5.3.1 Neurones

Question 1

What do neurones do and what are nerves

Answer 1

neurones carry electrical signals around body, bundle of neurones is a nerve

Question 2

Diagram of Neurone with notes

Answer 2

Axon terminal contains lots of nerve endings, allows neurones to connect to other neurones and receive impulses from other neurones.

Some are myelinated (axon insulated by myelin sheath)

Myelin sheath made from schwann cells

Electrical impulses jump between nodes of ranvier so do not have to travel down whole axon so less time is wasted transferring impulses from one cell to another

So in non-myelinated neurones the axon is uninsulated and the impulse takes longer to travel down entire length of axon

Question 3

What are the 3 types of neurone

Answer 3

• Sensory
• Motor
• Relay

Question 4

What do Relay Neurones do?

Answer 4

Connect sensory and motor neurones

Short but highly branched with axons and dendrites

Question 5

Sensory Neurones

Answer 5

Carry impulses from receptors to CNS

Contains a cell body branching off middle.

Dendron carries impulse to cell body from receptor.

Axon carries impulse away from cell body

Question 6

Motor Neurones

Answer 6

Carry impulses from CNS to effectors.

Contain large cell body at one end lying in spinal cord or brain.

lots of branched dendrites so high surface area for axon terminals of other neurones.