B5

Question 1

What is homeostasis?

Answer 1

Maintaining the internal conditions of the body.

Question 2

What three things are controlled by homeostasis?

Answer 2

1) Blood glucose concentration.
2) Body temperature.
3) Water levels.

Question 3

Why is homeostasis important?

Answer 3

Cells and enzymes need to stable conditions or work in.

Question 4

What does the CNS consist of?

Answer 4

1) The brain.
2) The spinal cord.

Question 5

What does the nervous system enable us to do?

Answer 5

It enables humans to react to their surroundings and coordinate their behaviour.

Question 6

What are the five sense organs?

Answer 6

1) Eyes
2) Ears
3) Nose
4) Tongue
5) Skin

Question 7

Where are receptors found?

Answer 7

In the sense organs.

Question 8

What a reflex action?

Answer 8

It is a reaction. It is automatic and rapid. It does not involve the conscious part of the brain.

Question 9

Explain what happens in a reflex reaction.

Answer 9

1) There is a stimuli which is a change in environment (such as touching something sharp or hot).
2) Receptor cells detect his and send electrical impulses.
3) The electrical impulses then go to the sensory neurone.
4) They then go to the relay neurone.
5) They then go to the motor neurone.
6) They then go to the effector. There are two types of effectors: muscle and glands.
7) Then there is a response. The response depends on the effector. If the effector is muscle, there will be a muscle contraction. If the effector is glands, hormones are secreted
8) A synapse is a gap between two heroines which allows electrical impulses to diffuse across.

Question 10

Why are reflex actions important?

Answer 10

1) It involves the subconscious part of the brain.
2) It is automatic and rapid.
3) It protects us from harm and danger.