HTN and Stroke Flashcards
What is mean arterial pressure (MAP)?
It is defined as the average arterial pressure during a single cardiac cycle
Formulate MAP:
(2 x diastolic) + systolic ] divided by 3
Define Hypertension
a chronic medical condition in which the blood pressure in the arteries is persistently elevated
defining is controversial but often regarded as ≥140/90 mmHg
How does HTN affect the body?
Over time high BP will damage the walls of your arteries, they become weak and form an enlargement called an aneurysm, or burst and bleed into the surrounding tissue. Small tears from the weakness can attract calcium and fat to form build up called plaque, which increases and decreases blood flow as the diameter is decreasing. Blood cells can stick to the plaque and form clots, further reducing the BF. Damage to arteries raises BP even more as the heart works harder to get the blood where it needs to go. HTN can eventually cause stroke, heart failure, kidney disease.
What is a stroke?
A stroke occurs when blood flow in parts of the brain is blocked. After just a few minutes the starved brain cells begin to die.
What is a Thrombotic stroke
A thrombotic stroke occurs when a blood clot (thrombus) forms in one of the arteries that supply blood to your brain. A clot may be caused by fatty deposits (plaque) that build up in arteries and cause reduced blood flow (atherosclerosis) or other artery conditions.
What is an Ischaemic stroke?
This is when an artery in the brain narrows or becomes completely blocked, preventing normal blood flow. It could become blocked by a thrombus (blood clot) which forms in an unhealthy artery in the brain. It could also be caused by an embolis, a blood clot that forms elsewhere in the body and travels to the brain.
Ischaemic = starved.
What is a hemorrhagic stroke?
Abnormal bleeding disrupts normal blood flow- i.e. a blood vessel bursting and bleeding on the brain and robbing the intended tissue of its nourishment.
What is an Embolic stroke?
. An embolic stroke occurs when a blood clot that forms elsewhere in the body (embolus) breaks loose and travels to the brain via the bloodstream. Eventually, the clot lodges in a blood vessel and blocks the flow of blood, causing a stroke
What is a Systemic hypoperfusion stroke?
Systemic hypoperfusion (low blood flow) is caused by circulatory failure of the heart, causing stroke.
What is an cerebral Venous sinus thrombosis stroke? (CVST)
Cerebral venous sinus thrombosis (CVST) occurs when a blood clot forms in the brain’s venous sinuses. This prevents blood from draining out of the brain. As a result, blood cells may break and leak blood into the brain tissues, forming a hemorrhage.
What percentage of strokes are ischaemic?
80%
Decussation means?
'’Crossed over’’
What three things affect BP?
- Cardiac output- (the amount of blood the ventricles push out of the heart each minute). As cardiac output increases, so does BP.
- Blood volume
- Resistance- anything working against the blood flow through the arteries
What contributes to resistance in the arteries?
- Flexibility in the walls of the arteries. (The walls are supposed to expand with every beat to reduce pressure on the walls)
- Artery diameter
- Blood viscosity
What is an aneurysm?
An excessive localized swelling of the wall of an artery.
Name some assessments for a stroke:
FAST – time of onset vital to outcome and treatment options • CT scan • MRI • Angiography • ECG • Chest x-ray • Blood tests • Holter monitor • Cardiac markers • FBC • Coagulation studies
The Wernicke’s area in the brain is responsible for what?
Language and comprehnsion
The Broca’s area in the brain is responsible for what?
Speech control
If a client had a stroke on the right side of his brain, what problems would you expect to see?
A stroke on the right side of the brain can cause changes in: (THE LEFT SIDE OF THE BODY)
Paralysis on the left side of the body Vision problems Quick, inquisitive behavioral style Memory loss Spatial-perceptual deficits Impulsive behaviour Impaired time concepts Impaired judgement
If a client had a stroke on the left side of his brain, what problems would you expect to see?
Paralysis on the right side of the body
Speech/language problems (aphasias)
Slow, cautious behavioural style
Memory loss
Aware of deficits, depression, anxiety
Impaired comprehension related to language and mathematics
What is systemic vascular resistance?
The force opposing the movement of blood within the blood vessels.
What is the principal factor determining vascular resistance?
The radius of the small arteries and arterioles
Define elevated serum lipids?
High amounts of fat in blood serum
Define blood serum?
the clear yellowish fluid that remains from blood plasma after clotting factors (as fibrinogen and prothrombin) have been removed by clot formation.
How much blood needs to flow into the brain per minute?
750ml/min
What provides the blood supply to the brain?
The circle of willis, via the internal carotid arteries and vertebral arteries.
What is cerebral autoregulation?
It regulates the diameters of cerebral BV in response to changes in pressure so that BF can remain the same.
What makes up the blood brain barrier?
Endothelial cells which are connected by tight junctions with an extremely high electrical resistivity. The astrocyte cell surround the endothelial cells, providing biochemical support. (The astrocyte cell is necessary to create the BBB).
