Term
| Brain anatomy: The _____ matter contains the cerebral and cerebellar cortexes. |
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Definition
| Brain anatomy: The GRAY matter contains the cerebral and cerebellar cortexes. |
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Term
| Myelin sheaths, axons and astrocyte fibers compose the ____ matter of the brain. |
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Definition
| Myelin sheaths, axons and astrocyte fibers compose the White matter of the brain. |
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Term
| Foci of gray matter in the white matter of the brain that are composed of clusters of neurons are called ____. |
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Definition
| Foci of gray matter in the white matter of the brain that are composed of clusters of neurons are called NUCLEI. |
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Term
| Name the three layers of the brain's meninges in order from most superficial to the deepest layer. |
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Definition
1) Outer dura or pachymeninges
2) Middle arachnoid
3) Inner pia |
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Term
| What are the four major functions of the meninges of the brain? |
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Definition
Protect the CNS
Contain the CSF
Support blood vessels
Cranial and spinal nerve sheath provision |
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Term
| What two arteries supply blood to the brain? |
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Definition
Internal carotid
Vertebral artery |
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Term
| What is the name of the perivascular space in the brain? |
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Definition
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Term
| Why do we have a blood brain barrier? |
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Definition
| To block the entrance of undesirable substances from entering the brain |
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Term
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Definition
| The Circle of Willis is depicted in this picture. |
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Term
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Definition
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Term
| Spinal cord: The _____ ____ contains the cell bodies of motor neurons. |
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Definition
| Spinal cord: The VENTRAL HORNS contains the cell bodies of motor neurons. |
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Term
| In the white matter of the spinal cord the ______ tracts carry electrical impulses from the spinal cord to the brain. |
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Definition
| In the white matter of the spinal cord the ASCENDING tracts carry electrical impulses from the spinal cord to the brain. |
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Term
| The lateral and ventral funiculi of the spinal cord contain ______ _____ and ______ _____ tracts. |
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Definition
| The lateral and ventral funiculi of the spinal cord contain ASCENDING SENSORY and DECENDING MOTOR tracts. |
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Term
| In the CNS there are two cell types, what are these? |
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Definition
1) Neurons
2) Glial cells |
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Term
| Name the five (5) types of Glial cells found in the CNS. |
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Definition
1) Astrocytes
2) Oligodendrocytes
3)Microglial Cells
4)Ependymal Cells
5) Choroid plexus epitheial cells |
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Term
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Definition
| RER/ribosome, unique to the cell body and are required for making PROTEIN. |
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Term
| Why is Nissl Substance required in the CNS, that is what is it needed for? |
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Definition
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Term
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Definition
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Term
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Definition
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Term
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Definition
Oligodendrocytes
They are there to lay down the myelin sheath (interfasicular type)
Similar function to a lymphocyte (Saltellite type) |
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Term
| What is the main function of Oligodendrocytes? |
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Definition
| To lay down myelin sheath in the CNS |
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Term
| What is the purpose of the astrocyte? |
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Definition
| These are multifunctional cells that we are finding new functions for. They are thought to be CNS "fibroblasts" |
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Term
| What is the origin of Microglial cells in the CNS? |
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Definition
| Monocyte-macrophage origin |
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Term
| Where are Ependymal cells found in the CNS? |
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Definition
| They line the ventricular system and the central canal of the spinal cord |
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Term
| What type of CNS cell produces the CSF? |
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Definition
| Choroid plexus epithelial cells |
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Term
| Choroid plexus epithelial cells are modified _______ cells. |
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Definition
| Choroid plexus epithelial cells are modified EPENDYMAL cells. |
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Term
| What are the three reasons that neurons are so vulnerable to injury? |
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Definition
1) They have a high metabolic rate
2) They have very little stored energy
3) They have a DEPENDANT AXON!!! |
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Term
| Why is the axon of a neuron unable to make its own protein? |
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Definition
| The axon does not have any Nissl substance. |
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Term
| The entire axon is supported by the ____ _____. It produces the protein for the axon and is responsible for disposing of waste from the axon. |
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Definition
| The entire axon is supported by the CELL BODY. It produces the protein for the axon and is responsible for disposing of waste from the axon. |
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Term
True or False:
Neurons are highly regenerative. |
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Definition
| False, they cannot regenerate |
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Term
| What is the most common type of response that a neuron will have to injury? What are it's four main causes? |
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Definition
Most common response: Acute necrosis
Main causes: 1) Ischemia
2) Hypoxia
3) Hypoglycemia
4) Toxemic |
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Term
| How does ischemia cause acute necrosis in a neuron? |
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Definition
| Ischemia --> ↓O2 --> ↓cell respiration --> ↓ATP --> Cell death!!! |
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Term
| What characterizes a neuron that has undergone acute necrosis (histolgically) |
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Definition
Red = DEAD!!! Cytoplasm
Shrunken cell body
Nucleus is pyknotic and karyorrhectic
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Term
| Chromatolysis occurs after damage is incurred on the _____ of a neuron. |
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Definition
| Chromatolysis occurs after damage is incurred on the AXON of a neuron. |
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Term
True or False:
During chromatolysis of a neuron, the axon is damaged and then it swells . The Nissl substance in the axon will disperse and clear centrally. |
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Definition
| False, The axon is damaged, but the swelliing and Nissl substance dispersion occurs in the cell body as an adaptive response to the injury. |
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Term
True or False:
If a neuron's axon is damaged in the periperal nervous system, it may be possible for the cell to rebuild and repair itself. |
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Definition
True, but usually this is ONLY IN THE PNS!!!
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Term
| _____ ______ is the response of an axon to damage. Where on the axon does this occur? |
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Definition
WALLERIAN DEGENERATION is the response of an axon to damage. Where on the axon does this occur?
It occurs DISTAL to the insult (away from the cell body) |
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Term
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Definition
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Term
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Definition
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Term
| What is the "classic" cause of Wallerian degeneration? |
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Definition
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Term
| What are the sequence of events that occur in peripheral Wallerian degeneration assuming there is not too much distance between the two pieces. |
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Definition
1) Axonal insult
2) Swelling and fragmentation of axon
3) Ellipsoid formation due to myelin fragmentation
4) Macrophage phagocytosis o debris
5) Axon stump regenerates a sprout on proximal end and enters endoneurium. 1-4mm/day regen
6) Schwan cells remyelinate axon |
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