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100 Cards in this Set
- Front
- Back
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Neurons are completely dependent on continuous and uninterrupted blood supply for _________ needs, and___________
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metabolic needs, oxygen
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___________ _________ removes CO2 and metabolic by-products
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venous drainage
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Brain composes ___% of body mass but requires ___% of blood supply and more than ___% of oxygen and metabolized glucose
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2%, 20%, 20%
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How much blood is pumped per minute?
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750 ml
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Circulated blood is emptied into the ________ ______ system for circulation through the _____________ and ________
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venous drainage, heart, lungs
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How many seconds can you go without brain blood circulation before it causes unconsciousness?
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5-8 s
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How long before vascular deprivation eliminates electrical activity?
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20 to 25 s
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How long before lack of brain blood circulation causes irreversible damage?
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4 to 6 min
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_______ ___________ involves the networks of arteries and ________ extending to each section of the body
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vascular circulation, veins
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Large ________ carrying oxygenated blood branch into smaller _________ and _________. Terminal blood vessels are called __________ _________. Exchange of oxygen & nutrients takes place through __________ that infest brain tissue. Deoxygenated blood is picked up by __________. These transport it to larger _________ on the cortical surface. Veins then empty into _________ _______.
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arteries
arteries, capillaries capillary beds venules veins venous sinsuses |
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Vessels traveling in subarachnoid space are covered by external tissue until it reaches ___________ size where exchange takes place
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capillary
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Capillary bed is a combination of __________ and _______ side.
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artery and vein
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Smaller penetrating vessels are covered by __ ______ closer to the surface.
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pia mater
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What are the two main arterial supply systems in the brain?
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1) internal carotid
2) vertebral basilar |
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The common carotid artery splits into _________ & __________ carotid arteries bilaterally.
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internal & external
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External carotid supplies __________ muscles, _________, and oral, nasal, & ______ cavities.
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facial
forehead orbital |
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The internal carotid enters the skill cranium through the __________ _________ that makes up the anterior circulation of the brain.
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carotid foramen
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____________ arteries make an inverted v-shape and fuse to form the _______ artery.
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vertebral
basilar |
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What are the 2 arterial branches that immediately split off the internal carotid?
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anterior choroidal & opthalmic arteries
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The opthalmic artery supplies the ________ and ocular muscles.
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eyeball
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After splitting, the internal carotid then joins the ________ of ______ and gives off two major cortical arteries. What are they?
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circle of willis
anterior cerebral artery (ACA) middle cerebral artery (MCA) |
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Bilateral vertebral arteries enter the crainum through the __________ _________. They then continue along the ventrolateral surface of the _______.
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foramen magnum
medulla |
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Vertebral arterires merge at the _______ _____ to form the basilar artery that runs along the ventral surface of the ___________.
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basilar artery
brainstem |
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The basilar artery terminates in the _______ of ________ but gives of important brainstem & cerebellar arteries before doing so.
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circle of willis
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What are the 3 major arteries given by the vertebral arteries?
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1) posterior spinal
2) anterior spinal 3) PICA |
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What does the posterior spinal artery do? (2)
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1) Supplies the dorsal medulla and dorsal rostral third of the spinal cord
2) Supplies the dorsal column system (gracili and cuneatus) |
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What does the anterior spinal artery do? (3)
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1) Descends along the ventral midline
2) Supplies ventral medulla including pyrimidal fibers and medial lemniscus 3) Supplies ventral rostral third of spinal cord |
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What does the PICA do?
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1) Supplies lateral medulla & inferior cerebellum
2) Arises from vertebral artery @ medulla |
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What are the branches of the basilar artery? (3)
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1) Anterior inferior cerebral artery (AICA)
2) Pontine level branches (internal auditory artery) 3) Superior cerebral artery |
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What does AICA cover?
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pons
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What do the small pontine level branches in the Basilar artery network do?
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(Internal uaditory artery)
Supplies cochlea & vestibular structures |
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What does the superior cerebellar artery do?
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1) Arises from the top of the basilar artery
2) Supplies rostral pons & anterior-dorsal surface of cerebellum |
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Many short & long ____________ arteries and ____________ arteries arise from basilar artery to supply pons & midbrain.
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circumferential
paramedian |
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What is the Circle of Willis? What does it encircle?
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A ring of blood vessels at the base of the brain that encircles the optic chiasm & pituitary stalk.
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The Circle of Willis connects bilateral _______ ________s with the basilar artery.
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internal carotids
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What kind of communicating arteries link the two systems in the Circle of Willis?
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posterior communicating
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What kind of artery links the bilateral internal carotids?
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anterior communicating
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Where do all cortical arteries emerge from?
