Exam 3 Review:  Chapter 11:  Histology of the Neuron  

neurolemma - The outer cell membrane or plasmalemma of a neuron; impulse transmission, an action potential,  is initiated when the neurolemma is depolarized in response to a threshold or greater stimulus from a sensory receptor or an adjacent presynaptic neuron.

soma - The major portion of a nerve cell which contains the nucleus, the bulk of the cytoplasm and cytoplasmic organelles but does not include the dendrites or axon.  aka cell body.

chromatophilic substance - A prominently staining substance found in the cytoplasm of motor neurons (within the cell body and dendrites only which is an aggregate of extensive rough endoplasmic reticulum, which is visible as purple granules when stained with H&E).  aka - Nissl bodies

neurofibrils - Any of the long, thin, microscopic fibrils (cytoskeletal elements) which run through the cell body of a neuron and extend into the axon and dendrites, regarded as a system for the transportation of molecules from the cell body to the axonal terminals and vice versa.

dendrite - A branched protoplasmic extension of a nerve cell that conducts nerve impulses from adjacent cells inward toward the cell body; a single nerve may possess many dendrites; typically dendrites are relative short.

Sketch and Label:

3. A neuron and its parts. Define the function of each part.

     [Note:  for definitions of neuron cell parts, refer to the terms above and to the definitions at Histology of the Neuron's Axon .]