The Brain By: Michael, Calvin, Arif, Andrew

Brain Functions  Allows us to think, move, feel, see, hear, taste, and smell  Controls our body  Receives, analyzes and stores information (our memories)  Produces electrical signals carried by nerves  Electrical signals let different parts of the body communicate

Brain Size  Average human brain weighs about 3 pounds ( g).  Volume is around 1.6 L

Composition of Brain  Consists of gray matter (40%) and white matter (60%) contained within the skull  Brain cells include neurons and glial cells  3 main parts: -Cerebrum -Cerebellum -Brainstem

Nourishment of Brain  Brain is only 2% of the body's weight, but uses 20% of the oxygen supply and gets 20% of the blood flow.  Blood vessels (arteries, capillaries, and veins) supply the brain with oxygen and nourishment, and take away wastes.  If brain cells do not get oxygen for 3 to 5 minutes, they begin to die. Whenever a specific part of your brain is activated, blood vessels widen to increase blood flow to that area. Strokes, clogged arteries and brain tumors can all block or reduce the flow of blood. When this happens, brain cells can be damaged or die, leading to death or permanent disability.

What is a Stroke?  An interruption of the blood supply to any part of the brain, resulting in damaged brain tissue  Interruption may be due to: blood clots (most common cause of stroke), or bleeding in the brain (occurs when blood vessel ruptures or if there is a significant injury)  Hemorrhagic Stroke

Symptoms of a Stroke  Depend on what part of the brain is damaged When the left hemisphere of the brain is affected by stroke, the result is the right side of the body being paralyzed and vice versa Since the left side of the brain controls reasoning and logic, the person suffering from stroke on left hemisphere of brain may have difficulty speaking and solve problems  Person may not even be aware that he or she has had a stroke

Symptoms of Stroke  Most commonly, a SUDDEN development of one or more of the following indicates a stroke: Numbness, tingling or decreased sensation Uncontrollable eye movements or loss of eyesight Unable to move certain parts of body Loss of coordination Headache Having hard time swallowing Loss of ability to communicate fluently

Hemorrhagic stroke  Blood vessel bursts in the brain and damages surrounding tissue  Damage is done very quickly since the brain is very sensitive to blood  Pressure of blood in brain increases, resulting in higher pressure on the skull  High blood pressure is usually the cause of stroke

Hemorrhagic Stroke Hemorrhage Brain Cross Section (Vertical)

Can Brain Stroke Cause Death?  In fact, brain stroke can cause death  About one in 4 people die from a stroke  Half of the people who has stroke develop disabilities  One in 4 people recover from stroke  Death from stroke can be caused by loss of brain functions  It can also decrease life span

Brain Aneurysm  Occur when there is a weakened area in the wall of any blood vessel that supplies the brain  May be a congenital (present from before birth) defect or may develop later

Types of Brain Aneurysms  Saccular / Berry aneurysm Size varies from a few millimeters to over a centimeter Looks like a sack of blood attached to one side of the blood vessel by a narrow neck More common in adults  Fusiform Aneurysm Due to widening of the entire circumference of the blood vessel Part of a blood vessel that supplies the brain balloons out May be caused by trauma and infection, which can injure the blood vessel wall

How do Cerebral Aneurysms cause Problems?  Rupturing which results in bleeding into the fluid spaces surrounding the brain or into the brain itself.  Growing and compressing adjacent areas of the brain or specific nerves (e.g. optic nerve), resulting in symptoms such as abnormal sensations, blindness, seizures or paralysis.  Containing blood clots that may dislodge and be carried by blood flow further into the brain, blocking smaller arteries, which can lead to a stroke. Cerebral Aneurysm

Brain Aneurysm  Symptoms do not appear until bleeding occurs  A ruptured cerebral aneurysm is an emergency condition when it is discovered  Goal of treatment is to control symptoms and prevent further bleeding  Lowering blood pressure can reduce the risk of further bleeding  Main treatment involves neurosurgery  Base of aneurysm is closed off using clamps or sutures to prevent further blood flow into aneurysm

Vocabulary  Stroke: Lack of oxygen enters through artery of the brain resulting in one part of the brain becoming dysfunctional.  Hemorrhagic stroke: Blood vessels bursting in the brain. The blood puts pressure on the skull.  Aneurysm: An abnormal widening or ballooning of a section of the blood vessel. This occurs in the weakened area of the blood vessel.