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31 Cards in this Set
- Front
- Back
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what are 2 ways (besides skull) that the brain is protected?
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suspended by meninges
CSF |
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where are the bridging veins? what type of hematoma can lead lead to?
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come off cerebral vessels in subarachnoid space and empty into superior sagittal sinus in space b/w 2 dura layers
rupture leads to subdural hematoma |
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how does a subarachnoid hematoma usually develop?
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rupture of cerebral aa in subarachnoid space
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what are the portions of the dura that divide the cerebral hemispheres? sep the cerebellum?
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falx cerebri
tentorium cerebelli |
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what are arachnoid villi/granulations?
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extensions of arachnoid into dura; drain CSF into venous system
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what are the 2 dura layers?
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meningeal (inner) and periosteal (outer)
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how do you distinguish b/w epidural and subdural hematomas on radiograph?
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epidural- lens shaped; fast bleeding and pooling of blood
subdural- crescent shape; slow bleeding |
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how do subdural hematomas usually present?
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headaches
gradual, weeks after trauma |
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rupture of what aa. usually leads to an epidural hematoma?
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middle meningeal a runs in epidural space and supplies meninges
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what is the tentorial incisura and what is its significance?
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tentorial notch
opening in the cranial cavity around midbrain formed by dura pressure in this area->compress CN 3 (ptosis, "down and out sx" |
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what are 3 dangers assoc with a space occupying lesion?
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compress adjacent tissue
incr intracranial pressure herniation of neural tissue |
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what are the cerebral peduncles?
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ventral surface of midbrain
collection of UMN axons before cross-over ~corticospinal tract |
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uncal transtentorial herniation: defn and triad
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uncus (medial temporal lobe) herniates through tentorial notch
1. "blown" pupil-dilated, fixed (CN3) 2. hemiplegia 3. coma 2 and 3 due to damaged reticular formation |
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what is the reticular formation?
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region in midbrain
critical for consciousness |
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what are the areas of the lateral ventricle?
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anterior horn, body, atrium, inferior horns, posterior horn
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what connects each lateral ventricle with the 3rd?
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foramen of monroe
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what are the exit points in the fourth ventricle?
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2 lateral exits: lateral foramina of luschka
1 medial exit: foramen of magendie |
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what makes the CSF?
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choroid plexus
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choroid plexus
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specialized vascular structure
fusion of blood vessels and ependymal cells lining ventricles->choroid epithelial cells |
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how is the content of CSF regulated?
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tight jxn b/w ependymal cells
tight control; highly diagnostic |
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how does CSF compare to blood?
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low cellularity
low protein Mg and Cl higher in CSF K+ lower in CSF (prevent random depol) |
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what happens to CSF in bacterial meningitis and why? what abt diagnosing MS?
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low glucose and high protein
(bacteria consume glucose) MS- high Ig in CSF |
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what are cisterns?
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spaces that collect CSF coming from the fourth ventricle;
in subarachnoid space |
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what is the breakdown of CSF? vol made and in each compartment?
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choroid plexus makes 500mL a day
140mL in total ventricular system 25mL in ventricles 115mL in subarachnoid space |
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what is hydrocephalus? what are 3 main causes? which is most common?
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"water in head"
build-up of CSF in brain 1. XS production 2.obstruction of flow (most common) 3. poor drainage |
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what is the name for a tumor of the choroid plexus? what would this cause?
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papilloma
XS CSF prod-> hydrocephalus |
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what are 2 classifications of hydrocephalus?
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communicating: ventricles communicate freely; flow obstructed in SA space or isnt absorbed by arachnoid villi
non-communicating: obstruction of flow b/w ventricles or b/w ventricles and SA space |
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what is Dandy Walker syndrome?
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failure to form exit foramina off 4th ventricle
ex of non-communicating hydrocephalus: CSF cant get from 4th ventricle to SA space causes enlargement of ventricles |
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what causes the BBB?
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formation of tight jxns b/w endothelial cells in brain INDUCED by neighboring astrocytes
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where else besides the BBB is there a barrier system in the brain?
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b/w choroid plexus and CSF; formed by tight jxns b/c choroid epithelial cells
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what is the name of the regions where the BBB is interrupted? ex (4)?
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circumventricular organs
ex: pineal gland, neurohypophysis, median eminence, area postrema (caudal wall in 4th ventricle of medulla) important for rel of neurohormones into blood also, leaky under stress |
