The Cells Of The Nervous System And Neurotransmitters At Synapses

Question 1

What makes up the neuron? (5 things)

Answer 1

Dendrites, cell body, axons, myelin sheath, glial cells.

Question 2

What is the myelin sheath?

Answer 2

The myelin sheath surrounds axons and insulates the axon which increases the speed of impulse conduction

Question 3

What is myelination?

Answer 3

Myelination is the production of the myelin sheath

Question 4

When does myelination occur?

Answer 4

From birth to adolescence

Question 5

What are responses to stimuli like in the first two years of life?

Answer 5

The responses to stimuli are not as rapid or coordinated as those of an adult.
The responses are slow and uncoordinated

Question 6

What does MS ( multiple sclerosis ) do?

Answer 6

MS destroys the myelin sheath which results in a loss of coordination

Question 7

What are glial cells?

Answer 7

Glial cells produce the myelin sheath and support neurons

Question 8

What is the purpose of the cell body in the neuron?

Answer 8

To produce proteins such as neurotransmitters

Question 9

What is the function of a dendrite?

Answer 9

Dendrites receive information from pre-synaptic neurons across the synaptic cleft.

Question 10

Where do neurons connect with other neurons or muscle fibres at?

Answer 10

The synaptic cleft

Question 11

What is the function of neurotransmitters?

Answer 11

Neurotransmitters relay impulses across the synaptic cleft

Question 12

Where are neurotransmitters stored?

Answer 12

Neurotransmitters are stored in vesicles in the axon endings of the presynaptic neuron

Question 13

When are neurotransmitters released?

Answer 13

Neurotransmitters are released on the arrival of an impulse by the vesicles of an axon into the synaptic cleft

Question 14

What do neurotransmitters do during diffusion?

Answer 14

Neurotransmitters diffuse across the synaptic cleft and then bind to receptors on the membrane of the postsynaptic neuron

Question 15

How can neurotransmitters be removed if they are sent in excess?

Answer 15

By degradative enzymes or reuptake to prevent continuous stimulation of postsynaptic neurons

Question 16

What do receptors on the postsynaptic neuron determine?

Answer 16

Receptors determine whether the signal is excitatory or inhibitory

Question 17

What happens to weak stimuli in the synapses?

Answer 17

Synapses can filter out weak stimuli which arise from insufficient secretion of neurotransmitters

Question 18

What is meant by the threshold on the postsynaptic membrane?

Answer 18

Threshold is the minimum number of neurotransmitter molecules that must attach to receptors in order to transmit the impulse to the PS membrane

Question 19

How can weak stimuli trigger an impulse?

Answer 19

Summation of a series of weak stimuli can release enough neurotransmitter to trigger an impulse

Question 20

How can convergent neural pathways trigger impulses

Answer 20

Convergent neural pathways can release enough neurotransmitter molecules to reach the threshold and trigger an impulse

Question 21

What is meant by an excitatory effect from neurotransmission?

Answer 21

An effect that switches on the next nerve cell

Question 22

What is meant by an inhibitory effect on neurotransmission?

Answer 22

The neurotransmitters cause an effect that switches off the post synaptic neuron