32

lack a myelin sheath and are unmyelinated fibers

__ in the CNS is due to myelin sheaths in this area

unmyelinated nerve tissue in the CNS comprise the __

peripheral neurons are able to regenerate because of the __

neurons can be grouped in two ways:

found in the eyes, nose, and ears, and have a single axon and a single dendrite extending from opposite sides of the cell body

are found in ganglia outside the CNS and have an axon and a dendrite arising from a single short fiber extending from the cell body

have many nerve fibers arising from their cell bodies and are commonly found in the brain and spinal cord

conduct impulses from peripheral receptors to the CNS and are usually unipolar, although some are bipolar neurons

multipolar neurons lying within the CNS that form links between other neurons

multipolar neurons that conduct impulses from the CNS to effectors

is usually polarized, with an excess of negative charges on the inside of the membrane

the distribution of ions is determined by the ___ that are selective for certain ions

pass through the membrane more readily than do sodium ions, making potassium ions a major contributor to membrane polarization.