Lecture 4 - Neural Tissue Flashcards
what are the neuronal support cells?
glial and endothelial
what mediates the enteric nervous system
vagus nerve
def: system with millions of neutrons stretching the length of the digestive tract
enteric nervous system
what is the ratio of neurons to glial to endothelial cells?
5:3:1
def: named for the predominance of axons, many of which are myelinated, contains few neuronal soma and few synapses
white matter
in the brain: white matter lies _____ to grey matter
deep
in H&E staining, the neuropil is so _______ that is difficult to study the morphology of any individual neuron
dense
neurons have _____ prominent nuclei
large
glial cells have _____ cytoplasm, prominent ______
pale cytoplasm, prominent nuclei
def: silver staining technique that stains a limited number of neurons in their entirety
Golgi’s stain
are granular neurons basophilic or eosinophilic?
basophilic
how does cressyl violet interact with neurons?
it stains cell bodies, dendrites, but not axons since they do not contain RER
what 3 neuronal ultrastructure details indicate the high metabolic activity of these cells?
- dispersed chromatin
- prominent nucleolus
- substantial amounts of RER in dendrites and soma
majority of the axon contains 2 prominent structural elements:
- microtubules
- neurofilaments
what is the enzymatic immunohistochemistry method normally used for neuron-specific applications that shows microtubule elements?
beta-tubulin III
in axonal cross section, microtubules are _______ relative to neurofilaments
large
myelin is _____-______
electron dense
is this a CNS axon or PNS axon: myelinated axons are densely packed and the myelin sheaths of neighbouring axons often make direct contact
CNS white matter
is this a CNS axon or PNS axon: myelinated fibers are separated by connective tissue, small calibre axons are not myelinated and organized in Remak bundle, formed by non-myelinated Schwann cells
PNS nerves
def: CT that encloses a nerve
epineurium
def: CT that encloses a fascicle
perineurium
def: CT that encloses the myelin sheath of a myelinated axon
endoneurium
def: myelin formation: Schwann cells form individual myelin sheaths around axons, each Schwann cell associates with only one axon, Schwann cell nuclei are located on the outside of the sheath
PNS myelin formation
def: myelin formation: oligodendrocytes form multiple myelin sheaths, each on separate axons
CNS myelin formation
def: formed by apposition of the glial plasma membrane
intraperiod line
def: formed by compaction of glial cytoplasm
major dense line
def: specialized sites for electrochemical communication between neurons or between other effector cells such as muscle fibers
synapses
def: terminates at a bulbous swelling or terminal bouton, separated from a plasma membrane of the opposed neuron or effector cell by a narrow intercellular gap of uniform width
presynaptic axon
are terminal boutons myelinated?
no
def: specialized synapse between motor axons and motor end plates of skeletal muscle
neuromuscular junction
def: autoimmune disorder that leads to skeletal muscle weakness and fatigue, autoantibodies against the acetylcholine post synaptic receptors at the NMJ of skeletal muscle
myasthenia gravis
