Motor Neurones

Question 1

Schwann Cell

Answer 1

Surrounds axon and provides a layer of myelin which electrically isolates the neurone

Question 2

Axon

Answer 2

Carries nerve impulse from cell body to axon terminals

Question 3

Cell Body

Answer 3

Contains the neurone nucleus

Question 4

Myelin Sheath

Answer 4

Layer of fatty tissues composed of Schwann cells

Question 5

Dendrites

Answer 5

Extensions from the cell body that receive nerve impulses

Question 6

Synaptic Bulbs

Answer 6

Swellings at the end of terminal axons, produce neurotransmitter

Question 7

Nodes of Ranvier

Answer 7

Gaps in the myelin sheath that allows nerve impulses to be conducted quickly

Question 8

Axon Diameter - Effect on Speed of Transmission?

Answer 8

Increases when bigger

Question 9

Axon Diamtere - Why does the speed of transmission increase when it is bigger?

Answer 9

Larger surface area over which ions can diffuse
Reduces internal resistance

Question 10

Myelination - Effect on speed of transmission?

Answer 10

Increases when myelinated

Question 11

Myelination - Why does speed of transmission increase when myelinated?

Answer 11

Myelination insulates the neurone
Depolarisation and action potentials cannot occur except at the Nodes of Ranvier (Saltatory Conduction)