This document discusses and compares chemical and electrical synapses. It defines a synapse as a junction between two neurons. There are three types of synapses: chemical, electrical, and conjoint. Chemical synapses use neurotransmitters for impulse transmission across the synaptic cleft in one direction, while electrical synapses have direct connections through gap junctions that allow for faster two-way transmission. Key differences are that chemical synapses exhibit synaptic properties and delay, while electrical synapses do not.

1. Chemical and
Electrical Synapse
GUIDED BY- DR. JITENDRA SIR
CREATED BY- HEMANT SONI (127)

2. Outline
 Synapse
 Physiological classification of synapse
 Comparison between chemical and
electrical synapse
 Summary

3. Synapse
 A synapse is a junction between two
neurons where the axon (or some
other part) of one neuron (called as
pre-synaptic neuron) terminates on
the dendrite (or another part) of the
second neuron (called as post-
synaptic neuron).

4. Pre-synaptic neuron
Pre-synaptic neuron
Post-synaptic neuronsynapse
Post-synaptic neuron
Synaptic cleft

5. Physiological classification
1)Chemical Synapse
2)Electrical Synapse
3)Conjoint Synapse

6. Chemical Synapse
 Chemical synapses use chemicals
(neurotransmitters) for conduction of
impulse along the junction.
 They are widely spread in the body.
 The two neurons are not in contact
physically.
 They usually transmit impulse in only one
direction.

7. Electrical Synapse
 Neurons forming electrical synapse have
gap junctions or low resistance bridges
between them.
 They are only seen in a few locations (e.g.
– within the retina, olfactory bulb,
hippocampus, etc.) in human nervous
system.
 Impulse is transmitted in both the
directions.

8. Conjoint Synapse
Conjoint synapse is a type
of synapse where both
chemical and electrical
transmission co-exist.

9. Chemical Synapse Electrical synapse
Use neurotransmitters
(chemical mediator) for
transmission of impulse
Impulse is transmitted through
gap junctions or low-
resistance bridges
Transmission is one way Transmission is two-way
They are seen at most of the
synaptic junctions in the body
They are found only in special
areas like retina, olfactory
bulb, Lateral vestibular
nucleus, Cerebral cortex,
Hippocampus etc.

10. Synaptic cleft is present Synaptic cleft gets
replaced by low-
resistance bridges
Synaptic delay (0.5
msec) is present (slower)
Synaptic delay is absent
because of low
resistance bridges
(faster)
Sensitive to hypoxia and
pH changes
Insensitive to hypoxia
and pH changes

11. Allows for large number of
synapses per neuron with a
variety of neurotransmitters.
This results in infinite processing
of information. This particularly
helps in process of learning
and memory.
There are not too many
synapses on a single neuron
thus transmission across it is
simple, rapid and efficient.
More vulnerable to Synaptic
fatigue
Does not get fatigued
Conduction is slower due to
presence of synaptic delay
Conduction is of same speed
as nerve conduction

12. It shows synaptic properties
(one-way conduction,
synaptic delay, summation,
convergence and
divergence, occlusion
phenomenon and subliminal
fringe)
It does not show synaptic
properties
It is found in higher
vertebrates and thus
evolution-wise, it is more
advanced
It is mainly found in
invertebrates and lower
vertebrates.

13. Summary
 Synapse is a junction between two neurons.
 Types of synapse:
 Chemical Synapse
 Electrical Synapse
 Conjoint Synapse
 Comparison-
 Chemical synapse uses neurotransmitters while electrical synapse has low-
resistance bridges.
 One-way transmission in chemical synapse, two way in electrical synapse.
 Synaptic Delay is present in chemical synapse and not in electrical synapse.
 Chemical synapse shows synaptic properties while electrical synapse does not.

14. Bibliography
 A. K. Jain
 Indu Khurana

17. Killing time is not a
murder, it is SUICIDE.
-Anonymous.