Notes

Heart Attack
When the blood is cut off from the heart, a heart attack can occur. The heart is a muscle. As with all cells and muscles in the body, the heart needs oxygen to function. When the heart is deprived of oxygen, the deprived cells will die.

The Coronary Artery. The heart is fed primarily by the coronary artery, with several other coronary arteries branching out to serve the heart. If plaque blocks the coronary artery (termed coronary artery disease) or a clot blocks the flow of blood to the heart, the heart becomes starved for oxygen. When the heart is starved for oxygen, permanent damage can occur to the cells within the heart. This is a heart attack.

A heart attack could also be caused by a burst aneurysm in a coronary artery. In such a case, blood would flow out of, rather than through, the coronary artery, and the heart would be oxygen-deprived. Coronary aneurysms can be fixed, but if the coronary aneurysm were to burst, it would likely be fatal.

Most people survive their first heart attack and recover. The affected cells, however, will not regenerate. The affected muscle will not contract as well, so the heart cannot pump as well. The heart will be permanently weakened, often leading to another heart attack sometime down the road, especially if preventative measures are not taken (see the "risk" and "protective factor" listed a little further down the page).

Further Information. The following is a link to an interesting and informative slideshow on heart attacks. Check it out.

Stroke

A blood clot or plaque fragment that blocks an artery to the brain is the most common cause of a stroke. Strokes can also
be caused by high blood pressure or an aneurysm (a bulge in the wall of a blood vessel). This diagram shows the cycle of high and
low blood pressure as blood is pumped through the heart and lungs. - FYI Online

A stroke occurs when the brain is deprived of oxygen. It is like a heart attack, but in the brain. Blood flow to the brain is disrupted, and the area of the brain served by that artery becomes starved for oxygen. As with heart attacks, the brain cells deprived of oxygen begin to die.

Effects on the Brain. Different areas of the brain are responsible for different functions. One area creates movement while another controls motor ability. One area controls speech and another deals with vision. One area controls memory while another area is responsible for cognition.

When one area of the brain is deprived of oxygen, those cells die and the function of that part of the brain will be affected. Thus, a stroke can cause full or partial paralysis, loss of muscle control, difficulty with speech or eyesight, and loss of memory and understanding. Of course, strokes can also be fatal.

Causes. The most common cause of a stroke is a blood clot or plaque fragment blocking an artery to the brain. This scenario is responsible for up to 80 percent of all strokes. The blood vessels in the brain are relatively small and are susceptible to blockage from clots floating around in the bloodstream.

Strokes can also be caused by a broken artery or blood vessel. This could be the result of high blood pressure or an aneurysm. A stroke may also result from a head injury such as a concussion. In such cases, the stroke might not be immediate; it could occur some time later when the blood pressure finally causes a break in the damaged blood vessel.

Risk and Prevention: Heart Disease
Common Risk Factors

Heredity (family history of heart attack, atherosclerosis, stroke, etc.)
Gender (Males are more at risk than females, but women have an equal risk after menopause.)
Diet: high LDL (bad cholesterol) /low HDL (good cholesterol)
High Blood Pressure
Stress
Obesity
Smoking
Age, risk increases after: 45 (men), 55 (women)
Protective Factors

Avoid the above-mentioned voluntary risk factors (poor diet, obesity, smoking).
Exercise. It tones the heart muscle, lowers blood pressure, raises the HDL count, cleanses the blood vessels (similar to flushing).
Maintain a good diet.
Practice stress management techniques.