Nasal Mucosa
Respiratory Mucosa
Mucous Membrane
Olfactory Mucosa
Mucociliary Clearance
Respiratory System
Microscopy, Electron, Scanning
Bacterial Adhesion
Haemophilus influenzae
Organ Culture Techniques
Intestinal Mucosa
Gastric Mucosa
Mouth Mucosa
Colon
Laryngeal Mucosa
Duodenum
Intestine, Small
Stomach Ulcer
Effects of inhaled beta agonist and corticosteroid treatment on nuclear transcription factors in bronchial mucosa in asthma. (1/2809)
BACKGROUND: Inhaled corticosteroids and beta agonists are the most commonly used treatments in asthma and are often used together. Recent evidence suggests that many of the anti-inflammatory actions of corticosteroids are mediated by cross-talk between the activated glucocorticoid receptor (GR) and other transcription factors such as the pro-inflammatory nuclear factor kappa B (NFkappaB). Beta agonists can activate the transcription factor cAMP response element binding protein (CREB). A mutual inhibition between GR and CREB occurs in vitro which raises the possibility of a negative interaction between corticosteroid and beta agonist drugs. A study was undertaken to determine whether these interactions occur during treatment with beta2 agonists and corticosteroids in asthma. METHODS: Seven subjects who were participating in a randomised, placebo controlled, crossover study of six weeks treatment with inhaled budesonide (400 microg twice daily), terbutaline (1 mg four times daily), and combined treatment were recruited. Biopsy samples of the bronchial mucosa were obtained after each treatment and analysed for the DNA binding activity of GR, CREB, and NFkappaB. RESULTS: Budesonide increased GR activity (p<0.05) and decreased NFkappaB activity (p<0.05). No treatment combination altered CREB activity and terbutaline had no significant effects on any transcription factor. CONCLUSIONS: Inhaled corticosteroids have significant effects on GR and NFkappaB activity in bronchial mucosa. A negative interaction between inhaled corticosteroids and beta agonists was not found. (+info)Passive IgA monoclonal antibody is no more effective than IgG at protecting mice from mucosal challenge with respiratory syncytial virus. (2/2809)
Respiratory syncytial virus (RSV) is a mucosally restricted pathogen that can cause severe respiratory disease. Although parenteral administration of sufficient RSV-specific IgG can reduce severity of lower respiratory tract infection in high-risk infants, delivery of antibody by direct airway administration is an attractive alternative. Topical and parenteral administration of an IgA monoclonal antibody (MAb) specific for the RSV F glycoprotein was compared with an IgG MAb, specific for the same antigenic site, for ability to protect mice against RSV infection. Administration of RSV-specific IgG was more effective in reducing RSV titers in lung (4.6 log10 pfu/g) than IgA MAb (3.6 log10 pfu/g) when given intranasally immediately prior to infection (P=.005). RSV titers in the nose were reduced only by prophylactic administration of IgG parenterally. Therefore, topical administration of IgA is no more effective than topically administered IgG and is less effective than systemically administered IgG for protecting against RSV infection. (+info)Differential sensitivity of normal and cystic fibrosis airway epithelial cells to epinephrine. (3/2809)
1. Exposure to epinephrine has been shown to have a range of effects on cells and tissues. A recent study suggested that the proliferative ability of CF epithelial cells, exposed to high concentrations of epinephrine (200 - 300 microM), was reduced when compared to that of normal cells. This approach could potentially provide a means to effectively separate cells with functional cyclic AMP-dependent Cl-ion transport from those defective in this pathway. 2. The sensitivity to killing by epinephrine is reported here for four different CF cell lines, three normal cell lines, and two CF epithelial cell lines complemented with wild-type (wt) CF transmembrane conductance regulator (CFTR) cDNA. 3. While each cell line exhibited varying sensitivity to 200 microM epinephrine, no predictable pattern was observed between the expression of wt-CFTR and cell survival following epinephrine exposure. Overall, normal cell lines did exhibit a greater resistance to epinephrine-induced cell death although, the most resistant cell line was derived from CF tracheal epithelium (SigmaCFTE29o-). 4. The expression of exogenous wt-CFTR increased the survival of one cell line (CFDEo-) when compared to the parent line, but in another complemented line, survival was reduced. 5. These findings suggest that while epinephrine induces cell killing, it is not consistently effective for preferential selection of normal over CF cells. Although CFTR may play a role in the mechanism(s) of epinephrine killing, other factors such as cell density, proliferative ability, cell type origin and phenotype are involved. (+info)Crucial role of the interleukin 1 receptor family member T1/ST2 in T helper cell type 2-mediated lung mucosal immune responses. (4/2809)
