central nervous system
the brain and spinal cord collectively
neuroglia
specialized supporting cells in the CNS
synapse
junction or point of close contact between neurons
tract
a bundle of nerve processes inside the CNS
association neurons
neuron serving as part of the conduction pathways between the sensory and motor neurons
peripheral nervous system
ganglia and spinal and cranial nerves
ganglion
collection of nerve cell bodies found outside the CNS
efferent neuron
neuron that conducts impulses away from the CNS to muscles and glands
afferent neuron
neuron that conducts impulses toward the CNS from the body periphery
neurotransmitters
chemicals released by neurons that stimulate or inhibit other neurons or effectors
axon hillock
region of the cell body from which the axon originates
axon terminal
secretes neurotransmitters
dendrite
receptive region of a neuron
myelin sheath
insulates the nerve fibers
neuronal cell body
site of the nucleus and is the most important metabolic area
neurofibril
may be involved in the transport of substances within the neuron
Nissl bodies
essentially rough endoplasmic reticulum, important metabolically
endonerium
each fiber is surrounded by a delicate connective tissue sheath which insulates it from the other neuron processes adjacent to it; additional sheath that surrounds the myelin sheath
perinerium
groups of fibers bound by a coarse connective tissue to form bundles of fibers called fascicles
epinerium
all the fascicles bound together by a white, fibrous connective tissue sheath forming the cordlike nerve