Hemorrhagic Stroke
November 12th, 2011 | 
Author: 
In a healthy brain that works, neurons do not come into direct contact with blood. The vital oxygen and nutrients that neurons need the blood to the neurons through the thin walls of brain capillaries. The glia (nervous system cells that support and protect neurons) form a blood-brain barrier or blood-brain – a complex plot that surrounds blood vessels and capillaries and controls which elements of the blood can pass through the neurons .
When you break an artery in the brain, the blood passes to surrounding tissue and upsets not only the blood supply but the delicate chemical balance neurons require to operate. In this type of stroke called hemorrhagic stroke. These hemorrhagic strokes account for approximately 20 percent of all strokes. Bleeding occurs in several ways. A common cause is a bleeding aneurysm, a weak or thin spot in an artery wall. Over time, these weak spots expand or balloon-like swelling under high blood pressure. The thin walls of these aneurysms balloon may rupture and spill blood in the space surrounding brain cells.
The bleeding also occurs when arterial walls break. Arterial walls encrusted with plaque eventually lose their elasticity and become brittle, thin, prone to breaking. Hypertension or high blood pressure increases the risk that a brittle artery wall yield and release blood into the surrounding brain tissue.
A person with an AVM also have an increased risk of hemorrhagic stroke. Arteriovenous malformations are a cluster of defective blood vessels and capillaries within the brain that have thin walls and can therefore be changed.
Blood from ruptured brain arteries can pass into the brain substance or different spaces surrounding the brain. An intracerebral hemorrhage occurs when a blood vessel within the brain sheds blood in the brain itself. Subarachnoid hemorrhage is bleeding under the meninges, or outer membranes of the brain to thin fluid-filled space surrounding the brain.
The subarachnoid space separates the arachnoid membrane of the underlying pia mater membrane. It contains a clear fluid (cerebrospinal fluid) and small blood vessels that supply blood to the outer surface of the brain. In a subarachnoid hemorrhage, one of the small arteries within the subarachnoid space is broken, flooding the area and contaminating blood cerebrospinal fluid. Since the cerebrospinal fluid flows through the skull into the spaces of the brain, subarachnoid hemorrhage can lead to extensive damage throughout the brain. In fact, subarachnoid hemorrhage is the most deadly of all strokes.
Random Posts
Tags: Hemorrhagic stroke