Features of the nervous system Flashcards
CNS
Central Nervous System - cells are neuron’s and glia, and spinal cord
PNS
Peripheral Nervous System - consists of peripheral nerves and ganglia - cells are neurons and glia
Dendrites…
receive input, send info to cell body
Cell body…
contains nucleus and organelles, sums input
Axon…
carries electrical impulses (action potentials) between brain areas, may or may not be myelinated
Axon terminals
end (terminus) of the axon, neurotransmitter release
Input zone
dendrites and cell body
receives chemical signals from other neurons
Summation zone
axon hillock (where the axon leads into the cell body) summation of the inputs
Conduction zone
axon, may be quite long
carries action potentials between brain areas, to and from spinal cord, or from peripheral sensory receptors and to effector cells
Output zone
axon terminals
contact with input zone of other neurons or effectors
release of neurotransmitter = chemical
Multipolar neuron
multiple processes emanate from the cell body
Bipolar neuron
two processes emanate from the cell body
Unipolar neuron
one process emanates from the cell body, then branches into dendrite and axon
Anaxonic (axonless) neuron
no distinct axon, all process look alike
Glia:
Astrocytes
supply nutrients to neurons, ensheath blood capillaries, injury response
Glia:
Microglia
immune cells to the CNS, engulf microorganisms and debris
Glia:
Ependymal cells
line fluid-filled spaces of brain and spinal cord, have cilia (hair like processes) to circulate CSF
Glia:
Oligodendrocytes
support nerve fibres, ensheath them with myelin
CNS:
Nucleus
group of cell bodies
CNS:
Tract
bundle of axons
CNS:
Grey matter
group of cell bodies in cerebral cortex or spinal cord
CNS:
White matter
bundle of axons in cerebral cortex or spinal cord
PNS:
Ganglion
group of cell bodies
PNS:
Nerve
Bundle of axons
Glia:
Schwann cells
support peripheral nerve fibres, ensheath them with myelin, similar to oligodendrocytes
Glia:
Myelin sheath
lipid (fat) wrapped around axon, multiple Schwann cells in a line
Glia:
Nodes of Ranvier
gaps between myelin (Schwann cells), increases conduction velocity
Synapse
junction where neuron communication occurs, electrical to chemical energy and back again
Information going into the brain
afferent, ascending
Response that exits the brain
efferent, descending
