There are 2 types of stroke:
Ischemic stroke is a lack of oxygen in the brain, usually by a blood clot blocks caused a blood vessel.
Hemorrhagic stroke is caused by a break of a blood vessel in the brain.
Each of these types of stroke has various causes.
Ischemic stroke
Normally, a blood vessel is smooth inside so that blood flow easily. The atherosclerosis or hardening of the arteries can be rough outlines of the vessel wall. A blood clot can then form blocked the ship over the irregular surface. Or the blood clot can distribute and travel to the brain, to block the tallest building. Atherosclerosis risk factors are high blood pressure, high cholesterol and smoking. In certain diseases of the heart with the irregularities of heart rate, blood clots can form in the heart and travel to the brain. The medical term for this is cardiac embolism. A less common cause of stroke occurs when the blood of a person tends to be lighter than the average clot. In other cases, the cause is unknown.
Hemorrhagic stroke
The most common cause for this type of stroke is high blood pressure. Years of high blood pressure, to weaken the wall of blood vessels eventually cause failure.
In other cases, it is not normal to the wall of blood vessels in the brain. For example, aneurysms can balloon to a wall of blood vessels. Aneurysms can burst, causing a brain haemorrhage. There are several other vessel wall abnormalities that cause, are some people that rather bleeding have a brain. Sometimes, the slimness of the blood of a person of hemorrhagic stroke may be vulnerable.