synapses

Question 1

chemical synapses occur between a neuron and what?

Answer 1

another neuron, muscle or gland cell

Question 2

describe the events that take place in a chemical synapse

Answer 2

. action potential depolarises presynaptic ending
. influx of calcium ions into prseynaptic ending
. vescles migrate towards membrane, realsing transmitters into cleft
. transmitters bind to receptors on post-synaptic cell
. inactivation of transmitters

Question 3

name the two waybs by which transmitters are inactivated

Answer 3

enzyme degradation, reuptake into presynaptic cell

Question 4

what happens if the transmitter causes depolarisation?

Answer 4

increased activity

Question 5

what happens if the transmitter causes hyperpolarisation?

Answer 5

inhibitory post-synaptic potential

Question 6

what is summation in relation to polarisation at a synapse?

Answer 6

the addition of excitatory polarisations

Question 7

what must occur for the post-synaptic cell to fire?

Answer 7

sufficient excitation drives membrane potential beyond the threshold

Question 8

what is neural convergence?

Answer 8

One post synaptic cell receives inputs from various presynaptic cells

Question 9

what is neural divergence?

Answer 9

each neuron synapses with many other cells

Question 10

what is a neuromuscular juntion and what is the associated transmitter?

Answer 10

synapse between moter nerve and muscle fibre

acetylcholine

Question 11

in what ways may a drug affect a synapse?

Answer 11

may enhance or supress:
. synthesis or storage of transmitter
. release of transmitter
. action of transmitter on receptor
. second messenger system
. inactivation of transmitter