PHYS-Male Repro Physiology

Question 1

How do testosterone levels fluctuate from the fetal period to puberty and old age?

Answer 1

theres a surge in the fetal period for sex differentiation

another neonatal surge because the cells are differentiating

final puberty surge that causes puberty and that gradually declines till you die

Question 2

what happens at puberty to start the production of sex androgens?

Answer 2

there is a pulsatile secretion of GnRH resulting in a pulsatile secretion of FSH/LH that results in testosterone production

Question 3

what happens if the secretion of GnRH is continuous rather than pulsatile?

Answer 3

the constant production of sex androgen inhibits the cycle via negative feedback decreasing LH/FSH and testosterone

Question 4

what stimulates leydig cells? what is their function once stimulated?

Answer 4

LH stimulates –> leydig –> testosterone production from cholesterol

Question 5

where do leydig cells get their cholesterol?

Answer 5

de novo or from circulation

Question 6

what stimulates sertoli cells?

Answer 6

FSH –> sertoli cells –> spermatogenesis along with

several endocrine and exocrine and maintenance functions

Question 7

what are the endocrine functions of sertoli cells?

Answer 7

secretes AMH, inhibin, and aromatase

Question 8

what are the exocrine functions of sertoli cells?

Answer 8

aqueous fluid for sperms transport to the epididymis

produce androgen binding protein

Question 9

what is the function of androgen binding protein?

Answer 9

binds and concentrates testosterone in the sertoli cells

Question 10

what are the supportive functions of the sertoli cells?

Answer 10

prodvide nutrients for sperm and form tight junction to prevent autoimmunity

Question 11

what are the steps of spermatogenesis starting with a spermatogonia?

Answer 11

spermatogonia –> mitosis –> primary spermatocyte –> meiosis I –> secondary spermatocyte –> meiosis II –> spermatids –> nuclear and cytoplasmic changes –> spermatogonia (mature sperm(

Question 12

what are the parts of sperm? what does each part do?

Answer 12

head-contains nucleus and acrosome

tail-motility

Question 13

what is the function of the acrosome?

Answer 13

contains hyaluronidase and proteolytic enzymes to breakdown the outer layer of egg

Question 14

what does the tail contain to make it motile?

Answer 14

axoneme, mitochondria, dynein ATPase

Question 15

what is the ideal sperm environment? life span?

Answer 15

alkalina, lower than body temp, 1-2 months

Question 16

what is the pathway of sperm from creation through ejaculation?

Answer 16

seminiferous tubule –> epididymis –> vas deferens –> ejaculatory duct –> nothing (hangs out for awhile –> urethra –> penis

Question 17

what is the function of the epididymis?

Answer 17

store sperm, educate them on motility, mature sperm

“decapitation” to prevent premature acrosome activation

Question 18

what is the function of the vas deferens?

Answer 18

sperm storage in ampulla till sex

secretes fructose and citrate to nourish sperm

Question 19

what is the function of the seminal vesicle?

Answer 19

to secrete the fluid part of semen composed of fructose, prostaglandins, and citrate important for fertilization

Question 20

what is the function of the ejaculatory duct?

Answer 20

empty sperm into prostatic urethra and stores it until ejaculation

Question 21

what is the function of the prostate?

Answer 21

secrete an alkaline fluid

helps promote motility and neutralizes acid to help with fertilization

Question 22

what is the function of the bulbourethral glands?

Answer 22

secrete clear fluid to lubricate urethra

Question 23

what is the main component of sperm? what else is there?

Answer 23

fluid from seminal vesicle 60% (SEMINal vesicle makes semen)

alkaline prostate fluid 30%
10% sperm
some bulbourethral gland fluid

Question 24

what are the two negative feedback loops in the HPT axis?

Answer 24

testosterone from leydig inhibiting GnRH and FSH/LH release

inhibin from sertoli inhibiting GnRH and FSH/LH

Question 25

what hormones are required for spermatogenesis?

