1 Meninges, CSF
About this set
Created by:
guitarjess11 on January 28, 2012
Subjects:
Log in to favorite or report as inappropriate.
Order by
168 terms
Terms | Definitions |
|---|---|
 How many meninges surround the brain and spinal cord? | 3 |
| Name the meninges that surround the brain and spinal cord | Dura mater, arachnoid mater, pia mater |
| What composes the cranial dura? | Endosteal layer and meningeal layer |
| Which layer of meninges is NOT continuous with dura of spinal cord? | Endosteal layer |
| Which layer of meninges IS continuous with dura of spinal cord? | Meningeal layer |
| What two main structures do the cranial dura form? | Septa and venous sinuses |
| What layer of cranial dura is reflected inward to form septa? | Meningeal layer |
| At how many locations in the brain does this layer of cranial dura reflect to make septa? | 4 |
| Location of falx cerebri | longitudinal/interhemispheric fissure between 2 cerebral hemispheres |
| Corpus collosum consists of: | horizontally running axons connecting areas of the two hemispheres |
| Location of tentorium cerebelli | horizontally between occipital lobes and cerebellum; attached to falx cerebri medially and laterally attached to bone of the skull |
| What fits through the tentorium incisure/notch? | Midbrain |
| What does the tentorium cerebelli form a "roof" over? | Posterior cranial fossa |
| What age group more commonly gets infratentorial tumors? | Children |
| What age group more commonly gets supratentorial tumors? | Adults |
| Where is the Falx cerebelli? | between 2 hemispheres of the cerebellum |
| What forms the roof of the hypophyseal fossa? | Diaphragma sellae |
| Function of the dural septa: | SUPPORT and PROTECTION for the brain |
| What lines venous sinuses? | endothelium |
| Between which two layers do venous sinuses form? | Between endosteal and meningeal OR between two meningeal layers |
| Superior sagittal sinus: location and between which layers of dura? | Between endosteal and meningeal layers of dura; within attached borders of the falx cerebri |
| From where does the Superior Sagital Sinus receive blood? | Superior cerebral veins; drains blood from convexity of cerebral hemispheres; ALSO, from meninges, bone, scalp, nose --> route of infection spread to CNS |
| What is the major sinus for CSF to be returned to general systemic circulation? | Superior Sagital Sinus |
| Location of Inferior Sagital Sinus, and between what two layers of dura? | along inferior free margin of Falx Cerebri; between TWO MENINGEAL LAYERS of dura |
| Where does the inferior sagital sinus drain blood from? | medial aspect of brain |
| What is the straight sinus a continuation of? | Inferior sagital sinus, posteriorly |
| What vein joins the Inferior Sagital Sinus to form the straight sinus? | Great Cerebral Vein of Galen |
| What kind of lesion can compress the straight sinus? | SUPRA-tentorial space-occupying lesion |
| Straight sinus empties into: | ___ empties into the transverse (lateral) sinus |
| Transverse/lateral sinus continues anteriorly as the: | sigmoid sinus |
| Sigmoid sinus empties into the: | ____ sinus empties into the internal jugular vein |
| Confluence of sinuses: | superior sagittal, straight, and the two transverse sinuses converge |
| Venous sinus that is close to the internal carotid artery: | Cavernous sinus |
| Cavernous sinus receives blood from: | veins of face, nose, pharynx --> route for infection to reach CNS |
| Two important functions of dural venous sinuses: | 1) Venous drainage of blood from brain; 2) route where CSF is returned to general systemic circulation |
| Arachnoid mater separated by ____ layer of cranial dura by the subdural space | ___ follows closely the meningeal layer of dura |
| What kind of space is subdural space? | POTENTIAL space |
| What does subarachnoid space contain? | 1) Trabeculae 2) CSF 3) blood vessels |
| Areas where arachnoid and pia mater are widely separated: | cisterns |
| 4 major cisterns: | cerebellomedullary, pontine, interpeduncular, lumbar |
| Location of lumbar cistern: | L1/L2 |
| Significance of lumbar cistern: | spinal tap/deliver meds "spinals" = intrathecal injections |
