Nerveous Coordination (15)

Question 1

What is the role of the dendrites on a nerve cell?

Answer 1

Carry nerve impulses towards the cell body, many different nerve pathways to contract muscle

Question 2

What is the role of the axon in a nerve cell?

Answer 2

Single long fibre carries nerve impulses away from the cell body. Synapses cause delay between nerve cells

Question 3

What is the role of myelin sheath?

Answer 3

Insulates the axon causing electrochemical impulses to jump, moves quicker

Question 4

What is the role of the multiple axon terminal?

Answer 4

All muscle stimulated at the same time so faster

Question 5

Describe the 4 points in establishing a resting PD in a nerve cell

Answer 5

More Na+ pumped out than K+ ions pumped in

K+ can diffuse out —> K+ channels open, more K+ channels

Overall more positive charge outside than in

Inside relatively speaking has a negative P.D

Question 6

Describe how the relative potential difference changes inside a neurone from resting —> action potential —> resting (GRAPH)

Answer 6

Na+ voltage gated channels open and Na+ flood in —> then more Na+ channels open ( PD is rising)
Threshold met for an AP

At highest PD during an Action Potential Na+ channels close and K+ channels open and K+ flood in

PD starts dropping

Hyper-polarisation of the membrane

Active pumping of the Na+ and K+ during the refractory period back to resting