Answers, BIO 2320, Male

Objectives – 4, BIO 2320, Male Reproductive SystemAnswers


1.Suspend the testes outside of the body cavity to provide a cooler temperature for sperm production.


3.Can pull the scrotum closer to the body for testis warmth or further away from the hot body for cooling

4.T. albuginea is white connective tissue surrounding the testis. The seminiferous tubules are tightly coiled tubes that are the sight for sperm production. These straighten out as they carry sperm out of the testis to become straight tubules which finally form a network of tubules, the rete testis and exit the testis to the epididymis. In between the seminiferous tubules are the interstitial cells that make testosterone

5.Spermatogonia are diploid cells that can undergo mitosis to replenish the numbers. Close to 300 million sperm are made each day starting at puberty. The spermatogonium that is destined to become a sperm enlarges to become a primary spermatocyte. It undergoes meiosis I to become a secondary spermatocyte which undergoes meiosis II to become a spermatid. The spermatid is haploid and undergoes spermiogenesis to mature into a spermatozoan (sperm). While testosterone is necessary for this process, the main driving hormone is FSH, released from anterior pituitary gland.

6.Head has nucleus with the 23 chromosomes with a cap called the acrosome that contains enzymes to dissolve through the wall of the egg. The midpiece has numerous mitochondria for energy production and the tail allows motility.

7.Sperm in the ejaculate, sex drive, hair growth at specific sites on the body, muscle enlargement, enlargement of sex organs, lowering voice…

8. GnRH made by hypothalamus is the inciting hormone for puberty. It stimulates the pituitary gland to make FSH which stimulates spermatogenesis and LH which stimulates the interstitial cells to make testosterone. Inhibin, made by the testes, inhibits FSH. Testosterone has negative feedback on LH & GnRH.

9.Head, body, tail. It is a site for sperm maturation & storage.

10.Inguinal canal

11.Vas deferens, testicular A&V, lymphatics, nerves

12.From testes, sperm enter the epididymis, then pass through the vas deferens into the urethra.


14.Prostatic urethra runs through prostate gland, membranous urethra passes from prostate to penis, penile = spongy urethra courses through the penis.

15.Prostate, seminal vesicles, bulbourethral glands contribute to semen. Semen allows a fluid medium for the sperm, provides nutrients for the sperm and is slightly alkaline to neutralize the acid environment in the female’s vagina.

16.The corpus spongiosum in the center surrounds the urethra, the larger & lateral bodies of erectile tissue are the corpora cavernosa.


18.Vascular. Increased blood flow to penis due to Parasympathetic stimulation which fills the erectile tissue and squishes the veins exiting the penis therefore trapping the blood.

19.SNS initiates the orgasm. The emission phase moves sperm to the beginning of urethra and mixes with accessory gland fluids. Ejaculation is the movement of the semen out of penis

20.Sperm plus accessory sex gland fluids, 2.5 -5 mls; 300,000,000 sperm per ejaculate

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