliary arteries supply the choroid, ciliary body, and iris. Non-terminal branches are distributed to the ...
The number of short posterior ciliary arteries varies between individuals; one or more short posterior ciliary arteries ... subsequently dividing to form up to 20 short posterior ciliary arteries. The short posterior ciliary arteries branch off the ... in horizontal section Long posterior ciliary arteries Anterior ciliary arteries Gupta, Neha; Motlagh, Mahsaw; Singh, Gurdeep ( ... The short posterior ciliary arteries are a number of branches of the ophthalmic artery. They pass forward with the optic nerve ...
ciliares posteriores longae Short posterior ciliary arteries Aa. ciliares posteriores breves Anterior ciliary artery A. ... giving off 1 to 5 posterior ciliary arteries (PCA) that subsequently branch into the long and short posterior ciliary arteries ... anatomists made little distinction between the posterior ciliary arteries and the short and long posterior ciliary arteries ... The ophthalmic artery (OA) is an artery of the head. It is the first branch of the internal carotid artery distal to the ...
... the Cilio retinal artery itself is a branch of the Short Posterior Ciliary Arteries which is derived from the Ophthalmic Artery ... The central retinal artery (retinal artery) branches off the ophthalmic artery, running inferior to the optic nerve within its ... If this artery is present, the central vision will be preserved even in case of central retinal artery occlusion (CRAO). The ... The veins are darker in appearance than the arteries. (Central retinal artery visible but not labeled). Horizontal section of ...
Additional branches of the ophthalmic artery include the ciliary arteries, which branch into the anterior ciliary arteries. ... The exact number and arrangement of these ciliary arteries may vary. Branches of the infraorbital artery supply the inferior ... Each rectus muscle receives blood from two anterior ciliary arteries, except for the lateral rectus muscle, which receives ... This is done either directly or indirectly, as in the lateral rectus muscle, via the lacrimal artery, a main branch of the ...
They run forward with the ciliary arteries in a wavy course. One bundle is set above the optic nerve, while the other bundle is ... Sympathetic connections of the ciliary and superior cervical ganglia. Pathways in the Ciliary Ganglion. Long ciliary nerves ... the postganglionic parasympathetics leave the ciliary ganglion in the short ciliary nerve and supply the ciliary body and iris ... The short ciliary nerves are nerves of the orbit around the eye. They are branches of the ciliary ganglion. They supply ...
The anterior optic nerve receives blood primarily from the posterior ciliary arteries. The anterior optic nerve, a.k.a. the ... When T-cells damage arteries supplying the optic nerve, a blood clot forms and stops blood flow. When blood flow stops, oxygen ... A sample (biopsy) of the temporal artery should be obtained to confirm the diagnosis and guide future management, but should ... The posterior optic nerve receives blood primarily from the pial branches of the ophthalmic artery. The optic canal, a boney ...
A cycloanemization is a surgical obliteration of the long ciliary arteries in the treatment of glaucoma. An ... A cyclectomy is an excision of portion of the ciliary body. A cyclotomy, or cyclicotomy, is a surgical incision of the ciliary ... A ciliectomy is the surgical removal of part of the ciliary body or the surgical removal of part of a margin of an eyelid ... A corectomedialysis, or coretomedialysis, is an excision of a small portion of the iris at its junction with the ciliary body ...
The long and short ciliary nerves and the long posterior ciliary arteries pass anterior-ward within the suprachoroid lamina. ...
Larvae are thought to enter the eye through the optic nerve, central retinal artery, short posterior ciliary arteries, soft ...
Suprachoroidal hemorrhage is a rare complication of intraocular surgery, which occurs when damaged ciliary arteries bleed into ... either in the ciliary sulcus-the space between the iris and the ciliary body-in the anterior chamber in front of the iris, or ... The lens is implanted in the eye's lens capsule, where the contractions of the ciliary body, which would focus the eye with the ... When the posterior capsule is damaged, the IOL may be inserted into the ciliary sulcus, or a glued intraocular lens technique ...
... may refer to Circulus arteriosus major, an anastomosis of the anterior ciliary arteries Circulus arteriosus ...
... tympani Chorionic villi choroid choroid plexus chyle ciliary arteries ciliary body ciliary ganglion ciliary muscle ciliary ... artery left common carotid artery left gastroepiploic artery left mainstem bronchi left marginal artery left pulmonary artery ... atrium right colic artery right common carotid artery right gastroepiploic artery right mainstem bronchi right marginal artery ... cerebellar artery posterior lobe of the cerebellum posterior nasal artery posterior septal artery posterior spinal arteries ...
... any emboli arising from vasculature preceding the retinal artery, ophthalmic artery, or ciliary arteries may cause this ... ophthalmic artery, or ciliary artery blood flow, leading to a decrease in retinal circulation which, in turn, causes retinal ... Giant cell arteritis can result in granulomatous inflammation within the central retinal artery and posterior ciliary arteries ... and/or ciliary arteries, causing decreased blood flow to the ipsilateral retina; examples being those arising due to (1) atrial ...
