Wat is a stroke????Wat can cause it?

Types of stroke
Ischaemic stroke - this type of stroke happens when the blood supply to part of the brain is blocked. The block can be caused by a blood clot or a piece of fatty material.
Haemorrhagic stroke - this type of stroke is caused by bleeding inside the brain. This can be due to a blood vessel bursting inside the brain, or, more rarely, on the surface of the brain. Bleeding in the brain can also result from the rupture of an aneurysm - a weakness in a blood vessel. Blood vessels can also weaken because of infection, a head injury or a blood clotting disorder.
Transient ischaemic attack (TIA or "mini-stroke") - this is similar to a stroke. It happens when the blood supply to the brain is interrupted for a short time. The symptoms are very similar to stroke, but they are temporary and always clear up within 24 hours.
Symptoms
The symptoms of a stroke vary depending on the type of stroke and the part of the brain it affects. Symptoms include:

numbness, weakness or inability to move the face, arm or leg on one side of the body
trouble with vision - sudden loss of sight in one eye, blind spots or double vision
confusion or difficulty understanding
difficulty speaking (this is called dysphasia or aphasia)
difficulty swallowing (this is called dysphagia)
problems walking, loss of balance or co-ordination
dizziness
severe headache
loss of consciousness
Stroke symptoms usually come on suddenly, within seconds or minutes. Rarely, the symptoms can get worse over a period of hours or days.

How severe the symptoms are depends on where in the brain the stroke happened and how many brain cells were affected.

Caused by lack of blood to the brain.
Often a result of a blocked Carotid Artery, located on each side of the neck.
Coma is often associated.