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the Circle of Willis
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Communication between the vascular systems allows __________ __________ between brainstem, cerebrum, cerebellum, and both sides.
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pressure equalization
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What are anastamoses?
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Junction between two arterial systems that allows downstream arteries to receive blood from two sources
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What is the importance of the Circle of Willis?
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If one source is compromised, the other artery can compensate to an extent.
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What do the cortical branches of the Circle of Willis do?
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Supply superficial and external brain areas (circumferential)
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What do the central branches in the Circle of Willis do?
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Penetrate ventral brain surfaces to supply internal brain structures
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What are the cortical arteries in the circle of Willis?
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-Anterior cerebral artery (ACA)
-Middle cerebral artery (MCA) -Posterior cerebral artery (PCA) |
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ACA, MCA, & PCA _____________ at points of contact.
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anastamose
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The anterior cerebral artery travels ____________ in the longitudinal fissure along the mid-sagittal surface and curves around the ________ of the corpus callosum to supply medial and dorsal frontal & parietal lobes.
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rostrally
genu |
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What are the major branches of the anterior cerebral artery? (4)
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orbital
frontopolar callosomarginal pericallosal |
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What are symptoms of ACA interruption?
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paralysis & anesthesia (legs)
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What are frontal lobe symptoms of ACA? (4)
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1) disordered thinking
2) reasoning 3) self-monitoring 4) awareness |
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What is the largest cortical artery?
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MCA
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The MCA is the most significant for speech & language...
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comprehension, production, planning
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The MCA runs ________ and emerges through the ______ ________ on the lateral surface.
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laterally
Sylvian fissure |
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The MCA supplies the entire lateral surface (all lateral lobes including insula): auditory regions, ___________ motor regions, & _________ regions
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speech motor
language |
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What are interruption symptoms for the MCA? (6)
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-contralateral hemiplegia & hemi-anesthesia of facial, trunk, and/or limb regions
-loss of speech motor control (dominant hem) -aphasic syndromes (dominant hem) -reading/writing deficits (dominant hem) -hemi-neglect (dominant hem) -sensory integration (either hem) |
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PCA curves laterally and caudally along the _________ brain surface.
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ventral
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PCA provides cortical supply for the... (4)?
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-anterior & inferior temporal lobe
-uncus -inferior temporal gyri -inferior & medial occipital lobe |
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PCA provides subcortical supply for (2)?
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-midbrain
-large portion of thalamus |
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What are PCA occlusion symtpoms? (2)
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visual deficis
cortical blindness |
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What do the central arteries do? (5)
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supply blood to subcortical structures: thalamus, hypothalamus, basal ganglia, internal capsule, choroid plexus
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What are the important central arterires? (4)
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lenticulostriate
anteriomedial anterior & posterior choroidal |
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What arteries have marked overlapping through anastamotic links & individual variability?
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central arteries
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What does the lentriculostriate do?
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arises from MCA, main supply to basal ganglia
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What does the anterior choroidal artery do?
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arises from the interal carotid just before Circle of Willis; supplies choroid plexus, internal capsule, hippocampus, globus pallidus, putamen.
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What are occlusion symptoms for the ACA?
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anesthesia, movement disorders, memory disturbances
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What does the posterior choroidal do?
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arises from PCA; supplies choroid plexus (3rd ventricle), tectum, pineal gland, parts of thalamus & midbrain structures (reticular formation)
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What do the central arteries do? (5)
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supply blood to subcortical structures: thalamus, hypothalamus, basal ganglia, internal capsule, choroid plexus
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What are the important central arterires? (4)
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lenticulostriate
anteriomedial anterior & posterior choroidal |
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What are occlusion symptoms for the posterior choroidal?
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movement disorders, coma (if reticular formation is compromised)
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What arteries have marked overlapping through anastamotic links & individual variability?
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central arteries
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Explain the spinal cord vascular supply.
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1) Branches from vertebral artery form Anterior & Posterior spinal arteries.
2) Anterior spinal artery joins to form a single artery on the ventral surface (supplies anterior 2/3 of the spinal cord. Interruption affects motor nuclei & sensory motor tracts. 3) Posterior spinal artery descends on dorsal |
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What does the lentriculostriate do?
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arises from MCA, main supply to basal ganglia
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What does the anterior choroidal artery do?
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arises from the interal carotid just before Circle of Willis; supplies choroid plexus, internal capsule, hippocampus, globus pallidus, putamen.
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What are occlusion symptoms for the ACA?
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anesthesia, movement disorders, memory disturbances
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What does the posterior choroidal do?
