Term
| What cells form the CSF-BIF-Barrier. |
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Definition
| This barrier is formed by the ependymal cells which line the ventricles. |
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Term
| Do Adrenaline, dopamine and serotonin cross the BBB |
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Definition
| NO, but their amino acid precursors do. |
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Term
| What are Circumventricular (CV) organs |
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Definition
Areas in the brain that lack BBB. Examples include anterior pituitary.
the area postrema, subfornical organ, lamina terminalis, subcommissural organ, median eminence, and neurohypophysis. |
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Term
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Definition
| CV organs do have tight junctions in specialized ependymal cells called tanycytes, to prevent transport from BIF to CSF |
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Term
| What cells for the blood-CSF-barrier (B-CSF-B) |
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Definition
The Choroid plexus. The choroid plexus
is composed of modified, highly vascular projections of the pia |
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Term
| As innervation becomes denser, What happnes to the area of skin to which a particular neuron branches? |
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Definition
| It becomes smaller, reducing the size of the receptor field. |
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Term
| Which receptors sense touch |
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Definition
| Meissner, hair follicles, Merkel, and ruffini |
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Term
| Which receptor senses vibration |
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Definition
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Term
| Which have larger receptor fields, cold or hot thermoreceptors? |
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Definition
| Hot have larger fields. Cold have spot like receptor fields. Also of interest is the fact that cold receptors have a higher firing rate at normal skin temp |
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Term
| Substance P and nociceptor sensitization |
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Definition
| Released by activated nociceptor nerve endings. This and calcitonin gene related peptides cause mast cell degranulation and increased venule permeability which then leads to increased stimulation and lowering of threshhold of the nociceptor. This is termed Nociceptor sensitization. |
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Term
| Levels of what compounds are higher in the brain? Which are lower? |
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Definition
| Cl is higher. Glucose and protein are lower. pH is lower. |
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Term
| Communicating hydrocephalus |
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Definition
| movement of CSF through subarachnoid space and to venous system is blocked. |
|
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Term
| Non-communicating hydrocephalus |
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Definition
| Obstruction of CSF movement in ventricles. Usually occurs in the aqueduct. |
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Term
| Where does reabsorption of CSF occur? |
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Definition
| Arachnoid villi, which are projections of the arachnoid into dural venous sinuses. |
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Term
| What are the two types and mechanisms of edema in the brain? |
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Definition
Cytotoxic edema: intracellular accumulation of water (cell swelling)
Mechanism: loss of volume regulation due to reduced ATP for
maintaining pumps
Causes: early cerebral ischemia, hypoxia, infection -malaria, -meningitis;
metabolic -hyponatremia.
Both gray and white matter swell; often BBB is intact so no increase in
CSF protein..
Vasogenic edema: increased fluid in extracellular space
Mechanism: disruption in BBB, protein and fluid leak into interstitium
mostly in white matter
Causes: breakdown of BBB during late cerebral ischemia, tumor, trauma
Mannitol (reverses osmotic gradient) or ventricular puncture (removes
CSF) are necessary to reverse edema. |
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Term
| What controls the composition of the BIF and CSF respectively? |
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Definition
| The endothelial cells of the brain capillaries control the composition of the BIF and the epithelial cells of the choroid plexus control the composition of the CSF. |
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