Intro to synaptic transmission

Question 1

what type of synapses make up the majority?

Answer 1

chemical

Question 2

what synapses are more common in the developing nervous system compared to the mature nervous system?

Answer 2

electrical

Question 3

which type of synapses are simple but have fast transmission?

Answer 3

electrical

Question 4

is signal transmission in electrical synapses passive or energy consuming?

Answer 4

passive

Question 5

what are the three types of chemical synapses and what do they contact?

Answer 5

1) axodendritic - axon of pre to dendrite of post
2) axiosomatic - axon on pre to soma of post
3) axoaxonic - axon of pre to axon of post

Question 6

what has a big role to play in how the post synaptic cell reads the signal?

Answer 6

location of the synapse

Question 7

what NT is used at the NMJ?

Answer 7

Ach

Question 8

what happens to the post synaptic membrane to initiate excitation or inhibition?

Answer 8

excitation - depolarisation

inhibition - hyperpolarisation

Question 9

what are three roles of neuromodulation?

Answer 9

1) to alter the pre synaptic cells ability to release more transmitter
2) alter post synaptic cells ability to respond
3) change how sensitive cells are to receive signals

Question 10

what four criteria define a neurotransmitter?

Answer 10

1) synthesised in a neuron
2) present in pre syn terminal and released in sufficient amounts to exert an effect on the post syn/effector organ
3) mimic endogenous action when administered exogenously as a drug
4) has a specific mechanism to removing it from the synaptic cleft

Question 11

what is the sequence of events at a chemical synapse? (9 events)

Answer 11

1) transmitter is pre-synthesised and stored in vesicles
2) AP arrives at the pre syn terminal
3) depolarisation of the pre syn causes opening of VG calcium channels on the pre syn membrane
4) calcium floods into pre syn and causes vesicles to fuse with the membrane
5) NT is released across the synaptic cleft
6) transmitter binds to receptor molecules on post syn
7) post synaptic channels open or close
8) post synaptic current causes excite or inhibition that changes excitability of the post syn/effector cell
9) removal of NT by glial update or enzyme degradation

Question 12

what type of cell removes NT from the synaptic cleft?

Answer 12

glial cells