Chemical and electrical synapse

what is synapse
types of synapse

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 neuron synapse Post-synaptic neuron Synaptic cleft

5. Physiological classification Chemical Synapse Electrical Synapse 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

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