Nerve Impulses 2

Question 1

What are electrical changes in an axon which allow nerve impulses to be detected

Answer 1

Electrical changes in an axon that low nerve impulses to be detected are:
Potential difference across axon changes due to voltage gated sodium channels opening, sodium ions cause depolarisation. This is followed by potassium channels opening and potassium ions cause repolarisation.

Question 2

What is refractory period

Answer 2

Refractory period is that a new action potential cannot be generated in same section of membrane for about 5milliseconds

Question 3

Why does myelinated axon have a higher impulse velocity than a non myelinated axon

Answer 3

Myelinated axon has higher impulse velocity than a non myelinated axon because of saltatory conduction

Question 4

How does saltatory conduction work

Answer 4

Saltatory conduction works by:
Depolarisation at node of Ranvier
Electric current between nodes, which reduces potential difference at next node, initiating another action potential.

Question 5

How can intensity of a stimulus be changed

Answer 5

Intensity of stimulus can be changed by changing the:
Frequency of impulses
Number of neurones that are conducting an impulse

Question 6

What factors increase speed of conduction

Answer 6

Factors that increase speed of conduction are:
Diameter, wider diameter faster impulse travels (less leakage of sodium ions)
Myelination because of saltatory conduction