Nerve endings

Efferents

Function: transmission of impulses from motor neuron to effector cell

Location: skeletal muscle fibers

Location: secretory cells of many glands

Afferent (sensory) receptors

Function: nerve impulse initiation in response to: external stimuli (temperature, touch, smell, sound, vision) - exteroceptors; stimuli from within the body (filling or stretch of the alimentary canal, bladder, blood vessels) - enteroceptors; sensation of body position and muscle tone and movement - proprioceptors.

Location: epithelia, connective tissue

Encapsulated endings

Location: skin and joint capsules (end bulb of Krause, Ruffini corpuscles, Meissner's corpuscles, Pacinian corpuscles); skeletal muscle (neuromuscular spindles); muscle-tendon junctions (Golgi tendon organ)

Synapses

Function: transmission of impulses from one neuron to the next in the chain.

Location: between axons and dendrites.

Location: between axons and the cell body.

Location: between axons and axons.

Location: between dendrites and dendrites.

Composition:

Presynaptic knob (component)

Function: the end of neuron process from which neurotransmitter is released.

Synaptic cleft

Function: 20-30 nm space that neurotransmitter must cross.

Postsynaptic membrane (component)

Function: receptor sites on the plasma membrane with which the transmitter interacts