neurons and synaptic transmission

Question 1

sensory neuron

Answer 1

• carry nerve impulses from sensory receptors to the spinal cord and the brain

Question 2

relay neuron

Answer 2

• allows the sensory and motor neurons to communicate with each other
• exist solely in the brain and spinal cord

Question 3

motor neuron

Answer 3

• they connect the central nervous system, to effectors such a muscles and glands

Question 4

action potential

Answer 4

when information is passed down the axon of the neuron as an electrical impulse

Question 5

synaptic vesicle

Answer 5

• contain chemical messengers (neurotransmitters)

Question 6

neurotransmitter

Answer 6

• carry signals across the synaptic cleft
• bind to receptor sites on the post-synaptic cell

Question 7

inhibition

Answer 7

neuron becomes more negatively charged and less likely to fire

Question 8

excitation

Answer 8

neuron becomes more positively charged and is more likely to fire

Question 9

summation

Answer 9

determines how frequently the neuron will fire by the combined effects of excitatory and inhibitory signals

Question 10

what % of neurons are located in the brain

Answer 10

80%

Question 11

how are sensory neurons adapted for their function

Answer 11

long dendrites and axon

Question 12

how are relay neurons adapted for their function

Answer 12

short dendrites
short axons

Question 13

how are motor neurons adapted for their function

Answer 13

short dendrites
long axons

Question 14

Process of synaptic transmission

Answer 14

• Electrical impulse (action potential) travels down the axon.
• Reaches the presynaptic terminal
• Triggers vesicles to release neurotransmitters into the synaptic cleft.
• Neurotransmitters diffuse across the gap.
• Bind to receptor sites on the postsynaptic neuron.
• May cause excitatory or inhibitory effects.
• Summation occurs — if total excitatory input is strong enough, a new impulse is triggered.
• Neurotransmitters are reabsorbed (reuptake) or broken down.

Question 15

neuron

Answer 15

nerve cells that transmit information throughout the nervous system using electrical and chemical signals

Question 16

cell body (soma)

Answer 16

contains the nucleus, which holds the cell’s genetic material

Question 17

Dendrites

Answer 17

extend from the cell body and receive signals from other neurons

Question 18

axon

Answer 18

carries electrical impulses away from the cell body towards the axon terminal.

Question 19

myelin sheath

Answer 19

covers axon
which insulates it and speeds up transmission.

Question 20

Nodes of Ranvier

Answer 20

gaps in the myelin sheath that help the impulse “jump” along the axon (saltatory conduction)

Question 21

axon terminal

Answer 21

ends in terminal buttons, which pass the signal to the next neuron across a synapse using neurotransmitters