Common Homeostatic Imbalances of the Cardiovascular System

Myocardial Infarction
Also known as a heart attack or coronary, myocardial infarctions occur when coronary arteries are blocked. The infarct is formed from a prolonged angina. Heart cells die, which causes the heart to become blocked, and ventricles begin to beat at their own rate. Rate is much slower than usual. This is caused by damage to AV node, and ventricles are no longer controlled by the SA node.

Ischemia
Ischemia is damage to the SA node, which results in slower heart rate. There is a lack of an adequate blood supply to the heart muscle, and may lead to fibrillation (rapid uncoordinated shuddering of the heart muscle). It is the major cause of death from heart attacks, because the heart cannot function as a pump any longer.

Hypotension
Also known as low blood pressure, hypotension is defined as dizziness and temporary low blood pressure, which occurs when people rise suddenly. Usually the elderly are most commonly afflicted by this disorder because the sympathetic nervous system reacts slower when aged. Therefore, there is a reduced blood delivery to the brain.

Hypertension
Also known as high blood pressure, hypertension is defined as a condition of sustained arterial pressure of 140/90. It slowly strains the heart and damages arteries. The heart is forced to pump against increased resistance, and the myocardium enlarges. Therefore, blood vessels are ravaged, which causes small tears in the endocardium.

Atherosclerosis
This occurs when the walls of vessels thicken from objects and protrude inside. It is affected in the aorta and coronary arteries most often.

Congenital Heart Disorders
CHD accounts for half of infant deaths from congenital defects. It is caused by internal infection and ingested drugs during pregnancy in the first three months. Disorders include ductus ateriosus, septal openings, and structural abnormalities of the heart.