HomeoStasis: The Menstrual Cycle.

Question 1

What happens during puberty?

Answer 1

• Reproductive hormones causes secondary sexual characteristics to develop.
  Men: Testes produce testosterone= Stimulates Testes to produce sperms.
  Females: Ovaries produce Oestrogen= Eggs in the ovaries start to mature during puberty. Every 28 days an egg is released. (Ovulation).

Question 2

What happens during the menstrual cycle?

Answer 2

• Every 28 days Ovulation takes place (Ovary releases an egg).
• Preperation: Uterus lining becomes thick and spongy.
• Egg makes it way down to the uterus (If sperm is present then the egg can be fertilised and it can implant into the uterus wall and develop into a baby).
• If egg does not get fertilised: Egg + Uterus lining released.
• Period.

Question 3

What are the 4 key hormones involved in the menstrual cycle?Folli

Answer 3

Follicle stimulating Hormone: Causes an egg to mature in the ovary.
Luteinising Hormone; Causes the egg to be released, ovulation.
Oestrogen (Produced by Ovary) and Progresterone:
- Involved in maintaining uterus lining in case the egg is fertilised and implants.

Question 4

How do these hormones interact with one another during the menstrual cycle?

Answer 4

1) FSH is Released by the pituitary glands. Travels into the blood to the ovaries where it causes an egg to mature.
Same Time: Triggers ovaries to make Oestrogen.

2) Oestrogen causes the lining of the uterus to become thick + Stops the pituary gland from releasing any more FSH.
- Instead releasing Luteinising Hormone.

3) LH triggers ovulation. Once the ovary has released it’s egg the ovary now produces the hormone progesterone.
2 effects:
- stops the pituitary glands from releasing FSH and LH.
(Prevents any more eggs from maturing or being released).

• Keeps the lining of the Uterus thick in case fertlised egg implants.
  If fertilisation does not take place: Level of Progesterone falls.

4) Uterus lining and the matured egg are now released/

Question 5

How do we interpret graphs of the hormones during the menstural cycle?

Answer 5

• Level of FSH rises triggers ovaries to release Oestrogen.
• As Level of Oestrogen rises= Inhibits the produce of FSH so the level falls.
• Oestrogen triggers the release of LH so the LH level rises to a peak at around day 14.
• LH triggers ovulation. Ovary now releases progresterone. Progresterone levels increases.

Fertilsation does not happen: Progresterone level falls again and the women has her period.