PostSynaptic Potentials

Question 1

What will happen if an excitatory nerve fiber is stimulated?

Answer 1

It will release of an excitatory chemical transmitter such as acetyl choline, noradrenaline, dopamine, serotonin, substance p

Question 2

What will the neurotransmitter cause?

Answer 2

Increase the membrane permeability to Na+
Cause Ca 2+ influx

Question 3

What are the characters of excitation?

Answer 3

Localized, not followed by ARP, doesn’t obey all or none rule
Summated by either spatial or temporal summation

Question 4

Define spatial summation

Answer 4

Many synaptic knobs discharge at the same time, each knob produces EPSPs that summate together to reach the firing level

Question 5

Define temporal summation

Answer 5

Rapid repeated discharge from a single knob will produce frequent EPSPs that will summate producing a response

Question 6

What does the stimulation of an inhibitory presynaptic fiber leads to?

Answer 6

Release of an inhibitory chemical transmitter such as GABAand glycine

Question 7

What will the inhibitory transmitter cause?

Answer 7

K+ efflux
Cl- influx
Closure of Na+ or Ca 2+ channels
Leading to partial hyperpolarization and decreased excitability IPSP