The structure and functions of neurons

Question 1

What is the structure of a neurone?

Answer 1

Cell body includes a nucleus (genetic material of the cell)
Dendrites - protrude from cell body
Carry nerve impulses from neighbouring neurone towards cell body
Axon - carry impulses away from cell body down the neurone
Covered in fatty layer of MYELIN SHEATH - protects axon and speeds up electrical transmission of impulse
If continuous would have reverse effect and slow down impulse
Segmented gaps called nodes of ranvier -
Speed up transmission of impulse by forcing it to jump across gaps along axon
Terminal buttons - communicate with next neurone in chain across gap known as synapse

Question 2

What are motor neurons?

Answer 2

Transmit nerve impulses from CNS to effectors (muscles or glands)
Short dendrites
Long axons

Question 3

What are sensory neurons?

Answer 3

Transmit nerve impulses from receptors Organs found in the PNS to the CNS
Long dendrites
Short axons

Question 4

What are relay neurons?

Answer 4

Connect sensory neurons to motor neurons or other relay neurons.
Short dendrites
Short axons

Question 5

What is electrical transmission?

Answer 5

Firing of a neuron
When neuron is in resisting state
Cell - negatively charged compared to the outside
When activated by stimulus
Cell - positively charged for a split second
Causing action potential
Creating electrical impulse that travels down axon towards end of the neuron

Question 6

What is the location of motor neurones?

Answer 6

Their cell bodies are found in the CNS but axons from part of the PSN

Question 7

What is the location of sensory neuron’s?

Answer 7

Located in the PNS in clusters known as ganglia

Question 8

What is the location of relay neurons?

Answer 8

Located in the CNS (specifically brain and visual system)