A&P Test 3 Male Reproductive – Review 1. What is the scrotum? What are its three primary functions? -An external sac containing the testes subdivided by a vertical septum -Function: - Regulates temperature of the testes because sperm production & survival requires temperatures ~2-3 ˚C lower than core body -The temperature is further controlled by raising & lower the scrotum 2. What are the testes? Where do they develop and when do they descend? -They develop in the embryo on the posterior(back) abdominal wall. -They descend through the inguinal canals during the 7th month of development 3. Briefly describe the anatomy of the teste. -the testses are divided into a series of internal compartments—called lobules - Each lobule contains 1-3 tightly coiled seminiferous tubules - The seminiferous tubules are lined w/ spermatogenic cells which divide to produce sperm - from the basement to the lumen of the tubule, sperm get progressively more and more mature 4. What is a leydig cell? -these are found in the spaces between the seminiferous tubules(??) and they secrete testosterone 5. What is the epididymis and what is its purpose? -this is comma shaped. It is a long, coiled tube that rests on the top, exterior backside of each testicle. It functions in the transport and storage of the sperm cells and it also brings the sperm to maturity, because the sperm that emerge from the testes are immature and incapable of fertilization. 6. What is the ductus deferens and what is its purpose? -the vas deferens is a long, muscular tube that travels from the epididymis, through the inguinal canal into the pelvic cavity, to just behind the bladder. -stores & transports mature sperm to the urethra in preparation for ejaculation

7. What are the ejaculatory ducts and their purpose? -the ejaculatory ducts are an area, ~ 1 inch long, where the vas deferens & the seminal vesicles -the are located just posterior (below) the bladder & empty into the urethra (before it)

-they function to store sperm just before ejaculation

8. Urethra/purpose? -usually carries urine out of the body but, in males, it has the additional function of expelling (ejaculating) semen when the man reaches orgasm. When the penis is erect during sex, the flow of urine is blocked by a flap, allowing only semen to be ejaculated at orgasm. 9. What are the seminal vesicles? -the seminal vesicles are pouch-like glands that attach to the vas deferens near the base of the bladder & just above the rectum—they produce the majority, ~ 60% of semen’s volume 10. What 4 substances are found in the secretion of the seminal vesicles? What does each do? - fructose, fluid that provides sperm with a source of energy and helps with the sperms’ motility -alkaline fluid, which neutralizes the acidity of the female’s vagina because an acidic environment will kill sperm. -prostaglandis, which: - helps sperm motility (it’s ability to move spontaneously) & propels the sperm forward -Stimulates smooth muscular contractions in the male & female reproductive tracts - Fibrinogen – a clotting protein which temporarily clots the ejaculation, (this allows the group of sperm to stay somewhat together—necessary because just 1 little sperm can’t penetrate the egg all by itself.)

11. What is the prostate gland? What is found in its secretions? - It is located at the base of the bladder around the urethra -it secretes a slightly acidic fluid which: -contributes to sperm motility & viability -makes up 20-30% of semen’s volume

-it contains: -citrate – ionic form of citric acid used to generate ATP -acidic phosphates – function unknown -enzymes –that liquefy coagulated semen

12. What is the bulbourethral gland? What does it secrete? - it is a pea size gland, that is located on either side of the urethra below the prostate gland, -it secretes: -alkaline substance to neutralize acid environment in the males urethra -a mucus that lubricates the glans of the penis 13. What is semen? What is it’s pH? Why does it contain an antibiotic? -semen is composed of a mixture of sperm & seminal fluid---or liquid portion from the seminiferous tubules, seminal vesicles, prostate & bulbourethral glands -it has a pH 7.2 – 7.7 -it also has an antibiotic to kill certain bacteria in both the seminal fluid & vagina fluid 14. Why is a high number of sperm required in semen? -High numbers are required because only a few ever actually reach the egg and additionally, a single sperm cannot dissolve the barrier; it requires the combined action of many sperm

15. What is the penis? Briefly describe the anatomy of the penis. -it is the male copulatory organ, which transfers sperm directly into the female during intercourse -it contains 3 cylindrical portions: -the urethra—carries semen and urine out of the body -the corpora spongiosum(erectile ) - surrounds the urethra & makes up glans of the penis

-the corpora cavernosa– made up of 2(erectile) bodies– dorsum & sides 16. Briefly describe what occurs during an ejaculation. A sympathetic reflex -1st —smooth muscle at the base of the urinary bladder closes and prevents urine from being expelled during the ejaculation -2nd —Peristaltic contractions of the ductus deferens, seminal vesicles & prostate gland to propel semen into the urethra -3rd —muscles at the base of the penis also aid in ejaculation by?

17. What is spermatogenesis? What occurs during the two phases of meiosis? sperm-production; Occurs from puberty til death and occurs in the testis. Meiosis 1: Spermotogenic cells give rise to 2N spermatogonium; Spermatogonium go through meiosis I to produce two 1N 2* spermatocytes; Homologous chromosomes are now in separate cells but chromatids are still attached. Meiosis 2: Chromatids are split into separate cells and get four 1N spermatids; Differentiation: spermatids then aquire an enzyme head(break through females defenses)& flagellum

18. What are the three parts of the sperm and the purpose of each? HEAD: contains the nucleus & the acrosome(enzyme granular on the head)these enzymes are designed to be released and penetrate the oocyte. MIDPIECE: contains mitochondria for the metabolism of ATP FLAGELLUM: for swimming….whipping motion to propel the sperm forward toward the egg. 19. A surge of what hormone must occur during development for a male to develop? Testosterone

20. List the four hormones involved in the male reproductive system and the function of each. 1.) GnRH: functions to stimulate the release of LH & FSH 2.) LH: Stimulates testosterone secretion by Leydig cells

3.) FSH: acts with testosterone to stimulate spermatogenesis 4.) Testosterone: primary male sex hormone, responsible for sex drive, male secondary sexual characteristics, stimulates spermatogenenesis, acts on several other organs: prostate, seminal vesicals.