5.3 Hormonal Coordination in Humans PART 2

Question 1

What is contraception?

Answer 1

Contraception refers to any method of preventing pregnancy.

Question 2

What are the two types of oral contraceptives?

Answer 2

● Combined contraceptive pill (contains oestrogen and progesterone).
● Mini pill (contains only progesterone).

Question 3

How does the contraceptive pill prevent pregnancy?

Answer 3

● Inhibits FSH - eggs do not mature.
● Prevents the development of the uterus lining - eggs cannot implant.
● Increases the thickness of cervical mucus - immobilises sperm cells.

Question 4

What is the contraceptive patch?

Answer 4

● Contains both oestrogen and progesterone.

● It is a patch that is placed onto the skin for 7 days at a time.

Question 5

What is the contraceptive implant?

Answer 5

A small rod inserted under the skin which continuously releases the hormone progesterone - lasts for 3 years.

Question 6

What is the contraceptive injection?

Answer 6

An injection containing the hormone progesterone - lasts for approximately 3 months.

Question 7

What is the IUS?

Answer 7

The IUS (intrauterine system) is 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.

Question 8

What is the IUD?

Answer 8

The IUD (intrauterine device) is a small copper-containing device inserted into the uterus, which prevents the implantation of embryos.

Question 9

What is a spermicide?

Answer 9

A spermicide is a chemical that kills or immobilises sperm cells - however, they are not very effective, and work better when combined with barrier methods.

Question 10

What is a barrier method of contraception?

Answer 10

A barrier method of contraception involves a physical separation between the sperm and the egg. They include:
● Condoms - thin sheath worn on the penis or inside the vagina - protects against STIs but may tear/break.
● Diaphragms - a thin cap placed over the cervix - prevent entry of sperm.

Question 11

What surgical methods of contraception are available?

Answer 11

Sterilisation - in males, the sperm ducts are tied (vasectomy) and in females, the oviducts are tied.

Question 12

What is abstinence?

Answer 12

Abstinence is the practice of not having sex, which also avoids pregnancy. Some people abstain from sex around the time of ovulation - this is known as the rhythm method, but it is quite unreliable.

Question 13

How do fertility drugs increase the chance of pregnancy?

Answer 13

Many fertility drugs contain FSH - which stimulates oestrogen production and the maturation of eggs in the ovary. They also contain LH which triggers ovulation.

Question 14

What is IVF?

Answer 14

IVF (in vitro fertilisation) is type of fertility treatment:
● Mother is given FSH and LH - stimulates maturation of eggs and ovulation.
● Eggs are fertilised using sperm in a laboratory - develop into embryos.
● 1 or 2 embryos are inserted into the mother’s womb

Question 15

What are the advantages of fertility treatment?

Answer 15

● Allows infertile couples to have children

● Can store a woman’s eggs for later

Question 16

What are the disadvantages of fertility treatment?

Answer 16

● It can be a very expensive process.
● It has a low success rate - especially for older couples.
● Increases chance of multiple pregnancies - dangerous for mother and babies.
● Side effects of fertility drugs.

Question 17

What is negative feedback?

Answer 17

Negative feedback is a type of control where the body responds to an increase or decrease in a factor by returning it to the optimum level.

Question 18

What is thyroxine?

Answer 18

Thyroxine is a hormone released by the thyroid gland. Its release is triggered by the thyroid stimulating hormone (TSH). Thyroxine controls the body’s metabolic rate, growth and development.

Question 19

How is the release of thyroxine controlled by negative feedback?

Answer 19

● Levels of blood thyroxine falls - detected by receptors in the brain.
● Pituitary gland releases more TSH.
● More thyroxine produced and released by the thyroid gland.
● Blood thyroxine level returns to normal.

Question 20

What is adrenaline?

Answer 20

Adrenaline is a hormone secreted by the adrenal gland in times of stress. It is responsible for the ‘fight or flight response’

Question 21

What are the effects of adrenaline?

Answer 21

● Increase in heart and breathing rate - delivers oxygen and glucose to the body.
● Stored glycogen converted to glucose.
● Dilation of pupils.
● Increased mental awareness.
● Blood diverted away from digestive system to muscles.