Menstrual Cycle, Controlling Fertility and Adrenaline and Thyroxine Flashcards
What is a hormone?
A chemical messenger produced in glands and carried by the blood to specific organs in the body
What is Puberty?
The time when sexual maturity occurs, over a period of time gradually.
What is Testosterone?
Produced by the testes - is the main male reproductive hormone and it stimulates sperm production.
What is Oestrogen?
Produced by the ovaries - is the main female reproductive hormone. At puberty, eggs begin to mature and one is released approximately every 28 days. This is called ovulation.
What is the Menstrual Cycle?
A reoccurring cycle which takes around 28 days.
What happens during the Menstrual Cycle?
1) The Uterus lining breaks down for about four days
2) The uterus lining begins to build up again, into a spongy layer full of blood vessels, ready for a fertilised egg
3) An egg develops and is released - ovulation
4) Wall is maintained, until day 28, where the lining breaks down and the whole cycle repeats
What is FSH, what does it do and where is it produced?
Follicle stimulating hormone (FSH), causes the maturation of an egg in the ovary.
Produced in Pituitary Glands
What is LH,what does it do and where is it produced?
Luteinising hormone (LH) stimulates the release of the egg.
Produced in Pituitary Glands
What does Oestrogen do and where is it produced?
Is involved in repairing and thickening the uterus lining, while progesterone maintains it.
Produced in Ovaries
What can Oestrogen be used for?
To prevent the release of the egg - method of contraception
What is another hormone can be used to reduce fertility?
Progesterone
What is The Pill?
An oral contraceptive containing oestrogen and progesterone, it has over 99% effectiveness at preventing pregnancy, but has side effects, and does not protect against STDs
What are two other contraceptives that also contain hormones?
1) The contraceptive injection (contains progesterone) lasts around 2-3months
2) Contraceptive patch (contains oestrogen and progesterone), a small patch that is stuck to skin lasts a week.
Name 3 non-hormonal forms of contraception?
1) Condom - the only form of contraception that protects against STDs
2) Spermicide (not as effective only 70-80%)
3) Sterilisation - a permanent procedure cuts sperm duct or fallopian tubes
What hormones can be given to women as a fertility drug?
FSH and LH - to stimulate ovulation
What are the cons of using FSH and LH as a fertility drug?
1) Don’t always work - can be expensive
2) Too many eggs stimulated could lead to multiple pregnancies
What does IVF involve?
Collecting eggs from women’s ovaries and fertilising them in a lab using the man’s sperm
What happens to the fertilised egg in IVF?
Grows into embryos, which are then transferred into the women’s Uterus to improve the chance of pregnancy.
FSH and LH are given to the egg before collection to stimulate eggs to mature
What are some downsides to IVF?
1) Multiple births can occur if more than one embryo develops - higher risk for miscarriage
2) The low success rate at around the UK average of 26%, can be stressful and expensive.
Why are some people against IVF?
1) Unethical due to unused embryos which is a potential life
2) Genetic Testing before implantation could lead to preferred characteristics of e.g gender or eye colour.
Where is Adrenaline released?
By the adrenal glands just above the kidneys
What is Adrenaline released in response to?
A stressful or scary situation - fear is detected which sends nervous impulses to adrenal glands/
What does the triggering of the “Fight or Flight” mechanism in the body cause?
Increased supply of oxygen and glucose to cells in the brain and the muscles.
How can hormone releases be affected by a negative feedback loop?
The body controls the level of hormones, so if it detects it above or below the normal level it will bring it back to normal.
