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Urethral Fossa
A stallion is an adult male horse that has not been gelded ( castrated). Stallions follow the conformation and phenotype of their breed, but within that standard, the presence of hormones such as testosterone may give stallions a thicker, "cresty" neck, as well as a somewhat more muscular physique as compared to female horses, known as ''mares'', and castrated males, called ''geldings''. Temperament varies widely based on genetics and training, but because of their instincts as herd animals, they may be prone to aggressive behavior, particularly toward other stallions, and thus require careful management by knowledgeable handlers. With proper training and management, stallions are effective equine athletes at the highest levels of many disciplines, including horse racing, horse shows, and international Olympic competition. "Stallion" is also used to refer to males of other equids, including zebras and donkeys. Herd behavior Young female horses usually leave their band an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zebras
Zebras (, ) (subgenus ''Hippotigris'') are African equines with distinctive black-and-white striped Animal coat, coats. There are three Extant taxon, living species: Grévy's zebra (''Equus grevyi''), the plains zebra (''E. quagga''), and the mountain zebra (''E. zebra''). Zebras share the genus ''Equus (genus), Equus'' with Wild horse, horses and Asinus, asses, the three groups being the only living members of the family Equidae. Zebra stripes come in different patterns, unique to each individual. Several theories have been proposed for the function of these patterns, with most evidence supporting them as a deterrent for biting flies. Zebras inhabit East Africa, eastern and southern Africa and can be found in a variety of habitats such as savannahs, grasslands, woodlands, shrublands, and mountainous areas. Zebras are primarily grazing (behaviour), grazers and can subsist on lower-quality vegetation. They are preyed on mainly by lions, and typically flee when threatened but ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erection
An erection (clinically: penile erection or penile tumescence) is a Physiology, physiological phenomenon in which the penis becomes firm, engorged, and enlarged. Penile erection is the result of a complex interaction of psychological, neural, vascular, and endocrine factors, and is often associated with sexual arousal, sexual attraction or libido, although erections can also be spontaneous. The shape, angle, and direction of an erection vary considerably between humans. Physiologically, an erection is required for a male to effect penetration or sexual intercourse and is triggered by the parasympathetic division of the autonomic nervous system, causing the levels of nitric oxide (a vasodilation, vasodilator) to rise in the Trabeculae of corpora cavernosa of penis, trabecular artery, arteries and smooth muscle of the penis. The arteries Vasodilation, dilate causing the Corpus cavernosum penis, corpora cavernosa of the penis (and to a lesser extent the corpus spongiosum) to fill ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retractor Penis Muscle
In some animals, the male penis possesses a muscle enabling retraction into the prepuce. In particular animals The retractor penis muscle occurs in marsupials and carnivorans, but it is absent in humans. A stag's penis forms an S-shaped curve when it is not erect, and is retracted into its preputial sheath by the retractor penis muscle. In Tandonia, the retractor penis inserts at the boundary between the penis and epiphallus.  "Genus summary for ''Tandonia''", last modified 23 May 2010, accessed 2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corpus Cavernosum Penis
A corpus cavernosum penis (singular) (from Latin, characterised by "cavities/ hollows" of the penis, : corpora cavernosa) is one of a pair of sponge-like regions of erectile tissue, which contain most of the blood in the penis of several animals during an erection. It is homologous to the corpus cavernosum clitoridis in the female. Structure The corpora cavernosa are two expandable erectile tissues along the length of the penis, which fill with blood during penile erection. The two corpora cavernosa lie along the penile shaft, from the pubic bones to the head of the penis, where they join. These formations are made of a sponge-like tissue containing trabeculae, irregular blood-filled spaces lined by endothelium and separated by septum of the penis. The male anatomy has no vestibular bulbs, but instead a corpus spongiosum, a smaller region of erectile tissue along the bottom of the penis, which contains the urethra and forms the glans penis. Physiology In some circ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tumescence
Tumescence is the quality or state of being tumescent or swollen. Tumescence usually refers to the normal engorgement with blood ( vascular congestion) of the erectile tissues, marking sexual excitation, and possible readiness for sexual activity. The tumescent sexual organ in males is the penis and in females is the clitoris and other parts of the genitalia like the vestibular bulbs. Arteries in the penis dilate to increase blood volume. Detumescence is the reversal of this process, by which blood leaves the erectile tissue, returning the erectile tissue to the flaccid state. Something that causes an erection is sometimes referred to as a tumefier (tumefyer) or tumescer. See also *Clitoral erection *Erection * Hard flaccid syndrome *Intumescent, a substance that swells up when heated * Priapism * Nocturnal clitoral tumescence *Nocturnal emission *Nocturnal penile tumescence * Sexual swelling *Sleep sex *Swelling (medical) Edema (American English), also spelled oedema (Bri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retractor Muscle Of The Penis