... advantages of being a quicker procedure that involves less trauma than a resection and preserves the anterior ciliary arteries ...
... artery of the eye formed by anastomoses of the anterior ciliary arteries and long posterior ciliary arteries at the ciliary ... The major arterial circle of the iris is situated within the ciliary stroma in the anterior part of the ciliary body near the ... It supplies arterial blood to the iris, ciliary processes of the ciliary body, and anterior choroid. ... Gupta, Neha; Motlagh, Mahsaw; Singh, Gurdeep (2022), "Anatomy, Head and Neck, Eye Arteries", StatPearls, Treasure Island (FL): ...
... supplied by the long and short posterior ciliary arteries, while the surrounding retina is pale due to retinal artery ... A cherry-red spot is a finding in the macula of the eye in a variety of lipid storage disorders and in central retinal artery ... The cherry red spot is seen in central retinal artery occlusion, appearing several hours after the blockage of the retinal ... central retinal artery occlusion) Drugs: Quinine toxicity Dapsone toxicity Poisoning: Carbon monoxide Methanol Blunt ocular ...
... supplied in humans by posterior ciliary arteries, originating from the ophthalmic artery (a branch of the internal carotid ... Along with the ciliary body and iris, the choroid forms the uveal tract. The structure of the choroid is generally divided into ... The retinal circulation, on the other hand, derives its circulation from the central retinal artery, also a branch of the ... artery). The arteries of the uveal circulation, supplying the uvea and outer and middle layers of the retina, are branches of ...
... is a rare complication of intraocular surgery in which blood from the ciliary arteries enters the space between the choroid and ... causing tears in the vessels of the ciliary body and iris. Certain medical conditions-such as leukemia, hemophilia, Von ...
The ophthalmic artery supplies the choroid via the short posterior ciliary arteries and the retina via the central retinal ... times are approximate 0 seconds - injection of fluorescein 9.5 sec - posterior ciliary arteries 10 sec - choroidal flush (or " ... late staining Fluorescein enters the ocular circulation from the internal carotid artery via the ophthalmic artery. ... retinal artery occlusions, edema of the optic disc, and tumors. Additionally, the transit time (the period between injection of ...
... rupture of long posterior ciliary artery from progressive stretching with progressive serous choroidal detachment; usually ... into a cyclodialysis cleft between the ciliary body and the sclera if tissue is dissected posterior to the scleral spur.[ ...
... nerve branches Trochlear nerve branches Ophthalmic nerve branches Abducent nerve branches Ciliary ganglion Ophthalmic artery ...
... ciliary arteries Anterior ciliary artery Central retinal artery Muscular artery anterior cerebral artery middle cerebral artery ... artery middle colic artery right colic artery intestinal arteries ileocolic artery arcuate artery interlobular artery afferent ... artery Sternocleidomastoid artery Superior laryngeal artery Cricothyroid artery Ascending pharyngeal artery Lingual artery ... artery proper hepatic artery Terminal branches right hepatic artery Cystic artery left hepatic artery right gastric artery ...
The anterior optic nerve is supplied by the short posterior ciliary artery and choroidal circulation, while the retrobulbar ... internal carotid artery, anterior cerebral artery, and anterior communicating arteries. Ischemic optic neuropathies are ... optic nerve is supplied intraorbitally by a pial plexus, which arises from the ophthalmic artery, ...
... artery Internal carotid artery Ophthalmic artery Central retinal artery Lacrimal artery Short posterior ciliary arteries Long ... artery Ileocolic artery Right colic artery Middle colic artery Inferior mesenteric artery Left colic artery Sigmoid arteries ... rectal artery Middle suprarenal artery Renal artery Ovarian artery Testicular artery Common iliac artery Internal iliac artery ... Uterine artery Vaginal artery Middle rectal artery Internal pudendal artery Inferior rectal artery Perineal artery Arteries of ...
... namely the ciliary body and annular suspension of the lens of the eye. The arteries of the choroid and iris. The greater part ... The ciliary muscle receives parasympathetic fibers from the short ciliary nerves that arise from the ciliary ganglion. The ... ciliary ganglion via the postganglionic parasympathetic fibers which travel in the short ciliary nerves and supply the ciliary ... The ciliary muscle is an intrinsic muscle of the eye formed as a ring of smooth muscle in the eye's middle layer, uvea ( ...
Their axons ascend with the internal carotid artery as a plexus of nerves, the internal carotid plexus. Sympathetic fibers ... The parasympathetic root of ciliary ganglion provides parasympathetic supply to the ciliary ganglion. The ciliary ganglion is a ... and the short ciliary nerves (from the ciliary ganglion). Sympathetic fibers in the short ciliary nerves pass through the ... They leave the ciliary ganglion in the sensory root of ciliary ganglion, which joins the nasociliary nerve-a branch of the ...