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arises from PCA; supplies choroid plexus (3rd ventricle), tectum, pineal gland, parts of thalamus & midbrain structures (reticular formation)
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What are occlusion symptoms for the posterior choroidal?
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movement disorders, coma (if reticular formation is compromised)
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Explain the spinal cord vascular supply.
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1) Branches from vertebral artery form Anterior & Posterior spinal arteries.
2) Anterior spinal artery joins to form a single artery on the ventral surface (supplies anterior 2/3 of the spinal cord. Interruption affects motor nuclei & sensory motor tracts. 3) Posterior spinal artery descends on dorsal surface (supplying dorsal columns) 4) Blood supply augmented by radicular arteries from aorta |
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What is collateral circulation?
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Backup blood supply if main arterial supply is compromised. It is important for compensating blood supply & natural recovery. It is more effective if supply is occluded near major branches rather than terminal arteries.
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What are the common points of collateral circulation?
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-anterior communicating artery connect bilateral ACA
-vertebral basilar feeds circle of willis if internal carotid compromised -terminal branches of cortical areries anastamose w/ eachother (watershed zone) |
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What are strokes/CVAs?
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sudden development of focal neurological defecit
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What are 3 common types of CVA/strokes?
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1) Occlusive Vascular Pathologies (Thrombosis/Embolism)
2) Hemorrhage 3) Arteriovenous Malformations |
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What is atherosclerosis?
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Hardening of arterial walls; primary cause of occlusion; slow process by lipids, platelets, calcium deposits, fatty partcles, other undissolved substances; causes narrowing of lumen
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What are contributing factors to atherosclerosis?
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1) Blood coagulation
2) Stasis 3) Fatty diet |
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What is ischema?
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Insufficient blood supply that occurs as a result of narrowed/blocked arterial lumen
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What is a TIA?
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Temporary interruption/insufficient blood circulation to the brain. Symptoms depend on area affected. May include weakness, double vision, headache, paresthesia, hemianesthesia, dysarthria, dizziness, may last a few to 24 hours, can cause brain damage, can indicate a larger stroke
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What is treatment for TIA?
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Blood thinners to prevent CVA.
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How does the body compensate for atherosclerosis?
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Heart compensates for reduced blood flow by pumping blood with greater force which can lead to high blood pressure (hypertension)
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What is an embolism?
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Blockage in a distal artery w/ narrow lumen. Embolus is detached part of thrombosis which enters blood stream and eventually blocks a small end artery (often in young people)
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What is a thrombosis?
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Localized buildup of fatty substances & platelets, gradual buildup, symptomatic in later years
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Define hemorrhagic strokes.
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Result from ruptured blood vessels when a weakened arterial wall ruptures under pressure of constant blood flow. It can occur anywhere in the arterial system but most common in BG & thalamus.
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What are the (3) types of hemorrhage?
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1) Intercerebral hemorrhage
2) Subdural hematoma 3) Aneurysm |
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What is an intercerebral hemorrhage?
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Space-occupying lesion, involves the rupture of an intracranial artery, blood is released. If not drained, blood can accumulate to form a hematoma.
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What is a subdural hematoma?
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Usually results from a traumatic injury. Blood vessel ruptures in arachnoid tissue and pools below dura. If not drained, it will expand and compress brain tissue, causing irreversible damage.
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What is an aneurysm?
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Localized balloon-like dilation of artery as result of either weakness of vessel wall or congenital malformation.
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What are the 2 ways an aneurysm can cause neurological symptoms?
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1) arterial dilation can compress surrounding area
2) aneurysm can no longer withstand the pressure and ruptures, causing blood in brain or on its surface |
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What is an arteriovenous malformation?
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A congenital condition in which tangled arteries & veins become connected in a localized area. With age, they can grow and be susceptible to hemorrhage. Malformation can often cause seizures. Depending on the location, it can also cause language impairments, motor speech disorders, visual disorders, sensory loss, hemiplegia
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Where do superficial veins drain?
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Into the superior sagittal sinus & cavernous sinus (between layers of dura)
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Where do deep veins drain?
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Into the great vein of Galen
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All venous drainage eventually reaches...?
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Internal jugular veins
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Explain superficial venous drainage.
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1) superior sagittal sinus empties into transverse sinuses
2) transverse sinus turns down into sigmoid sinus 3) then through jugular foramen into internal jugular vein 4) cavernous sinus @ base of brain drains into superior & inferior petrosal sinus and to internal jugular |
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Explain deep venous drainage.
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1) Drain into cerebral veins to reach great vein of Galen
2) enters dura of tentorium 3) joined by inferior sagittal sinus 4) forms straight sinus 5) empties into transverse sinus |