| Severe headache after a spinal tap: | "Low pressure" headache |
| Minute pieces of arachnoid penetrate through apertures in the meningeal layer of dura and protrude into the venous sinuses: | arachnoid villi |
| Groups of arachnoid villi | arachnoid granulations |
| What happens to arachnoid granulations as people age? | Calcify; visible in MRI scans = normal in elderly |
| Innermost meningeal layer, vascular membrane: | Pia |
| What surrounds vessels as they enter brain substance? | a sleeve of pia and subarachnoid (perivascular) space; Virchow-Robin space |
| Why do older individuals show tiny "bright spots" in T2 weighted MRIs? | decrease in brain volume, CSF collecting in Virchow-Robin spaces |
| CSF-filled cavities in the brain that are continuous with subarachnoid space: | ventricles |
| Walls of ventricles consist of: | thin, with layer of lining epithelium = ependyma -- cuboidal epithelium |
| Vascular tufts of pia invaginating into ventricles | tela choroidea |
| choroid plexus = ____ + _____ | tela choroidea + ependyma = _____ |
| Majority of choroid plexus in adult in ____ ventricles | lateral ventricles |
| What makes CSF? | choroid plexuses in the ventricles of the brain |
| Where is CSF found? | Ventricles, subarachnoid space, cisterns |
| What two entities have the same specific gravity? | Brain and CSF |
| What is CSF? | a filtrate of blood |
| Normal appearance of CSF: | clear and colorless |
| Protein in CSF: | 15-45 mg/dL |
| Glucose in CSF: | 2/3rds blood glucose level (around 40-80 mg/dL) |
| Cells in CSF: | 0-5 mononuclear lymphocytes per mm^3 |
| Pressure in CSF: | 50-150 mm water (~10 mmHg) |
| Volume of CSF: | 125-175mL |
| Relative to blood CSF has more or less Na+? | More Na+ |
| Relative to blood CSF has more or less Glucose? | Less glucose |
| Relative to blood CSF has more or less Cl-? | More Cl- |
| Relative to blood CSF has more or less K+? | Less K+ |
| More or less protein? | VERY LITTLE PROTEIN |
| If CSF looks pink: | blood in CSF, due to rupture or bleeding from aneurysm in subarachnoid space |
| If CSF looks yellow and clots spontaneously: | increased protein content |
| When can increased protein content occur? | If tumors are present |
| When can CSF look yellow? | from lysis of red blood cells where liberated hemoglobin is broken down to form bilirubin |
| If CSF looks cloudy or "white": | bacterial meningitis --- mostly PMNs |
| Bacterial meningitis has increased/decreases protein? Increased/decreased glucose? | INCREASED protein, DECREASED glucos |
| If CSF is clear or slightly cloudy? | Aseptic meningitis --- elevated WBCs, mostly mononuclear lymphocytes |
| Aseptic meningitis has increased/decreases protein? Increased/decreased glucose? | near normal values for protein and glucose |
| Usual cause of aseptic meningitis? | Viral |
| How do ventricles secrete CSF? | Cuboidal epithelial cells (part of choroid plexus) actively secrete Na+ --> + charge --> attracts Cl- ion from blood --> elevated osmotic pressure draws in more water and other DIFFUSABLE substances |
| Why are glucose and protein concentrations low in CSF? | not very diffusable (molecules too large) |
| Why low K+ in CSF? | Active K+ transport mechanims in opposite direction through epithelial cells |
| What substances can enter the brain substance itself from the CSF? | Alcohol and other lipid soluble substances |
| Rate of choroidal secretion of CSF: | 500-750 mL/day (4-5x the total volume in the system at any given time -- nml 125-175mL) |
| What propels circulation of CSF? | pulses of arteries that lie in subarachnoid space |
| CSF produced from lateral ventricle passes through: | small hole in septum pellucidum |
| name of the small hole in the septum pellucidum: | Interventricular foramen of Monro |
| CSF from third ventricle connects to 4th ventricle through: | cerebral acqueduct/aqueduct of Sylvius |
| From which ventricle does CSF enter the subarachnoid space? | 4th ventricle |
| Through what holes does CSF enter the subarachnoid space? | 2 lateral foramina of Luschka; medial foramen of Magendie |
