It is involuntary. The parasympathetic division enhances digestion and slows the heart rate, where the sympathetic division increases energy consumption by speeding up the heart rate and the metabolic rate. Both act as a stop and go mechanism. Explain how neurons can be classified by function. A neuron is specialized for transmitting signals from one location to another in the body.
Neurons are the functional unit of the nervous system.
There are many different kinds of neurons, but many differ in their structural details depending on what they do. Most have some common features. Explain how the action potential is propagated along a neuron. An action potential is generated as sodium ions flow inward across the membrane at one location. The depolarization of the first action potential spreads to the neighboring region of the membrane, depolarizing it and initiating a second action potential.