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Flashcards in Nerves Deck (50)
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31

What is the bouton?

Expanded area of the axon that contributes the presynaptic membrane

32

Describe the synaptic cleft

Gap between neurons that contains fine filaments and electron dense material

33

What is the subsynaptic web?

Filamentous materials associated with the post synaptic membrane

34

What is the tripartite synapse?

Astrocytic processes at the synaptic cleft form connections with neuronal synapses and each other with gap junctions

35

Does neurogenesis occur?

Yes, throughout life.

Neural stem cells have astrocytic and neuroepithelial potential

Ependymal cells of the central canal are pluripotential

36

What is dedifferentiation?

Progenitor cells are mono or uni-potent. If a cell becomes bipotent it has dedifferentiated to a stem cell

37

What is transdifferentiation?

A cell becoming a cell type from a different embryonic lineage

38

Where is epineurium located?

Around entire nerve fiber

39

Where is perineurium located?

Around each fasicle

40

What are the perineural cells?

A sleeve-like layer of epithelioid cells immediately around fasicles

41

What is endoneurium?

Surrounds individual axons (along with myelin)

42

How many neurons can schwann cells envelop?

One, many schwann cells on one axon

43

Describe unmyelinated fibers

Several nerve fibers sit in simple clefts of schwann cells

44

What is the gap between schwann cells called?

Node of ranvier

45

What is each separate myelin segment referred to as?

Internode

46

Why don't myelin sheaths stain?

They're made of mostly lipids

47

Where are satellite cells located?

Surrounding the perikarya in the ganglion

48

What neuron types do not leave the CNS?

Interneuron, upper motor neuron

49

What are the 3 layers of connective tissue that surround the CNS?

dura mater (outer)
arachnoid (inner)
pia mater (inner)

50

What space is filled with CSF?

Subarachnoid space