Ischemic Stroke - causes, symptoms, diagnosis, treatment, pathology

There are two main types of stroke: an ischemic stroke which is when there’s a blocked artery

that reduces blood flow to the brain and a hemorrhagic stroke which is when an artery

in the brain breaks, creating a pool of blood that damages the brain.

Of the two, ischemic strokes are much more common, and the amount of damage they cause

is related to the parts of the brain that are affected and how long the brain suffers

from reduced blood flow.

Now if symptoms self-resolve within 24 hours, it’s called a transient ischemic attack

and there are usually minimal long-term problems.

OK - let’s start with some basic brain anatomy.

The brain has a few regions - the most obvious is the cerebrum, which is divided into two

cerebral hemispheres, each of which has a cortex - an outer region - divided into four

lobes including the frontal lobe, parietal lobe, temporal lobe, and the occipital lobe.

There are also a number of additional structures - including the cerebellum, which is down

below, as well as the brainstem which connects to the spinal cord.

The right cerebrum controls muscles on the left side of your body and vice versa.

The frontal lobe controls movement, and executive function, which is our ability to make decisions.

The parietal lobe processes sensory information, which lets us locate exactly where we are

physically and guides movements in a three dimensional space.

The temporal lobe plays a role in hearing, smell, and memory, as well as visual recognition

of faces and languages.

Finally there’s the occipital lobe which is primarily responsible for vision.

The cerebellum helps with muscle coordination and balance.

And finally there’s the brainstem plays a vital role in functions like heart rate,

blood pressure, breathing, gastrointestinal function, and consciousness.

The brain receives blood from the left and right internal carotid arteries, as well as

the left and right vertebral arteries, which come together to form the basilar artery.

The internal carotid arteries turn into the left and right middle cerebral arteries which

serve the lateral portions of the frontal, parietal, and temporal lobes of the brain.

Each of the internal carotid arteries also give off branches called the anterior cerebral

arteries which serve the medial portion of the frontal and parietal lobes and connect

with one another with a short little connecting blood vessel called the anterior communicating

artery.

Meanwhile, the vertebral arteries and basilar artery gives off branches to supply the cerebellum

and the brainstem.

In addition, the basilar artery divides to become the right and left posterior cerebral