Hormones in human reproduction Flashcards
What do sex hormones cause during puberty?
they cause secondary sexual characteristics to develop
What happens to girls during puberty?
At puberty, eggs begin to mature and one is released approximately every 28 days. This is called ovulation.
What is oestrogen
Oestrogen is the main female reproductive hormone produced in the ovary.
What is testosterone?
Testosterone is the main male reproductive hormone produced by the testes and it stimulates sperm production.
What are the several hormones involved in the menstrual cycle of a woman?
(In order of when they are released in the cycle)
1) Follicle-stimulating hormone (FSH)
2) Oestrogen
3) Luteinising hormone (LH) stimulates the release of the egg.
4) progesterone
What does Follicle-stimulating hormone (FSH) do?
what is it secreted by?
the first part of the cycle
causes maturation of an egg in the ovary.
stimulates the ovaries to produce oestrogen
secreted by the pituitary gland
What does Luteinising hormone (LH) do?
what is it secreted by?
stimulates the release of the egg. (ovulation)
secreted by the pituitary gland
What does oestrogen do?
what is it secreted by?
causing the lining of the uterus to grow
inhibits FSH release
stimulates LH release
secreted by ovaries
What does progesterone do?
what is it secreted by?
- maintains the lining of the uterus during the second half of the cycle
- inhibits both FSH and LH release as progesterone stimulates the production of thick mucus which prevents any sperm getting through and reaching the eff
- secreted by empty follicle in ovaries
How are oestrogen and progesterone used as contraceptives
These hormones, taken every day, keeps their blood levels high.
High levels of oestrogen and progesterone inhibit FSH production and egg/ovum maturation.
Ovulation cannot take place.
Progesterone also stimulates the production of thick cervical mucus so that sperm are unable to enter the uterus to fertilise an egg.
What are the hormonal methods of contraception?
•oral contraceptives that contain oestrogen and progesterone to inhibit FSH production so that no eggs mature
•injection, implant or skin patch of slow-release progesterone to inhibit the maturation and release of eggs for a number of months or years
•intrauterine devices which prevent the implantation of an embryo or release a hormone
What are the non-hormonal methods of contraception?
barrier methods such as condoms and diaphragms which prevent the sperm reaching an egg
•spermicidal agents which kill or disable sperm
•abstaining from intercourse when an egg may be in the oviduct
•surgical methods of male and female sterilisation.
How do people increase fertility to give birth the natural way?
giving FSH and LH in a ‘fertility drug’ to a woman. She may then become pregnant in the normal way.
Describe In Vitro Fertilisation process
• IVF involves giving a mother FSH and LH to stimulate the maturation of several eggs.
• The eggs are collected from the mother and fertilised by sperm from the father in the laboratory.
• The fertilised eggs develop into embryos.
• At the stage when they are tiny balls of cells, one or two embryos are inserted into the mother’s uterus (womb).
Describe what Intra-cytoplasmic Sperm Injection (ICSI)
sperm is injected directly into an egg
useful if the man has a low sperm count
