Stroke Flashcards
Cerebrum
Frontal love - motor function, provlem solving, high level thinking
Temporal - memory, hearing, speech
Parietal - sensation, space
Occipiral - Sight
Contralateral processing
Information of each hemisphere is responsible for the opposite sside of the body!!!
Other parts of the body anatomy
Cerebellum - fine motor movements
Brain stem - HR, BP, respiratrion, 10 cranial nerves, essential for life
Thalamus - sensory
hypothalamus - smooth muscle, HR, digestion, senses, hormones, body temp
Ventricles - cavities in the brain filled with CSF
Cerebral spinal fluid/CSF - Clear fluid that provides cushioning for the brain and spinal cord
Meninges - 2 protective layers (dura mater, arachnoid mater, pia meter), csf between arachnoid and pia
Blood brain barrier - wall between capillaries and brain tissue
Cerebral circulation = internal carotid arteries and vertebral arteris
Regulation of cerebral blood flow
Continuous need for oxygen and glucose as the brain cannot store glucose
Cellular death occurs if 5 minutes of no flow
Effected by
1) Systemic BP
2) CO
3) Blood thickness/viscosity
4) Intracranial pressure (ICP)
Autoregulation of the brain
Protective mechanism that the brain can regulate its blood flow despire systemic blood pressure
Has limits
Carbone dioxide =
High - vasodilation (get rid of it)
Low - Vasoconstriction
Oxygen
Low = Vasodilate (to get more of it)
pH =
Low= Vasodilates (get rid of the CO2)
Collateral circulation
Sometimes the brain can receive blood from different blood vessels
Stroke
Ischemia or hemorrhage = death of cells
Note that the skull is rigid so the brain doesn’t have space to expand when ICP is high
Ischemic stroke
Most common due to to inadequate blood flow to the brain
Penumbra
Zone of borderline with ischemic tissue
= Reversible tissue that can be saved within 3 HOURS window of opportunity
not that Swelling occurs with cell death, damage seen in 3 days as macrophades infiltrate and eat away necrotic tissue and cause scarring
1) Transient ischemic attack (TIA)
temporary ischemia, warning sign that a larger stroke can occur
Usually lasts less than 1 hour, but can last longer
Usually due to carotid stenosis (artherosclerosis) and atrial fibrilatio
2)Thrombotic
Blood clot in cerebral artery that causes occlusion/block caused by atherosclerosis
Symptoms progress within 72 hours
3) Embolic
Thrombus breaks off and travels to the brain
Commonly from heart issues - mitral valve, endocarditis, atrial fib, rheumatic heart disease - but can be from fat embolus, air embolus, tumor, bacterial clump etc.
- Afib - contraction of atria causes pooling and clots to form
- Infective endocarditis causes inflammation and clumps of bacteria
Sudden onset - faster occurrence than thrombotic
Hemorrhagic stroke
Skull is rigid, therefore only certain amount of blood tissue and CSF can flow
Bleeding causes compression, swelling, ischemia, ICP and necrosis
1) Intracerebral hemorrhage
Bleeding due to ruptured vessel
Rosk factors = HTN, brain trauma, meds like anticoagulants
Sudden onset, usually during periods of activity
Worst HA ever
Subarachnoid hemorrhage
Bleeding into subarachnoid space, more common
Commonly due to ruptured aneurysm - weakening of artery that stretches like a ballon and bursts
More common in women
NA, stiff neck, seizure, nausea
Hematoma
Bleed that already clottes and slowed, whereas hemorrhage is current active bleedings
