The Menstrual Cycle Flashcards
What is FSH
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.
Where is FSH produced
In tje pituitary gland
What is oestrogen
A hormone that causes the lining of the uterus to build up
Where is oestrogen produced
Made and secreted in the ovaries
What is LH
- luteinising hormone
Causes ovulation
Where is LH produced
In the pituitary gland
What is progesterone
A hormone that Completes the development of the uterus wall, promotes glycogen storage
Where is progesterone produced
Corpus leutum (yellow body)
Why does menopause occur
The eggs in a women become infertile
What is ovulation
When the egg is released from the ovary
Why does oestrogen inhibit FSH production
This usually prevents more than one egg maturing. It also stimulates the pituitary gland to release luteinising hormone (LH).
What happens when progesterone levels increase
FSH and LH levels are inhibited.
-> FSH is inhibited to stop more than one egg maturing
-> LH is inhibited to stop ovulation
What happens when there is a lot of oestrogen
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
What is a contraceptive latch and what does it do
It is a small patch placed on the skin, which steadily releases progesterone
It needs to be changed every week
What does the progesterone only pill do
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
What does the contraceptive implant do
You insert it under the skin and it releases oestrogen and progesterone
What does the contraceptive injection do
Releases progesterone
What is IUD and how does it work
Intrauterine device, and are inserted into the uterus to prevent the egg from being implanted.
Some also release progesterone
What is a diaphragm and how does it work
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
What is IVF
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
Diesavanteges of IVF
-> a lot of stress
-> multiple pregnancies could occur (twins/triplets)
-> expensive
-> not guaranteed to get pregnant
What happens from say 1-14 of menstruation
The ovaries are simultaneously preparing to ovulate again
FSH has been released and is stimulating the follicle to mature an egg
What Happens from days 14-28
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
Name two hormone that peak immediately before ovulation
FSH
LH
OESTROGEN
Where in the ovary is progesterone
Corpus leutieum / yellow body
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.
19.98
The failure of a follicle to increase in size means that
Less oestrogen is produced, meaning that the uterine lining does not build up
Explain how hormones can be used to treat infertility in women
-> 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
Explain how hormones can be used by women for contraception.
-> 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
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.
-> 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
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.
-> 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
What is the most likely day ovulation occurs
Day 14
Describe how oestrogen and FSH interact in the menstrual cycle
-> FSH stimulates oestrogen production
-> oestrogen inhibits FSH prediction to stop more than one egg maturing
