Increasing speed of conduction

Question 1

What three ways can nerve impulses be sped up by?

Answer 1

• Temperature
• Axon diameter
• myelination

Question 2

How does temperature speed up nerve impulses?

Answer 2

• More Kinetic Energy
• Faster molecules will move
• Past a certain point - they will DENATURE

Question 3

How does axon diamater speed up nerve impulses?

Answer 3

• wider
• speed up
• less resistance

Question 4

How does myelination (saltatory conduction) speed up nerve impulses?

Answer 4

• Myelin acts an insulator for the axon - it does not allow any ion movement across it
• this mean that depolarisation can only occur where there is no myelin - NODES OF RANVIER
• Na+ will have to diffuse further, skipping the sections where there is myelin and creating longer local currents
• Action potential only occurs at the nodes of Ranvier
• This speeds up the overall nerve impulses because the action potentials are not occurring in large sections of the axon.