module 5 - 13.5 synapses Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

what is the synaptic cleft?

A

a gap that separates the axon of one neurone from the dendrite of the next neurone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is involved in the structure of a synapse?

A
  • synaptic cleft
  • presynaptic neurone
  • postsynaptic neurone
  • synaptic knob
  • synaptic vesicles
  • neurotransmitter receptors
  • voltage gated calcium ion channel proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the presynaptic neurone?

A

action potential (impulse) arrives at the synapse along its neurone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is the postsynaptic neurone?

A

neurone that receives the neurotransmitter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the synaptic knob?

A

swollen end of the presynaptic neurone, with many mitochondria and extensive ER to synthesise neurotransmitters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are the synaptic vesicles?

A

contain neurotransmitter that fuses with presynaptic membrane and diffuses into synaptic cleft

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are neurotransmitters that are sodium ion channel proteins?

A

specific protein molecules in postsynaptic plasma membrane where the transmitter will bind too

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what does polarised mean?

A

more positive charge on outside than inside

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what does depolarised mean?

A

more negative charge on outside than inside 1 (Na+ goes into cell)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what does repolarisation mean?

A

more positive goes out, more negative on inside (K+ goes out of cell)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is an excitatory neurotransmitter/what does it do?

A
  • cross synaptic cleft
  • cause localised depolarisation of postsynaptic membrane, if this reaches threshold potential then action potential is initiated
  • common in CNS and neurotransmitter junctions
  • e.g. acetylcholine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is an inhibitory neurotransmitter/what does it do?

A
  • cross synaptic cleft
  • cause hyperpolarisation of the postsynaptic membrane
  • prevent action potentials being initiated
  • e.g. GABA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is an electrical synapse?

A
  • the place where there is a direct physical connection between pre and postsynaptic neurone
  • connection takes the form of a channel (gap junction) that allows current int eh form of ions to flow directly from one cell to another
  • allows very fast cell signalling
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is an example of an electrical synapse?

A

transmission of the depolarising current from cell to cell, across chambers of the heart, so cells contract in unison

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is meant by ‘unidirectional impulses’ as a role of a synapse?

A
  • neurotransmitter receptors are only present in postsynaptic membrane
  • allows impulse from one neurone to transmit to a number of neurone
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is meant by ‘divergence’ as a role of a synapse?

A

impulses from a single neurone are passed to more than one neurone

17
Q

what is meant by ‘convergence’ as a role of a synapse?

A

impulses from morethan one neurone are passed to a single postsynaptic neurone, so stimuli from different receptors produce a single result

18
Q

what is meant by ‘filter out’ as a role of a synapse?

A

filter out background and low level stimuli, ensuring that only stimulation that is strong enough will be passed on

19
Q

what is summation?

A
  • each stimulus from presynaptic neurone causes same amount of neurotransmitter release into synaptic cleft
  • sometimes neurotransmitter from a single impulse isn’t enough to initiate action potential in postsynaptic neurone
  • if the amount of neurotransmitter buildup in synaptic cleft, an action potential is initiated
20
Q

what are the 2 types of summation?

A
  • temporal summation
  • spatial summation
21
Q

what are 2 types of drugs?

A
  • recreational drugs
  • medicinal drugs
22
Q

what are the 2 types of modes of action of drugs on synapses?

A
  1. STIMULATE the NS by creating more action potentials in postsynaptic neurone
  2. INHIBIT the NS by reducing amount of action potentials in postsynaptic neurone
23
Q

what is GABA?

A
  • an inhibitory neurotransmitter
  • causes hypoerpolarisation of postsynaptic membrane
24
Q

explain GABA receptors and ethanol?

A
  • GABA receptor is a chloride ion channel protein and pore opens when GABA binds to its binding site
  • influx of chloride ions into postsynaptic neurone prevents action potentials from being initiated
  • ethanol also binds to the GABA receptors and the pore remains open longer, so more Cl- goes into postsynaptic neurone
  • this increases inhibitory effects on GABA synapses and cause ethanol induced effects on humans