Chapter 8 Stroke Flashcards
What is cerebral circulation?
Blood supply to the brain
What are the two main arteries that supply blood to brain?
1) internal Carotid arteries
2) Vertebral arteries
whats the other name for internal carotid arteries?
Anterior circulation
What is the other name for vertebral arteries?
Posterior circulation
where does the major artery systems ( anterior and posterior) connected?
Circle of Willis
what is circle of willis?
Interconnects both major artery systems ICA ( anterior) and VA (posterior)
what does brain requires?
Brain requires continuous flow of blood for glucose and oxygen
without blood flow, how long til metabolic disruption occurs?
- 30 seconds
without blood flow, how long till metabolism stops?
2 minutes
How long does cellular death occur without blood flow?
5 minutes :(
Blood flow to the brain is affected by? (3)
- Systemic BP
- Cardiac output ( how much blood the heart pumps per minute)
- Blood viscosity ( thickness of blood )
What is collateral circulation
- May develop in situations of low cerebral blood flow if the blood supply is cut off to one area of the brain due to blockage it can sometimes receive blood from different blood vessels
- Varies depending on individual patient and they develop to sustain perfusion when primary route are blocked.
What is Stroke?
Occurs when there is inadequate blood flow to the brain (ischemia) or hemorrhage into the brain
Stroke results in what?
results in death of brain cells
What area will be impaired or loss due to stroke? (3)
Functions such as movement, language, sensation that were controlled by the area of damage will be impaired or loss.
What is the leading cause of disability in Canada for adults
Stroke
Stroke is the __ leading cause of death in Canada
3rd
what is the major cause of stroke?
Atherosclerosis
What is Atherosclerosis
- Hardening and thickening of artery
Atherosclerosis is characterized by
- Characterized by deposits of lipids within intima of artery
- Soft deposits that hardens as we get older
What is the steps of Atherosclerosis?
1) Chronic endothelial Injury ( Damage endothelium)
2) Fatty streak
3) Fibrous Plaque
4) Complicated lesion
What causes endothelial Injury (Damaged endothelium) (7)
- Hypertension
- Tobacco use
- Hyperlipidemia
- Hyperhomocysteinemia
- Diabetes
- Infections
- Toxins
Explain what happens in fatty streak
- Lipids accumulate and migrate into smooth muscle cells
- Lipids comes and oxidize
- Ingested by macrophages becoming foam cells
- Foam cells creates fatty streaks
Fibrous Plaque
- Lipids and platelets stimulate arterial wall thickening
- Collagen covers fatty streak called fibrous plaque
- Vessels diameter becomes narrower
- Risk for plague rupture