T1/ST2 is an orphan receptor of unknown function that is expressed on the surface of murine T helper cell type 2 (Th2), but not Th1 effector cells. In vitro blockade of T1/ST2 signaling with an immunoglobulin (Ig) fusion protein suppresses both differentiation to and activation of Th2, but not Th1 effector populations. In a nascent Th2-dominated response, anti-T1/ST2 monoclonal antibody (mAb) inhibited eosinophil infiltration, interleukin 5 secretion, and IgE production. To determine if these effects were mediated by a direct effect on Th2 cells, we next used a murine adoptive transfer model of Th1- and Th2-mediated lung mucosal immune responses. Administration of either T1/ST2 mAb or T1/ST2-Ig abrogated Th2 cytokine production in vivo and the induction of an eosinophilic inflammatory response, but failed to modify Th1-mediated inflammation. Taken together, our data demonstrate an important role of T1/ST2 in Th2-mediated inflammatory responses and suggest that T1/ST2 may prove to be a novel target for the selective suppression of Th2 immune responses. (+info)Epithelial P2X purinergic receptor channel expression and function. (5/2809)
P2X purinergic receptor (P2XR) channels bind ATP and mediate Ca(2+) influx--2 signals that stimulate secretory Cl(-) transport across epithelia. We tested the hypotheses that P2XR channels are expressed by epithelia and that P2XRs transduce extracellular ATP signals into stimulation of Cl(-) transport across epithelia. Electrophysiological data and mRNA analysis of human and mouse pulmonary epithelia and other epithelial cells indicate that multiple P2XRs are broadly expressed in these tissues and that they are active on both apical and basolateral surfaces. Because P2X-selective agonists bind multiple P2XR subtypes, and because P2X agonists stimulate Cl(-) transport across nasal mucosa of cystic fibrosis (CF) patients as well as across non-CF nasal mucosa, P2XRs may provide novel targets for extracellular nucleotide therapy of CF. (+info)Effect of fluticasone propionate and salmeterol on Pseudomonas aeruginosa infection of the respiratory mucosa in vitro. (6/2809)
The purpose of this study was to investigate the effect of the corticosteroid, fluticasone propionate (FP), on Pseudomonas aeruginosa infection of the respiratory mucosa of an organ culture model in vitro. Organ cultures infected with P. aeruginosa had significantly (p< or =0.05) elevated levels of mucosal damage and significantly (p< or =0.05) less ciliated cells compared to controls. Preincubation of tissue with FP (10(-6) or 10(-5) but not 10(-7) M) prior to P. aeruginosa infection significantly (p< or =0.05) reduced the bacterially induced mucosal damage in a concentration-dependent manner. FP (10(-5) M) also significantly (p< or =0.05) prevented loss of ciliated cells. FP did not alter the density of bacteria adherent to the different mucosal features of the organ cultures, but did reduce total bacterial numbers due to the reduced amount of damaged tissue, which is a preferred site of P. aeruginosa adherence. It has previously been shown that the long-acting beta2-agonist salmeterol (4 x 10(-7)M) also reduces the mucosal damage caused by P. aeruginosa infection, probably via elevation of intracellular cyclic adenosine monophosphate concentrations. Preincubation of tissue with both 10(-7)M FP and 10(-7)M salmeterol, concentrations at which they did not by themselves influence the effect of P. aeruginosa infection, significantly (p< or =0.05) reduced P. aeruginosa-induced loss of cilia. However, there was no additional benefit from adding 4 x 10(-7)M salmeterol to 10(-6)M FP. In conclusion fluticasone propionate reduced mucosal damage caused by P. aeruginosa infection in vitro and preserved ciliated cells. There was a synergistic action with salmeterol in the preservation of ciliated cells. (+info)M1/MUC5AC mucin released by human airways in vitro. (7/2809)
