5 - sex hormone physiology

Question 1

what is sex hormone axis?

Answer 1

hypothalamus stimulated by kisspeptin to release pulses of gonadotropin releasing hormone (GnRH) →anterior pituitary releases LH & FSH →gonads release testosterone or oestrogen

Question 2

what is GnRH? what frequency stimulates which hormone?

Answer 2

GnRH = gonadotrophin releasing hormone

• high frequency = LH
• low frequency = FSH

Question 3

briefly describe hormone in menstrual cycle?

Answer 3

1. FSH stimulates growth of follicles
2. rising oestrogen exert negative feedback to temporarily lower FSH
3. oestrogen reaches certain threshold & causes pulsatility GnRH to make surge of LH
4. LH surge causes ovulation & regulates corpus luteum
5. progesterone made by corpus luteum

Question 4

what cells change to make corpus luteum?

Answer 4

granulosa + theca cells transform to luteal cells

Question 5

what are oestrogen & progesterone functions?

Answer 5

oestrogen = increase endometrium thickness, reduce pH, decrease mucous viscosity (for sperm penetration)

progesterone = increase endometrium thickness, relaxes smooth muscle