Hormones and the Menstrual Cycle Flashcards
Where are hormones produced?
Glands such as the pituitary gland and ovaries
How long are the effects of hormones?
Relatively long
What is the exact definition of hormones?
Hormones are chemical messengers which travel in the blood to active target cells
What two important hormones are secreted by the pituitary gland?
FSH and LH
What important hormone does the ovaries secrete?
Oestrogen
What are the differences between nerves and hormones?
Nerves are fast hormones are slower
Nerves act for a short time but hormones act for s long time
Nerves act on a precise area but hormones are more general
what is a hormone?
A chemical released directly into the blood
Carries by blood plasma to other parts of the body
Only affects target cells
Controls things in organs and cells that need constant adjustment
What happens at stage one of the period?
The uterus lining breaks down for roughly 4 days
What happens at stage 2 of the menstrual cycle?
The lining of the uterus builds up into a thick spongey layer full of blood vessels (day 4-14)
What happens at stage three of the menstrual cycle?
An egg is released (day 14)
What happens at stage four of the period?
The wall is maintained for 14 days until the 28th day
If no fertilised egg lands in the uterus wall the spongey lining breaks down and stage one begins again
How does FSH (follicle stimulating hormone) affect the menstrual cycle?
Causes the egg to mature in the ovaries
Stimulates the ovaries to produce oestrogen
How does Oestrogen affect the menstrual cycle?
It causes the pituitary gland to produce LH
Inhibits the further release of FSH
Repairs and develops uterus lining
How does Luteinising Hormone affect the menstrual cycle?
Stimulates the realised of an egg
How does progesterone affect the menstrual cycle?
Stops FSH and LH and causes uterus lining to thicken
Maintains uterus lining
Step by step menstrual cycle?
Pituitary gland produces FSH
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FSH causes egg to mature in ovary
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FSH causes ovaries to produce oestrogen
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Oestrogen inhibits FSH
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Oestrogen causes pituitary to produce LH
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Pituitary gland produces LH
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LH causes egg to be released from ovaryHow does oestrogen prevent the release of an egg (contraception)?
When oestrogen is taken every day the levels are permanently high
This inhibits the production of FSH and eventually stops egg development and production
How does progesterone reduce fertility?
Stimulates the production of thick cervical mucus which prevents sperm reaching the egg
What is “the pill”?
An oral contraceptive made in the 1950s
What side effects were linked with the original contraceptive pill?
Blood clots
What are the pros of the pill?
They’re over 99% effective at preventing pregnancy
Reduce s the risk of getting some types of cancer
What are the cons of the pill?
It isn’t 100% effective
It can cause side effects like headaches nausea and irregular menstrual bleeding
It doesn’t protect against STDs
How can fertility levels be increased?
By INJECTING FSH and LH into the woman
What are the pros of FSH and LH injections?
It helps a lot of women to get pregnant