The anterior ciliary arteries are derived from the muscular branches of the ophthalmic artery. The ophthalmic artery and its ... The short posterior ciliary arteries from six to twelve in number, arise from the ophthalmic artery as it crosses the optic ... The long posterior ciliary arteries, two for each eye, pierce the posterior part of the sclera at some little distance from the ... The ciliary arteries are divisible into three groups, the long posterior, short posterior, and the anterior. ...
Three groups of arteries found in the eye which supply the iris, pupil, sclera, conjunctiva, and the muscles of the iris. ... Ciliary Arteries. Three groups of arteries found in the eye which supply the iris, pupil, sclera, conjunctiva, and the muscles ...
... artery to the ophthalmic artery and the other through supraorbital artery-recurrent meningeal artery to the ophthalmic artery. ... artery to the ophthalmic artery and the other through supraorbital artery-recurrent meningeal artery to the ophthalmic artery. ... artery to the ophthalmic artery and the other through supraorbital artery-recurrent meningeal artery to the ophthalmic artery. ... artery to the ophthalmic artery and the other through supraorbital artery-recurrent meningeal artery to the ophthalmic artery. ...
The ophthalmic artery originates from the distal end of the internal carotid artery (ICA). After several microscopic branches ... emerge from the ICA in the petrous region, the ophthalmic artery proceeds toward the globe. ... the posterior ciliary arteries. The posterior one third of the optic nerve is supplied by penetrating arteries from the ... watershed infarction between the central retinal artery and the posterior ciliary arteries. Likewise, AION with severe visual ...
Isolated bovine posterior ciliary arteries were mounted in oxygenated organ baths and changes in isometric tension were ... Isolated bovine posterior ciliary arteries were mounted in oxygenated organ baths and changes in isometric tension were ... We conclude that the inhibitory action of GYY4137 on isolated bovine ciliary artery is dependent upon the endogenous production ... We conclude that the inhibitory action of GYY4137 on isolated bovine ciliary artery is dependent upon the endogenous production ...
... it should be noted that it had been reported that the drug is able to induce a relaxation of rabbit ciliary arteries ... Relaxing Effect and Mechanism of Tafluprost on Isolated Rabbit Ciliary Arteries. Exp. Eye Res. 87, 251-256. doi:10.1016/j.exer. ...
4-#235). The short posterior ciliary arteries directly supply the choroid. The long posterior ciliary arteries travel in the ... These vessels divide into 2 long posterior ciliary arteries and 12-20 short posterior ciliary arteries that enter the eye ... Some of the therapeutic agents transported through the posterior short ciliary, anterior ciliary and long ciliary arteries when ... supplied in humans by posterior ciliary arteries, originating from the ophthalmic artery. The arteries of the uveal circulation ...
It is caused by infarction of the short posterior ciliary arteries supplying the anterior optic nerve. There is no direct ... between an inferior compression of the internal carotid artery and a superior compression of the anterior communicating artery ... including central retinal artery occlusion during surgery and light perception vision at 6 months (1 participant); and ...
posterior ciliary arteries 5. *. long posterior ciliary arteries (supply the anterior part of the choroid and ciliary body and ... vertebral artery *posterior inferior cerebellar artery (PICA). * basilar artery * anterior inferior cerebellar artery (AICA)* ... middle cerebral artery (MCA) *M1 branches * lenticulostriate arteries *medial lenticulostriate arteries. *lateral ... meningo-ophthalmic artery: regression of proximal ophthalmic artery and entire orbit is supplied by the middle meningeal artery ...
AION represents an acute ischemic disorder (a segmental infarction) of the ONH supplied by the posterior ciliary arteries (PCAs ... Severe diminished blood flow velocities in the posterior ciliary arteries (PCAs), especially on the affected side, and high ... C. D. Pacient TL with arteritic-anterior ischemic optic neuropathy - Color Doppler Imaging of nasal posterior ciliary arteries ... Color Doppler Imaging of temporal posterior ciliary arteries (PCAs) of both eyes. Slight diminution of systolic blood flow ...
... caused by damage to the anterior ciliary arteries. To avoid ASI, a maximum of two rectus muscles are operated on at a time. ...
Meningeal artery B. c. Ciliary arteries d. Lacrimal artery e. Supraorbital artery: f. Posterior ethmoidal artery C. g. Anterior ... 191 Thyroid and Parathyroid Glands A.C. Arteries 1. Superior thyroid artery a. 1st branch of external carotid artery b. ... Supra-orbital artery: forehead as high as vertex 3. Lacrimal artery: upper eyelid laterally 4. Dorsal nasal artery: bridge of ... maxillary and facial arteries Septal branch of facial artery: from superior labial artery (source of nosebleeds,Nespecially in ...
However, blood was variably present in the retinal vessels, posterior ciliary arteries and vortex veins of the high IOP eyes. ...
... which is ensured by perforators from short posterior ciliary arteries constituting the Zinn-Haller arterial ring.25⇓-27 These ... C, Type C: ophthalmic artery originating in the inner curve of the carotid siphon. D, Type D: ophthalmic artery not involved in ... A, Type A: ophthalmic artery originating from the aneurysm sac. B, Type B: ophthalmic artery originating from the neck of the ... The origin of the ophthalmic artery correlated to the location of the aneurysm was assessed by using a 4-type ophthalmic artery ...
