Flashcards in Nerves Deck (50)
What is the bouton?
Expanded area of the axon that contributes the presynaptic membrane
Describe the synaptic cleft
Gap between neurons that contains fine filaments and electron dense material
What is the subsynaptic web?
Filamentous materials associated with the post synaptic membrane
What is the tripartite synapse?
Astrocytic processes at the synaptic cleft form connections with neuronal synapses and each other with gap junctions
Does neurogenesis occur?
Yes, throughout life.
Neural stem cells have astrocytic and neuroepithelial potential
Ependymal cells of the central canal are pluripotential
What is dedifferentiation?
Progenitor cells are mono or uni-potent. If a cell becomes bipotent it has dedifferentiated to a stem cell
What is transdifferentiation?
A cell becoming a cell type from a different embryonic lineage
Where is epineurium located?
Around entire nerve fiber
Where is perineurium located?
Around each fasicle
What are the perineural cells?
A sleeve-like layer of epithelioid cells immediately around fasicles
What is endoneurium?
Surrounds individual axons (along with myelin)
How many neurons can schwann cells envelop?
One, many schwann cells on one axon
Describe unmyelinated fibers
Several nerve fibers sit in simple clefts of schwann cells
What is the gap between schwann cells called?
Node of ranvier
What is each separate myelin segment referred to as?
Why don't myelin sheaths stain?
They're made of mostly lipids
Where are satellite cells located?
Surrounding the perikarya in the ganglion
What neuron types do not leave the CNS?
Interneuron, upper motor neuron
What are the 3 layers of connective tissue that surround the CNS?
dura mater (outer)
pia mater (inner)