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69 Cards in this Set
- Front
- Back
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Meninges (3)
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-brain is suspended w/in skull by a three-membrane connective tissue covering
-the function to stabilize, anchor it, and cushion -a layer of cerebrospinal fluid (CSF) lies w/in the meninegeal layer |
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Meninges consists of (3)
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-Dura mater
-Arachnoid -Pia mater |
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Meninges photo
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photo
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Dura Mater layer (5)
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-dense connective tissue of two layers
-periosteal layer is attached to bone and has meningeal arteries w/in it -meningeal layer is attached to arachnoid -two layers are fused except where they split forming venous sinuses -is pain sensitive |
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Dura matter photo
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photo
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Dura mater potential spaces (2)
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-epidural (extradural) space is b/t cranium and periosteal layer
-subdural space is b/t dura and arachnoid |
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photo of potential space
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photo
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Dura matter: Folds of the inner layer of Dura (3)
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-Flax cerebri lies in longitudinal fissure
-Flax cerebri extends from crista galli to tentorium cerebelli -Tentorial notch is the opening for brainstem |
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photo of flax cerebri
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photo
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Arachnoid (4)
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-thin connective tissue layer
-layers of cells line the Dura -Cells are joined by tight junctions -controls the passage of substances |
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Arachnoid's Subarachnoid space: (4)
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-network of collagen fibers called trabeculae connect pia and arachnoid
-space is filled with CSF -cerebral arteries and veins travel though this space -subarachnoid cisterns are pool of CSF |
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Arachnoid's Arachnoid villi (3)
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-evaginations protrude though dura into venous sinuses
-allow for reabsorption of CSF into venous system -flow is unidirectional |
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Pia Mater(3)
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-delicate connective tissue layer
-tightly adherent to brain surface -follows sulci and fissures |
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pia mater photo
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photo
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Optic Nerve (3)
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-surrounded by meninges
-dura fuses with sclera -subarachnoid space encircles nerve throughout its length |
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Papilledema (3)
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-sustained elevation of intracranial pressure compresses CRV (central retinal vein)
-edema and elevation of optic nerve head -evident with the ophthalmoscope |
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Blood supply to CNS: Anterior circulation (3)
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-Internal carotid artery enters the skull through carotid canal w/in temporal bone
-it passes through cavernous sinus -has 5 main branches |
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Anterior circulation: Five main branches of Internal carotid artery (5)
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-Opthalmic artery
-Anterior choroidal artery -Anterior cerebral artery -Posterior communicating artery -Middle cerebral artery |
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Blood supply to CNS: Posterior circulation (2)
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-Two vertebral arteries
-enters skull through foramen magnum |
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Blood supply to CNS: Posterior circulation (2)
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-Basilar artery formed by joining of vertebrals at pons/medulla junction
-main branches are posterior cerebral arteries |
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Circle of Willis (4)
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-Joining of anterior and posterior circulation
-internal carotid joined to posterior cerebral by posterior communicating artery -anterior cerebrals are joined by anterior communicating artery -it encircle the optic chiasm |
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photo of Circle of Willis
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photo
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Branches that supply brain stem and cerebellum: Vertebral arteries (1)
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-posterior inferior cerebellar
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Branches that supply brain stem and cerebellum: Basilar arteries (3)
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-anterior inferior cerebellar
-superior cerebellar -posterior cerebral |
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photo of branches that supply brain stem and cerebellum
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photo
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Branches that supply cerebrum: Anterior cerebral artery (3)
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-branches from internal carotid
-passes above optic nerve into longitudinal fissure -supplies MEDIAL surface of frontal and parietal lobes and internal capsue |
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Branches that supply cerebrum: Middle cerebral artery (7)
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-main continuation of internal carotid
-passes through Lateral Sulcus -supplies most of lateral frontal, parietal, temporal lobes -Optic Radiations -parts of Basal Ganglia -Internal Capsule -Thalamus |
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Posterior cerebral artery (6)
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-branches from basiler
-supplies midbrain -optic radiations -occipital lobe -medial and infrior temporal lobe -talamus |
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photo of Posterior cerebral artery and anterior cerebral artery
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photo
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photo of middle cerebral artery
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photo
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cerebral arteries (2)
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-cortical branches (supply cortex)
-deep branches (supply deeper grey/white mater) |
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Other major arteries supplying deep structures: Anterior Choroidal artery (8)
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-branch of internal artery
-supplies optic tract -optic radiations -choroid plexus of LATERAL ventricles -Putamen -Thalamus -Internal capsule -Hippocampus |
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Other major arteries supplying deep structures: Posterior Choroidal artery (4)
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-branch of posterior cerebral
-supplies choroid plexus of THIRD ventricle -Thalamus -Hippocampus |
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Capillary network (2)
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-Endothelial cells are joined by tight junctions
-Perfusion - movement of fluid and solutes out and into tissue |
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Venous drainage (2)
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-Cerebral veins contain no valves and drain into venous sinuses
-Cerebral sinuses are reservoirs formed by splitting of the dura and lined by endothelial cells |
