Nervous system

Question 1

What detects a stimulus?

Answer 1

A sensory receptor

Question 2

What is the name of the neurones which take the impulse to the spinal cord?

Answer 2

Sensory neurone

Question 3

Explain the pathway of a reflex action when touching something hot. (5 marks)

Answer 3

Stimulus / heat detected by temperature receptors in skin Impulses travel along sensory neurone to spinal cord / CNS Chemical transmission across synapse via relay neurone Impulses to muscle / effector via motor neurone Muscle / effector contracts, moving the hand away

Question 4

Describe what happens at a synapse when an impulse arrives. (2 marks)

Answer 4

• impulse / information passes from one neurone to another or impulse / information passes across gap (synapse) - chemical / transmitter involved - chemical diffusion (across gap)

Question 5

Some people have a condition in which information from the skin does not reach the brain. Explain why this is dangerous for the person. (2 marks)

Answer 5

Brain / person not aware of pain /stimulus / can’t feel. Therefore, there is a possibility of (permanent / serious) damage / eg burning.

Question 6

What is the name of the neurone that carries impulses away from the central nervous system. (1 mark)

Answer 6

Motor neurone

Question 7

What are the 5 sense organs?

Answer 7

Eyes, ears, nose, tongue and skin

Question 8

What do rods and cones do?

Answer 8

They are light receptors found in the retina

Question 9

Rods and cones are light receptors, specialised to do a job but which 3 things do they have in common with other animal cells?

Answer 9

Cell membrane Cytoplasm Nucleus

Question 10

What are changes in the environment detected by?

Answer 10

Receptors

Question 11

Where do we find relay neurones?

Answer 11

In the spinal cord and brain

Question 12

Describe the pathway of a reflex arc

Answer 12

Stimulus Receptor Sensory neurone Relay neurone Motor neurone Effector Response

Question 13

How are neurones good at carrying electrical impulses?

Answer 13

Long and thin and insulated

Question 14

What do we find between the sensory and relay and the relay and motor neurones?

Answer 14

A gap called a synapse

Question 15

Does the impulse jump the synapse?

Answer 15

No, chemicals are released which diffuse across the gap and stimulate an electrical impulse in the next neurone

Question 16

If you don’t think about a stimulus until after you have responded, what do we call it?

Answer 16

A reflex arc

Question 17

What detects a stimulus

Answer 17

A receptor

Question 18

Where do we find receptors?

Answer 18

In sense organs

Question 19

Is a reflex arc continuous?

Answer 19

No, it has gaps called synapses

Question 20

Why do you have a nervous system?

Answer 20

To help you to respond to changes in your environment

Question 21

What is a nerve impulse?

Answer 21

An electrical signal which passes along neurones

Question 22

Are nerve impulses quick or slow?

Answer 22

Very quick

Question 23

What makes up the CNS? (Central nervous system)

Answer 23

Brain and spinal cord

Question 24

What is an effector?

Answer 24

A muscle or gland which responds to a nerve impulse

Question 25

Which receptors are found in the skin?

Answer 25

Touch, pressure,pain and temperature change receptors

Question 26

What are reflexes?

Answer 26

Fast automatic responses to certain stimuli

Question 27

What is this?

Answer 27

A sensory neurone - the cell body (the bit with the nucleus) is not on the end.

Question 28

What is this?

Answer 28

A motor neurone, you can see it is connected to a muscle

Question 29

What is this showing?

Answer 29

The chemical neurotransmitters diffusing across a synapse