Unit 1 Part 2: organ systems, Immunity and genetics

Question 1

what is the nervous system made up of?

Answer 1

nerve cells called neurons.

Question 2

what is a nerve impulse?

Answer 2

The electrical signals transmitted throughout the nervous system.

Question 3

in the structure of a neuron, explain the role of an axon.

Answer 3

A long nerve fibre of a neuron which carries a nerve impulse.

Question 4

in the structure of a neuron, explain the role of dendrites.

Answer 4

slender extensions from the cell body which connect with neighbouring neurons.

Question 5

in the structure of a neuron, explain the role of schwann cells.

Answer 5

specialised cells associated with the axons of the myelinated neurones, forms the insulating ,myelin sheath.

Question 6

in the structure of a neuron, explain the role of the myelin sheath.

Answer 6

fatty insulating layer around some axons produced by the schwann cells.

Question 7

in the structure of a neuron, explain the role of the node of ranvier.

Answer 7

gaps between the schwann cells that enable saltatory conduction. This speeds up nerve impulses.

Question 8

what is the name of the direction of nerve impulse along a neuron that travels towards the cell body?

Answer 8

dendrites

Question 9

what is the name of the direction of nerve impulse along a neuron that travels away from the cell body?

Answer 9

axons

Question 10

what is the (CNS)?

Answer 10

the (CNS) is the central nervous system linking the brain and spinal chord that coordinate a response to a stimulus. This only involves relay neurons.

Question 11

what is the (PNS)?

Answer 11

the (PNS) is the peripheral nervous system that involves all of the nerves outside the brain and spinal chord. This involves only sensory neurons and motor neurons.

Question 12

what are reflex reactions?

Answer 12

involuntary actions that involve sensory, relay and motor neurons however the brain is not initially involved.