8.1.2 - Neurones: Structure & Function

Question 1

What Are Neurones?

Answer 1

Specialised cells of the nervous system, which carry electrical impulses around the body.

Question 2

What Is A Nerve?

Answer 2

Bundle of neurones.

Question 3

What Features Are In All Neurones?
(5 Points)

Answer 3

~ Axon, which is a long fibre.

~ Cell body, containing a nucleus and other cellular structures.

~ Axon terminal, which is the end of the axon and has many nerve ending.

~ Dendrons.

~ Dendrites.

Question 4

What Is The Role Of The Axon Terminals?

Answer 4

Has many nerve endings allowing neurones to connect to it and to receive impulses from other neurones.

Question 5

What Carries Nerve Impulses Towards The Cell Body?

Answer 5

Dendrites and dendrons.

Question 6

What Carries Nerve Impulses Away From The Cell Body?

Answer 6

Axons.

Question 7

Describe The Myelin Sheath
(4 Points)

Answer 7

~ Is an electrical insulator.

~ Made up of Schwann cells, which wrap themselves around the axon.

~ The uninsulated gaps between the Schwann cells are the nodes of ranvier.

~ Electrical impulses jump from node to node, speeding up the impulse transmission.

Question 8

Describe What Happens In Non-Myelinated Neurones
(2 Points)

Answer 8

~ Axon is not insulated by Schwann cells.

~ Therefore the impulse travels more slowly, as it has to move through the entire length of the axon.

Question 9

What Are The 3 Main Types Of Neurones?

Answer 9

~ Motor neurones.

~ Sensory neurones.

~ Relay neurones.

Question 10

Where Do Sensory Neurones Carry Impulses From & To?

Answer 10

From the receptors to the CNS.

Question 11

What Do Relay Neurones Connect?

Answer 11

Sensory and motor neurones.

Question 12

Where Do Motor Neurones Carry Impulses From & To?

Answer 12

From the CNS to effector muscles or glands.

Question 13

Describe The Structure Of The Motor Neurone
(2 Points)

Answer 13

~ Many short dendrites that carry nerve impulses from the CNS to the cell body.

~ One long axon carries nerve impulses from the cell body to effector cells.

Question 14

Describe The Structure Of The Relay Neurone
(2 Points)

Answer 14

~ Many short dendrites that carry nerve impulses from sensory neurones to the cell body.

~ An axon carries nerve impulses from the cell body to motor neurones.

Question 15

Describe The Structure Of The Sensory Neurone
(3 Points)

Answer 15

~ One long dendron carries nerve impulses from receptor cells to the cell body.

~ Cell body is in the middle of the neurone.

~ One short axon carries nerve impulses from the cell body to the CNS.

Question 16

What Neurones Is This Showing?

Answer 16

Motor neurone.

Question 17

What Neurones Is This Showing?

Answer 17

Sensory neurone.

Question 18

What Neurones Is This Showing?

Answer 18

Relay neurone.