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photo of venous drainage
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photo
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Venous drainage: Superior sagittal sinus (2)
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-drains veins from upper cerebrum
-empties into transverse sinus |
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Venous drainage: Inferior sagittal sinus (3)
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-drains lower cerebrum
-unites with greater cerebral vein -to form straight sinus |
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Venous drainage: Confluence of sinuses (1)
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-Juncture of straight and transverse sinuses
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Cavernous sinus (5)
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-located on both sides of body of sphenoid bone
-drains blood from globe and orbit -carries all sensory, motor and autonomic nerves that supply the globe -empties into superior and inferior petrosal sinuses -all sinuses drain into Jugular veins |
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Photo of cavernous sinus
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photo
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Blood Brain Barrier (3)
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-tight junctions b/t capillary endothelial cells and arachnoid cell layer BOTH prevent large molecules from exiting the capillary
-excludes many pathogens from the CNS -can be a barrier to certain drugs and protein antibodies |
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BBB in Parkinson's disease (2)
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-Dopamine cannot pass barrier but it's precursor L-dopa can
-Once it is in the brain it is converted to dopamine |
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Auto-regulation of the CNS (3)
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-CNS can regulate its own blood supply
-One mechanism is by CO2 concentration -Autonomic system plays only a minor role |
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Hypercapnia (2)
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-Excess CO2 in extracellular fluid
-Relaxation of arteriole wall |
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Necessity of constant blood flow: brain storage (4)
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-brain cannot store glucose nor oxygen efficiently
-10 sec. of ischemia - loss of consciousness -20 sec. - electrical activity ceases -few minutes - irreversible damage |
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Necessity of constant blood flow: oxygen consumption (5)
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-oxygen consumption increases from brainstem to cerebral hemispheres
-cerebral cortex is more vulnerable than brainstem to lack of O2 -cerebral and cerebellar functions may be destroyed -brainstem remains functional (ie. life remains in coma pts) -anoxia can cause persistent vegitative state |
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Clinical Consideration where symptoms depend on site and size: Vascular disorders of Cerebrovascular accident (2)
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-embolus or thrombus obstruct blood flow
-slow occlusion may allow collateral vessels to compensate |
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Clinical consideration where symptoms depend on site and size: Vascular disorders of Hemorrhage (2)
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-Deprives tissue of blood but also exerts pressure on surrounding tissue
-infarct -necrotic area of tissue |
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Clinical consideration where symptoms depend on site and size: Vascular disorders of Transient ischemia attack (TIA) (4)
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-persists for only short time
-followed by complete recovery -caused by minute emboli -medical emergency due to risk of stroke is great |
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Clinical consideration: Aneurysm (3)
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-dilation of arterial wall
-as it grows it compresses structure much as a tumor would -can rupture causing hemorrhage |
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Clinical consideration: Arteriovenous malformation (3)
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-congenital connection b/t artery and vein
-may "steal" blood from adjacent tissue -may rupture and bleed |
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Neurological deficits resulting from stroke of Anterior cerebral artery: Cortical branches (4)
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-personality changes
-contralateral hemipleigia -contralateral hemisensory loss -most likely to affect the leg |
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Neurological deficits resulting from stroke of Anterior cerebral artery: deep branches (1)
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-Internal capsule
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Neurological deficit resulting from stroke of Middle cerebral artery: Cortical branches (6)
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-contralateral hemiplegia
-contralateral hemisensory loss -language impairment -spacial relationship difficulties -contralateral visual field loss -hand, tongue, face affected |
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Neurological deficits resulting from stroke of Middle cerebral artery: Deep branches (1)
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-Internal capsule
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Neurological deficits resulting from stroke of Posterior cerebral artery: Cortical banches (2)
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-eye movement paresis or paralysis
-contralateral visual field loss |
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Neurological deficit resulting from stroke of Posterior cerebral artery: Deep branches (3)
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-Thalamus
-contralateral hemiparesis -probably no sensory loss |
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Epidural (extradural) hemorrhage (4)
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-meningeal arteries run w/in dura
-head trauma may result in rupture and bleeding -symptoms develop over hours -characteristically takes a lens shape |
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Epidural (extradural) hemorrhage photo
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photo
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Subdrual hemorrhage (3)
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-often caused by tearing of cerebral veins (shaken baby syndrome)
-symptoms develop over days -characteristically takes a crescent shape |
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Subdural hemorrhage photos
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photos
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Subarachnoid hemorrhage (3)
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-aneurysm or rupture of cerebral arteries
-bleeding into CSF -symptoms w/in minutes |
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Subarachnoid hemorrhage photos
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photo
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Herniation (2)
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-space-occupying lesion can cause displacement of brain
-brain protrude through falx cerebri, tentorium or foramen |
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Herniation photos
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photos
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Photo: Hematoma puts pressure on cingulate gyrus which can slip below falx cerebri and press on opposite ________ guyrus
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photos
-cingulate gyrus |
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Photo: Tumor in temporal lobe exerts pressure against midbrain which is pressed against ________
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photo
-tentroium |
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Photo: Tumor in cerebellum herniates through foramen comprssing medulla against ______
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photo
-foramen |
