L7 - Reproductive Endocrinology

Question 1

PUBERTY

i) puberty is triggered by pulsatile secretion of which hormone?
ii) what staging system is used to gauge whether puberty is progressing? how many stages are there?
iii) name two things that can affect timing of puberty

Answer 1

i) GnRH
ii) Tanner stages - 5 stages
iii) stressors eg nutrition or genetics (parents age of puberty)

Question 2

MALE REPRODUCTIVE ENDOCRINOLOGY

i) what is released from the hypothalamus? what does this cause release of from the anterior pituitary?
ii) which cells in the testes make testosterone? which hormone influences this?
iii) which cells in the seminiferous tubules make sperm? which hormone influences this?
iv) name four effects of testosterone

Answer 2

i) GnRH released from HT which causes LH and FSH release from the ant pit
ii) leydig cells make testos (influ by LH)
iii) sertoli make sperm (influ by FSH)
iv) increased aggression/libido, enlarged larynx, male pattern pubic hair, maturation of genitalia, muscle dev, sperm prod

Question 3

FEMALE REPRODUCTIVE ENDOCRINOLOGY

i) what is the role of FSH in the follicular phase?
ii) which two hormones are at high levels when the follicle releases the egg
iii) what is the name of the remnant of the egg follicle? what two things does it secrete?
iv) what does effect does oestrogen have on the uterus?
v) what happens if the egg doesnt get fertilised? (3)
vi) what effect does rise in progesterone in the luteal phase have on FSH and LH?

Answer 3

i) FSH acts on the ovary to recruit a mature follicle which becomes the secondary follicle (produces oes)
ii) high oestrogen and LH when follicle releases egg (ovulation)
iii) remnant of follicle = corpus luteum which secretes oestrogen and progesterone
iv) oestrogen causes proliferation of lining of uterus to make it receptive to a fertilised egg
v) egg not fertilised = proges and oes decrease, corpus luteum degen, get period
vi) rise in progesterone in luteal has neg feedback on LH and FSH

Question 4

FEMALE HORMONES

i) which cells does LH work on? what does it cause these cells to produce?
ii) which cells does FSH work on? what does this cell produce? name two other things this cell makes

Answer 4

i) LH works on thecal cells to produce androgens

ii) FSH works on granulosa cells to produce oestrogen
- also prod inhibin and activin

Question 5

FEMALE OVARY

i) which second messenger is activated when LH activates a thecal cell?
ii) what does this second messenger cause to be produced?
iii) which cell does this product then travel to? what is it converted to?

Answer 5

i) PKA is activated
ii) thecal cell produces androgens
iii) androstenedione travels from thecal cell to granulosa cell where it is converted to oestrogen and released into the blood

Question 6

OXYTOCIN

i) where is it released from?
ii) what role does it play in breastfeeding?
iii) what does it activate in childbirth? (2) what kind of feedback loop is this part of?
iv) what class of receptor does oxytocin work on?

Answer 6

i) posterior pituitary gland
ii) contracts myoepithelial cells of the alveoli in breast which causes ejection of milk

iii) activates uterine contractions and prostaglandin release from uterine wall
- positive feedback loop

iv) activates a GPCR