Hormones in Humans: Reproduction & Metabolism (AQA GCSE Combined Science: Trilogy: Biology): Flashcards
Exam code: 8464
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What happens during puberty?
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Cards in this collection (26)
What happens during puberty?
Reproductive hormones cause secondary sex characteristics to develop.
Testosterone
The main male reproductive hormone, produced by the testes; it stimulates sperm production.
Oestrogen
The main female reproductive hormone, produced by the ovaries.
Ovulation
The release of an egg from the ovary, approximately every 28 days.
Name the four hormones involved in the menstrual cycle, and state where FSH and LH are made.
FSH and LH – made by the pituitary gland
Oestrogen and progesterone
State the role of FSH, LH, oestrogen and progesterone in the menstrual cycle.
FSH – causes an egg to mature in the ovary
LH – stimulates the release of the egg (ovulation)
Oestrogen and progesterone – involved in maintaining the uterus lining
stimulates the release of an egg from the ovary at ovulation.
LH (luteinising hormone) stimulates the release of an egg from the ovary at ovulation.
Explain how FSH, oestrogen, LH and progesterone interact to control the menstrual cycle. (Higher Tier Only)
FSH stimulates an egg to mature and stimulates the ovaries to release oestrogen.
Oestrogen thickens/repairs the uterus lining and inhibits FSH; when high, it stimulates the release of LH.
LH triggers ovulation and stimulates the ovary to produce progesterone.
Progesterone maintains the uterus lining and inhibits FSH and LH; when it falls, menstruation occurs.
Contraception
Methods used to prevent fertilisation and pregnancy.
What are the two broad categories of contraception?
Hormonal methods and non-hormonal methods.
How do oral contraceptives (the pill) work?
They contain hormones (oestrogen and/or progesterone) that inhibit FSH production, so that no eggs mature.
Oral contraceptives contain hormones that inhibit production, so that no eggs mature.
Oral contraceptives contain hormones that inhibit FSH production, so that no eggs mature.
Name three contraceptive methods that use slow-release progesterone.
Injection, implant and skin patch – these inhibit the maturation and release of eggs for months or years.
How do barrier methods of contraception work?
Condoms and diaphragms prevent the sperm from reaching an egg. Condoms also help prevent sexually transmitted infections.
Give three non-hormonal methods of contraception other than barrier methods.
Intrauterine device (IUD) – prevents implantation of an embryo
Spermicides – kill or disable sperm
Abstinence or surgical sterilisation
How can the hormones FSH and LH be used to treat infertility? (Higher Tier Only)
They are given as a 'fertility drug' to stimulate egg maturation and release, so the woman may then become pregnant naturally.
IVF (in vitro fertilisation) (Higher Tier Only)
A fertility treatment in which eggs are fertilised by sperm outside the body, in a laboratory.
Describe the main steps of IVF treatment. (Higher Tier Only)
The mother is given FSH and LH to stimulate the maturation of several eggs.
The eggs are collected and fertilised by sperm in the laboratory.
The fertilised eggs develop into embryos.
When they are tiny balls of cells, one or two embryos are inserted into the mother's uterus.
Give three disadvantages of fertility treatments such as IVF. (Higher Tier Only)
It is very emotionally and physically stressful.
The success rates are not high.
It can lead to multiple births, which are a risk to both the mother and the babies.
Give one ethical issue associated with IVF treatment. (Higher Tier Only)
More embryos may be produced than are used, and the unused embryos may be destroyed or used in research – which some people object to, as an embryo is a potential life.
Negative feedback (Higher Tier Only)
A control mechanism that keeps conditions within a narrow range by reversing any change away from the normal level, bringing it back to normal.
Give two examples of body conditions controlled by negative feedback. (Higher Tier Only)
Blood glucose level and core body temperature.
Adrenaline (Higher Tier Only)
A hormone produced by the adrenal glands in times of fear or stress.
What are the effects of adrenaline? (Higher Tier Only)
It increases heart rate and boosts the delivery of oxygen and glucose to the brain and muscles, preparing the body for 'fight or flight'.
What are the roles of thyroxine in the body? (Higher Tier Only)
It stimulates the basal metabolic rate and plays an important role in growth and development.
How are thyroxine levels controlled by negative feedback? (Higher Tier Only)
Thyroxine levels are controlled by TSH from the pituitary gland.
If thyroxine is too high, TSH release is inhibited, so less thyroxine is released.
If thyroxine is too low, more TSH is released, stimulating the thyroid to release more thyroxine.
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