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A2 Biology > Synapses > Flashcards

Flashcards in Synapses Deck (9)
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1
Q

How does a action potential reach the CNS or effector?

A

it has to be passed between several neurones

the junction between two neurones (or a neurones and an effector) is called a synapse

2
Q

How are impulses transmitted across a synapse?

A

using chemicals called neurotransmitters

3
Q

What is the synaptic cleft?

A

the gap which separates the axon of one neurone from the dendrite of the next neurone

4
Q

what is the presynaptic and postsynaptic neurone?

A

presynaptic - neurones along which the impulse has arrived

postsynaptic - neurone that receives the neurotransmitter

5
Q

What is the synaptic knob? What are its featuyres

A

the swollen end of the presynaptic neurone

it contrains many mitochondria na dlarge amounts of endoplascmic reticulum to enable it to manufacture neurotransmitters

6
Q

What are synaptic vesicles?

A

vesicles contraining neurotransmitters

the vesicles fuse with the presynaptic membrane and release their contents in the synaptic cleft

7
Q

WHat are neurotransmitter receptorss?

A

receptor molecules which the neurotransmitter binds to in the postysynaptic membrane

8
Q

What is a excitatory neurotransmitter?

A

these neurotransmitters result in the depolarisation of the postsynaptic neurone

if the threshold is reached in the post synaptic membrane an action potential is triggered

acetylcholine is an example of an excitatory neurotransmitter

9
Q

What is a inhibitory neurotransmitter?

A

result in the hyperpolarisation of the postsynaptic membrane

this prevents an action potential being triggered

Gamma-aminobutyric acid (GABA) is an example of an imhibtory neutrotransmitter that is found in some synapses in the brain

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