... including the retrobulbar arteries, certral retinal artery and short posterior ciliary artery. This study explains why one ... ST36 could lead to a significant increase in blood flow in one of the abdominal arteries, called the mesenteric artery, but no ... This study found that stimulating the same acupuncture point LR3 can dilate the arteries around the eyes and reduce the blood ... vessel resistance significantly, but there were no significant changes in blood flow to the abdominal artery. On the other hand ...
The optic nerve disc has a unique vasculature with contributions from the short posterior ciliary arteries, the pial ...
Left pointer: Anterior ciliary artery Right pointer: Inferior rectus muscle 31 . Inferior oblique muscle ... Lateral palpebral branch of lacrimal artery 8 . Superior tarsal branch of zygomatico-orbital artery (this vessel has only ... Palpebral arteries. Anterior view of right eyelids. Image #53-7. KEYWORDS: Connective tissue, Eye, Face, Vasculature. ...
... which is caused by progressive stenosis of the ophthalmic or posterior ciliary arteries, leading over time to vascular ... This artery is essentially occluded in the area of the axilla, but the axillary artery is reconstituted by extensive collateral ... Temporal artery biopsy and pathology. The decision to obtain a biopsy specimen should never delay the start of corticosteroids ... Temporal artery biopsies and MR angiograms are useful diagnostic adjuncts, but the diagnosis of GCA remains a clinical one. ...
Exome-Based Case-Control Analysis Highlights the Pathogenic Role of Ciliary Genes in Transposition of the Great Arteries. ... The enrichment of ciliary genes supports the roles of cilia in the pathogenesis of TGA. In total, 33% of the TGA probands had ... A near null variant of 12/15-LOX encoded by a novel SNP in ALOX15 and the risk of coronary artery disease ATHEROSCLEROSIS ... Common polymorphisms of ALOX5 and ALOX5AP and risk of coronary artery disease HUMAN GENETICS Assimes, T. L., Knowles, J. W., ...
The choriocapillaris is derived from the short posterior ciliary arteries, which also branch off the ophthalmic artery. The ... The internal carotid artery gives rise to the ophthalmic artery, from which the central retinal artery arises [33], entering ... Responses of retinal arterioles and ciliary arteries in pigs with acute respiratory distress syndrome (ARDS). Exp Eye Res. 2019 ... within the cerebral basal arteries [50], commonly the middle cerebral artery (MCA). Current clinical and research applications ...
The central retinal artery supplying the retina and the ciliary arteries supplying the choroid are the target vessels to ... 6 The external carotid artery (ECA) arises from the common carotid artery and supplies the maxillary artery. Two branches of ... There is a characteristic "blush" of contrast seen in the choroid delivered via the ciliary artery; this indicates proper ... There is a characteristic "blush" of contrast seen in the choroid delivered via the ciliary artery; this indicates proper ...
Artery. lacrimal artery, anterior ciliary arteries. Nerve. supratrochlear nerve. Identifiers. Latin. tunica conjunctiva. ... Long ciliary nerves Microanatomy[edit]. The conjunctiva consists of unkeratinized, both stratified squamous and stratified ... Pavlou AT, Wolff HG (July 1959). "The bulbar conjunctival vessels in occlusion of the internal carotid artery". A.M.A. Archives ... Carotid artery occlusion is associated with slower conjunctival blood flow and apparent capillary loss.[4] ...
The arterial supply to the orbit derives its origin from the internal carotid artery (ICA). In the head and the neck, the ... Ciliary arteries. The ciliary arteries (arteriae ciliares) are divided into 3 groups: short posterior, long posterior, and ... The short posterior ciliary arteries may number 6-12 vessels. Arising from the ophthalmic artery or its branches, the short ... The lateral rectus muscle is supplied by a single anterior ciliary artery arising from the lacrimal artery. [2] ...
The arterial supply to the orbit derives its origin from the internal carotid artery (ICA). In the head and the neck, the ... Ciliary arteries. The ciliary arteries (arteriae ciliares) are divided into 3 groups: short posterior, long posterior, and ... The short posterior ciliary arteries may number 6-12 vessels. Arising from the ophthalmic artery or its branches, the short ... The lateral rectus muscle is supplied by a single anterior ciliary artery arising from the lacrimal artery. [2] ...
O - "Orbital Branch": This artery supplies the orbit and its structures. P - "Posterior Ciliary Arteries": These branches ... M - "Medial Palpebral Arteries": These arteries supply the eyelids. I - "Internal Carotid Artery": The ophthalmic artery is a ... Submental Artery Mnemonic [ NEVER FORGET AGAIN ] September 9, 2023. Posterior Intercostal Artery - Mnemonic September 2, 2023. ... Sinoatrial Nodal Artery - Mnemonic [ NEVER FORGET AGAIN ] September 4, 2023. Coronary Artery - Mnemonic [ NEVER FORGET AGAIN ] ...