A series of monoclonal antibodies which bind to a mucin known as M1 (anti-M1 MAbs) have also been shown to detect the product of the human gene MUC5AC. The aim of this investigation was to determine the concentration of the M1 mucin in the surface epithelium of human bronchial preparations by means of immunohistochemistry and in the bronchial fluid derived from human airways by means of an immunoradiometric assay. Human bronchial ring preparations from the resection material of 20 patients were challenged with methacholine, leukotriene D4, or anti-immunoglobulin E. Experiments were performed in preparations with an intact epithelium as well as in tissues in which the epithelium had been mechanically removed. The anti-M1 MAbs stained the goblet cells in the epithelium intensely and there was also light and less uniform staining in the submucosa. The M1/MUC5AC mucin in the fluids secreted by the bronchial preparations was not modified during either the experimental protocol or stimulation with the different secretagogues. However, in preparations in which the epithelium had been removed, there was a significant reduction in the amount of M1/MUC5AC mucin detected. These data suggest that the M1/MUC5AC mucin detected in the biological fluids produced by human airways in vitro may be released constantly, and principally from the goblet cells in the epithelial layer. (+info)Arsenite exposure of cultured airway epithelial cells activates kappaB-dependent interleukin-8 gene expression in the absence of nuclear factor-kappaB nuclear translocation. (8/2809)
Airway epithelial cells respond to certain environmental stresses by mounting a proinflammatory response, which is characterized by enhanced synthesis and release of the neutrophil chemotactic and activating factor interleukin-8 (IL-8). IL-8 expression is regulated at the transcriptional level in part by the transcription factor nuclear factor (NF)-kappaB. We compared intracellular signaling mediating IL-8 gene expression in bronchial epithelial cells cultured in vitro and exposed to two inducers of cellular stress, sodium arsenite (As(III)), and vanadyl sulfate (V(IV)). Unstimulated bronchial epithelial cells expressed IL-8, and exposure to both metal compounds significantly enhanced IL-8 expression. Overexpression of a dominant negative inhibitor of NF-kappaB depressed both basal and metal-induced IL-8 expression. Low levels of nuclear NF-kappaB were constitutively present in unstimulated cultures. These levels were augmented by exposure to V(IV), but not As(III). Accordingly, V(IV) induced IkappaBalpha breakdown and NF-kappaB nuclear translocation, whereas As(III) did not. However, both As(III) and V(IV) enhanced kappaB-dependent transcription. In addition, As(III) activation of an IL-8 promoter-reporter construct was partially kappaB-dependent. These data suggested that As(III) enhanced IL-8 gene transcription independently of IkappaB breakdown and nuclear translocation of NF-kappaB in part by enhancing transcription mediated by low levels of constitutive nuclear NF-kappaB. (+info)Nasal mucosa refers to the mucous membrane that lines the nasal cavity. It is a delicate, moist, and specialized tissue that contains various types of cells including epithelial cells, goblet cells, and glands. The primary function of the nasal mucosa is to warm, humidify, and filter incoming air before it reaches the lungs.
The nasal mucosa produces mucus, which traps dust, allergens, and microorganisms, preventing them from entering the respiratory system. The cilia, tiny hair-like structures on the surface of the epithelial cells, help move the mucus towards the back of the throat, where it can be swallowed or expelled.
The nasal mucosa also contains a rich supply of blood vessels and immune cells that help protect against infections and inflammation. It plays an essential role in the body's defense system by producing antibodies, secreting antimicrobial substances, and initiating local immune responses.
Respiratory mucosa refers to the mucous membrane that lines the respiratory tract, including the nose, throat, bronchi, and lungs. It is a specialized type of tissue that is composed of epithelial cells, goblet cells, and glands that produce mucus, which helps to trap inhaled particles such as dust, allergens, and pathogens.
