6.2 Functional Classes of Neurons

Afferent Neurons

Neurons that carry information from sensory receptors at their peripheral endings to the central nervous system; cell body lies outside CNS

Efferent Neurons

Neurons that carry information away from the central nervous system

Interneurons

Neurons whose cell bodies and axons lie entirely in the central nervous system; form circuits with other interneurons or connect afferent and efferent neurons

Nerves

Groups of many axons from numerous neurons, encased in connective tissue and traveling together in the peripheral nervous system

Postsynaptic Neuron

Neuron that conducts information away from a synapse

Presynaptic Neuron

Neuron that conducts action potentials toward a synapse

Sensory Receptors

Cells or portions of a cell that contain structures or chemical molecules sensitive to changes in an energy form in the outside world or internal environment; in response to activation by this energy, the sensory receptors initiate action potentials in those cells or adjacent ones

Synapse

Automatically specialized junction between two neurons where electrical activity in one neuron influences excitability of second