Posterior ciliary artery * Major arterial circle of iris * Minor arterial circle of iris ...
... left posterior ciliary arteries, left choroid, and probably left retinal arteries. This represents at least the sixth case of ... left posterior ciliary arteries, left choroid, and probably left retinal arteries. This represents at least the sixth case of ... left posterior ciliary arteries, left choroid, and probably left retinal arteries. This represents at least the sixth case of ... left posterior ciliary arteries, left choroid, and probably left retinal arteries. This represents at least the sixth case of ...
The sclera receives its blood-supply from the short posterior ciliary and the anterior ciliary arteries, while its veins open ... The arteries of the chorioid are derived from the short posterior ciliary vessels which pierce the sclera around the entrance ... The two long posterior ciliary arteries pierce it, one on each side, some little distance from the entrance of the optic nerve ... Circular fibres of ciliary muscle. in the deeper part of this Parts of ciliary processes junction there is a circular canal, ...
Calcinai, forex gbp usd forecast coming week ciliary arteries. Values drive an organizations culture and priorities. Creates a ... Arteries forex fsa broker regulation fecal and urinary. fsa forex broker regulation Tissue. Fsa forex broker regulation The. ...
an arterial source is from the ophthalmic artery * the short posterior, long posterior, and anterior ciliary arteries ... the ciliary body produces aqueous humor into the posterior chamber which * flows through the space between the lens and iris ...
  • At autopsy, an unsuspected left atrial myxoma was found with embolization to the left middle cerebral artery, left posterior ciliary arteries, left choroid, and probably left retinal arteries. (elsevierpure.com)
  • Brain magnetic resonance imaging revealed mild stenosis of the distal aspect of the internal carotid arteries as well as of the proximal segment of the left middle cerebral artery. (ekjo.org)
  • i.p) or vehicle administered 24 hours after permanent middle cerebral artery occlusion (pMCAO) on behavior, angiogenesis, ultra-structural integrity of brain capillary endothelial cells, and expression of EPO and VEGF were assessed. (researchgate.net)
  • For example, embolization of a tumor supplied by the external carotid artery (e.g. meningioma or hemangiopericytoma ) can result in blindness. (radiopaedia.org)
  • This is almost invariably due to giant cell arteritis (GCA), which is a primary vasculitis that affects extracranial medium (especially external carotid artery-ECA-branches) and sometimes large arteries (aorta and its major branches)-large-vessel GCA [ 3 , 4 ]. (intechopen.com)
  • The blood supply to the palpebral conjunctiva (the eyelid) is derived from the external carotid artery . (wikipedia.org)
  • However, the circulations of the bulbar conjunctiva and palpebral conjunctiva are linked, so both bulbar conjunctival and palpebral conjunctival vessels are supplied by both the ophthalmic artery and the external carotid artery, to varying extents. (wikipedia.org)
  • This bifurcation leads to the external carotid artery and the ICA. (medscape.com)
  • The external carotid artery is an important vessel because of its blood supply to the orbit, dura, and cranial nerves. (medscape.com)
  • The blood supply is through the ophthalmic artery and the external carotid artery. (nftartranking.com)
  • Inadvertent occlusion of the ophthalmic or central retinal artery during external carotid artery embolization has been reported in 4 cases, 2 - 4 with immediate loss of vision. (jamanetwork.com)
  • each divides into two branches, the internal carotid artery and the external carotid artery. (bvsalud.org)
  • Approximately 40-50% of patients with GCA have ophthalmologic complications, including visual loss secondary to A-AION, central retinal artery occlusion, homonymous hemianopsia or cortical blindness (uni- or bilateral occipital infarction) [ 6 ]. (intechopen.com)
  • Carotid artery occlusion is associated with slower conjunctival blood flow and apparent capillary loss. (wikipedia.org)
  • A left central retinal artery occlusion was noted. (elsevierpure.com)
  • Atrial myxoma should be suspected in any young person with central retinal artery occlusion without predisposing disease. (elsevierpure.com)
  • Potentially serious ophthalmic problems associated with ROCM include occlusion of the central artery of the retina and infraction of the orbit including the optic nerve and can ultimately cause complete vision loss. (eyewiki.org)
  • You may find the Retinal Artery Occlusion article more useful, or one of our other health articles . (patient.info)
  • Central retinal artery occlusion (CRAO) is an ophthalmic emergency. (patient.info)
  • Depending on where the occlusion occurs, different layers and quarters of the retina can be affected: more proximal ophthalmic artery occlusion will have the most devastating effect, as all layers of the entire retina lose their blood supply, whereas a occlusion of a distal end branch of the retinal artery will only affect the inner neural retina of that part of the retina, sparing the photoreceptors and limiting visual loss. (patient.info)
  • Occlusion affecting the retinal artery prior to branching is termed CRAO. (patient.info)