The respiratory mucosa also contains cilia, tiny hair-like structures that move rhythmically to help propel the mucus and trapped particles out of the airways and into the upper part of the throat, where they can be swallowed or coughed up. This defense mechanism is known as the mucociliary clearance system.
In addition to its role in protecting the respiratory tract from harmful substances, the respiratory mucosa also plays a crucial role in immune function by containing various types of immune cells that help to detect and respond to pathogens and other threats.
Adenoids are a pair of masses of lymphoid tissue located in the nasopharynx, which is the upper part of the throat behind the nose. They are part of the immune system and help to protect against infection. Adenoids are largest in children and tend to shrink in size as people get older. In some cases, adenoids can become enlarged or infected, leading to problems such as breathing difficulties, ear infections, and sleep disorders. Treatment for enlarged or infected adenoids may include antibiotics, medications to reduce swelling, or surgical removal of the adenoids (adenoidectomy).
A mucous membrane is a type of moist, protective lining that covers various body surfaces inside the body, including the respiratory, gastrointestinal, and urogenital tracts, as well as the inner surface of the eyelids and the nasal cavity. These membranes are composed of epithelial cells that produce mucus, a slippery secretion that helps trap particles, microorganisms, and other foreign substances, preventing them from entering the body or causing damage to tissues. The mucous membrane functions as a barrier against infection and irritation while also facilitating the exchange of gases, nutrients, and waste products between the body and its environment.
The olfactory mucosa is a specialized mucous membrane that is located in the upper part of the nasal cavity, near the septum and the superior turbinate. It contains the olfactory receptor neurons, which are responsible for the sense of smell. These neurons have hair-like projections called cilia that are covered in a mucus layer, which helps to trap and identify odor molecules present in the air we breathe. The olfactory mucosa also contains supporting cells, blood vessels, and nerve fibers that help to maintain the health and function of the olfactory receptor neurons. Damage to the olfactory mucosa can result in a loss of smell or anosmia.
Mucociliary clearance is a vital defense mechanism of the respiratory system that involves the coordinated movement of tiny hair-like structures called cilia, which are present on the surface of the respiratory epithelium, and the mucus layer. This mechanism helps to trap inhaled particles, microorganisms, and other harmful substances and move them away from the lungs towards the upper airways, where they can be swallowed or coughed out.
The cilia beat in a coordinated manner, moving in a wave-like motion to propel the mucus layer upwards. This continuous movement helps to clear the airways of any debris and maintain a clean and healthy respiratory system. Mucociliary clearance plays an essential role in preventing respiratory infections and maintaining lung function. Any impairment in this mechanism, such as due to smoking or certain respiratory conditions, can increase the risk of respiratory infections and other related health issues.
The Respiratory System is a complex network of organs and tissues that work together to facilitate the process of breathing, which involves the intake of oxygen and the elimination of carbon dioxide. This system primarily includes the nose, throat (pharynx), voice box (larynx), windpipe (trachea), bronchi, bronchioles, lungs, and diaphragm.
The nostrils or mouth take in air that travels through the pharynx, larynx, and trachea into the lungs. Within the lungs, the trachea divides into two bronchi, one for each lung, which further divide into smaller tubes called bronchioles. At the end of these bronchioles are tiny air sacs known as alveoli where the exchange of gases occurs. Oxygen from the inhaled air diffuses through the walls of the alveoli into the bloodstream, while carbon dioxide, a waste product, moves from the blood to the alveoli and is exhaled out of the body.
The diaphragm, a large muscle that separates the chest from the abdomen, plays a crucial role in breathing by contracting and relaxing to change the volume of the chest cavity, thereby allowing air to flow in and out of the lungs. Overall, the Respiratory System is essential for maintaining life by providing the body's cells with the oxygen needed for metabolism and removing waste products like carbon dioxide.
