15.5 Structure And Function Of Synapse

Question 1

Synapse definition

Answer 1

Point between 2 neurones or neurone and effector

Question 2

What is the synaptic cleft?

Answer 2

Gap that separates neurones

Question 3

Neurotransmitters

Answer 3

Chemicals that transmit information from one neurone to another

Question 4

Presynaptic neurone definition

Answer 4

Neurone that releases the neurotransmitter

Question 5

Synaptic knob definition

Answer 5

Swollen portion of the neurone end

Question 6

Where is the neurotransmitter stored?

Answer 6

Synaptic vesicles

Question 7

How will the postsynaptic neurone receive the neurotransmitter?

Answer 7

Possesses specific receptor proteins on its membrane

Question 8

Draw the structure of a synapse

Answer 8

Page 360

Question 9

Which way does the neurotransmitter pass?

Answer 9

From the presynaptic neurone to the postsynaptic neurone

Question 10

Spatial summation definition

Answer 10

Number of DIFFERENT presynaptic neurones together release enough neurotransmitter to exceed the threshold level of the postsynaptic neurone

Question 11

Temporal summation definition

Answer 11

A SINGLE presynaptic neurone releases neurotransmitter many times over in a short period to exceed the threshold value of the postsynaptic neurone

Question 12

What are inhibitory synapses?

Answer 12

Synapses that make it less likely a new action potential will be created on the post synaptic neurone

Question 13

How do inhibitory synapses work?

Answer 13

• presynaptic neurone releases neurotransmitter
• neurotransmitter binds to Cl- channels on postsynaptic neurone
• Cl- channels open
• Cl- move into postsynaptic neurone by facilitated diffusion
• k+ channels open on postsynaptic neurone
• K+ move out of post synaptic neurone by facilitated diffusion
• causes hyperpolarisation

Question 14

Hyperpolarisation definition

Answer 14

Potential is much more negative than its resting potential

Question 15

What happens when hyperpolarisation occurs?

Answer 15

Less likely a new action potential will occur because a larger influx of Na+ is needed to produce one (larger generator potential needed)

Question 16

A single impulse along one neurone can do what at a synapse?

Answer 16

Initiate new impulses in a number of different neurones

Question 17

What is the advantage of having a single impulse along a neurone initiating new impulses to an number of other neurones at synapses?

Answer 17

Single stimulus can create a number of simultaneous responses

Question 18

What can happen to lots impulses at a single synapse?

Answer 18

Can be combined

Question 19

What does combining nerve impulses at a synapse allow?

Answer 19

Allow nerve impulses from receptors reacting to different stimuli to contribute to a single response

Question 20

What happens to the vesicles when an action potential reaches the synaptic knob

Answer 20

Vesicles fuse with the presynaptic membrane to release the neurotransmitter

Question 21

Where are the protein receptors complementary to the neurotransmitter found?

Answer 21

Only on the postsynaptic neurone

Question 22

Excitatory synapses definition

Answer 22

Synapses that produce new action potentials