Final Flashcards
(250 cards)
What would be the end result of the disease processes involving the peripheral nerves, neuromuscular function, & skeletal muscle?
Disease involving these structures result in muscular weakness
What’s the difference b/w disease process only involving muscle & disease process only involving peripheral nerves?
Disease process only involving muscle will result in motor dysfunction alone, whereas the peripheral nerves also have sensory & autonomic fibers
What does the term “nerve” really mean?
Collection of several integrated neurons
How do peripheral nerves receive their blood supply?
By small arterioles called the vasa nervorum
What is meant by the term “laminae”?
When the cell bodies of neurons tend to aggregate into sheets it’s called laminae. Lie w/i the gray matter of the CNS or are located in specialized ganglia in the PNS
How many glial cells are there in the body compared w/ neurons?
There are about 10x more glial cells than neurons & they occupy approx. half the volume of the brain
What is the cell body of a neuron AKA?
soma or perikaaryon
What is the nissl substance AKA?
endoplasmic reticulum
What is the function of endoplasmic reticulum?
Synthesizes proteins for export to the axon
What is the name of microtubule-assoc. protein in axons?
Tau protein
What is the name of microtubule-assoc. protein in dendrites?
MAP-2
What does a synapse consist of?
A presynaptic element containing synaptic vesicles
A synaptic cleft
A postsynaptic element
How wide is the synaptic cleft b/w neurons?
20-30nm wide
How wide is the synaptic cleft b/w neurons & skeletal neuromuscular junction?
50-100nm wide
What types of neuroglial or glial cells are in the CNS?
Astrocytes
Oligodendrocytes
Microglia
These cells for a framework or scaffolding for neurons (especially in the formation fo the blood-brain-barrier) & some expand into end-feet on the pial surfaces of the brain or on capillaries
Asrtocytes
These cells have fewer & thinner processes than astrocytes, they don’t possess gap junctions, & they form myelin sheaths around axons in the CNS
Oligodendrocytes
Type of cell of uncertain origin that act as as scavenger cells. Injury to the brain activates these cells which undergo proliferation & migrate to the point of injury where they become phagocytic & remove debris
Microglia
What types of neuroglial or glial cells are in the PNS?
Schwann cells
What is the function of Schwann cells?
Fill spaces between neurons & they form myelin sheaths around axons in peripheral nerves by enveloping them w/ concentric layers of plasma membranes
Are ependymal cells classified as glial cells?
Yes. Ependymal cells which line the ventricles of the brain may also be classified as glial cells
What factors makes the nervous system more susceptible to toxins?
Neurons have a very limited ability to regenerate
Nerve cells have a large surface area
The nervous system depends for its normal activity on a high degree of integrated activity
This consists of tightly-packed endothelial cells wrapped by astrocytes that line the capillaries in the brain
Blood brain barrier
What is the effect of the blood brain barrier on the CNS?
Reduces, doesn’t eliminate, the entry of toxins into the CNS