Sensory, motor neurones and action potentials

Question 1

What is the role of dendrites?

Answer 1

Very fine dendrites at the ned of the neurone, conduct impulses towards the cell body

Question 2

What is the role of an axon?

Answer 2

A single long process, the axon transmits impulses away from the cell body

Question 3

What it the myelin sheath and its role?

Answer 3

• formed by specialised cells called Schwann cells which wrap around the axon
• acts as electrical insulation but it has series of gaps in it called the nodes of Ranvier
• with the myelin sheath present the impulse does not pass straight along the axon but moves in a series of jumps
• allows action potential to move from node to node, thus speeding it up

Question 4

What is the role of the nervous system?

Answer 4

All organisms can detect changes in their environment and make appropriate responses to them
Coordination and control is achieved by the transmission of electrical signals, called nerve impulses, along specialised cells called neurones.