Definitions are documented in a counter-clockwise order (from bladder to sigmoid colon).
Bladder: A sac-like organ composed of musculomembranous fiber. Located in the pelvis, the bladder stores urine until it is excreted. The urine is passed to the bladder through ureters from each kidney in peristaltic (contractile) waves. During excretion, the urethral orifice below the bladder is opened and the urine passes through the urethra.
Though the urge to void the bladder of urine generally occurs when it has about 250 – 300 milliliters (8 – 10 ounces) in it, the average human bladder can hold almost twice this amount.
An average human excretes one to two quarts (or one to two liters) of urine per day, though this is greatly dependent upon the health, diet, and level of activity of the adult. Ingested water usually is excreted within four hours of ingestion. Urine is usually clear or yellow, though this depends upon the diet and health of the individual.
Urine has a distinct, ammonia-like smell which is primarily due to the nitrogenous wastes which make up 5 % of the urine. The chief constituent of these wastes is urea, though ammonia, uric acid, creatinine, and a host of other waste products also are present.
Pubic Bone: Part of the skeletal system undreneath the pubic hair area, above the penis.
Penis: The male sex organ that carries urine and semen from the male body, which is capable of erection by becoming engorged with blood during sexual arousal to make it more firm for penetration in sexual intercourse. The penis supports the urethra as it passes from the seminal vesicles, through the corpora cavernosa, to the meatus (opening) at the glans (head) of the penis.
Corpora Cavernosa: Made of spongy tissue which fill with blood during sexual arousal. As the blood fills these tissues, the penis begins to expand and become firm, and this condition is known as an erection. The erection facilitates the ejaculational transport of the semen to the female’s vagina.
Penis Glans: Enlarged tip, or head, of the penis. In its apex is the vertical meatus, or opening, of the urethra.
Foreskin: A loose fold of skin, or prepuce, which covers the glans of the penis. It is often removed from infants for sanitary and religious reasons. The removal of the foreskin is known as circumcision.
Urethra: A tube-like vessel that serves to transport urine and semen, conveying it from the bladder or testes through the penis.
Urethral Opening: The penis opening, or meatus.
Scrotum: The protective skin pouch which contains the testes (testicles). It is located in the groin, on the outside of the abdominal cavity. This positioning allows the testicles to remain at a temperature slightly below body temperature, a critical condition in the development of viable sperm. After puberty, the hair begins to grow on the scrotum and nearby skin. This pubic hair remains for the rest of the adult life.
Testis: (also known as testicle), The main reproductive organ of the male anatomy. They are responsible for generating the sperm cells (spermatozoa) and passing them into the epididymides for storage until ejaculation. The testes are slightly elongated globes, about 1 inch (2.5 cm) wide by 1 1/2 inches (3.8 cm) long. The testes are located outside of the abdominal cavity in a protective pouch of skin called the scrotum. This positioning allows them to remain slightly below body temperature, which is critical for the development of viable spermatozoa.
Epididymides: (plural for epididymis) Narrow, elongated storage vessels for newly generated sperm. They are located within the scrotum, adjoining each testicle. Sperm remain in the cord-like epididymides until ejaculation, at which time they eject them into the vas deferens.
Vas Deferens: The narrow continuation of the canal of the epididymis, serving to transport the sperm cells from the epididymis, up through a canal toward the bladder, and then to the ejaculatory duct.
Anus: The opening where solid waste is excreted.
Cowper’s Glands: (also known as bulbourethral glands) The two pea-sized lobes connecting to the side of the urethra, responsible for secreting a lubricant into the urethra to facilitate the transport of sperm during ejaculation. This lubricant is frequently referred to as “pre-cum” in English slang.
Prostate Gland: Responsible for secreting a fluid into the urethra during sexual arousal. This alkaline fluid comes before the sperm cells and helps reduce the acidity of vaginal secretions, so that the sperm cells are not destroyed by this acidity. The prostate gland is about 1 1/2 inches in diameter.
Ejaculatory Duct: Short tubule located just above the prostate gland. It is formed by the connection of the vas deferens and the seminal vesicles, and serves to transport sperm through the prostate gland and into the urethra.
Seminal Vesicles: Responsible for secreting a fluid component of semen as the sperm cells pass through the vas deferens. The two vesicles resemble small, bulbous pouches and are located just above the prostate gland.
Rectum: One of the last portions of the large intestine, which extends from the sigmoid colon to join the anal canal. Fecal wastes are stored in the rectum until they are expelled by passing them through the anal canal and out of the anus. The rectum is about five inches long,
Sigmoid Colon (spelled as sigismoid colon above): Connects the end of the descending colon to the rectum. The rectal and sigmoid sections are often referred to as the rectosigmoid.