  • Occlusion of one of the branches of the retinal artery is referred to as branch retinal artery occlusion (BRAO). (patient.info)
  • Arteritic anterior ischemic optic neuropathy (AAION) is caused by vascular occlusion of the posterior ciliary arteries that supply the optic nerve head (ONH). (ekjo.org)
  • Funduscopic examination revealed a chalky white swelling of the ONH in both eyes, as well as focal retinal edema adjacent to the ONH in the right eye due to the occlusion of the cilioretinal artery ( Fig. 1A ). (ekjo.org)
  • The short posterior ciliary arteries from six to twelve in number, arise from the ophthalmic artery as it crosses the optic nerve. (wikipedia.org)
  • The long posterior ciliary arteries, two for each eye, pierce the posterior part of the sclera at some little distance from the optic nerve. (wikipedia.org)
  • As the ophthalmic artery traverses the optic nerve, it gives off the central retinal artery and, more distally, the posterior ciliary arteries. (medscape.com)
  • The posterior one third of the optic nerve is supplied by penetrating arteries from the anterior communicating and anterior cerebral arteries. (medscape.com)
  • A watershed area is delineated near the head of the optic nerve between the posterior ciliary artery and the central retinal artery. (medscape.com)
  • It is caused by infarction of the short posterior ciliary arteries supplying the anterior optic nerve. (aetna.com)
  • The ophthalmic artery passes into the orbit via the optic canal . (radiopaedia.org)
  • AION represents an acute ischemic disorder (a segmental infarction) of the ONH supplied by the posterior ciliary arteries (PCAs), while PION has no specific location in the posterior part of the optic nerve and does not represent ischemia in a specific artery [ 1 ]. (intechopen.com)
  • As the artery crosses the optic nerve, it is accompanied by the nasociliary nerve and is separated from the frontal nerve by the superior rectus muscle and the superior levator palpebral muscle. (medscape.com)
  • One of the largest branches derived from the ophthalmic artery, the lacrimal artery (arteria lacrimalis) arises close to the optic foramen and, not infrequently, is given off before the ophthalmic artery enters the orbit. (medscape.com)
  • The cilioretinal artery is seen ophthalmoscopically as a single vessel emerging from the edge of the optic disc, most commonly towards the macula. (patient.info)
  • Atherosclerotic narrowing of the posterior ciliary arteries may predispose to nonarteritic optic nerve infarction, particularly after a hypotensive episode. (msdmanuals.com)
  • The sclera receives the circulation of two long and ten to twelve short posterior ciliary arteries around the optic nerve. (wikidoc.org)
  • Posteriorly there are aperatures around the optic nerve through which the long and short posterior ciliary arteries and nerves pass. (missionforvision.org)
  • It transmits the optic nerve and ophthalmic artery from the middle cranial fossa. (dartmouth.edu)
  • The outer retina is supplied by the choriocapillaries of the choroid that branches off the ciliary artery. (patient.info)
  • While the central retinal artery provides the inner retina's blood supply, most of its oxygen demand is supplied by diffusion from the underlying choroid (which is the sole supply of the avascular fovea), which is in turn supplied by the ciliary arteries. (arvojournals.org)
  • Exome-Based Case-Control Analysis Highlights the Pathogenic Role of Ciliary Genes in Transposition of the Great Arteries. (stanford.edu)
  • Rationale: Transposition of the great arteries (TGA) is one of the most severe types of congenital heart diseases (CHD). (stanford.edu)
  • After the origin of the ophthalmic artery, the ICA gives off the anterior choroidal and posterior communicating arteries. (medscape.com)
  • We analyzed ophthalmic consequences due to coverage of the origin of the ophthalmic artery by flow-diverting stents for the treatment of internal carotid artery aneurysms. (ajnr.org)
  • From April 2009 to April 2013, the clinical and angiographic outcomes of all 28 patients treated for aneurysms with flow-diverting stents covering the origin of the ophthalmic artery were prospectively collected. (ajnr.org)
  • The origin of the ophthalmic artery in relation to the target aneurysm was classified by using a 4-type classification. (ajnr.org)
  • The anterior ciliary arteries are derived from the muscular branches of the ophthalmic artery. (wikipedia.org)
  • The two terminal branches of the ophthalmic artery are the supratrochlear artery and the dorsal nasal artery . (radiopaedia.org)
  • Most branches of the ophthalmic artery arise in the posterior one third of the orbit and pass anteriorly. (medscape.com)
  • As outlined below, the branches of the ophthalmic artery are divided into an orbital group, distributing vessels to the orbit and surrounding parts, and an ocular group, distributing vessels to the muscles and bulb of the eye. (medscape.com)
  • The medial posterior choroidal artery is a small branch (often multiple - 40% of hemispheres) usually arising from the P2 segment of the PCA . (radiopaedia.org)
  • As it reaches the foramen of Monro it passes through it to anastamose with branches of the lateral posterior choroidal artery . (radiopaedia.org)