Answer 25

``` testosterone (via LH) FSH GH estrogens DHT plays a little role i think ```

Question 26

what is the potency order of male androgens?

Answer 26

DHT>testosterone>androstenedione

Question 27

LH kicks off testosterone production by upregulating what enzyme where?

Answer 27

cholesterol desmolase in the leydig cells

Question 28

what converts testosterone to DHT in target tissues?

Answer 28

5a reductase

Question 29

what is the function of GnRH

Answer 29

release FSH/LH from anterior pituitary

Question 30

what is the function of LH?

Answer 30

LH --> leydig --> testosterone

Question 31

what is the function of FSH?

Answer 31

FSH --> sertoli --> spermatogenesis

Question 32

what is the function of testosterone early on?

Answer 32

development of internal male genitalia | descent of testes

Question 33

what is the function of testosterone during puberty?

Answer 33

secondary sex characteristics | acts on sertoli cells to assist with spermatogenesis

Question 34

what are the secondary sex characteristics brought on by testosterone?

Answer 34

``` growth closure of epiphyseal plates muscle growth deepening of voice pubic/armpit hair libido penis growth increased BMR increased RBCs ```

Question 35

what is the function of DHT early on?

Answer 35

development of male external genitalia

Question 36

what is the function of DHT during puberty and beyond?

Answer 36

sebaceous gland, prostate growth, male pattern baldness

Question 37

a male comes in with c/o baldness and dysuria due to an enlarged prostate. what should you give em?

Answer 37

a 5a reductase inhibitor (finasteride)

Question 38

what is the function of inhibin

Answer 38

produced by sertoli cells to inhibit FSH/LH/GnRH

Question 39

what is the function of AMH

Answer 39

regression of mullarian duct during development

Question 40

what is the function of estradiol?

Answer 40

bone maturation, growth, breasts, role in spermatogenesis

Question 41

what nervous system and nerve are responsible for erection?

Answer 41

parasympathetic via pelvic splanchnic nerves --> inferior hypogastric plexus --> prostate subplexus nerves

Question 42

what substances are released and how do these cause an erection?

Answer 42

ACh, NO, VIP --> increase cGMP --> smooth muscle relaxation --> vasodilation in helicine arteries --> engorgement cuts off venous return --> boner

Question 43

what nervous system/nerves are involved in emission?

Answer 43

sympathetic via pudendal nerve

Question 44

what is emission?

Answer 44

movement of semen towards internal urethra via smooth muscle contractions

Question 45

what nervous system is involved in ejaculation?

Answer 45

sympathetic via pudendal nerve

Question 46

what occurs during the process of ejaculation?

Answer 46

rythmic contractions of bulbospongiosus and ischiocavernosus muscles increases pressure forcing semen out

Question 47

what causes erectile dysfunction? how would you treat this?

Answer 47

HTN, DM, atherosclerosis a phosphodiesterase inhibitor --> increases cGMP normally phosphodiesterase breaks down cGMP

Question 48

what is a cause of primary hypogonadism? where is the problem arising? what are testosterone, FSH, LH, and estrogen levels? what are symptoms?

Answer 48

Klinefelter syndrome XXY the testes are inadequate at producing testosterone low testosterone, high FSH/LH, high estrogen woman features, boobs, fat around hips, reduced hair seminiferous tubule dysgenesis

Question 49

what is a cause of secondary hypogonadism? where is the problem arising? what are testosterone, FSH, LH, GnRH levels? what are symptoms?

Answer 49

nonfunctioning pituitary tumor anterior pituitary low, low, low, high bitemporal hemianopia (loss of vision in lateral fields), HA

Question 50

what is a cause of secondary (but actually tertiary based off endocrine) hypogonadism? where is the problem arising? what are testosterone, FSH, LH, GnRH levels? what are symptoms?

Answer 50

GnHR neurons fail to migrate to hypothalamus during development hypothalamus low low low low delayed/absent puberty, infertility

Question 51

what causes enlarged prostate? sx? treatment?

Answer 51

DTH and age urinary issues 5a reductase inhibitor inhibits testosterone --> DHT