15.5 structure & functions of synapses

Question 1

how does unidirectionality benefit synaptic transmission?

Answer 1

information could only be transmitted in 1 direction

Question 2

what is temporal summation?

Answer 2

1 presynaptic neuron releases neurotransmitter many times in a short period to exceed threshold value

Question 3

what is spatial summation?

Answer 3

number of different presynaptic neurones release enough neurotransmitted to exceed the threshold value

Question 4

how is a synapse inhibited? (5)

Answer 4

1- presynaptic neurone releases neurotransmitted which binds to Cl- ion protein channels
2- Cl- protein channels open & Cl- ions move in postsynaptic neurone by facilitated diffusion
3- K+ protein channels open & K+ ions move out of postsynaptic neurone
4- both 2) & 3) makes postsynaptic neurone more negative & outside more positive
5- membrane potential increased to -80 mV -> hyperpolarisation
- larger influx of Na+ is needed to produce action potential