Penis: The external reproductive organ of males. It is composed of a mass of erectile tissue enclosed in three cylindrical fibrous compartments. Two of the three compartments, the corpus cavernosa, are placed side-by-side along the upper part of the organ. The third compartment below, the corpus spongiosum, houses the urethra.Vertebrates: Animals having a vertebral column, members of the phylum Chordata, subphylum Craniata comprising mammals, birds, reptiles, amphibians, and fishes.Penile Neoplasms: Cancers or tumors of the PENIS or of its component tissues.Penile Erection: The state of the PENIS when the erectile tissue becomes filled or swollen (tumid) with BLOOD and causes the penis to become rigid and elevated. It is a complex process involving CENTRAL NERVOUS SYSTEM; PERIPHERAL NERVOUS SYSTEMS; HORMONES; SMOOTH MUSCLES; and vascular functions.Erectile Dysfunction: The inability in the male to have a PENILE ERECTION due to psychological or organ dysfunction.Zebrafish: An exotic species of the family CYPRINIDAE, originally from Asia, that has been introduced in North America. They are used in embryological studies and to study the effects of certain chemicals on development.Clitoris: An erectile structure homologous with the penis, situated beneath the anterior labial commissure, partially hidden between the anterior ends of the labia minora.Penile Induration: A condition characterized by hardening of the PENIS due to the formation of fibrous plaques on the dorsolateral aspect of the PENIS, usually involving the membrane (tunica albuginea) surrounding the erectile tissue (corpus cavernosum penis). This may eventually cause a painful deformity of the shaft or constriction of the urethra, or both.Balanitis: Inflammation of the head of the PENIS, glans penis.Priapism: A prolonged painful erection that may lasts hours and is not associated with sexual activity. It is seen in patients with SICKLE CELL ANEMIA, advanced malignancy, spinal trauma; and certain drug treatments.Scrotum: A cutaneous pouch of skin containing the testicles and spermatic cords.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Gene Expression Regulation, Developmental: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action during the developmental stages of an organism.Evolution, Molecular: The process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.Penile Prosthesis: Rigid, semi-rigid, or inflatable cylindric hydraulic devices, with either combined or separate reservoir and pumping systems, implanted for the surgical treatment of organic ERECTILE DYSFUNCTION.Chordata, Nonvertebrate: A portion of the animal phylum Chordata comprised of the subphyla CEPHALOCHORDATA; UROCHORDATA, and HYPEROTRETI, but not including the Vertebrata (VERTEBRATES). It includes nonvertebrate animals having a NOTOCHORD during some developmental stage.Zebrafish Proteins: Proteins obtained from the ZEBRAFISH. Many of the proteins in this species have been the subject of studies involving basic embryological development (EMBRYOLOGY).Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Embryo, Nonmammalian: The developmental entity of a fertilized egg (ZYGOTE) in animal species other than MAMMALS. For chickens, use CHICK EMBRYO.Urologic Surgical Procedures, Male: Surgery performed on the male genitalia.Genitalia, Male: The male reproductive organs. They are divided into the external organs (PENIS; SCROTUM;and URETHRA) and the internal organs (TESTIS; EPIDIDYMIS; VAS DEFERENS; SEMINAL VESICLES; EJACULATORY DUCTS; PROSTATE; and BULBOURETHRAL GLANDS).Circumcision, Male: Excision of the prepuce of the penis (FORESKIN) or part of it.Fishes: A group of cold-blooded, aquatic vertebrates having gills, fins, a cartilaginous or bony endoskeleton, and elongated bodies covered with scales.Body Patterning: The processes occurring in early development that direct morphogenesis. They specify the body plan ensuring that cells will proceed to differentiate, grow, and diversify in size and shape at the correct relative positions. Included are axial patterning, segmentation, compartment specification, limb position, organ boundary patterning, blood vessel patterning, etc.Biological Evolution: The process of