Structure of Nerve Tissue - X Flashcards
Internerouns
Interconnect other neurons, 99.9% of all neurons
GVE - information pathway
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Ventral root of spinal cord, through ventral root out to smooth and cardiac muscle, glands, etc
Two neuron chain
GSA - movement of information, how
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Bring in information from the periphery/body to Spinal Cord.
Cell bodies located in Dorsal Root Ganglion
Information flows through the dorsal root into the dorsal horn of the spinal cord
Multipolar - def, e.g.
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most common
1 axon, 2+ dendrites
motor neurons and interneurons
Cell Body - characteristics
large pale staining nucleus dispersed chromatin nucleoli Lots of RER and Nissl bodies (free ribosomes) numerous mitochondria
Unipolar/ psuedounipolar - def, e.g.
1 long axon divides close to cell body into 2 long axial branches
typically prokaryotic
eukaryotic evolution - DRG cells
Axon Hillock - def, significance
initial segment of axon w/o Nissl bodies or Golgi
sight of nerve impulse generation - very excitable
Bipolar - def, e.g.
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1 axon, 1 dendrite
associated with receptors for special senses
Retrograde
towards cell body
Mediated by Dynein
viruses could be taken up nerve terminal and transferred int CNS
Rate : FAST
Anterograde - axonal transport
away from cell body
mediated by Kinesin
two rates : Slow (same as peripheral regeneration)
Fast
Neurofilaments - fxn
support
role in neuronal development and regeneration
Microfilaments - def, fxn
actin
Anchor
transfer molecules to/from cell membrane
Cause movement of growing axonal tips during development and regeneration
Microtubles
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cylindrical assemblies of tubuli, with axonal transport proteins
Presynatic terminal - a..k.a
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buton
Synapses - catergories
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axo-dendritic (majority))
axosomatic
axoaxonic
dendrodentritic
Neuromuscluar junction
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specialized synapses on skeletal muscle
ACH as nt
junctional folds on muscle fiber membrane
Neuroglial cells - fxn, types
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support and myelination in PNS
Peripheral = Schwann and Satellite cells
Schwann Cells - fxn
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Myelinate peripheral axons
Myelin sheath - concentric rings of Schwann around axon
also surrounds/nurtures unmyelinated axons
thicker myelin = faster conduction
DRG
contains cell bodies of pseudounipolar sensory neurons
cell bodies surrounded by satellite cells
NO synapses occur here
Schidmt-Laternams clefts - def., fxn
islands of Schwann cytoplasm bwtn lamellae of myelin
= characteristic fishbone appearance on LM
fxn - Intracelluar communication
Autonomic Ganglia - characterstics
Multipolar
Synapses OCCUR
Sateliite Cells - def, fxn
glial cells that surround peripheral ganglia
Maintain controlled local enviroment
Provide electrical insulation
Path for metabolic exchange
CT coverings on nerves
Epineurium
Perineurium
Endoneurium
Epineurium
Surround entire nerve