Synaptic transmission UPSC Zoology previous year solved question in English and Hindi
The notes talks about synapse, nerve impulse transmission through synapse via acetylcholine as neurotransmitter
Description
Synapse term given by Sherrington in 1897.
It is the specialized, complex, functional intercellular junction between axon terminal of one neuron and dendrite of another adjacent neuron.
Types of Synapse
Chemical synapse
Electrical synapse
Q. Describe the processes of synthesis, secretion and action of acetylcholine during synaptic transmission? UPSC IFS 2020. 15 Marks.
Acetylcholine is a potent neurotransmitter, in both central and peripheral nervous system particularly released at the neuromuscular junction or motor end.
This chiefly excitatory neurotransmitter is synthesized in cytosol of pre-synaptic neuron by combination of Acetyl co-enzyme with choline under presence of enzyme Choline Acetyltransferase.
The choline in turn is sourced from most abundant phospholipid of the membrane the phosphatidyl-choline or lecithin.
The Acetylcholine is secreted from synaptic neuron in response to action potential or wave of depolarization.
The mechanism of secretion and action of acetylcholine in synaptic transmission can be described in following points :-
+ Step 1 = Arrival of action potential at the pre-synaptic neuron.
+ Step 2 = Opening of voltage gated calcium channel at pre-synaptic membrane & influx of calcium.
+ Step 3 = The calcium fuses to synaptic vesicles causing its mobilization.
+ Step 4 = The synaptic vesicle exocytosis & release of acetylcholine in synapse.
+ Step 5 & 6 = The acetylcholine binds ligand gated sodium/potassium/cation channel of the post-synaptic membrane causing influx of sodium ion into post synaptic neuron & travelling of action potential.
+ Step 7 = The Acetylcholine is released in synapse breaks down to acetyl & choline by action of acetylcholine esterase & again gets endocytosed by the presynaptic neuron.
Student Reviews
No reviews yet.