Properties Of Synaptic Transmission

Question 1

What are the properties of synaptic transmission?

Answer 1

Law of forward direction, synaptic delay, synaptic fatigue, summation of postsynaptic potentials, effects of ph, O2, drugs and chemicals

Question 2

Explain law of forward direction

Answer 2

Impulses are transmitted in one direction only from the pre- to the postsynaptic neuron

Question 3

Explain the synaptic delay and what it is needed for

Answer 3

It is about 0.5 msec and is needed for:
Release of the neurotransmitter from the synaptic knobs
Diffusion of the transmitter across the synaptic cleft
Summation of postsynaptic potentials to produce the response

Question 4

Explain synaptic fatigue

Answer 4

It is gradual decrease in the response due to repeated stimulation of the presynaptic neurons, due to depletion of the neurotransmitter in the synaptic knob

Question 5

Why is synaptic fatigue important?

Answer 5

Its a protective mechanism against excess neuronal activity as it is the main cause of termination of an epileptic fit

Question 6

Explain summation of postsynaptic potentials

Answer 6

Spatial and temporal summation, both types can coexist if several presynaptic neurons are successively stimulated at an interval not exceeding 15 milliseconds

Question 7

Explain effect of ph, O2, drugs and chemicals

Answer 7

Ph → alkalosis → increase the excitability, acidosis → depresses the synaptic excitability
Hypoxia → decreases the synaptic transmission

Question 8

Example of drugs that increase the synaptic transmission

Answer 8

Caffeine, theophylline, theobromine

Question 9

Drugs that inhibit synaptic transmission

Answer 9

Alcohol, anesthetics, sedatives and hypnotics