L24 - hormones and reproduction

Question 1

where are seminiferous tubules located

Answer 1

testes

Question 2

what occurs in seminiferous tubules

Answer 2

sperm production

Question 3

what is found in spaces between seminiferous tubules

Answer 3

blood vessels
nerve tracks
leydig cells

Question 4

what stimulates legdig cells

Answer 4

LH

Question 5

what cells are found in seminiferous tubules

Answer 5

sertoli cells (large)
spermatogonium (smaller in clusters)

Question 6

function of FSH

Answer 6

stimulates gamete production (sperm/egg)

Question 7

function of LH

Answer 7

stimulates production of steroid hormones

Question 8

name the sex steroid hormones

Answer 8

androgens
oestrogens
progesterones

Question 9

how do the steroid hormones generally bring about their effect

Answer 9

cross membrane and bind to intracellular receptors - alter gene transcription

Question 10

function of androgens

Answer 10

male reproductive characteristics

Question 11

what is the main androgen

Answer 11

testosterone

Question 12

where are androgens synthesised and released from

Answer 12

testes and adrenal gland

Question 13

function of oestrogens

Answer 13

female reproductive hormones

Question 14

main oestrogen

Answer 14

oestradiol

Question 15

where are oestrogens synthesised and released

Answer 15

mainly synthesised from androgens and released rom ovaries

Question 16

function of progestogens 
main progestogen

Answer 16

involved in menstrual cycle and pregnancy

progesterone

Question 17

explain HPG axis (female)

Answer 17

1. hypothalamus releases GGnRH to anterior pituitary
2. anterior pituitary releases FSH and LH
3. FSH and LH act on gonads to produce gametes and steroid hormones
4. steroid hormones have -ve feedback on AP and H

Question 18

explain male HPG axis

Answer 18

1. hypothalamus GnRH
2. anterior pituitary LH, FSH
3. LH stimulates leydig cells to produce and release testosterone
4. FSH & testosterone stimulate spermatogenesis
5. FSH regulates spermatogenesis by acting on sertoli cells

Question 19

in what cells does spermatogenesis occur

Answer 19

spermatogonial cells

Question 20

function of sertoli cells

Answer 20

support, nutrition, protection, regulation

Question 21

name the 3 phases of the menstrual cycle and the times they occur

Answer 21

1. follicular phase (day 1-10)
2. ovulatory phase (day 11-14)
3. luteal phase (12-28)

Question 22

what initiates and regulates the menstrual cycle

Answer 22

changes in levels of LH, FSH, oestradiol, progesterone

Question 23

describe follicular phase

Answer 23

1. FSH stimulates follicle growth

2. theca and granulosa cells (that surround follicle) stimulated by LH to release oestradiol

Question 24

how many follicles make it do day 10 and why

Answer 24

1

competition for FSH

Question 25

describe ovulatory phase

Answer 25

1. when oestradiol levels high enough it stimulates LH causing LH surge 2. LH surge triggers ovulation

Question 26

what does LH surge trigger

Answer 26

ovulation

Question 27

explain relationship between oestradiol and LH

Answer 27

normally oestradiol inhibits LH (-ve feedback) but when levels are high enough it causes LH surge

Question 28

describe luteal phase

Answer 28

1. oocyte released - remaining follicle becomes corpus luteum 2. corpus luteum releases oestradiol and progesterone to prepare for possible pregnancy 3. no pregnancy = corpus luteum degenerates

Question 29

what does corpus luteum release and why

Answer 29

oestradiol and progesterone to prepare for possible pregnancy

Question 30

what happens to corpus luteum if no pregnancy

Answer 30

degenerates

Question 31

where is oestradiol released from and how

Answer 31

LH stimulates theca and granulosa cells (that surround follicle) to release oestradiol

Question 32

what stimulates spermatogenesis

Answer 32

FSH and testosterone

Question 33

describe ovaries appearance

Answer 33

follicles surrounded by connective tissue and stroma

Question 34

what is in the centre of an ovary follicle

Answer 34

oocyte