Biopsychology - the structure and function of neurons

Question 1

What is a neuron?

Answer 1

Specialised nerve cells which are part of the nervous system

Question 2

How do they transmit information?

Answer 2

Electrically (through action potentials) and chemically (through neurotransmitters)

Question 3

What do all neurons consist of?

Answer 3

Cell body, dendrites and axons
3mm - 1m long

Question 4

What are dendrites and what do they do?

Answer 4

Branch like structures protruding from cell body
They receive signals from other neurons
Connected to cell body

Question 5

What is the cell body and what do they do?

Answer 5

They control the centre of neuron
They contain all genetic information of the cell
Connected to axon

Question 6

What is the axon and what does it do?

Answer 6

Long protruding structure
Action potential carried along axon where it terminates at terminal button

Question 7

What is the axon terminal and what does it do?

Answer 7

Where neurotransmitters are stored in vesicles

Question 8

What is the myelin sheath and what does it do?

Answer 8

Fatty coating insulating layer that forms around the axon to protect it and so nerve impulses transmit more rapidly along it (if it’s damaged, nerve impulses slow down

Question 9

What is the node of ranvier and what does it do?

Answer 9

It speeds up transmission by forcing electrical impulses to ‘jump’ across gaps along the axon

Question 10

Sensory neurons (SN):
What size dendrites and axons do they have?

Answer 10

Long dendrites
Short axons

Question 11

(SN):
What is its function?

Answer 11

Carry messages from sense receptors in the PNS to the CNS

Question 12

(SN):
Do all messages go to the brain?

Answer 12

No - some terminate in spinal cord to allow reflex actions to occur quickly without delay of sending impulses to rain

Question 13

Motor neuron (MN):
What size dendrites and axons do they have?

Answer 13

Short dendrites
Long axons

Question 14

(MN):
What is its function?

Answer 14

Takes messages from CNS to effectors (muscles/glands)

Question 15

(MN):
Where is its cell body and axon located?

Answer 15

Cell body located in spinal cord and fibre (axon) projects outside spinal cord (PNS) to directly or indirectly control effector organs, mainly muscles and glands

Question 16

Relay neuron (RN):
What size dendrites and axons do they have?

Answer 16

Short dendrites and short axons

Question 17

(RN):
What is its function?

Answer 17

Connects the sensory neurons to the motor or other relay neurons
Only found in the brain and spinal cord and makes up 97% of all neurons