Scanning electron microscopy (SEM) is a type of electron microscopy that uses a focused beam of electrons to scan the surface of a sample and produce a high-resolution image. In SEM, a beam of electrons is scanned across the surface of a specimen, and secondary electrons are emitted from the sample due to interactions between the electrons and the atoms in the sample. These secondary electrons are then detected by a detector and used to create an image of the sample's surface topography. SEM can provide detailed images of the surface of a wide range of materials, including metals, polymers, ceramics, and biological samples. It is commonly used in materials science, biology, and electronics for the examination and analysis of surfaces at the micro- and nanoscale.
Bacterial adhesion is the initial and crucial step in the process of bacterial colonization, where bacteria attach themselves to a surface or tissue. This process involves specific interactions between bacterial adhesins (proteins, fimbriae, or pili) and host receptors (glycoproteins, glycolipids, or extracellular matrix components). The attachment can be either reversible or irreversible, depending on the strength of interaction. Bacterial adhesion is a significant factor in initiating biofilm formation, which can lead to various infectious diseases and medical device-associated infections.
Intranasal administration refers to the delivery of medication or other substances through the nasal passages and into the nasal cavity. This route of administration can be used for systemic absorption of drugs or for localized effects in the nasal area.
When a medication is administered intranasally, it is typically sprayed or dropped into the nostril, where it is absorbed by the mucous membranes lining the nasal cavity. The medication can then pass into the bloodstream and be distributed throughout the body for systemic effects. Intranasal administration can also result in direct absorption of the medication into the local tissues of the nasal cavity, which can be useful for treating conditions such as allergies, migraines, or pain in the nasal area.
Intranasal administration has several advantages over other routes of administration. It is non-invasive and does not require needles or injections, making it a more comfortable option for many people. Additionally, intranasal administration can result in faster onset of action than oral administration, as the medication bypasses the digestive system and is absorbed directly into the bloodstream. However, there are also some limitations to this route of administration, including potential issues with dosing accuracy and patient tolerance.
Haemophilus influenzae is a gram-negative, coccobacillary bacterium that can cause a variety of infectious diseases in humans. It is part of the normal respiratory flora but can become pathogenic under certain circumstances. The bacteria are named after their initial discovery in 1892 by Richard Pfeiffer during an influenza pandemic, although they are not the causative agent of influenza.
There are six main serotypes (a-f) based on the polysaccharide capsule surrounding the bacterium, with type b (Hib) being the most virulent and invasive. Hib can cause severe invasive diseases such as meningitis, pneumonia, epiglottitis, and sepsis, particularly in children under 5 years of age. The introduction of the Hib conjugate vaccine has significantly reduced the incidence of these invasive diseases.
Non-typeable Haemophilus influenzae (NTHi) strains lack a capsule and are responsible for non-invasive respiratory tract infections, such as otitis media, sinusitis, and exacerbations of chronic obstructive pulmonary disease (COPD). NTHi can also cause invasive diseases but at lower frequency compared to Hib.
Proper diagnosis and antibiotic susceptibility testing are crucial for effective treatment, as Haemophilus influenzae strains may display resistance to certain antibiotics.
Organ culture techniques refer to the methods used to maintain or grow intact organs or pieces of organs under controlled conditions in vitro, while preserving their structural and functional characteristics. These techniques are widely used in biomedical research to study organ physiology, pathophysiology, drug development, and toxicity testing.
Organ culture can be performed using a variety of methods, including:
1. Static organ culture: In this method, the organs or tissue pieces are placed on a porous support in a culture dish and maintained in a nutrient-rich medium. The medium is replaced periodically to ensure adequate nutrition and removal of waste products.
2. Perfusion organ culture: This method involves perfusing the organ with nutrient-rich media, allowing for better distribution of nutrients and oxygen throughout the tissue. This technique is particularly useful for studying larger organs such as the liver or kidney.
3. Microfluidic organ culture: In this approach, microfluidic devices are used to create a controlled microenvironment for organ cultures. These devices allow for precise control over the flow of nutrients and waste products, as well as the application of mechanical forces.
Organ culture techniques can be used to study various aspects of organ function, including metabolism, secretion, and response to drugs or toxins. Additionally, these methods can be used to generate three-dimensional tissue models that better recapitulate the structure and function of intact organs compared to traditional two-dimensional cell cultures.
