12. Action potentials

Question 1

Name the three parts all neurons have

Answer 1

• Dendrites
• Cell body
• Axon

These components are essential for the transmission of nerve impulses.

Question 2

Describe what myelinated means

Answer 2

Axon of the neuron is covered by myelin

Myelin is a fatty insulating layer that facilitates faster transmission of action potentials.

Question 3

Assess the importance of the Relay (inter) Neurone

Answer 3

Connects sensory and motor neurons

Relay neurons play a crucial role in processing information within the nervous system.

Question 4

What is an action potential?

Answer 4

Sending of a nerve impulse from dendrites to axon terminals

Action potentials involve changes in ion concentrations across the neuron’s membrane.

Question 5

Fill in the blank: The sodium-potassium pump regulates the distribution of _______ and _______ ions.

Answer 5

Na+ and K+

This pump is essential for maintaining the resting potential of the neuron.

Question 6

What is the membrane potential?

Answer 6

Difference in total charge between the inside and outside of the cell

The resting potential is typically around -70mV.

Question 7

What occurs during depolarisation?

Answer 7

Cell becomes more positively charged inside than outside

This is triggered when Na+ channels open and Na+ ions diffuse into the cell.

Question 8

What is the refractory period?

Answer 8

Allows the sodium-potassium pump to return ions to their original positions

This period is essential for resetting the neuron’s resting potential.

Question 9

How does saltatory conduction differ from unmyelinated conduction?

Answer 9

Action potential jumps across gaps (nodes) in myelinated axons

This results in faster transmission compared to unmyelinated neurons.

Question 10

True or false: Unmyelinated axons have a fatty insulating layer.

Answer 10

FALSE

Unmyelinated axons lack myelin, which affects the speed of action potential transmission.