AP 1 (11-4)

• 1. Axon and myelin degenerate distal to injury
• 2. Schwann cells proliferate along original axon path. Macrophages move in and remove cellular debris
• 3. Axon grows along original path created by Schwann cells.
• 4. Schwann cells wrap around elongating axon

nerve function that does not fully restore.

• 1. Many more axons involved.
• 2. Astrocytes produce scar tissue that can prevent axon growth.
• 3. Astrocytes release chemicals that block axon regrowth.
• 4. Lack of neurilemma

• on the basis of structural differences
• by functional differences

• -the cell processes look alike (dendrites vs. axons)
• -Located in brain and special sense organs
• -Functions are poorly understood

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

• -found in ganglia outside the CNS
• -have an axon and a dendrite arising from

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

• Anaxonic
• Bipolar
• Unipolar
• Multipolar

• Sensory
• Motor
• Interneurons

-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.