8.1.5 - Synapses: Structure & Function

Question 1

What Are Synapses?

Answer 1

Junctions between neurones or effectors.

Question 2

Describe The Structure Of Synapses
(3 Points)

Answer 2

~ Synaptic cleft, gap between neurones.

~ Pre-synaptic neurone has a synaptic knob and vesicles contains neurotransmitters.

~ Post-synaptic neurone, has receptors which neurotransmitter binds to.

Question 3

Describe Neurotransmitters
(2 Points)

Answer 3

~ Trigger an action potential, when bound to receptors on post-synaptic membrane.

~ Need to be removed from the synaptic cleft, to prevent action potential from continuously happening.

Question 4

Describe The Process Of Synaptic Transmission
(7 Points)

Answer 4

~ Action potential, stimulates a voltage gated calcium ion channels to open.

~ Causing a calcium ion influx, into the pre-synaptic membrane.

~ Vesicles contain neurotransmitters, fuse with the pre-synaptic membrane.

~ Vesicles then release neurotransmitters into the synaptic cleft, via exocytosis.

~ Neurotransmitters diffuse across the synaptic cleft, binds to specific receptors on the post-synaptic membrane.

~ Causing sodium ion channels to open.

~ Influx of sodium ions, generates an action potential, causing depolarisation in the post-synaptic neurone.