Neurons are cells that are specialized to receive, propagate, and transmit electrochemical impulses.
In the human brain alone, there are over eighty billion neurons.
As Na ions enter the cell, the membrane potential is further depolarized, and more voltage-gated sodium channels are activated.
Such a process is also known as a positive feedback loop.
When there is a change in voltage in the terminal bouton, voltage-gated calcium channels embedded in the membranes of these boutons become activated.
These allow Ca2 ions to diffuse through these channels and bind with synaptic vesicles within the terminal boutons.
Moreover, the distinctions based on function between neurons and other cells such as cardiac and muscle cells are not helpful.
Thus, the fundamental difference between a neuron and a nonneuronal cell is a matter of degree.
As the rising phase reaches its peak, voltage-gated Na channels are inactivated whereas voltage-gated K channels are activated, resulting in a net outward movement of K ions, which repolarizes the membrane potential towards the resting membrane potential.
Repolarization of the membrane potential continues, resulting in an undershoot phase or absolute refractory period.
Plastic change often results from the alteration of the number of neurotransmitter receptors located on a synapse.