TANNER RICHARDSON
BIOLOGY 102, LAB SECTION 12
THE BIOLOGY OF A STROKE
Description
A stroke is a disease that affects the arteries leading to and within the brain. A stroke occurs when a blood vessel that carries oxygen and nutrients to the brain is either blocked by a clot or bursts. When that happens, part of the brain cannot get the blood and oxygen that is needed, causing brain cells to die. Although not the direct cause many pathogens have been identified that increase the risk of having a stroke. The two main types of strokes the first being an Ischemic Stroke which is when a blood vessel becomes blocked, usually by a blood clot. The second is a Hemorrhagic Stroke which occurs when a blood vessel in the brain bursts or breaks, causing bleeding in the brain.
Epidemiology
Each year approximately 795,000 people suffer a stroke in the United States. Roughly 600,000 of these are first attacks, and 185,000 are recurrent attacks. Strokes are more prevalent in women compared to men. Each year, women have more strokes than men, and strokes kills more women than men. The chance of having a stroke approximately doubles for each decade of life after age 55. People have a larger chance to develop the disease if a close relative has it, which may suggest an inherited, genetic tendency related to developing the disease.
Chromosome(s)/Genes Involved
Studies suggest that specific genes on the Y chromosome are differentially expressed in blood following ischemic stroke. These genes provide insight into potential molecular contributors to sex differences in ischemic stroke. Some strokes may be symptoms of genetic disorders like CADASIL (Cerebral Autosomal Dominant Arteriopathy with Sub-cortical Infarcts and Leukoencephalopathy), which is caused by a gene mutation that leads to damage of blood vessel walls in the brain.
Risk Factors
There are many risk factors associated with increased chance of stroke including age, the older you are the more susceptible you are to stroke, your chance approximately doubles for each decade of life after age 55. The next risk factor is Heredity, or your family history. Your stroke risk may be greater if a parent, grandparent, sister or brother had a stroke. Gender also plays a role in risk factors associated to strokes, each year more women have strokes than men. If you have already had a stroke your chances of having another is many times more than that of a person who has not. High blood pressure is the leading cause of stroke and also the most important controllable risk factor. Cigarette smoking is an important risk factor for stroke
Symptoms
Symptoms include trouble with walking, you may stumble or experience sudden dizziness, loss of balance or loss of coordination. You may have trouble with speaking and understanding, confusion or slurring of words can take place. Paralysis or numbness of the face, arm or leg. Trouble with seeing in one or both eyes, sudden blurred or blackened vision in one or both eyes. A sudden, severe headache, which may be accompanied by vomiting, dizziness or altered consciousness.
Diagnosis
There are many ways in which a stroke can be diagnosed. The first is through physical examination from a doctor. The next step is blood tests checking your sugar balances and other chemical balances. Also Computerized tomography scans to examine the brain can be performed. Along with a magnetic resonance imaging to examine brain tissue. An ultrasound can take place. Cerebral angiograms can examine arteries in your brain and neck.
Treatment
The best form of treatment is to reduce risk factors involved with stroke. Medical treatments may be used to control high blood pressure and/or manage atrial fibrillation among high risk patients. Those medicines include anticoagulants/antiplatelets such as
