5.3 Homeostasis and response (hormones in human reproduction and contraception) Flashcards
What is the function of male reproductive organs during puberty?
to develop secondary sexual characteristics
What is the function of female reproductive organs during puberty?
to develop secondary sexual characteristics and the maturation of eggs
What is the main male reproductive hormone?
testosterone - which controls sperm production
What is the main female reproductive hormone?
oestrogen - which is involved in the menstrual cycle
What is the menstrual cycle?
The monthly cycle of physiological changes that occur in females, involving the shedding of the uterus lining (menstruation) and ovulation
Describe the events of the menstrual cycle?
- The uterus lining thickens and an egg begins to mature in the ovaries
- An egg is released from one of the ovaries, and the uterus lining remains thick
- If the egg is fertilized, pregnancy may occur. If not, both the egg and the uterus lining are shed during menstruation
What is ovulation?
the release of a mature egg from the ovaries, which occurs approximately every 28 days
What is menstruation?
the shedding of the uterus lining
Name the four main hormones involved in the menstrual cycle?
- oestrogen
- progesterone
- follicle stimulating hormone (FSH)
- Luteinising hormone (LH)
What is the role of FSH in the menstrual cycle?
it controls the maturation of eggs within the ovaries (inside a follicle)and triggers the production of oestrogen by the ovaries
What is FSH secreted by?
the pituitary gland
What is the role of oestrogen in the menstrual cycle?
- oestrogen causes the regrowth of the uterus lining and triggers the production of LH and restricts the release of more FSH
What is the role of LH in the menstrual cycle?
LH is produced in the pituitary gland as a result of oestrogen. Its release triggers ovulation
Where is LH produced?
in the pituitary gland
What is the role of progesterone in the menstrual cycle?
It is secreted from the follicle of the ovary. It sustains the uterus lining and inhibits FSH and LH
What is contraception?
Any method of preventing pregnancy
What are the two types of oral contraceptives?
- combined contraceptive pill (contains oestrogen and progesterone)
- mini pill (contains only progesterone)
How does the contraceptive pill prevent pregnancy?
- It inhibits FSH so eggs do not mature
- Prevents the development of the uterus lining, so eggs cannot implant
- increases the thickness of cervical mucus - so immobilises sperm cells
What is the contraceptive patch?
- It is a patch that contains both oestrogen and progesterone that is placed on the skin for 7 days at a time
What is the contraceptive implant?
A small rod inserted under the skin which continuously releases the hormone progesterone - lasts for 3 years
What is the contraceptive injection?
An injection containing the hormone progesterone - lasts for approximately 3 months
What does IUS stand for?
intrauterine system
What is the IUS?
A small plastic device that is inserted into the uterus. It releases progesterone which thickens cervical mucus and prevents the build-up of the uterine lining
What does the IUD stand for?
intrauterine device
What is the IUD?
A small copper-containing device inserted into the uterus, which prevents the implantation of embryos
What is a spermicide?
A chemical that kills or immobilises sperm cells - however they are not every effective, and work better when combined with barrier methods
What is a barrier method of contraception?
A physical separation between the sperm and the egg
What are 2 examples of barrier contraceptives?
- Condoms
- Diaphragms
What are condoms?
a thin sheath worn on the penis or inside the vagina - protects against STIs but may tear or break
What are diaphragms?
A thin cap placed over the cervix - prevent the entry of sperm
What surgical methods of contraception are available?
sterilisation - in males, the sperm ducts are tied and in females the oviducts are tied
What is abstinence?
The practise of not having sex, which also avoids pregnancy
What is the rhythmn method?
When people abstain from having sex around the time of ovulation - however it is quite unreliable
How do fertility drugs increase the chance of pregnancy?
Many fertility drugs contain FSH and LH
What does IVF stand for?
In vitro fertilisation
What is the process of in vitro fertilisation?
- The mother is given FSH and LH , which stimulates maturation of eggs and ovulation
- Eggs are fertilised using sperm in a laboratory and develop into embryos
- 1 or 2 embryos are inserted into the mother’s womb
What are the advantages of IVF?
- allows infertile couples to have children
- can store a woman’s eggs for later
What are the disadvantages of IVF?
- it can be a very expensive process
- it has a low success rate - especially for older couples
- increases the chance of multiple pregnancies which is dangerous for mother and babies
- side effects of fertility drugs