  • While optical coherence tomography angiography provides an en face depiction of the choroidal vasculature, it does not reveal flow dynamics. (arvojournals.org)
  • Two intraorbital anastomoses were also noted between the internal and external carotid arterial systems: one through the lacrimal artery-middle meningeal artery to the ophthalmic artery and the other through supraorbital artery-recurrent meningeal artery to the ophthalmic artery. (utmb.edu)
  • Embryologically, the orbit has dual supply: from the supraorbital branch (which later becomes the middle meningeal artery ) and from the ophthalmic artery. (radiopaedia.org)
  • Embolism is the most common cause, the major source of this being carotid artery disease, usually due to atherosclerotic plaques. (patient.info)
  • In addition, ultrasonography and biopsy of the temporal artery as well as brain magnetic resonance imaging were planned to definitively diagnosis GCA and to differentiate it from carotid artery disease. (ekjo.org)
  • The ophthalmic artery passes over the nerve (in 85% of cases) to reach the medial wall of the orbit. (medscape.com)
  • The ophthalmic artery is a branch of the supraclinoid (C6) segment of the internal carotid artery . (radiopaedia.org)
  • The ophthalmic artery is a branch of the internal carotid artery. (medicalsupernotes.com)
  • The central retinal artery (CRA) is a branch of the ophthalmic artery, which is the first branch of the internal carotid artery. (patient.info)
  • It pierces the spheno-mandibular ligament, and descends in the mylo-hyoid groove, in company with the mylo-hyoid nerve, to the floor of the mouth, where it anastomoses, on the superficial surface of the mylo-hyoid muscle, with the submental branch of the external maxillary artery. (co.ma)
  • The mental terminal branch, which passes through the mental foramen, emerges beneath the quadratus labii inferioris, and anastomoses with its fellow of the opposite side, with the inferior labial, and with the submental arteries. (co.ma)
  • Structures located within the cone (after passing through the annulus of Zinn) include the motor innervations to the rectus muscles (cranial nerves III and VI) and the afferent sensory fibers from the globe, which are carried by the short and long posterior ciliary nerves before joining the nasociliary nerve (a branch of cranial nerve V1). (medscape.com)
  • The arterial supply to the orbit derives its origin from the internal carotid artery (ICA). (medscape.com)
  • These vessels run medially and anastomose with the medial palpebral arteries, forming an arterial circle. (medscape.com)
  • On the other hand, stimulating another very important point, ST36 could lead to a significant increase in blood flow in one of the abdominal arteries, called the mesenteric artery, but no significant change in the vascular resistance of some eye arteries, including the retrobulbar arteries, certral retinal artery and short posterior ciliary artery. (selfgrowth.com)
  • Greater and lesser palatine foramina (for palatine nerves and arteries) and posterior nasal spine Vomer 1. (slideshare.net)
  • The nerve supply of sclera comes through the ciliary nerves. (wikidoc.org)
  • It also has its own nerve supply and is supplied by the long ciliary nerves anteriorly and short ciliary nerves behind the equator. (nftartranking.com)
  • Anteriorly, anterior ciliary vessels, branches of vessels to the rectus muscle, and nerves pass. (missionforvision.org)
  • The nerves travel through the sclera usually originating from the long ciliary nerves (arrow 2) and some may approach the surface of the sclera about 1-6 mm from the limbus (arrow 1). (missionforvision.org)
  • At the junction of the medial wall with the roof, the anterior and posterior ethmoidal foramina transmit the nerves and arteries of the same name. (dartmouth.edu)
  • Retrobulbar block also provides sensory anesthesia of the cornea, uvea, and conjunctiva by blocking the ciliary nerves. (medscape.com)
  • Afferent fibers from the globe travel via the long and short posterior ciliary nerves. (medscape.com)
  • anteriorly it is continued into the ocular conjunctiva, and is also attached to the ciliary region of the bulb. (co.ma)
  • The diagnosis of GCA requires age more than 50 years at disease onset, new headache in the temporal area, temporal artery tenderness, and/or reduced pulse, jaw claudication, systemic symptoms, erythrocyte sedimentation rate (ESR) exceeding 50 mm/hr, and typical histologic findings (granulomatous involvement) in temporal artery biopsy (TAB) [ 5 ]. (intechopen.com)
  • One case of AAION associated with GCA, which was confirmed by temporal artery biopsy and exhibited typical systemic symptoms, was reported by our research team in Korea [ 5 ]. (ekjo.org)
  • Here we report a case of bilateral AAION associated with GCA in an elderly Korean man, as confirmed by temporal artery biopsy. (ekjo.org)
  • The ICA provides collateralization with the middle meningeal artery and lacrimal and ethmoidal anastomoses. (medscape.com)
  • The ophthalmic artery rarely arises from the middle meningeal artery. (medscape.com)
  • They ascend, in the temporal fossa, between the temporal muscle and the squamous portion of the temporal bone, supplying the muscle and anastomosing with the temporal and lacrimal arteries, and, through the substance of the temporal bone, with the middle meningeal artery. (co.ma)
