Organelle containing a cell’s genes and controlling its activities.
myelin sheath
Casing of the axon made of a fatty substance (myelin) providing electrical insulation for the neuron and increasing the conduction speed of the nerve impulse.
axon hillock
Part of the cell body in which the axon lies.
cell body
Bulging part of a neuron ensuring maintenance of its structure and function.
dendrite
Each of the short branch extensions of the cell body that receive nerve impulses from surrounding neurons.
sheath of Schwann
Outer casing of the axon, it surrounds the myelin sheath.
collateral
Branch of the axon. An axon can be divided into one or several collaterals.
node of Ranvier
Constriction lacking myelin located at regular intervals along the entire length of the axon; it accelerates the distribution of nerve impulses.
terminal arborization
Final branch of the axon storing a chemical substance (neurotransmitter) used to transfer a nerve impulse to the dendrites of the neighboring neuron.
synapse
Contact zone between two neurons through which nerve impulses are transmitted.
axon
Neuron extension communicating nerve impulses to other cells (including nerve and muscle cells). The axons of motor neurons can be more than 3 ft long.
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