The Menstrual Cycle

Question 1

What is FSH

Answer 1

FSH - Follicle stimulating hormone

• This is secreted by the pituitary gland. It travels to the ovaries where it causes an egg to develop and mature.

Question 2

Where is FSH produced

Answer 2

In tje pituitary gland

Question 3

What is oestrogen

Answer 3

A hormone that causes the lining of the uterus to build up

Question 4

Where is oestrogen produced

Answer 4

Made and secreted in the ovaries

Question 5

What is LH

Answer 5

• luteinising hormone
  Causes ovulation

Question 6

Where is LH produced

Answer 6

In the pituitary gland

Question 7

What is progesterone

Answer 7

A hormone that Completes the development of the uterus wall, promotes glycogen storage

Question 8

Where is progesterone produced

Answer 8

Corpus leutum (yellow body)

Question 9

Why does menopause occur

Answer 9

The eggs in a women become infertile

Question 10

What is ovulation

Answer 10

When the egg is released from the ovary

Question 11

Why does oestrogen inhibit FSH production

Answer 11

This usually prevents more than one egg maturing. It also stimulates the pituitary gland to release luteinising hormone (LH).

Question 12

What happens when progesterone levels increase

Answer 12

FSH and LH levels are inhibited.

-> FSH is inhibited to stop more than one egg maturing
-> LH is inhibited to stop ovulation

Question 13

What happens when there is a lot of oestrogen

Answer 13

Stops FSH from being produced, and triggers an increase in LH.

-> FSH is lowered so that more than one egg does not mature
-> LH IS released so that it triggers ovulation

Question 14

What is a contraceptive latch and what does it do

Answer 14

It is a small patch placed on the skin, which steadily releases progesterone

It needs to be changed every week

Question 15

What does the progesterone only pill do

Answer 15

Stimulates the production of thick, sticky, mucus which is very difficult for sperm to penetrate
Also inhibits FSH prediction so that eggs don’t mature

Question 16

What does the contraceptive implant do

Answer 16

You insert it under the skin and it releases oestrogen and progesterone

Question 17

What does the contraceptive injection do

Answer 17

Releases progesterone

Question 18

What is IUD and how does it work

Answer 18

Intrauterine device, and are inserted into the uterus to prevent the egg from being implanted.
Some also release progesterone

Question 19

What is a diaphragm and how does it work

Answer 19

A shallow plastic cup which is inserted into the vagina. Stops from sperm approaching the egg, and some are covered in spermicide to kill sperm

Question 20

What is IVF

Answer 20

In vitro fertilisation
-> woman is given FSH and LH to stimulate eggs maturing and ovulation
-> eggs are taken to Laboratory where they are fertilised by using the husbands sperm
-> implanted back into the women’s uterus

Question 21

Diesavanteges of IVF

Answer 21

-> a lot of stress
-> multiple pregnancies could occur (twins/triplets)
-> expensive
-> not guaranteed to get pregnant

Question 22

What happens from say 1-14 of menstruation

Answer 22

The ovaries are simultaneously preparing to ovulate again
FSH has been released and is stimulating the follicle to mature an egg

Question 23

What Happens from days 14-28

Answer 23

After the release of the egg, levels of FSH and LH decrease.
The corpus luteum produces progesterone, and if it is fertilised then it continues to release progesterone to make sure uterine lining lasts
If not, the lining is shed

Question 24

Name two hormone that peak immediately before ovulation

Answer 24

FSH
LH
OESTROGEN

Question 25

Where in the ovary is progesterone

Answer 25

Corpus leutieum / yellow body

Question 26

An egg develops in a follicle before ovulation. The follicle has a diameter of 25 × 10^_3
mm at the start. This follicle grows to 20 mm in diameter just before the egg is
released.
Calculate the increase in size of the diameter of the follicle.
Give your answer to 2 decimal places.

Answer 26

19.98

Question 27

The failure of a follicle to increase in size means that

Answer 27

Less oestrogen is produced, meaning that the uterine lining does not build up

Question 28

Explain how hormones can be used to treat infertility in women

Answer 28

-> FSH and LH are the 2 main hormones used in these treatments
-> FSH stimulates the follicle, and helps the gg mature
-> LH causes ovulation, meaning that the mature egg can implant it self and conception may take place

Question 29

Explain how hormones can be used by women for contraception.

Answer 29

-> many contraceptive treatments contain oestrogen and oregesterone
-> by doing so, FSH is inhibited, stopping egg from maturing
-> when LH is limited, ovulation does not occur, stopping conception
-> progesterone produces a thick sticky mucus which the sperm cannot penetrate, stopping them from reaching the egg

Question 30

Infertility can also be caused by problems in the male.
Plasmin is a protease enzyme important in sperm movement.
Explain how changes to the structure of DNA could result in the plasmin enzyme being
faulty.

Answer 30

-> order of bases in DNA is changed
-> order of amino acids is changed in the protein, meaning the shape of the enzyme is also changed

Question 31

The lining of the uterus is shed during menstruation.
New cells are needed to replace the lining of the uterus.
Describe the processes that occur to make these new cells.

Answer 31

-> mitosis starts to take place
-> DNA is first replicated
-> chromosomes line up on the equator and are pulled apart by spindle fibres
-> cell collapses in on itself dividing into two identical cells
-> this process repeats to build up the lining of the uterus

Question 32

What is the most likely day ovulation occurs

Answer 32

Day 14

Question 33

Describe how oestrogen and FSH interact in the menstrual cycle

Answer 33

-> FSH stimulates oestrogen production
-> oestrogen inhibits FSH prediction to stop more than one egg maturing