Exam 4- Male Reproductive Physiology I

Question 1

from what do sertoli cells originate?

Answer 1

pluripotent coelomic epithelial cells of the gonadal ridge

Question 2

what do sperm originate from?

Answer 2

spermatogonia

Question 3

what do leydig cells originate from?

Answer 3

mesenchyme of gonadal ridge

Question 4

what do leydig/interstitial cells produce?

Answer 4

testosterone

Question 5

what do sertoli/sustentacular cells produce?

Answer 5

anti-mullerian hormone (AMH)/mullerian inhibiting substance (MIS)
inhibin
estrogen
androgen-binding protein (ABP)

Question 6

what gonadotropins/hormones does the hypothalamus produce?

Answer 6

GnRH
LH and FSH
prolactin
oxytocin
vasopressin
estrogen from testosterone via aromatase

Question 7

what areas of the brain are involved in reproduction?

Answer 7

pituitary/hypothalamus

Question 8

what is the tonic center of the hypothalamus?

Answer 8

important in male
small frequent surges of GnRH from hypothalamus induce LH which stimulates production testosterone

Question 9

what is the surge center of the hypothalamus?

Answer 9

important in female
high amplitude surge GnRH leads to large surge LH which leads to ovulation

Question 10

what is puberty?

Answer 10

age at which majority of males in given breed/species/population exhibit sufficient size and libido and produce adequate sperm to produce pregnancies

Question 11

how does testosterone defeminize the hypothalamus?

Answer 11

fetal testes produce
aromatase converts to estradiol
estradiol eliminates surge center
alpha-fetoprotein binds estradiol (gonadal) to prevent from crossing blood-brain barrier

Question 12

what binds to estradiol and prevents it from crossing the blood-brain barrier?

Answer 12

alpha-fetoprotein

Question 13

what does androgen binding protein do?

Answer 13

binds to testosterone
increases concentration testosterone in seminiferous tubules which is necessary for spermatogenesis to occur

Question 14

what are the factors that lead to puberty?

Answer 14

metabolic: major
environmental/social cues
genetics/breed

Question 15

how is puberty inhibited?

Answer 15

GnRH neurons
tonic center only
decreased sensitivity as puberty approaches

Question 16

what increases at puberty?

Answer 16

testosterone
GnRH secretion

Question 17

why do accessory sex glands and cells related to secondary sexual development have testosterone receptors?

Answer 17

have 5-alpha reductase in cells
converts testosterone to dihydrotestosterone (DHT): very potent
both males and females

Question 18

what are the accessory sex glands that develop due to increased testosterone?

Answer 18

ampulla
prostate: body/disseminate parts
vesicular gland
bulbourethral gland

Question 19

what two hormones’ secretion patterns change at puberty?

Answer 19

GnRH and LH

Question 20

how long is the complete cycle of seminiferous epithelium?

Answer 20

60 days

Question 21

what do sertoli cells secrete to control spermatogenesis?

Answer 21

inhibin
estradiol
AMH/MIS

Question 22

what do leydig cells secrete to control spermatogenesis?

Answer 22

testosterone

Question 23

what receptors do leydig cells have?

Answer 23

LH receptors

Question 24

what stimulates the anterior pituitary to release FSH?

Answer 24

GnRH from tonic center

Question 25

why is it necessary to have episodic testosterone levels in the testes?

Answer 25

would have: metabolic overload sustained negative feedback on GnRH neurons (reduced LR and testosterone) sustained negative feedback on FSH

Question 26

what produces androgen-binding protein?

Answer 26

sertoli cells

Question 27

what is needed in the seminiferous tubules to support spermatogenesis?

Answer 27

high concentration testosterone

Question 28

what are the three components of immune privilege?

Answer 28

anatomical physiological immunological

Question 29

what is the immunological component of the immune privilege of the testes?

Answer 29

blood-testis barrier immune cells within interstitial space

Question 30

what can produce antibodies against sperm and where are the antibodies found?

Answer 30

accessory sex glands seminal fluid

Question 31

what develops without estradiol in the brain?

Answer 31

surge center

Question 32

what produces alpha-fetoprotein?

Answer 32

fetal liver

Question 33

how do GnRH neurons inhibit puberty?

Answer 33

have increased sensitivity to negative feedback of testosterone

Question 34

how does luteinizing hormone impact testosterone?

Answer 34

increases its secretion from leydig/interstitial cells in testes

Question 35

what are the substances that interfere with GnRH/LH?

Answer 35

GnRH vaccine LHRH agaonists LHRH antagonists

Question 36

what is involved in developing secondary sex characteristics?

Answer 36

dihydrotestosterone

Question 37

why is luteinizing hormone not secreted for hours, instead of minutes?

Answer 37

would result in: metabolic overload sustained negative feedback on GNRH neurons in hypothalamus (reduced LH and testosterone secretion) sustained negative feedback on FSH

Question 38

what are the components of the physiological component of immune privilege in the testes?

Answer 38

specialized transport systems testosterone is immunosuppression within interstitial space

Question 39

what converts testosterone to dihydrotestosterone?

Answer 39

5-alpha reductase