| What is the central canal of the spinal cord continuous with? | 4th ventricle |
| Arachnoid villi "valves" are controlled by: | pressure differences |
| Cerebral blood flow depends on: | Cerebral perfusion pressure |
| Cerebral Perfusion Pressure (CPP) = | MAP-ICP [mean arterial pressure - intracranial pressure) |
| Ways a mass lesion with increased ICP can damage the brain: | stroke/infarction; hemorrhage; herniation --> damage to brain --> death |
| ways a subarachnoid hemorrhage can occur: | traumatic or non-traumatic (spontaneous) |
| Most common type of subarachnoid hemorrhage: | spontaneous -- from rupture of an aneurysm [spontaneous can also be from leakage of arteriovenous malformation AVM or angioma (blood vessel tumor)] |
| Most common type of aneurysm: | berry or saccular aneurysm at arterial junctions in the circle of willis |
| Where in the circle of willis do most aneurysms occur? | anterior part of circle of willis |
| CARDINAL SYMPTOMS of subarachnoid hemorrhage: | SUDDEN ONSET of severe headache (often during exertion), stiff neck (nuchal rigidity), altered level of consciousness |
| What causes nuchal rigidity? | Irritation of meninges in posterior fossa and cervical canal |
| What does subarachnoid hemorrhage look like on MRI? | "crab of death" -- blood follows contours of the brain, within sulci and cisterns |
| Two types of hydrocephalus in adults: | non-communicating (obstructive) and communicating |
| How does non-communicating hydrocephalus occur? | From blockage |
| Common area for non-communicating hydrocephalus: | acqueduct of Sylvius |
| What type of lesion causes blockage of acqueduct of sylvius? | supratentoriall space-occupying lesion |
| Susceptible to acqueductal stenosis/hydrocephalus: | infants whose mothers were infected with mumps or rubella --- inflammatory adhesions form |
| Arnold-Chiarai malformation | outflow of CSF from 4th ventricle into subarachnoid space is blocked; cerebellum herniates and brain stem is displaced down spinal canal, pulling foramina in the roof of 4th ventricle shut |
| Most common reason for adults to have obstructive hydrocephalus: | complication of another disorder, i.e. secondary to a brain tumor |
| 2 reasons to have a communicating hydrocephalus: | 1) too much CSF produced/not enough removed 2) reduced resorption of CSF |
| Increases production of CSF | choroid plexus papilloma (secretory tumor) |
| Reduces reabsorption of CSF | congenital absence of arachnoid villi; blockage of vill subsequent to subarachnoid hemorrhage or infection, increased protein in CSF |
| * Why is decreasd CSF production generally not a problem clinically? * | Question asked in notes * |
| A life-threatening sequelae to meningitis: | Reduced absorption and subsequent hydrocephalus |
| Normal Pressure Hydrocephalus | in elderly adults, loss of brain volume --> hydrocephalus and chronically dilated ventricles WITHOUT an increase in ICP |
| 2 types of cerebral or brain barenchymal edema: | interstitial/extracellular edema OR cytotoxic/intracellular edema |
| Causes of interstitial/extracellular edema: | absence of lymphatic drainage in brain; increased permeability of brain capillary endothelial cells (Vasogenic edema), increased CSF pressure |
| Causes of cytotoxic/intracellular edema: | intracellular fluid volume -- failure of ATP-dependent sodium pump, i.e. as result of HYPOXIA |
| Most dangerous type of meningitis: | bacterial |
| sequelae of bacterial meningitis if not treated: | permanent hearing loss, intellectual disabilities, death |
| Age when meningitis most common: | infants and children |
| SYMPTOMS of meningitis: | high fever, irritability, lethargy (decreased level of consciousness), severe headache, vomiting, sensitivity to light and sound (photophobia and phonophobia), nuchal rigidity, muscla "twitching" |
| COMMON symptoms between subarachnoid hemorrhage and meningitis: | decreased consciousness, nuchal rigidity, headache |
| Symptoms that would NOT be present in subarachnoid hemorrhage: | fever, phono/photophobia, slower onset of headache |
| Routes for infection of CNS: | cardiopulmonary, nasopharynx and sinuses, middle ear, skull fracture, scalp/face, along nerves |