cumulative change over successive generations through which organisms acquire their distinguishing morphological and physiological characteristics.Lampreys: Common name for the only family (Petromyzontidae) of eellike fish in the order Petromyzontiformes. They are jawless but have a sucking mouth with horny teeth.Tuberculosis, Male Genital: MYCOBACTERIUM infections of the male reproductive tract (GENITALIA, MALE).Copulation: Sexual union of a male and a female in non-human species.Hagfishes: Common name for a family of eel-shaped jawless fishes (Myxinidae), the only family in the order MYXINIFORMES. They are not true vertebrates.Hypospadias: A birth defect due to malformation of the URETHRA in which the urethral opening is below its normal location. In the male, the malformed urethra generally opens on the ventral surface of the PENIS or on the PERINEUM. In the female, the malformed urethral opening is in the VAGINA.Reptiles: Cold-blooded, air-breathing VERTEBRATES belonging to the class Reptilia, usually covered with external scales or bony plates.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Invertebrates: Animals that have no spinal column.Penile Implantation: Surgical insertion of cylindric hydraulic devices for the treatment of organic ERECTILE DYSFUNCTION.Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.Genitalia: The external and internal organs related to reproduction.In Situ Hybridization: A technique that localizes specific nucleic acid sequences within intact chromosomes, eukaryotic cells, or bacterial cells through the use of specific nucleic acid-labeled probes.Xenopus Proteins: Proteins obtained from various species of Xenopus. Included here are proteins from the African clawed frog (XENOPUS LAEVIS). Many of these proteins have been the subject of scientific investigations in the area of MORPHOGENESIS and development.Genital Diseases, Male: Pathological processes involving the male reproductive tract (GENITALIA, MALE).Sequence Alignment: The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.Conserved Sequence: A sequence of amino acids in a polypeptide or of nucleotides in DNA or RNA that is similar across multiple species. A known set of conserved sequences is represented by a CONSENSUS SEQUENCE. AMINO ACID MOTIFS are often composed of conserved sequences.Species Specificity: The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.Amphibians: VERTEBRATES belonging to the class amphibia such as frogs, toads, newts and salamanders that live in a semiaquatic environment.Chordata: Phylum in the domain Eukarya, comprised of animals either with fully developed backbones (VERTEBRATES), or those with notochords only during some developmental stage (CHORDATA, NONVERTEBRATE).Homeodomain Proteins: Proteins encoded by homeobox genes (GENES, HOMEOBOX) that exhibit structural similarity to certain prokaryotic and eukaryotic DNA-binding proteins. Homeodomain proteins are involved in the control of gene expression during morphogenesis and development (GENE EXPRESSION REGULATION, DEVELOPMENTAL).Urethra: A tube that transports URINE from the URINARY BLADDER to the outside of the body in both the sexes. It also has a reproductive function in the male by providing a passage for SPERM.Pubic Symphysis: A slightly movable cartilaginous joint which occurs between the pubic bones.Encyclopedias as Topic: 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)Urethral Neoplasms: Cancer or tumors of the URETHRA. Benign epithelial tumors of the urethra usually consist of squamous and transitional cells. Primary urethral carcinomas are rare and typically of squamous cells. Urethral carcinoma is the only urological malignancy that is more common in females than in males.Urinary Bladder: A musculomembranous sac along the URINARY TRACT. URINE flows from the KIDNEYS into the bladder via the ureters (URETER), and is held there until URINATION.Pudendal Nerve: A nerve which originates in the sacral spinal cord (S2 to S4) and innervates the PERINEUM, the external GENITALIA, the external ANAL SPHINCTER and the external urethral sphincter. It has three major branches: the perineal nerve, inferior anal nerves, and the dorsal nerve of penis or clitoris.
