How would you descrive the transmission of a nerve impulse across a synapse?
Nerve impulse transmission across synapse takes place by
1. Neurosecretion and
Synaptic transmission is achieved by use of neurochemicals.
Synapse has three structural entities:
- presynaptic axonic terminal/knob,
- synaptic cleft and
- postsynaptic dendritic terminal/membrane.
Synaptic impulse transmission takes place from presynaptic to postsynaptic neuron.
- When nerve impulse reaches presynaptic terminal, calcium ions flow in. This prompts secretory vesicles stored inside axonic terminal to burst and release neurohumor substances in synaptic cleft.
- Neurohumor molecules act as neurotransmitters, and are of different types: acetylcholine, serotonin, etc. Neurotransmitter molecules diffuse through synaptic cleft and reach dendritic terminal.
- Postsynaptic dendritic membrane ramains associated with specific receptors for specific neurohumor. Attachment of neurohumor to receptor causes depolarisation and a new action potential is formed in the postsynaptic neuron.