Attention: I’m not a teacher.
Hi pink dragon,
There are some definitions concerning the word in question as well as a brief excerpt of a medical article. You could see for yourself that your primary speculation is trustworthy. “
Stroke” is countable.
Ischemic strokes, which account for about 80 percent of all
strokes, are caused by an obstruction in an artery, generally one of the carotid arteries, the major arteries in the neck that carry oxygen-rich blood from the heart to the brain. The path to
an ischemic stroke begins when atherosclerosis, in which fatty deposits build up on the inner wall of an artery, develops in one of the carotid arteries (
see Arteriosclerosis).
Atherosclerosis does not actually cause
ischemic strokes, but it sets up the conditions that make them likely to occur. The actual obstruction that cuts off blood flow in
an ischemic stroke is a blood clot. When the blood clot, or thrombus, develops at the site of an atherosclerotic deposit and cuts off blood flow to part of the brain, a stroke results.
A transient ischemic attack (TIA) sometimes precedes an ischemic stroke. In a TIA, also known as a
ministroke, strokelike symptoms develop but disappear within five minutes to 24 hours. About 10 percent of ischemic strokes are preceded by TIAs.
Hemorrhagic
strokes account for the remaining 20 percent of all
strokes. They occur when weakened blood vessels within the brain rupture and bleed into the surrounding tissue. Though hemorrhagic
strokes occur less frequently than ischemic strokes, they tend to affect larger areas of the brain.
Hemorrhagic strokes can result from an aneurysm, which develops when the wall of a blood vessel weakens and thins, ballooning outward. If left untreated, the aneurysm continues to expand and weaken, increasing the likelihood of rupture.
Hemorrhagic strokes can also result from an arteriovenous malformation (AVM), a cluster of enlarged, structurally weak blood vessels that forms during fetal development or possibly at birth.
stroke 
[countable]
1
illnessMI if someone has a stroke, an artery (=tube carrying blood) in their brain suddenly bursts or becomes blocked, so that they may die or be unable to use some muscles:
She died following a massive stroke.
have/suffer a stroke
I looked after my father after he had a stroke.
one of a set of movements in swimming or rowing in which you move your arms or the oar forward and then back:
She swam with strong steady strokes.
the action of hitting the ball in games such as tennis, golf, and cricket:
a backhand stroke
a single movement of a pen or brush when you are writing or painting:
A few strokes of her pen brought out his features clearly.
AV a line made by a pen or brush:
the thick downward strokes of the characters
a gentle movement of your hand over something:
I gave her hair a gentle stroke.
Regards.
V.
