Male Reproductive Physiology Flashcards
Why are the scrotum situated outside of the abdominal cavity?
Because a lower temperature than abdominal body temp. is required for sperm production
What is the epididymis?
Long coiled tube where sperm produced in the testes is stored and allowed to mature
Located on posterior of testes
Describe the pathway of sperm from formation to ejaculation
- Testes
- Epididymis
- Vas deferens
(combines with seminal & prostate secretions) - Urethra
How are the testes organized anatomically?
- Surrounded by CT sheath called Tunica Albuginea
- Tunica albuginea penetrates into the testes and divides it into several lobules
- Inside each lobule are seminiferous tubules which are the site of sperm production
What are the three segments of the epididymis?
- Head (receives sperm from testes)
- Body
- Tail (joined to the vas deferens)
What are the three types of cell types in the seminiferous tubules? Function of each?
Germ cells - produce sperm
Sertoli / Sustentacular Cells - support sperm production, produce inhibin (located in between germ cell layers)
Interstitial / Leydig Cells - produce testosterone (surround the seminiferous tubules)
What are the two main functions of the testes?
- Sperm production
- Testosterone production
Functions of testosterone?
Development and maintenance of male secondary characteristics
Control spermatogenesis
How long does it take sperm to mature, from production to ejaculation?
About 64 days (3 months)
The time from when a sperm is produced to when it is ejaculated
What are the effects of FSH and LH on the testes?
FSH - stimulates the sertoli cells to increase spermatogenesis
LH - stimulates the Leydig Cells to increase testosterone production
What is the function of inhibin? Where is it produced?
Produced by sertoli cells
Acts to negatively feedback on production of FSH & LH from the anterior pituitary when there is adequate sperm production occurring
What feedback mechanisms is testosterone involved in?
Negative feedback on both the hypothalamus and the anterior pituitary
When there is adequate testosterone it negatively feedbacks to inhibit the release of GnRH, FSH & LH
What is the effect of testosterone on sperm production?
Testosterone stimulates sertoli cells to increase spermatogenesis
What are the two stages of spermatogenesis? Brief description of what occurs during each?
Spermatocytogenesis - clonal expansion and maturation through mitotic and meiotic processes
Spermiogenesis - differentiation into mature sperm cells
How long does the process of spermatogenesis take?
64 days
