Chapter 4: Neurone and Synapses

Question 1

Name 3 types of neurones

Answer 1

Sensory, connector, motor neurone

Question 2

Function of sensory neurone

Answer 2

conducts an impulse from a receptor to the CNS

Question 3

Function of connector neurone

Answer 3

connects neurone within CNS

Question 4

Function of motor neurone

Answer 4

conducts impulses from CNS to an effector

Question 5

What is the myelin sheath formed of?

Answer 5

schwann cells

Question 6

What are nodes of Ranvier?

Answer 6

small gaps between schwann cells

Question 7

What is resting potential?

Answer 7

neurones are described as polarised due to inside negative and outside positive

Question 8

How is an action potential generated?

Answer 8

Membrane becomes permeable to sodium ions which are able to diffuse into the axon this causes the membrane to become depolarised and reach a threshold value. This causes gated sodium ion channels to open and an influx of sodium ions into axon as they rapidly diffuse in. Rapid depolarisation of membrane allows an action potential to occur.

Question 9

What happens after an action potential?

Answer 9

REFRACTORY PERIOD. Sodium ions both diffuse and are pumped out of the axon causing repolarisation of axon membrane for resting potential to be restored. HYPERPOLARISATION is slight overshoot inside membrane

Question 10

What is the all or nothing law?

Answer 10

Only once the threshold stimulus is reached can action potential occur. Action potential can either occur or it does not