List the function and anatomy of each of the following:
4) Seminiferous Tubules
6) Vas Deferens
7) Seminal Vesicles
8) Prostate Gland
9) Bulbourethral gland
2) Testicles: The primary functions of the testes are to produce sperm (spermatogenesis) and to produce androgens, primarily testosterone. The presence of both testosterone and follicle-stimulating hormone (FSH) is needed to support spermatogenesis. Contains very fine coiled tubes called seminiferous tubules.
3) Scrotum: : Keep the temperature of the testes slightly lower than that of the rest of the body. The temperature is controlled by the scrotum moving the testicles closer to the abdomen when the ambient temperature is cold, and further away when it is hot.
4) Seminiferous Tubules: located in the testes, and are the specific location of meiosis, and the subsequent creation of gametes, namely spermatozoa.
5) Epididymis: Sperm acquires motility, mature, and are stored. Tightly-coiled tube connecting the efferent ducts from the rear of each testicle to its vas deferens. During ejaculation, sperm flow from the lower portion of the epididymis (which functions as a storage reservoir). They have not been activated by products from the prostate gland, and they are unable to swim, but are transported via the peristaltic action of muscle layers within the vas deferens, and are mixed with the diluting fluids of the seminal vesicles and other accessory glands prior to ejaculation (forming semen).
6) Vas Deferens: Transport sperm from the epididymis in anticipation of ejaculation. During ejaculation the smooth muscle in the walls of the vas deferens contracts reflexively, thus propelling the sperm forward. This is also known as peristalsis.
7) Seminal Vesicles: The seminal vesicles secrete a significant proportion of the fluid that ultimately becomes semen. Lipofuscin granules from dead epithelial cells give the secretion its yellowish color. Seminal vesicle fluid is alkaline, resulting in human semen having a mildly alkaline pH. The alkalinity of semen helps neutralize the acidity of the vaginal tract, prolonging the lifespan of sperm. Acidic ejaculate (pH <7.2) may be associated with Ejaculatory duct obstruction. The vesicle produces a substance that causes the semen to become sticky/jelly-like after ejaculation, which is thought to be useful in keeping the semen near the womb. The thick secretions from the seminal vesicles contain proteins, enzymes, fructose, mucus, vitamin C, flavins, phosphorylcholine and prostaglandins.
8) Prostate Gland: The function of the prostate is to secrete a slightly alkaline fluid, milky or white in appearance, that usually constitutes 20-30% of the volume of the semen along with spermatozoa and seminal vesicle fluid. The alkalinity of semen helps neutralize the acidity of the vaginal tract, prolonging the lifespan of sperm. The alkalinization of semen is primarily accomplished through secretion from the seminal vesicles. The prostatic fluid is expelled in the first ejaculate fractions, together with most of the spermatozoa. In comparison with the few spermatozoa expelled together with mainly seminal vesicular fluid, those expelled in prostatic fluid have better motility, longer survival and better protection of the genetic material (DNA). The prostate also contains some smooth muscles that help expel semen during ejaculation. Prostatic secretions vary among species. They are generally composed of simple sugars and are often slightly alkaline.
9) Bulbourethral gland: During sexual arousal each gland produces a clear, salty, viscous secretion known as pre-ejaculate. This fluid helps to lubricate the urethra for spermatozoa to pass through, neutralizing traces of acidic urine in the urethra, and helps flush out any residual urine or foreign matter. It is possible for this fluid to pick up sperm, remaining in the urethral bulb from previous ejaculations, and carry them out prior to the next ejaculation.