Name: The Human Nervous System
Uploaded: 2019-07-19
Duration: 48 min 17 s
Description: For normal functioning, body coordination between the different parts of the body is needed. But which system in our body helps in that coordination? Let's f...

Question

Explain the transmission of nerve impulse through a nerve fibre with the help of suitable diagrams.

Accepted Answer

A nerve impulse is transmitted from one neuron to another through junctions called synapses. A synapse is formed by the membranes of a pre-synaptic neuron and a post-synaptic neuron, which may or may not be separated by a gap called synaptic cleft. There are two types of synapses: electrical synapses and chemical synapses. At electrical synapses, the membranes of pre and post synaptic neurons are in very close proximity compared to chemical synapses. These synapses are electrically conductive links between two neurons and are also called ‘gap junctions’.

At a chemical synapse, the membranes of the pre and post synaptic neurons are separated by a fluid-filled space called synaptic cleft (a structural gap and a functional bridge).

Chemicals called neurotransmitters are involved in the transmission of impulses at these synapses. The axon terminals contain vesicles filled with these neurotransmitters. When an impulse (action potential) arrives at the axon terminal, it depolarizes the membrane opening voltage gated calcium channels.

Acetyl choline is the most common neurotransmitter. Epinephrine, norepinephrine, dopamine, serotonin etc. are either excitatory or inhibitory neurotransmitters. Glycine, GABA (Gamma Amino Butyric Acid) are inhibitory neurotransmitters. The post synaptic membrane has ligand gated channels.

Explain the transmission of nerve impulse through a nerve fibre with the help of suitable diagrams.

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