Nervous System 2 Flashcards
components of the nervous system
nervous system - the central nervous system and peripheral nervous system ( all nerves lying outside the brain and spinal cord )
components of the central nervous system
brain and spinal cord
components of the peripheral nervous system
Cranial nerves ( above neck muscles ) and spinal nerves ( from the neck down )
cells of the nervous system (2) and functions
nerve cells / nuerons = communication and control Glial Cells ( neuoglial cells) supporting cells like 'nerve glue' and support nerve cell function
nerve cell components functions
axon - carries the electrical signal
terminal buttons- contain and release neurotransmitters
dendrites - receive chemical messages from other nerve cells
cell body - generates electrical impulse in response to other nerve cells
what is myelination?
process of insulation of nerve cells
2 types of glial cells that are involved in myelination?
Schwann cells (only in the peripheral nervous system ) Oligodendrocytes (only in the central nervous system)
definition of nerve
bundle of axons, running together outside the CNS
definition of tract
bundle of axons within the CNS
definition of tract
bundle of axons within the CNS
structure of a nerve (3)
Epineurium (around entire nerve)
Perineurium (around axon bundles)
Endoneurium (around individual axons) a.k.a. endoneurial tubes
nerve damage degeneration (2)
distal degeneration - when axon and myelin breakdown (further away) and proximal degeneration - degenerates back to the nearest node (closer)
Schwann cells remain alive but become phagocytic and help to remove degenerating axon and myelin material.
nerve regeneration
axon regrowth slow (1mm per day), Schwann cells remyelinate and axons grow down the endoneurial tubes to the destination, function regained only if new axons reach correct of destination.
phantom limb sensation can be caused by bundle of axons that reach a dead end when get an amputation o arm or leg.