  • One important variation is the presence of a cilioretinal artery. (patient.info)
  • Giant Cell Arteritis Giant cell arteritis involves predominantly the thoracic aorta, large arteries emerging from the aorta in the neck, and extracranial branches of the carotid arteries. (msdmanuals.com)
  • Atherosclerosis Atherosclerosis is characterized by patchy intimal plaques (atheromas) that encroach on the lumen of medium-sized and large arteries. (msdmanuals.com)
  • This artery, thought to be present in 15-30% of people, supplies the macular retina to a varying degree and may help preserve some vision after CRAO. (patient.info)
  • This artery runs along the lateral wall of the orbit, accompanying the lacrimal nerve along the upper border of the lateral rectus muscle, and supplies the lacrimal gland. (medscape.com)
  • It gives rise to the lacrimal artery, which nourishes the lacrimal gland. (medicalsupernotes.com)
  • Three groups of arteries found in the eye which supply the iris, pupil, sclera, conjunctiva, and the muscles of the iris. (centralx.com)
  • Blood to the bulbar conjunctiva is primarily derived from the ophthalmic artery. (wikipedia.org)
  • The superior and inferior lateral palpebral arteries, which are terminal branches of the lacrimal artery, irrigate the upper and lower eyelids, respectively, and the conjunctiva. (medscape.com)
  • The infraorbital foramen, for the nerve and artery of the same name, is less than 1 cm inferior to the inferior margin. (dartmouth.edu)
  • The floor (maxilla, zygomatic, and palatine bones) presents the infraorbital groove and canal for the nerve and artery of the same name. (dartmouth.edu)
  • The artery then proceeds forward horizontally, beneath the lower border of the superior oblique muscle, and divides into 2 terminal branches, frontal and dorsal nasal. (medscape.com)
  • The ophthalmic artery (arteria ophthalmica) is the major blood supply of the orbit. (medscape.com)
  • This artery supplies the orbit and its structures. (medicalsupernotes.com)
  • The disease preferentially affects the extracranial branches of the carotid arteries and, less often, causes clinical involvement of the aorta and its major branches. (hcplive.com)
  • The diagnosis is a clinical one, aided by information from temporal artery biopsies and, in some cases, MRI studies of the aorta and its primary branches. (hcplive.com)
  • The anterior ciliary arteries and veins penetrate the sclera nearly 3 to 4 mm away from the limbus. (wikidoc.org)
  • The ciliary arteries are divisible into three groups, the long posterior, short posterior, and the anterior. (wikipedia.org)
  • Herein, the authors report a variant of the CRA that originated from the temporal short posterior ciliary artery. (utmb.edu)
  • It receives its supply through the anterior ciliary arteries, long posterior ciliary arteries, and short posterior ciliary arteries. (nftartranking.com)
  • It passes upwards, on the medial side of the external pterygoid muscle, enters the middle fossa of the skull through the foramen ovale, supplies the semilunar ganglion and the dura mater, and terminates by anastomosing with branches of the middle meningeal and internal carotid arteries. (co.ma)
  • These fibers pass through the intraconal ciliary ganglion. (medscape.com)
  • The ophthalmic artery and its branches Iris, front view. (wikipedia.org)
  • The ophthalmic artery originates from the distal end of the internal carotid artery (ICA). (medscape.com)
  • The ophthalmic artery arises medial to the anterior clinoid process as the internal carotid artery exits the cavernous sinus . (radiopaedia.org)
  • It originates from the antero- or supero-medial surface of the internal carotid artery. (radiopaedia.org)
  • His right femoral artery was cannulated, and a microcatheter was advanced toward the internal carotid artery (ICA). (asahq.org)
  • In addition to supplying the anterior part of the brain, eye, and adnexa, the internal carotid artery (ICA) sends branches to the forehead and the nose. (medscape.com)
  • Although variations in the peripapillary division pattern of the central retinal artery (CRA) are common, variations in the origin of this artery are seldom reported in the literature. (utmb.edu)
  • The muscular branches of the lacrimal artery supply the superior and lateral recti muscles. (medscape.com)
  • Left: Illustration of an eye and the four rectus muscles with the anterior ciliary arteries. (lu.se)
  • The condition occurs due to damage of the anterior ciliary arteries that course along the rectus muscles and therefore gets damaged during surgical manipulation. (lu.se)
  • It anastomoses in the substance of the muscle with branches of the transverse facial and with the masseteric branches of the external maxillary artery. (co.ma)
  • It supplies the buccinator muscle, the skin and mucous membrane of the cheek, and anastomoses with the buccal branches of the external maxillary artery. (co.ma)
  • the posterior ciliary arteries supply the peripheral nerve substance. (medscape.com)
  • As it descends it gives off the artery of the pterygoid canal, and several small twigs which pass through the accessory palatine canals to supply the soft palate, and to anastomose with the ascending palatine and tonsillar branches of the external maxillary and with the ascending pharyngeal artery. (co.ma)