KA2- Hormonal control of Reproduction

Question 1

What happens at the beginning of puberty?

Answer 1

The hypothalamus secretes a releaser hormone who’s target is the pituitary gland.

Question 2

What hormones does the pituitary gland produce?

Answer 2

FSH in males and females, ICSH in males, LH in females.

Question 3

What does the release of the hormones trigger?

Answer 3

The one set puberty, sperm production in males and the menstrual cycle in women.

Question 4

What hormones does the pituitary gland release for the control of sperm production?

Answer 4

FSH and ICSH.

Question 5

What does FSH do in males?

Answer 5

FSH stimulates sperm production in the seminiferous tubules.

Question 6

What is the role of ICSH in sperm production?

Answer 6

ICSH stimulates the interstitial cells to release the hormone testosterone.
Both FSH and ICSH control the actions of the testes.

Question 7

What is the role of testosterone?

Answer 7

It stimulates sperm production in the seminiferous tubules and activates the prostate gland and the seminal vesicles to produce their secretions.

Question 8

How is the release of hormones regulated in males?

Answer 8

By negative feedback.

Question 9

Describe the negative feedback control in males.

Answer 9

As the concentration of testosterone builds up in the bloodstream, it reaches a certain level, where it inhibits the secretion of FSH and ICSH by the pituitary gland, leading to a decrease in testosterone concentration.
When testosterone levels drop, the inhibitory effect is switched off and the pituitary gland makes FSH and ICSH again and so on…

Question 10

What hormones are secreted by the pituitary gland for the hormonal control of menstruation?

Answer 10

FSH and LH.

Question 11

Name the stages of menstrual cycle.

Answer 11

Follicular Phase and the Luteal Phase.

Question 12

Describe the role of FSH in the follicular stage.

Answer 12

FSH stimulates development and maturation of a follicle and stimulates production of oestrogen by the follicle.

Question 13

What is the role of oestrogen in the follicular stage?

Answer 13

Oestrogen stimulates repair and proliferation of the endometrium, preparing it for implantation. It also affects the consistency of cervical mucus, making it more easily penetrated by sperm and peak levels of oestrogen stimulate a surge in the production of LH.
Surge of LH leads to ovulation.

Question 14

Describe the role of LH in the luteal phase.

Answer 14

LH causes the follicle to develop into the corpus luteum. Corpus luteum starts to secrete progesterone.

Question 15

State what is the role of progesterone in the luteal phase.

Answer 15

Progesterone promotes further development and vascularisation of the endometrium preparing it for implantation if fertilisation occurs.

Question 16

Explain the negative feedback effect of the ovarian hormones?

Answer 16

High oestrogen and progesterone levels inhibit the secretion of FSH and LH by the pituitary gland.
Concentration of LH and FSH decrease preventing new follicles from developing.

Question 17

What happens if fertilisation doesn’t occur?

Answer 17

Lack of LH leads to degeneration of the corpus luteum and therefore a drop in progesterone levels, leading to mentruation.

Question 18

What happens if fertilisation occurs?

Answer 18

The corpus luteum does not degenerate and progesterone levels remain high.