  • For the symbol of the erect penis, see phallus . (wikidoc.org)
  • According to a study published on assessing the phallic sizes, it was pointed out that an average flaccid length is 8.8 cm (3.5 inches), average erect length is between 12.9 and 15 cm (5-6 inches) and the average circumference of the erect penis is 12.3 cm (4.75 inches). (boldsky.com)
  • During this process, the erect penis of the male is inserted into the female's vagina until the male ejaculates semen, which contains sperm, into the female's vagina. (ucoz.com)
  • It is put on a man's erect penis and physically blocks ejaculated semen from entering the body of a sexual partner. (manaa.org)
  • Halata & Spathe (1997) reported that "the glans penis contains a predominance of free nerve endings, numerous genital end bulbs and rarely Pacinian and Ruffinian corpuscles. (wikipedia.org)
  • The urethral plate epithelium extends to the distal tip of the genital tubercle where, in the clitoris, it persists as an epithelial cord or, in the penis, it canalizes to form a urethral tube. (biologists.org)
  • The results confirmed that the social milieu of ducks can have a profound effect on their genital growth: Dominant male ducks grow larger penises when they have mating competition. (mtholyoke.edu)
  • Her current research includes investigating genital evolution in vertebrates, and genital and sperm traits in ducks. (mtholyoke.edu)
  • RICHARD PRUM is an evolutionary ornithologist at Yale University, where he is the Curator of Ornithology and Head Curator of Vertebrate Zoology in the Yale Peabody Museum of Natural History. (edge.org)
  • The Latin word " phallus " (from Greek φαλλος) is sometimes used to describe the penis, although "phallus" originally was used to describe images , pictorial or carved, of the penis. (wikidoc.org)
  • We used high-speed video of phallus eversion and histology to describe for the first time the functional morphology of the avian penis. (royalsocietypublishing.org)
  • Resurrecting embryos of the tuatara, Sphenodon punctatus, to resolve vertebrate phallus evolution. (seenthis.net)
  • The reproductive system of the copperhead is very similar in structure and function to the various other classes, with the exception of the hemipenes, which is analogous to the phallus in the Canvasback Duck and the penis in other taxa. (murraystate.edu)
  • In humans, offspring normally receive two pairs of X chromosomes or an X and a Y. The presence of a Y chromosome releases a hormone telling the body to develop a penis and testes (and so on) instead of a vagina and ovaries. (gizmodo.com.au)
  • The complexity of sacs and spirals in the waterfowl vagina has been found to be linked to the male penis length amongst the 14 species of ducks and geese investigated by the team, pointing to a war between the sexes in controlling mating. (incrediblebirds.com)
  • Beyond the four biological functions of reproduction, a lot of people utilize their intercourse organs (penis, vagina) to state their attraction to or love for a intimate or intimate partner. (digitalkal.com)
  • In this case, in these species, the female has evolved a vagina that has dead end cul-de-sacs, so that if the penis goes down the wrong direction it'll get bottled up and doesn't perceive to be closer to the oviduct, or further up the oviduct and closer to ova. (edge.org)
  • And they're right to be: as Brennan says, no other biological structures have co-evolved as closely as the vagina and the penis. (aeon.co)
  • Androgen receptors happen in many various vertebrate overall body technique tissues, and both of those males and females react equally to related levels. (dsiblogger.com)
  • The outer epithelium has the protective function of internalising the glans (clitoris and penis), urethral meatus (in the male) and the inner preputial epithelium, thus decreasing external irritation or contamination. (cirp.org)
  • it's in a basement and the smell really is chokingly pungent, meaning Rob doesn't get many visitors), the ramifications of this study have been wide, casting doubt on the interpretations of many early vertebrates. (science20.com)
  • External fertilization seems to be most common in early vertebrates, while internal fertilization using an intermittent organ such as the hemepenes in the copperhead seems more prevalent in later vertebrates. (murraystate.edu)
  • B. The cavity lying at the upper end of the alimentary canal, bounded on the outside by the lips and inside by the oropharynx and containing in higher vertebrates the tongue, gums, and teeth. (healthtap.com)
  • It emphasizes that the study, which focuses primarily on animals, is also relevant for humans, because "All vertebrates have similar sex hormone receptors. (findingdulcinea.com)
