Synapses (Chemical synapses) By Mayur Anant Dakhore
1. SHRI SHIVAJI SCIENCE COLLEGE,
AMRAVATI
2022 - 2023
Department Of Zoology
B.Sc.Part-III (Semester- V)
Topic:- Synapse
(Chemical synapse)
Presented By - Mayur Anant Dakhore
Assigned By - Dr. Jayashree Dhote
2. Synapse:-
● Synapses refer to the points of contact between
neurons where information is passed from one
neuron to the next.
● Synapses most often form between axons and
dendrites, and consist of a presynaptic neuron,
synaptic cleft, and a postsynaptic neuron.
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1. Electrical synapse:- Cell association between two
nerve cells where ions are used to transmit nerve
impulses rapidly.
2. Chemical synapse:- Cell-to-cell connection via
which neurotransmitters transfer nerve impulses in
one way.
Two categories of
synapse:-
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The synapse consists of three elements:-
1. The presynaptic membrane which is formed by the
terminal button of an axon.
2. The postsynaptic membrane which is composed of
a segment of dendrite or cell body.
3. The space between these two structures which is
called the synaptic cleft.
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✘ Web of filaments which is
implanted on the post synaptic
menbrane and extend to
considerable distance in the
postsynaptic cytoplasm
✘ The web of filaments is known
as subsynaptic web
✘ It is observed in central
synapses of the brain cortex
and in retinal synapses.
✘ Average width :- 200 Ao (20nm)
✘ It represent the real
discontinuity of cell cytoplasm
in the synaptic junction.
✘ In cleft of brain cortex (Central
synaptic) there is presence of
inter synaptic filaments of
about 500 Ao crossing the
synaptic cleft.
✘ The filaments are in membrane.
Synaptic cleft and subsynaptic
web:-
8. Mitochondrion and it's function:-
There is mitochondrion present on postsynaptic node.
It take part in synthetic of transmitter substance.
Synapse vesicles and it's function:-
1. Normally present in terminal of axon.
2. They are more concentrated towards the site
fronting the synaptic cleft.
3. It contain excitatory transmitter material that
mediates transmittion of impulse from presynaptic
neurons to postsynaptic neurons.
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