Hormonal Control - Females

Question 1

Where is GnRH released from?

What does it cause to be released?

It is released in a pulsitile manner. T/F?

Answer 1

Gonad releasing hormone - hypothalamus

FSH and LH from anterior pituitary

T - pulistile manner

Question 2

LH and FSH are produced by the same cells in the anterior pituitary. So what is it that leads to an increase of one over the other?

Answer 2

Pulistale manner of GnRH release controls what hormone gets released

(e.g. increased frequency of GnRH = more of LH)

Question 3

What effect does oestrogen and progesterone have on frequency of GnRH pulses?

There are no oestrogen or progesterone receptors on GnRH neurons however. So how does this work?

Answer 3

Oestrogen - increases pulses
Progesterone - decreases pulses

Act on kisspeptin neurons which then pass the signal to GnRH neurons

Question 4

A surge in what hormone causes ovulation?

Answer 4

LH

Question 5

What are the 2 phases of menstural cycle?

In what phase is oestrogen highest?
In what phase is progesterone highest?
Why?

Answer 5

Follicular phase - 1-~14 days
Luteal phase - 14 days post ovulation

Follicular phase - oestrogen highest
Luteal phase - progesterone highest

Corpus luteum (once Graafian follicle releases ovum) produces progesterone

Question 6

What effect does oestrogen have on the endometrium?

Answer 6

Causes hyperplasia and angiogenesis of endometrium

Question 7

If the corpus lutuem becomes fertilised and implanted , what does it secrete.

Why is this hormone important?

Answer 7

HCG

Measured in pregnancy tests

Question 8

What hormones does the placenta secrete?

Answer 8

hPL (human placental lactogen)
Placental progesterone
Placental oestrogens

Question 9

What is progesterone made from?

Answer 9

Cholesterol

Question 10

What happens to the corpus luteum during the LH surge?

Answer 10

Angiogenesis -> increase in cholesterol -> increase in progesterone

Question 11

What hormone is responsible for decreasing the pH of the vagina and reducing the thickness of the cervical mucus?

Answer 11

Oestrogen

Question 12

What hormone causes the a mucus plug to form?

Answer 12

Progesterone

Question 13

How long is the average menstrual cycle?

Answer 13

28-35 days

Question 14

When does ovulation occur?

Answer 14

14 days before menstruation

Question 15

What hormone is responsible for causing primary follicles to develop into secondary follicles?

Answer 15

FSH

Question 16

During the menstrual phase:

What causes the drop in oestrogen and progesterone levels?
What does this cause?

Answer 16

If the ovum isn’t fertilised in the post-ovulation phase (14 days post ovulation) the corpus luteum stops releasing progesterone and oestrogen

This leads to a drop in prostaglandins

This causes constriction of the uterine spiral arterioles -> stratum functionalis coming away from status basalis -> BLEED

Question 17

What is a Graafian follicle?

Answer 17

The largest secondary follicle that goes on to ovulate each month

Question 18

What do the endometrium glands secrete in the post-ovulation phase?

Answer 18

Glycogen - provide nutrients for the implanted embryo

Question 18

What do the endometrium glands secrete in the post-ovulation phase?

Answer 18

Glycogen - provide nutrients for the implanted embryo 1

Question 19

What effect does oestrogen have on the uterus?

Answer 19

Causes proliferation of the endometrium