  • Introduction: Myiasis is an infestation of live humans and vertebrate animals with dipterous larvae which, at least for a certain period, feed on the host's dead or living tissues, liquid substances, or ingested food. (ebscohost.com)
  • Placoderms have previously been found to be the most primitive jawed animal - the earliest known vertebrate forerunner of humans. (news24.com)
  • The hormone functions as a vasoconstrictor, which causes a flaccid penis. (boldsky.com)
  • In general, reptiles are lung-breathing vertebrates with two pairs of limbs and a horny, scaly skin. (encyclopedia.com)
  • Reptiles (phylum Chordata, subphylum Vertebrata, superclass Tetrapoda, class Reptilia) are vertebrates (animals with a backbone and a hollow tube of nervous tissue called a spinal cord) characterised by their limited physiological means to maintain the body temperature within a narrow range, and their ability to produce water-tight eggs. (blogspot.co.nz)
  • It is moulded on the rounded ends of the corpora cavernosa penis, extending farther on their upper than on their lower surfaces. (wikipedia.org)
  • A lack of regular sexual activity can cause the penis to shrink, that is, the smooth muscle, elastin, and other tissues within the penis may be affected. (boldsky.com)
  • It contains columns of tissue that cause the penis to become firm and erect when stimulated. (britannica.com)
  • During sex, the blood circulation is temporarily trapped and increased in your penis so that it becomes increased and elevated, an ailment referred to as erection. (digitalkal.com)
  • If you think that depression helps maintain an erection of the penis to maintain it. (asianave.com)
  • Squamate hemipenes also develop from a different cell origin, originating from the same embryonic cells that produce the limbs, whereas mammalian penises arise from the embryonic cells that develop the tail. (wikipedia.org)
  • A look at the embryonic underpinning of hemipenes and penises of other animals suggests that there are fundamental differences in their developmental stages, particularly their origin of development relative to the embryonic cloaca . (wikipedia.org)
  • Together, the two penises of squamates (snakes and lizards) are called hemipenes, and each individually is called a hemipenis. (blogspot.com)
  • Hi, androgen is a steroid hormone that stimulates the development and maintenance of masculine characteristics in vertebrates. (steadyhealth.com)
  • Testosterone and the classical nuclear androgen receptor first appeared in gnathostomes (jawed vertebrates). (vascuwavetreatment.com)
  • Androgen is the generic term for any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of masculine characteristics in vertebrates by binding to androgen receptors. (t-vox.org)
  • Nervous tissue is the fourth major class of vertebrate tissue. (statemaster.com)
  • The hypodermis , also called the hypoderm , subcutaneous tissue , or superficial fascia is the lowermost layer of the integumentary system in vertebrates . (thefullwiki.org)
  • A layer of tissue that lies immediately below the dermis of vertebrate skin. (thefullwiki.org)
  • noun The dense, semirigid, porous, calcified connective tissue forming the major portion of the skeleton of most vertebrates. (wordnik.com)
  • noun An animal tissue, consisting of branching cells lying in an intercellular substance made hard with earthy salts (consisting of calcium phosphate with small amounts of calcium carbonate and magnesium phosphate, etc.), and forming the substance of the skeleton or hard framework of the body of most vertebrate animals. (wordnik.com)
  • The circumference of the base of the glans forms a rounded projecting border, the corona glandis, overhanging a deep retroglandular sulcus (the coronal sulcus), behind which is the neck of the penis. (wikipedia.org)
  • This theory proposes that the single unpaired penis is the ancestral state for amniotes, and that this trait was retained by most amniotes today. (wikipedia.org)
  • Amniotes include nearly all of the large plant- and flesh-eating vertebrates on land today, and they live all over the planet in virtually every habitat. (tolweb.org)
  • The nondistensible penis of ascothoracidans is a less-extensive modification of the seventh pair of trunk limbs seen in more primitive crustaceans. (britannica.com)
  • Ducks' penises are very bizarre: beside a great variation a half-inch (1.2 cm) to 17 inches long, they are extremely variable in shape, from smooth to covered with spines, grooves and variably curled. (incrediblebirds.com)
  • For example, the penis of ducks is counter-clockwise coiled and often has ridges or even teeth-like structures on the outside. (edge.org)