Structure and function of neurones and synaptic transmission

Question 1

Three types of neurone?

Answer 1

Motor
Sensory
Relay

Question 2

Name the features of a neurone

Answer 2

o Cell body (contains nucleus)
o Dendrites 
o Axon 
o Myelin sheath 
o Nodes of Ranvier
o Terminal button

Question 3

Roles of the three neurones and their structure?

Answer 3

o Motor - connect the CNS to effectors such as muscles and glands, short dendrites and long axons
o Relay - connect the sensory neurones to the motor or other relay neurones, short dendrites and short axons
o Sensory - carry messages from the PNS to the CNS, long dendrites and short axons

Question 4

What are effectors?

Answer 4

Muscles and glands

Question 5

What charge does a neurone have in a resting state (resting potential)?

Answer 5

-65/70 mv (negative)

Question 6

What causes an action potential?

Answer 6

o Neurone becomes positively charged after a stimulus, if threshold is reached an action potential is created

Question 7

What is an excitatory neurotransmitter and an example?

Answer 7

o increases the positive charge of the postsynaptic neurone therefore making it more likely to fire
o Adrenaline

Question 8

What is an inhibitory neurotransmitter and an example?

Answer 8

o makes the postsynaptic neurone more negative therefore making it less likely to fire
o Serotonin

Question 9

Outline the process of synaptic transmission?

Answer 9

o Electrical impulse reaches presynaptic terminal causing vesicles containing neurotransmitters to fuse with the presynaptic membrane
o Neurotransmitters released into the synapse and diffuse across
o Receptors on the post-synaptic neurone are specific to the neurotransmitter, allowing the neurotransmitter to bind
o Chemical message then converted into an electrical one once again