Term
| 2 types of cells of the CNS & their functions |
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Definition
1. Neurons: excitation/inhibition & impulse conduction
2. Neuroglia (interstitial cells): astrocytes, oligodendrites, microglia & ependymal cells |
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Term
| Cell bodies of neurons embedded in a neuropil made up of unmyelinated cell processes plus glial cells. |
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Definition
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Term
| A group or cluster of N cell bodies with similar fxn within the CNS is termed: |
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Definition
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Term
| Gray matter is located in 3 places: |
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Definition
1. central part of the spinal chord
2. brain stem (portions)
3. cortical tissue of the brain |
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Term
| Long processes fo neurons (predominantly myelinated) plus glial cells |
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Definition
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Term
| ___________ are grouped in Tracts |
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Definition
| Functionally related processes |
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Term
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Definition
| Neuron cell bodies plus myelinated cell processes plus glial cells. |
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Term
| Are there CT fibers within the CNS? |
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Definition
| No, except when some are assoc with capillaries |
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Term
| What is the structural and functional unit of the CNS? |
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Definition
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Term
Cell Body of a Neuron (perikaryon)
-Size
-nucleus
-Nissl
-contents
-pigments |
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Definition
Cell Body of a Neuron (perikaryon)
-Size: 4um to 135um
-nucleus:usually central (except with ANS), chromatin: chromatin, single large nucleolus near center of nucleus
-Nissl:"blue patches" stacks of flat cistern of RER mixed with lots of free ribosome, NOT in axons
-contents: golgi, mitochondria, microfilaments & microtubules
-pigments: lipofuscin (up with cell age) and melanin (abundant in the substantial nigra of the midbrain) |
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Term
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Definition
1. axon hillock: proximal part, a little thicker
2. axolemma: plasmamembrane of axon
3. axoplasm: cytoplasm of axon (NO golgi, rER & free ribosomes are rare). |
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Term
Dendrites branch dichotomously at 30 degree angles?
T/F |
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Definition
| FALSE, branch at right angles |
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Term
| Dendrites contain ribosomes, Missl, filaments, & mitochondria? T/F |
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Definition
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Term
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Definition
| many dendritic processes + 1 axon (MOST neurons) |
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Term
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Definition
| 2 dendritic processes + 1 axon (inner ear, retina of eye) |
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Term
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Definition
| 1 axon only (retina of eye) |
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Term
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Definition
| dendritic processes + axonal process (somatic sensory fibers) |
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Term
| What 2 size types of neurons are there? |
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Definition
1. Large Golgi Type I
2. Small Golgi Type II |
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Term
| Pyramidal Cells (cerebral cortex) |
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Definition
| Large Golgi Type I neuron, axon rises from base, several basal dendrites, apical dendrite, pyramid shape, and Betz cells or motor area of cerebral cortex |
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Term
| Purkinje Cells (Large Golgi Type I neuron) |
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Definition
| Flask shaped, 1-2 dendrites extend toward surface, axon from base of perikaryon passes deep into the cerebellum |
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Term
| Lower Motor Neurons (large golgi type I)...where? |
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Definition
| within the ventral horns of spinal chord and motor nuclei of cranial NN |
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Term
| Small Golgi Type II neurons |
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Definition
Outnumber type I, includes interneurons, body as small as 5um, axons usually unmyelinated
Examples:
Stellate Cell
Cell of Martinotti
Granule Cell
Horizontal Cell |
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Term
| Which golgi type II neuron is located in the deepest of the 3 layers of cerebellar cortex? |
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Definition
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Term
| Do intermediate forms of cells exist (between golgi type I and II?) |
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Definition
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Term
| Horizontal Cells (golgi type II neuron) |
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Definition
| in cerebral cortex and retina, long axis parallel to cortical surface |
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Term
| Stellate Cells & Cell of Marinotti (type II golgi neuron) both in the... |
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Definition
| cerebral cortex & cell of martinotti resemble stellate except it has a longer axon which is directed toward the cortical surface |
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Term
| Oligodendrocytes have a _____________ nucleus with ________chromatin. |
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Definition
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Term
| In white matter, the ________________ are disposed in rows between the axons while in gray matter they appear to be randomly located. |
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Definition
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Term
| Numerous cytoplasmic processes (from oligodendrocytes) project from the cells to wrap around axons which leads to... |
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Definition
-the continued wrapping of the processes forms myelin sheath in much the same manner as schwann cells myeline peripheral nerves
-each process projects to a diff axon
-THUS a single oligodendrocytes wraps portions of several axons and sniffle axon is wrapped by several oligoes. |
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Term
| ____________ have nuclei that are larger than other glial cells and somewhat irregular in shape |
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Definition
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Term
T/F
Astrocytes contain 1 process that projects in 1 direction. |
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Definition
FALSE
contain many processes that project in several directions |
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Term
| The end processes widen and spread over the surfaces of ___________ & ____________ as astrocyte feet. Most ___________ are completely ensheathed by astrocytic feet. |
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Definition
| Neurons, capillaries, capillaries |
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Term
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Definition
| support and chemical transport b/w neurons and capillaries |
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Term
T/F
Astrocytes contain lots of microfilaments |
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Definition
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Term
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Definition
1. fibrous: in white matter
2. protoplasmic: in gray matter |
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Term
Ependymal Cells
-location
-structure |
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Definition
Location: line the ventricles of the brain and the central canal of the spinal cord
Structure: cuboidal to columnar in shape, ependyma is ciliated in the ventricles and non-ciliated elsewhere |
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Term
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Definition
| small with dark flattened nuclei |
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Term
| There are 2 schools of thought about origin and function of the microglia, expand. |
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Definition
1. most in CNS are neuroectodermal in origin, no known fxn, and are resting microglia. In damaged areas of brain, microglia known as reactive microglia and derived from blood monocytes and therefore mesodermal in origin and phagocytic in fxn.
2. all microglia are mesodermal in origin (arising from monocytes & phagocytic in fxn) |
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Term
| Neuropil appears as large thick area between cell axons of neurons. T/F |
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Definition
FALSE: at light microscopic level
appear as fine mottled area between cell bodies of neurons |
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Term
| Electron microscope level vision of neuropil |
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Definition
-conglomerate of cell bodes & cell processes of astrocytes along with processes of neurons (mostly unmyelinated)
-fine intercellular spaces b/w cells and their processes
-glycosaminoglycans (GAGS: hyaluronic acid, chondroitin & heparin sulfates) present in spaces (similar to ground substance of CT) |
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