Neurones 5.3.2

Question 1

What is the nervous system?

Answer 1

This communication system controls and coordinates functions throughout the body and responds to internal and external stimuli

Question 2

What is a nerve?

Answer 2

A bundle of axons of many neurones (single nerve cells) make up a nerve.

Question 3

Describe the structure of a neurone (basic)

Answer 3

• Cell body: nucleus and organelles
• Dendrites: conduct/transport to cell body
• Axons: transport away from cell body

Question 4

What are sensory neurones?

Answer 4

They carry an action potential from sensory receptors to the CNS

Question 5

What are motor neurones?

Answer 5

They carry an action potential from the CNS to an effector

Question 6

What are relay neurones?

Answer 6

They connect motor and sensory neurones

Question 7

Describe the structure of a sensory neurone

Answer 7

• Cell body on the axon
• Myelinated
• One end (dendron) connects to a sensory receptor, and the other end (axon) have synaptic endings - nearer the CNS

Question 8

Describe the structure of a motor neurone

Answer 8

-

Question 9

What is an axon?

Answer 9

It carries impulses away from the cell body

Question 10

What do dendrites do?

Answer 10

They carry impulses towards the cell body

Question 11

Describe the structure of a relay neurone

Answer 11

• Non-myelinated
• have both dendrites and synaptic endings -however the synaptic endings are located at the bottom of the axon
• Cell body within the neurone

Question 12

What are Schwann cells?

Answer 12

• Glial cell that produces myelin
• Small gaps between neighbouring Schwann cells, called Nodes of Ranvier, allow a nerve impulse to travel along a myelinated axon in a series of jumps

Question 13

What is myelin?

Answer 13

A fatty material which forms a layer around axons