In some animals, the male penis possesses a muscle Muscle is a soft tissue, one of the four basic types of animal tissue. There are three types of muscle tissue in vertebrates: skeletal muscle, cardiac muscle, and smooth muscle. Muscle tissue gives skeletal muscles the ability to muscle contra ... enabling retraction into the prepuce. In particular animals The retractor penis muscle occurs in marsupials and carnivorans, but it is absent in humans. A stag's penis forms an S-shaped curve when it is not erect, and is retracted into its preputial sheath by the retractor penis muscle. In Tandonia, the retractor penis inserts at the boundary between the penis and epiphallus. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Penile Sheath
Almost all mammal penises have foreskins or prepuces. In non-human mammals, the prepuce is sometimes called the penile sheath or preputial sheath. In koalas, the foreskin contains naturally occurring bacteria that play an important role in fertilization. In some bat species, the prepuce contains an erectile tissue structure called the ''accessory corpus cavernosum''. During musth, a male elephant may urinate with the penis still in the sheath, which causes the urine to spray on the hind legs.Sukumar, pp. 100–08. Male dogs and wild dogs have a large and conspicuous penile sheath. In stallions, the retractor penis muscle contracts to retract the stallion's penis into the sheath and relaxes to allow the penis to extend from the sheath. The penile sheath of a male axis deer is elongated and urine-stained. When rubbing trees with their horns, these stags sometimes move the penis back and forth rapidly inside its sheath. Male bison and fallow deer Fallow deer is the co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Penis
A penis (; : penises or penes) is a sex organ through which male and hermaphrodite animals expel semen during copulation (zoology), copulation, and through which male placental mammals and marsupials also Urination, urinate. The term ''penis'' applies to many intromittent organs of vertebrates and invertebrates, but not to all. As an example, the intromittent organ of most Cephalopoda is the hectocotylus, a specialized arm, and male spiders use their pedipalps. Even within the Vertebrata, there are morphological variants with specific terminology, such as Hemipenis, hemipenes. Etymology The word "penis" is taken from the Latin word for "Latin profanity#Synonyms and metaphors, tail". Some derive that from Proto-Indo-European language, Indo-European ''*pesnis'', and the Greek word πέος = "penis" from Indo-European ''*pesos''. Prior to the adoption of the Latin word in English, the penis was referred to as a "yard". The Oxford English Dictionary cites an example of the w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scrotum
In most terrestrial mammals, the scrotum (: scrotums or scrota; possibly from Latin ''scortum'', meaning "hide" or "skin") or scrotal sac is a part of the external male genitalia located at the base of the penis. It consists of a sac of skin containing the external spermatic fascia, testicles, epididymides, and vasa deferentia. The scrotum will usually tighten when exposed to cold temperatures. The scrotum is homologous to the labia majora in females. Structure In regards to humans, the scrotum is a suspended two-chambered sac of skin and muscular tissue containing the testicles and the lower part of the spermatic cords. It is located behind the penis and above the perineum. The perineal raphe is a small, vertical ridge of skin that expands from the anus and runs through the middle of the scrotum front to back. The scrotum is also a distention of the perineum and carries some abdominal tissues into its cavity including the testicular artery, testicular vein, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Testes
A testicle or testis ( testes) is the gonad in all male bilaterians, including humans, and is homologous to the ovary in females. Its primary functions are the production of sperm and the secretion of androgens, primarily testosterone. The release of testosterone is regulated by luteinizing hormone (LH) from the anterior pituitary gland. Sperm production is controlled by follicle-stimulating hormone (FSH) from the anterior pituitary gland and by testosterone produced within the gonads. Structure Appearance Males have two testicles of similar size contained within the scrotum, which is an extension of the abdominal wall. Scrotal asymmetry, in which one testicle extends farther down into the scrotum than the other, is common. This is because of the differences in the vasculature's anatomy. For 85% of men, the right testis hangs lower than the left one. Measurement and volume The volume of the testicle can be estimated by palpating it and comparing it to ellipsoids (an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genitourinary System
The genitourinary system, or urogenital system, are the sex organs of the reproductive system and the organs of the urinary system. These are grouped together because of their proximity to each other, their common embryological origin and the use of common pathways. Because of this, the systems are sometimes imaged together. In placental mammals (including humans), the male urethra goes through and opens into the penis while the female urethra and vagina empty through the vulva. The term "apparatus urogenitalis" was used in '' Nomina Anatomica'' (under splanchnologia) but is not used in the current ''Terminologia Anatomica''. Development The urinary and reproductive organs are developed from the intermediate mesoderm. The permanent organs of the adult are preceded by a set of structures that are purely embryonic and that, with the exception of the ducts, disappear almost entirely before the end of fetal life. These embryonic structures are on either side: the pronephros, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