The intestinal mucosa is the innermost layer of the intestines, which comes into direct contact with digested food and microbes. It is a specialized epithelial tissue that plays crucial roles in nutrient absorption, barrier function, and immune defense. The intestinal mucosa is composed of several cell types, including absorptive enterocytes, mucus-secreting goblet cells, hormone-producing enteroendocrine cells, and immune cells such as lymphocytes and macrophages.
The surface of the intestinal mucosa is covered by a single layer of epithelial cells, which are joined together by tight junctions to form a protective barrier against harmful substances and microorganisms. This barrier also allows for the selective absorption of nutrients into the bloodstream. The intestinal mucosa also contains numerous lymphoid follicles, known as Peyer's patches, which are involved in immune surveillance and defense against pathogens.
In addition to its role in absorption and immunity, the intestinal mucosa is also capable of producing hormones that regulate digestion and metabolism. Dysfunction of the intestinal mucosa can lead to various gastrointestinal disorders, such as inflammatory bowel disease, celiac disease, and food allergies.
Gastric mucosa refers to the innermost lining of the stomach, which is in contact with the gastric lumen. It is a specialized mucous membrane that consists of epithelial cells, lamina propria, and a thin layer of smooth muscle. The surface epithelium is primarily made up of mucus-secreting cells (goblet cells) and parietal cells, which secrete hydrochloric acid and intrinsic factor, and chief cells, which produce pepsinogen.
The gastric mucosa has several important functions, including protection against self-digestion by the stomach's own digestive enzymes and hydrochloric acid. The mucus layer secreted by the epithelial cells forms a physical barrier that prevents the acidic contents of the stomach from damaging the underlying tissues. Additionally, the bicarbonate ions secreted by the surface epithelial cells help neutralize the acidity in the immediate vicinity of the mucosa.
The gastric mucosa is also responsible for the initial digestion of food through the action of hydrochloric acid and pepsin, an enzyme that breaks down proteins into smaller peptides. The intrinsic factor secreted by parietal cells plays a crucial role in the absorption of vitamin B12 in the small intestine.
The gastric mucosa is constantly exposed to potential damage from various factors, including acid, pepsin, and other digestive enzymes, as well as mechanical stress due to muscle contractions during digestion. To maintain its integrity, the gastric mucosa has a remarkable capacity for self-repair and regeneration. However, chronic exposure to noxious stimuli or certain medical conditions can lead to inflammation, erosions, ulcers, or even cancer of the gastric mucosa.
The mouth mucosa refers to the mucous membrane that lines the inside of the mouth, also known as the oral mucosa. It covers the tongue, gums, inner cheeks, palate, and floor of the mouth. This moist tissue is made up of epithelial cells, connective tissue, blood vessels, and nerve endings. Its functions include protecting the underlying tissues from physical trauma, chemical irritation, and microbial infections; aiding in food digestion by producing enzymes; and providing sensory information about taste, temperature, and texture.
The colon, also known as the large intestine, is a part of the digestive system in humans and other vertebrates. It is an organ that eliminates waste from the body and is located between the small intestine and the rectum. The main function of the colon is to absorb water and electrolytes from digested food, forming and storing feces until they are eliminated through the anus.
The colon is divided into several regions, including the cecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum, and anus. The walls of the colon contain a layer of muscle that helps to move waste material through the organ by a process called peristalsis.
The inner surface of the colon is lined with mucous membrane, which secretes mucus to lubricate the passage of feces. The colon also contains a large population of bacteria, known as the gut microbiota, which play an important role in digestion and immunity.
The laryngeal mucosa is the mucous membrane that lines the interior surface of the larynx, also known as the voice box. This mucous membrane is composed of epithelial cells and underlying connective tissue, and it plays a crucial role in protecting the underlying tissues of the larynx from damage, infection, and other environmental insults.
The laryngeal mucosa is continuous with the respiratory mucosa that lines the trachea and bronchi, and it contains numerous mucus-secreting glands and cilia that help to trap and remove inhaled particles and microorganisms. Additionally, the laryngeal mucosa is richly innervated with sensory nerve endings that detect changes in temperature, pressure, and other stimuli, allowing for the regulation of breathing, swallowing, and voice production.
