synapses

Question 1

describe the structure of a synapse

Answer 1

-presynaptic neurone
calcium ion channels
vesicles with neurotransmitters
-synaptic knob
-synaptic cleft
-postsynaptic neurone
sodium ion channels
-presynaptic and postsynaptic membrane

Question 2

describe the neuromuscular junction

Answer 2

motor neruone and muscle cell
-presynaptic neurone, synaptic cleft, vesicles with neurotrnsmitters
-sarcolemma (membrane)
-muscle fibre

Question 3

cholinergic synapse

Answer 3

-action potential opens calcium ion channels
-calcium ions enter
-vesicles with acetylcholine move to and fuse with presynaptic membrane
-acetycholine released and diffuses through synaptic cleft
-binds to receptors on sodium ion channels on postsynaptic membrane
-sodium ions enter and depolarisation occurs

Question 4

what is spatial summation

Answer 4

many neurones release neurotransmitters to exceed threshold

Question 5

what is temporal summation

Answer 5

one neurone repeatly releases neurotransmitters over a short period of time to exceed threshold value

Question 6

why is transmission unidirectional

Answer 6

-onloy presynaptic neurones release acetylchoene
-only postsynaptic neurones have receptors

Question 7

what do inhibitory synapses do

Answer 7

bind to receptors on chloride ion channels
chloride ions enter and pottassium ions leave causing hyperpolarisation