| Meningitis most commonly involves which dural layers? | Arachnod/subarachnoid space/pia |
| Leptomeninges | arachnoid and pia |
| Serious complication of meningitis: | dense adhesions between pia and arachnoid |
| complication of adhesions between pia and arachnoid: | impede circulation of CSF, can't return to general systemic circulation = COMMUNICATING hydrocephalus |
| complication of involvement of subarachnoid space: | blood vessels in subarach. Space can become inflamed and damaged |
| location of headache in meningitis: | entire head and neck |
| Nerve that innervates dura supratentorially= | trigeminal (V) nerve |
| Nerve that innervates dura infratentorially = | Vagus (X) nerve |
| referred pain from meningitis: | forehead/face, head and back of neck |
| Herniation | displacement of brain tissue into a space |
| Uncal herniation | transtentorial |
| What happens in uncal herniation? | Uncus herniates into the tentorial incisure of tentorium cerebelli |
| Symptoms of uncal herniation: | decreasd level of consciousness, dilation of pupil of the eye on the side of the herniation |
| Reason for dilation of pupil in uncal herniation: | compromised parasympathetic fibers; only sympathetics are controlling cranial nerve III |
| If herniation compresses motor fibers of CN III: | pupils fixed "Down and out" and dilated |
| Uncal herniation can be followed by: | tonsillar herniation |
| Tonsillar herniation: | transforaminal herniation |
| What is the tonsil | tiny medially located structure under cerebellar hemisphere |
| What happens in tonsillar herniation? | tonsil herniates into foramen magnum |
| Area of the brain where critical respiratory and cardiovascular centers are located: | Reticular formation |
| Danger of tonsillar herniation: | compress medullary portion of retiuclar formation |
| Location of the most life-threatening fractures of the skull: | base of the skull |
| Serious clinical signs of basal fracture: | leak CSF from nose; bleed from auditory canal |
| What type of bleeding do skull fractures increase the risk of? | Meningeal bleeding |
| Why do skull fractures increase risk of meningeal bleeding? | Meningeal vessels are also distributed to the bone -- sheared or ruptured during a fracture |
| Infant hemorrhage | extra or epi-dural hemorrhage |
| How does epidural hemorrhage happen? | Dura ripped or separated from cranial bone, i.e. during trauma |
| appearance of epidural hemorrhage on CT: | lens-shaped biconvex hematoma; lenticular shape |
| Most common cause of epidural hemorrhage: | blow to side of head |
| What artery is ruptured in an epidural hemorrhage? | middle meningeal artery, anterior division, in epidural space between bone and dura |
| Clinical signs of rupture of anterior division of middle meningeal artery: | difficulty in voluntary motor movement on contralateral side |
| Concussion is followed by | period of lucidity, then subsequent decompensation as result of hematoma |
| Subdural hemorrhage | bleeding into subdural/potential space |
| appearance of subdural hemorrhage on CT/MRI: | crescent-shaped hematoma |
| Most common cause of subdural hemorrhage/hematoma: | Anterior-posterior displacement of the brain |
| Cause of the bleeding in subdural hemorrhage: | tears in bridging veins -- branches of superior cerebral veins |
| In what age group are subdural hemorrhages more common? | Elderly |
| Concussion | "To shake violently"; a transient disruption in brain function, seeing stars |
| Area of brain damage from a concussion: | white matter underlying prefrontal cortex |
| Symptoms of a severe concussion: | performance deficits on tests of executive function |
| Risk factor for developing Alzheimer's dz | concussion -- prefrontal cortex damage |
| Risk for developing amyotrophic lateral sclerosis (ALS) | concussion |
| Chronic Traumatic Encephalopahty (CTE) caused by: | repeated head trauma or repeated concussion |
| Symptoms of CTE: | memory loss, paranoia, depression, ataxia |
First Time Here?
Welcome to Quizlet, a fun, free place to study. Try these flashcards, find others to study, or make your own.