Question

What is the role of synapses in nerve impulses?

Answer 1

Synapses

1. Synapses refer to the points of contact between neurons where information is passed from one neuron to the next.
2. A nerve impulse is transmitted from one neuron to another through junctions called synapses.
3. There are two types of synapses: electrical and chemical.
4. Chemical synapses are biological junctions through which neuron signals can be sent to each other and to non-neuronal cells such as those in muscles or glands.
5. An electrical synapse refers to cell junctions between nerve cells through which the transmission of nerve impulses occurs by means of ions.
6. The synaptic cleft of an electrical synapse is small, and the two plasma membranes of the neurons are connected together via a gap junction.

Role of synapses in nerve impulses:

1. 1. Neurotransmitters are the chemicals that are involved in the transmission of nerve impulses across chemical synapses. These chemicals do not participate in the transmission of nerve impulses at electrical synapses.
2. When a wave of depolarization reaches the pre-synaptic membrane, calcium channels, open up. Due to the opening of calcium channels, Ca²+ diffuses inside the cytoplasm of a synaptic knob from the extracellular fluid.
3. The Ca2+, in some way, stimulates the movement of synaptic vesicles towards the pre-synaptic membrane.
4. Thereafter, the membrane, of synaptic vesicles fuses with the plasma membrane of a synaptic knob, i.e., the presynaptic membrane, resulting in the rupture of the synaptic vesicles. This results in the release of neurotransmitters in the synaptic cleft.
5. These released neurotransmitters rapidly pass to the other side of the gap. These released neurotransmitters bind to their specific receptors present on the postsynaptic membrane.
6. This binding opens the ion channels in the post-synaptic neuron, allowing the entry of ions. This entry of ions generates a new potential or nerve impulse in the postsynaptic neuron.