Question

Follow some sperm cells from the testes through the length of the male reproductive tract. Describe how the sperm cells change along the way. Describe how different glandular structures contribute their secretions to seminal fluid and what the functions of those secretions are.

Answer 1

To fertilize an egg, sperm must be moved from the seminiferous tubules in the testes, through the epididymis, and later during ejaculation along the length of the male reproductive tract.From the lumen of the seminiferous tubules, the immotile sperm are surrounded by testicular fluid and moved to the epididymis a coiled tube attached to the testis where newly formed sperm continue to mature . It takes an average of 12 days for sperm to move through the coils of the epididymis. Sperm enter the head of the epididymis and are moved along predominantly by the contraction of smooth muscles lining the epididymal tubes. As they are moved along the length of the epididymis, the sperm further mature and acquire the ability to move under their own power. The more mature sperm are then stored in the tail of the epididymis until ejaculation occurs.During ejaculation, sperm exit the tail of the epididymis and are pushed by smooth muscle contraction to the ductus deferens. The ductus deferens is a thick, muscular tube that is bundled together inside the the external sac of skin that encloses the testes with connective tissue, blood vessels, and nerves into a structure called the spermatic cord.As sperm pass through the ampulla of the ductus deferens at ejaculation, they mix with fluid from the associated seminal vesicle.

The fluid, now containing both sperm and seminal vesicle secretions, next moves into the associated ejaculatory duct, a short structure formed from the ampulla of the ductus deferens and the duct of the seminal vesicle. The paired ejaculatory ducts transport the seminal fluid into the next structure, the prostate gland.the prostate is formed of both muscular and glandular tissues. It excretes an alkaline, milky fluid to the passing seminal fluid now called semen that is critical to first coagulate and then decoagulate the semen following ejaculation. The temporary thickening of semen helps retain it within the female reproductive tract, providing time for sperm to utilize the fructose provided by seminal vesicle secretions. When the semen regains its fluid state, sperm can then pass farther into the female reproductive tract.The final addition to semen is made by two bulbourethral glands that release a thick, salty fluid that lubricates the end of the urethra , and helps to clean urine residues from the penile urethra.