histology of the nervous system

cell membrane

phospholipid bilayer where lipid soluble stuff can pass

cell body

central portion of neuron called ‘soma’; contains organelles exceot centrioles

nucleus

DNA storage

dendrites

receptive portion of a neuron that carries impulses TOWARDS the cell body (input)

microtubules

transport of proteins in the cell that is made up on the protein tubulin

intermediate filaments

adds structure to the cell - like scaffolding to a neuron

microfilaments

made of actin protein that aids in migration of cells and formation of synapses

axon

carries impulses AWAY from the cell body (output)

divergent synapses

when one axon branches and synapses with many other neurons

convergent synapses

branches of neurons terminating on one neuron

multipolar neurons

many extensions; many dendrites lead toward cell body, one axon leads away from cell body

bipolar neurons

two extensions; one fused dendrite leads toward cell body, one axon leads away from cell body

pseudo-unipolar neurons

a single process (stem) arises from the soma and one end projects to the periphery and the other to the CNS

unipolar neurons

one process from cell body with both dendrites and axons on it

microglia

removes cell debris, wastes, and pathogens by phagocytosis

ependymal cells

helps make cerebrospinal fluid (CSF)

oligodendrocytes

produces myelin in CNS

schwann cells

produces myelin in PNS

astrocytes

star shaped neuroglia that helps form the blood brain barrier (BBB)

endothelium cells

assist in maintenance of “tight junctions”

lumbar puncture

inserting sterile needle between lumbar vertebrae to sample CSF

hydrocephalus

water in head

kinesin

motor protein that transports vesicles on microtubules from soma to axon terminal

dynein

motor protein that transports vesicles on microtubules from axon terminal to soma

anterograde

soma —> axon terminal

retrograde

axon terminal —> soma

choroid plexus

input that makes cerebrospinal fluid (on-ramp)

aracnoid granul

the output of cerebrospinal fluid that is reabsorbed into venous circulation (off-ramp)

myelin

insulation of the nervous system to limit current loss from the axon

endoneurium

connective tissue that wraps around each axon (and myelin)

perineurium

connective tissue that wraps around each fascicle (bundle) of axons

epineurium

connective tissue that wraps around each nerve

mixed nerves

nerves that carry impulses both to and from the CNS which contain both sensory and motor axons

sensory (afferent) nerves

nerves that only carry sensory impulses toward the CNS

motor (efferent) nerves

nerves that only carry sensory impulses away the CNS

wallerian degeneration

nerve fiber that is cut or crushed away from the neuron's cell body and breaks down and dies

senile plaques

tar-like buildup in brain that may be a possible cause of Alzheimer’s

neurofibrillary tangles

tau protein buildup in the brain that doesn’t allow the transport of cellular proteins, may be a possible cause of Alzheimer’s

anterograde transneuronal degeneration

when a postsynaptic neuron degenerates after axonal injury to the presynaptic neuron

retrograde transneuronal degeneration

when a presynaptic neuron that synapses with a damaged neuron degenerated after axonal injury to the postsynaptic neuron