Female hormone

Question 1

What hormones does hypothalamis produce

Answer 1

GnRH
Oxytocin

Question 2

what are the 3 Pituitary hormones

Answer 2

LH
FSH
Prolactin

Question 3

Gonadal hormones in females are

Answer 3

estradiol
progesterone

inhibin
relaxin
testosterone

Question 4

Uterus/placenta hormones in females (about 5)

Answer 4

PGF2a
progesterone
relaxin
chorionic gonadotropins
pacental lactogen

Question 5

What is the HPG axis

Answer 5

hypothalamic pituitary gonadal axis
regulated production of reproductive hormones in both sexes
positive and negative feedback loops (different to males)

Question 6

3 specialised portions in the hypothalamus are:

Answer 6

• surge centre (GnRH)
• Tonic centre (GnRH
• para-ventricular nucleus (secrete oxytocin)

Question 7

Tonic and surge centre: how do these effect patterns of GnRH secretion amounts?

Answer 7

tonic = slow drip GnRH
surge = rapid and fast flood of GnRH
- very important as created a pre-ovulatory LH surge -> trigger for ovulation in females*

Question 8

What is the importance of the surge centre in females for hormones?

Answer 8

Surge centre: rapid release of GnRH
-> very important as created a pre-ovulatory LH surge -> trigger for ovulation in females*

Question 9

What does LH bind to (what cells)

Answer 9

LH binds to theca interna cells to produce testosterone

Question 10

What does FSH bind to in females?

Answer 10

FSH binds to FSH receptors in Granulosa cells, which drives conversion of T to estradiol

Question 11

Role of LH

Answer 11

produce testosterone in theca cells

Question 12

role of FSH

Answer 12

drive conversion of T to estradiol

Question 13

Estrogen verse estradiol

Answer 13

Estradiol (E2) is major estrogen

• sometimes used interchangably
  
  • two other forms of estrogen (Estrone E1 and Estriol E3

Question 14

What does production of estradiol require

Answer 14

2cells and 2 gonadotropins:

• theca and granulosa cells
  
  • LH and FSH

Question 15

Actions of estradiol in the brain

Answer 15

• induced mate seeking behaviour
  
  • makes females receptive to mating

Question 16

actions of estradiol in female tract

Answer 16

• outward signs of receptivity (red, swollen vulva)
• primes tract for mating (mucus etc.)
  
  • prepares for possible pregnancy (uterine glands, tone for transport, cilia/fluid in oviduct)

Question 17

As a whole, what stage is estradiol a key hormone for?

Answer 17

mating

Question 18

What are the 3 important negative feedback loops of HPG axis

Answer 18

Inhibin blocks FSH secretion by AP

E2 blocks FSH secretion by AP

Low E2 and high P4 limits GnRH secretion

Question 19

What is the 1 important positive feedback loop in HPG axis

Answer 19

High E2 (with no P4) promotes a surge of GnRH at a threshold concentration

Question 20

What are the feedback mechanisms important for in the HPG axis?

Answer 20

• Regulate hormone production which is critical for follicle maturation and ovulation

Question 21

LH in corpus luteum: what does LH binding lead to in the corpus luteum?

Answer 21

LH binds to LH receptors in luteal cells → produces progesterone instead of testosterone

Question 22

Actions of progesterone

Answer 22

• Mammary glands
• endometrium development
• myometrium (decreases uterine tone)
• brain (inhibits receptive behaviours)

Question 23

What is progesterone important for in the surge and tonic centre? (think negative)

Answer 23

• in tonic centre = reduced pulse frequency
• In surge centre = blocks surge completely
• thus progesterone will block ovulation if high → no ovulation

Question 24

What happens if progesterone is high

Answer 24

Progesterone will block ovulation, so a corpus luteum needs to degenerate before ovulation can actually occur (because progesterone is produced here by LH*

Question 25

When is oestrogen at its peak??

Answer 25

Just before ovulation → E2 drive GnRH surge which causes LH surge leading to ovulation

Question 26

When do we have a rise in progesterone

Answer 26

after ovulation, a developing CL causes increased P4 to try maintain pregnancy

Question 27

Relationship between LH and estrogen that differs from males relationship between LH and T

Answer 27

* Small pulses of LH and E2 remains low between ovulations (doesn't have a peak straight after LH like T does in males..) * prior to ovulation, E2 peaks due to follicle development, causing GnRH and LH surge

Question 28

What are the 2 cells and 2 gonadotropins involved in producing estradiol

Answer 28

theca interna and granulosa FSH and LH

Question 29

Prostaglandin F2a or PGF2a - what process does this hormone drive?

Answer 29

* Luteolysis - the luteal phase * made by the uterus but has action on CL in the ovary

Question 30

How does prostaglandin F2a hormone go from uterine to ovary

Answer 30

by counter current exchange between the uterine vein and the ovarian artery to get to the CL of the ovary

Question 31

What are chorionic gonadotropins

Answer 31

* gonadotropins produced by placenta * only produced in women (hCG) and mare (eCG/PSMG) * Lh/FSH like activity in other species

Question 32

Where is oxytocin produced and what does it stimulate?

Answer 32

* hypothalamus and ovary in CL * positive feedback loops with PGF2a → drive luteolysis * stimulates contractions during parturition and lactation (milk let down)

Question 33

relaxin - where is it produced and what does it cause

Answer 33

produced by placenta in CL causes softening of pelvic ligaments and cervix for parturition