Control in the body - Hormones

Question 1

What are hormones?

Answer 1

Chemical messengers which travel in the blood to activate target cells

Question 2

How are hormones trasported?

Answer 2

They are carried in the blood plasma to other parts of the body

Question 3

What sort of cells do hormones affect?

Answer 3

Target cells

Question 4

What do hormones control?

Answer 4

Things in organs and cells than need constant adjustment

Question 5

What are hormones produced and sectreted by?

Answer 5

Glands

Question 6

How fast do hormones travel through the body?

Answer 6

At ‘the speed of blood’

Question 7

What does the pituitary gland produce?

Answer 7

Many important hormones including FSH and LH

Question 8

What do the ovaries produce?

Answer 8

Oestrogen

Question 9

3 differences between the ways hormones and the nervous system

Answer 9

Nerves

• Very fast action
• Act for a very short time
• Act on a very precise area

Hormones

• Slower action
• Act for a long time
• Act in a more general way

Question 10

Definition of the menstrual cycle

Answer 10

The monthly release of an egg from a woman’s ovaries, and the build-up and breakdown of the protective lining in the uterus (womb)

Question 11

What happens on day 1-5 of the menstrual cycle?

Answer 11

The uterus lining breaks down. This is called menstration.

The pituitary gland releases FSH

Question 12

What happens on day 5-14 of the menstrual cycle?

Answer 12

FSH causes an egg folicle inside the ovary to grow and mature.

Oestrogen is released from the egg follicle as it grows and matures

Oestrogen makes the pituitary gland stop FSH and start LH and causes the uterus lining to thicken

Question 13

What happens on day 14 of the menstrual cycle?

Answer 13

LH levels peak and the egg is released from the follicle

LH stops Oestrogen release

The release of the egg is called ovulation

Question 14

What happens day 14-21 of the menstrual cycle?

Answer 14

Progesterone is released by the empty follicle - this maintains the uterus lining and stops LH

Question 15

What happens day 21-28 of the menstrual cycle?

Answer 15

If the egg is not fertilised then the levels of progesterone start to fall

The uterus lining will soon break down again

If the egg is fertilised the uterus wlining must ont break down (otherwise the fertilized egg will not develop)

Corpus luteum continues to produce progesterone

Question 16

How does Oestrogen reduce fertility?

Answer 16

It prevents the release of an egg - if the oestrogen is taken every day to keep the level of it permanently high which inhibits the production of FSH - after a while egg development and production stop and say stopped

Question 17

How does progesterone reduce fertility?

Answer 17

It stimulates the production of thick cervical mucus (which prevents any sperm getting thorugh and reaching the egg)

Question 18

Pro’s of the combined pill?

Answer 18

• The pill’s over 99% effective at preventing pregnancy
• It reduces the risk of getting some types of cancer

Question 19

Cons of the pill?

Answer 19

• It isn’t 100% effective
• It can cause side effects like headaches, nausea, irregular mestrual bleeding and fluid retention
• It doesn’t protect you against STD’s

Question 20

A reason why some women can’t get pregnant

Answer 20

They have low FSH levels which mean the egg can’t meture - meaning no eggs are released and the woman can’t get preggers

Question 21

How can fertility be increased?

Answer 21

By injecting hormones FSH and LH to stimulate egg release in their ovaries

Question 22

Pro’s of increasing fertility?

Answer 22

It helps a lot of women to get pregnant when previously they couldn’t

Question 23

Cons of increasing fertility?

Answer 23

It doesn’t always work, some women may have to do it many times - which can be expensive

Too many eggs could be stimulated, resulting in unexpected multiple births (21% of IVF babies are twins)

Question 24

Pro of IVF?

Answer 24

It can give an infertile couple a child

Question 25

Cons of IVF?

Answer 25

• Some women have a strong reaction to the hormones given (before egg collection to stimulate egg production) eg abdominal pain, vomiting, dehydrating
• There have been some reports of an increased risk of cancer due to the hormonal treatment
• Multiple births can happen if more than one embryo grows into a baby (risk for for the mother and babies - miscarriage, stillbirth)