Lecture 28: Male Reproductive Physiology

Question 1

Discuss the formation and maturation of sperm

Answer 1

goes from spermatagonia to spermatid to spermatazoon. cycle takes 72 days. has acrosome (head) with enzymes to penetrate zona pellucida

Question 2

Describe the function of Sertoli cells, Leydig cells, and Androgen binding protein

Answer 2

Sertoli cells help sperm mature before they go to the epididymis for further maturation. FSH acts here indirectly
Leydig cells are acted on by luteinizing hormone, act to produce testosterone
androgen binding protein: binds to testosterone to prevent it from leaving seminiferous tubule. this enables spermatogenesis

Question 3

Explain how erection and ejaculation occurs

Answer 3

Erection is parasympathetic inputs from the pelvic nerve. Blood leaks through sinusoids fills cavities. cGMP produced by guanylyl cyclase promotes vasodilation

ejaculation occurs via sympathetic inputs from the pudendal nerve and hypogastric nerve. hypogastric pushes it through vas deferens to ejaculatory duct, pudendal pushes it through urethra

Question 4

Describe the hormonal regulation of sexual maturation and testicular feedback

Answer 4

testosterone feeds back onto both ant pit and hypothalamus to reduce hormone release. sertoli cells also release inhibin that acts at the anterior pituitary

testosterone comes from pregnenolone
DHT (dihydroxytestosterone) promotes sexual maturation
slow bursts of GnRH results in FSH, fast bursts leads to LH

Question 5

What are the 3 functions of testes?

Answer 5

spermatogenesis, produce semen, maintain secondary sex characteristics