Damage to the laryngeal mucosa can occur as a result of various factors, including irritants, infection, inflammation, and trauma, and may lead to symptoms such as pain, swelling, difficulty swallowing, and changes in voice quality.
The duodenum is the first part of the small intestine, immediately following the stomach. It is a C-shaped structure that is about 10-12 inches long and is responsible for continuing the digestion process that begins in the stomach. The duodenum receives partially digested food from the stomach through the pyloric valve and mixes it with digestive enzymes and bile produced by the pancreas and liver, respectively. These enzymes help break down proteins, fats, and carbohydrates into smaller molecules, allowing for efficient absorption in the remaining sections of the small intestine.
The small intestine is the portion of the gastrointestinal tract that extends from the pylorus of the stomach to the beginning of the large intestine (cecum). It plays a crucial role in the digestion and absorption of nutrients from food. The small intestine is divided into three parts: the duodenum, jejunum, and ileum.
1. Duodenum: This is the shortest and widest part of the small intestine, approximately 10 inches long. It receives chyme (partially digested food) from the stomach and begins the process of further digestion with the help of various enzymes and bile from the liver and pancreas.
2. Jejunum: The jejunum is the middle section, which measures about 8 feet in length. It has a large surface area due to the presence of circular folds (plicae circulares), finger-like projections called villi, and microvilli on the surface of the absorptive cells (enterocytes). These structures increase the intestinal surface area for efficient absorption of nutrients, electrolytes, and water.
3. Ileum: The ileum is the longest and final section of the small intestine, spanning about 12 feet. It continues the absorption process, mainly of vitamin B12, bile salts, and any remaining nutrients. At the end of the ileum, there is a valve called the ileocecal valve that prevents backflow of contents from the large intestine into the small intestine.
The primary function of the small intestine is to absorb the majority of nutrients, electrolytes, and water from ingested food. The mucosal lining of the small intestine contains numerous goblet cells that secrete mucus, which protects the epithelial surface and facilitates the movement of chyme through peristalsis. Additionally, the small intestine hosts a diverse community of microbiota, which contributes to various physiological functions, including digestion, immunity, and protection against pathogens.
Gastritis is a medical condition characterized by inflammation of the lining of the stomach. It can be caused by various factors, including bacterial infections (such as Helicobacter pylori), regular use of nonsteroidal anti-inflammatory drugs (NSAIDs), excessive alcohol consumption, and stress.
Gastritis can present with a range of symptoms, such as abdominal pain or discomfort, nausea, vomiting, loss of appetite, and bloating. In some cases, gastritis may not cause any noticeable symptoms. Depending on the severity and duration of inflammation, gastritis can lead to complications like stomach ulcers or even stomach cancer if left untreated.
There are two main types of gastritis: acute and chronic. Acute gastritis develops suddenly and may last for a short period, while chronic gastritis persists over time, often leading to atrophy of the stomach lining. Diagnosis typically involves endoscopy and tissue biopsy to assess the extent of inflammation and rule out other potential causes of symptoms. Treatment options depend on the underlying cause but may include antibiotics, proton pump inhibitors, or lifestyle modifications.
A stomach ulcer, also known as a gastric ulcer, is a sore that forms in the lining of the stomach. It's caused by a breakdown in the mucous layer that protects the stomach from digestive juices, allowing acid to come into contact with the stomach lining and cause an ulcer. The most common causes are bacterial infection (usually by Helicobacter pylori) and long-term use of nonsteroidal anti-inflammatory drugs (NSAIDs). Stomach ulcers may cause symptoms such as abdominal pain, bloating, heartburn, and nausea. If left untreated, they can lead to more serious complications like internal bleeding, perforation, or obstruction.
The ileum is the third and final segment of the small intestine, located between the jejunum and the cecum (the beginning of the large intestine). It plays a crucial role in nutrient absorption, particularly for vitamin B12 and bile salts. The ileum is characterized by its thin, lined walls and the presence of Peyer's patches, which are part of the immune system and help surveil for pathogens.
Nasal mucosa