Vocabulary | Definition |
neuron | a nerve cell that conducts impulses |
axon | cellular extension of a neuron that carries an impulse away from the soma |
soma | the cell body of a neuron; contains majority of cellular organelles |
dendrites | cellular extensions of a neuron that carry impulses towards the soma |
Nissl bodies | groups of ribosomes in the cytoplasm that produce proteins |
neurotransmitters | chemicals (proteins) released at a synapse |
neurofibrils | similar to microtubules in that they aid in transportation and support for the neuron |
telodendria | branches of an axon |
axon end bulb | enlarged portion of axon at the end of a telodendrion |
axonal hillock | a slight elevation from which the axon arises from the soma |
golgi bodies | cellular organelle that packages proteins into membranous sacs or vesicles; produces synaptic vesicles containing neurotransmitters |
ER | cellular organelle that forms a tubular network for transportation |
mitochondria | cellular organelles that create ATP through aerobic respiration |
myelin | a phospholipid (fat) that insulates an axon allowing the impulse to travel faster; produced by Schwann cells in the PNS and oligodendrocytes in the CNS |
neurilemma | the cytoplasm and nucleus that is squeezed to the outer margins as a cell wraps itself around an axon, neurilemma appears to surround the myelin |
nodes of Ranvier | gaps in the axon that do not contain myelin |
saltatory conduction | explains how an impulse "jumps" from node to node as it travels the length of an axon |
white matter | any area of the nervous system that contains myelin (usually contains axons) |
gray matter | any area of the nervous system that does not contain myelin (usually made up of somas and dendrites) |