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प्रश्न
Give a brief account of Mechanism of synaptic transmission.
उत्तर
Mechanisms of synaptic transmission
synapse is a junction between two neurons. It is present between the axon terminal of one neuron and the dendrite of next neuron, separated by a cleft.
There are two types of synaptic transmission.
- Chemical transmission
- Electrical transmission
1. Chemical transmission:
- When a nerve impulse reaches the end plate of the axon, it releases a neurotransmitter (acetylcholine) across the synaptic cleft. This chemical is synthesised in the cell body of the neuron and is transported to the axon terminal.
- The acetylcholine diffuses across the cleft and binds to the receptors present on the membrane of the next neuron. This causes depolarization of membrane and initiates an action potential.
2. Electrical transmission:
- In this type of transmission, an electric current is formed in the neuron. This electric current generates an action potential and leads to the transmission of nerve impulses across the nerve fibre.
- This represents a faster method of nerve conduction than the chemical method of transmission.
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संबंधित प्रश्न
Compare the following:
Resting potential and action potential
A person is showing symptoms like increased BMR, heart rate, pulse rate, blood pressure and deposition of fats in eye sockets. Name the disease he is suffering from.
Long answer question.
Explain the process of conduction of nerve impulses up to the development of action potential.
Complete the flowchart of the process of conduction of nerve impulses.
| Application of stimulus on a resting nerve |
| ⇓ |
| Permeability of membrane changes |
| ⇓ |
| ______________________________ |
| ⇓ |
| Positive ions inside axon increases |
| ⇓ |
| ________________________________ |
| ⇓ |
| Polarity reverses and depolarisation takes place |
| ⇓ |
| Repolarisation - potassium gates open |
| ⇓ |
| ______________________________ |
| ⇓ |
| ______________________________ |
| ⇓ |
| Axoplasm becomes negatively charged and ECF becomes positive |
Dendrites transmit impulse ______ cell body and axon transmit impulse ______ cell body.
What are the number of Na+ ions pumped out, and K+ ions pumped into the cell, with respect to the Na+ - K+ pump?
Match the Column - I with Column - II:
| Column I | Column II | ||
| i. | P - wave | p. | Depolarisation of ventricles |
| ii. | QRS complex | q. | Repolarisation of ventricles |
| iii. | T - wave | r. | Coronary ischemia |
| s. | Development of atria | ||
| t. | Repolarisation of atria |
Neurotransmitters are removed from synaptic cleft by ____________ after transmission of impulse.
The axoplasm inside the axon contains high concentration of (i) ions and low concentration of _(ii)_ ions, during the resting state of the neuron.
Under which of the following conditions will the ionic gradients across the resting membrane be maintained?
Which of the following situations is responsible for resting membrane potential?
Identify the correct path of transmission of nerve impulse.
Which of the following statements is TRUE for medullated nerve fibre?
When stimulus is applied to a membrane of neuron, it causes rapid influx of ____________.
Potential difference across resting membrane is negative. This is due to differential distribution of the following ions ______.
The electronegativity inside the membrane is due to
