neurons + synaptic transmission

Question 1

What are the three types of neurons?

Answer 1

Sensory neuron, Relay neuron, Motor neuron

Question 2

What does the cell body of a neuron contain?

Answer 2

3 nuclei, which contain the genetic material of the cell

Question 3

What is the function of dendrites?

Answer 3

Carry nerve impulses from neighbouring neurons towards the cell body

Question 4

What carries impulses away from the cell body?

Answer 4

The axon

Question 5

What is the function of the myelin sheath?

Answer 5

Protects the axon and speeds up electrical transmission of the impulse

Question 6

What are the gaps in the myelin sheath called?

Answer 6

Nodes of Ranvier

Question 7

What is the role of the nodes of Ranvier?

Answer 7

Speed up the transmission of the impulse by forcing it to jump across the gaps along the axon

Question 8

Where are motor neurons located?

Answer 8

In the CNS but have long axons forming part of the PNS

Question 9

Where are sensory neurons located?

Answer 9

Outside of the CNS, in the PNS in clusters known as ganglia

Question 10

What percentage of all neurons are relay neurons?

Answer 10

97%

Question 11

Where are most relay neurons found?

Answer 11

In the brain and in the visual system

Question 12

What charge does a neuron have in its resting state?

Answer 12

Negatively charged inside compared to the outside

Question 13

What happens when a neuron is activated by a stimulus?

Answer 13

The inside of the cell becomes positively charged, causing an action potential

Question 14

What does an action potential create?

Answer 14

An electrical impulse that travels down the axon

Question 15

What is a synapse?

Answer 15

-gaps between neurons

Question 16

What is the process of synaptic transmission?

Answer 16

1-Information is passed down the axon of the neuron as an electrical impulse known as action potential
2-This triggers the nerve-ending of the pre-synaptic neuron to release chemical messengers called neurotransmitters
3-These chemicals diffuse across the synapse and bind with receptor molecules on the membrane of the next neuron
4-Receptor molecules on the second neuron bind only to the specific chemicals released from the first neuron. This stimulates the second neuron to transmit the electrical impulse
5-The NT is reabsorbed in the vesicles of the pre-synaptic neuron after it has performed its function of transmitting a neural impulse

Question 17

What are the two effects a neurotransmitter can have on the post-synaptic neuron?

Answer 17

-excitatory or inhibitory

Question 18

What is excitation?

Answer 18

-when receptor stimulation results in an increase in the positive charge of the postsynaptic neuron and increases the likelihood of the neuron firing and passing on the electrical impulse.

Question 19

What is inhibition?

Answer 19

-when receptor stimulation results in an increase in he negative charge of the postsynaptic neuron and decreases the likelihood of the neuron firing and passing on the electrical impulse.