Lecture 6 - Introduction To Stroke Flashcards
Why is it important to study stroke?
It is the 3rd leading cause of death. If it doesn’t kill, it can majorly affect the lives of survivors.
To understand the impact a stroke has on the healthcare system, family dynamics, work etc.
To increase our understanding of the pathophysiology of stroke.
To develop effective prevention and intervention.
What are 3 main components that make up the brain and what are their functions?
Brainstem - connects brain to the top of the spine and is in charge of lots of important functions such as heart function and breathing.
Cerebellum - sits at the back and bottom of the brain and is involved in balance and movement.
Cerebrum - the largest part of the brain and consists of 4 lobes which work together to perform functions.
What are the 4 lobes that make up the cerebrum and what are their functions?
Frontal lobe (at the front of the brain) - involved in motor cortex, judgement, inhibition, personality, emotions and language production.
Temporal lobe (at the bottom in the middle/back) - involved in auditory perception and memory.
Parietal lobe (at the top near the back) - involved in sensory processing and orientation.
Occipital lobe (at the back) - involved in vision.
Why is blood supply to the brain important?
Most of the brain consists of neurons and specialised cells. These are interconnected and rely on oxygen and glucose to function which is supplied by the blood.
These cells are in charge of what we think, how we feel, how we move etc.
What are the main arteries that lead to the brain?
The carotid arteries and the vertebral arteries.
How can the blood circulation in the brain be divided?
Anterior supply (front) which the carotid arteries give rise to.
Posterior supply (back) which the vertebral arteries give rise to.
These arteries join to form the basilar arteries.
What is the Circle of Willis?
The basilar arteries split into 2 to form a circle known as the Circle of Willis.
This circle gives rise to the posterior cerebral artery, middle cerebral artery and the anterior cerebral artery which supply blood to the lobes in the brain.
There are 2 other important arteries in Circle of Willis which are the internal carotid artery and common carotid artery.
The circle of Willis is really specialised because if there is a blockage in one of the arteries, there is still another way for the blood to go around or the brain can receive collateral supply from another vessel.
What blood vessels/arteries supply blood to which parts of the brain?
The frontal lobe is supplied by the anterior cerebral artery and the middle cerebral artery.
The temporal lobe is supplied by the posterior cerebral artery.
The parietal lobe is supplied by the middle cerebral artery.
The occipital lobe is supplied by the posterior cerebral artery.
The brainstem is supplied by the pontine branches and anterior spinal artery.
The cerebellum is supplied by the posterior inferior cerebellar artery, inferior cerebellar artery and the superior cerebellar artery.
Which artery is the most commonly blocked?
The middle cerebral artery - important because it supplies such a large area.
What is a stroke?
A stroke is a brain attack, which results in an interruption to the blood supply to the brain. This interruption leads to cell death due to the cells not receiving oxygen and glucose from the blood.
They can happen in any part of the brain and affect how our brain functions.
What is an ischaemic stroke and what are the 3 types?
An ischaemic stroke is a blockage of blood such as a clot.
These are categorised into cerebral thrombosis, cerebral embolism and systemic hypoperfusion.
What is a haemorrhage and what are the 3 types?
A haemorrhage is a bleed into the brain e.g. from a burst blood vessel.
The 3 types are intracerebral haemorrhage, subarachnoid haemorrhage and epidural haemorrhage.
What is a transient ischaemic attack?
A TIA is a ‘mini stroke’ where the blood supply to the brain is temporarily blocked.
They usually resolve themselves (e.g. blood clot dissolves itself) but can be a warning sign of a major stroke.
Can have same symptoms as an ischaemic stroke and symptoms usually last less than 24 hours.
How does a thrombotic stroke occur?
Occurs when the blood clot has formed in one of the major arteries leading to the brain. This blocks the blood supply to the surrounding region and the area that has lost blood supply can lead to an infarction (cell death).
How does an embolic stroke occur?
A blood clot forms somewhere else in the body and then travels around the body in the bloodstream and lodges in the brain.
Blood clot forms at the donor site and ends at the recipient site.
It can often occur due to atherosclerosis (fatty build up in arteries that breaks off and leads to a clot).
How does systematic hypoperfusion occur?
There is a general reduction in circulating blood volume resulting in inadequate supply of blood to body tissues.
It often occurs due to reduced cardiac output or problems with heart functions.
It affects the entire body, not just the brain.
Could affect different parts of the brain or the entire brain.