gonads

Question 1

what do gonads develop as in males

Answer 1

testes

Question 2

in males, what gene influences development of testes

Answer 2

SRY gene

Question 3

what do gonads develop as in females

Answer 3

ovaries

Question 4

2 functions of gonads

Answer 4

production of gametes for reproduction (gametogenesis); production of steroid hormones (steroidogenesis)

Question 5

name of gametogenesis in males

Answer 5

spermatogenesis

Question 6

name of gametogenesis in females

Answer 6

oogenesis

Question 7

activation of spermatogonia: when and duration

Answer 7

very high before birth and maintains high levels throughout life as differentiation and self-renewal; begins at puberty

Question 8

activation of oogonia: when and duration

Answer 8

very high before birth; rapid atresia of many primordial follicles before birth; continued atresia through puberty until menopause, when no more cells activated

Question 9

name of degeneration of ovarian follicles which do not ovulate

Answer 9

atresia

Question 10

what hormone “rescues” follicles from atresia

Answer 10

FSH

Question 11

how many oocytes are present at 24 weeks of gestation

Answer 11

maximum of 6 million

Question 12

how many oocytes will mature and reach ovulation

Answer 12

300-400

Question 13

stages of spermatogenesis and number and sex of chromosomes

Answer 13

germ cell → spermatogonia → primary spermatocytes (all 44+XY; diploid) → (1st meiotic division) secondary spermatocytes (2nd meiotic division) → spermatids → spermatozoa (all 22X or 22Y; haploid)

Question 14

stages of oogenesis and number and sex of chromosomes

Answer 14

germ cell → oogonia → primary oocytes (all 44XX; diploid) → (1st meiotic division) secondary oocytes (+ 1st polar body; 2nd meiotic division) → ovum (22X (+22X); haploid; + 2nd polar body)

Question 15

what is a polar body

Answer 15

the other oocyte which doesn’t contain cytoplasm so eventually dies

Question 16

anatomy of testes: where do testes develop

Answer 16

develop in abdomen

Question 17

anatomy of testes: where do testes descend into before birth

Answer 17

descend into scrotum (lower than core temperature)

Question 18

anatomy of testes: what does puberty cause an increase in

Answer 18

testosterone secretion

Question 19

anatomy of testes: where does spermatogenesis occur

Answer 19

coiled seminiferous tubules

Question 20

anatomy of testes: where are spermatozoa collected

Answer 20

rete testis

Question 21

anatomy of testes: what are spermatozoa drained via

Answer 21

vasa efferentia

Question 22

anatomy of testes: where are spermatozoa then stored

Answer 22

epididymis

Question 23

anatomy of testes: what are spermatozoa expelled by to the urethra

Answer 23

vas deferens (surrounded by smooth muscle)

Question 24

cross section of seminiferous tubule

Answer 24

across basement membrane: spermatogonia, leydig cells outside

Question 25

what cells are inside spermatogonia

Answer 25

Sertoli cells

Question 26

function of Sertoli cells

Answer 26

form seminiferous tubules; act as blood-testes barrier so large molecules in blood can’t enter; spermatocytes cross into and are enclosed inside Sertoli cells where they mature

Question 27

what hormonal receptors do Sertoli cells contain

Answer 27

FSH and androgen receptors

Question 28

in response to FSH what do Sertoli cells produce

Answer 28

inhibin and other molecules

Question 29

what is inhibin intimately associated with

Answer 29

developing spermatocytes

Question 30

function of Leydig cells

Answer 30

synthesise LH receptors, and in reponse to LH are principle source of testicular androgens, mainly testosterone

Question 31

why is a close connection between Leydig cells and the seminiferous tubules necessary

Answer 31

spermatogenesis won’t take place without raised level of androgen

Question 32

anatomy of ovaries

Answer 32

Graafian follicles surrounded by follicular fluid; granulosa cells then thecal cells; ovarian stroma

Question 33

what is a Graafian follicle

Answer 33

max size oocyte as most sensitive to FSH

Question 34

what does the Graafian follicle convert to upon ovulation

Answer 34

corpus luteum