Blood Types Humans have 4 blood types: A B AB O ● Each blood type is based on the type of chemicals you have on the surface of your red blood cells. These chemicals are called antigens. ● Different blood types not only have different chemicals on their red blood cells’ surfaces but also may have different chemicals in their plasma. These chemicals are called antibodies. ● Because the body makes antibodies against the antigens that are not on its own red blood cells, there are only certain blood types that each blood type can receive in a safe transfusion. These are the types of blood that each can receive in a safe transfusion. A - A,O B - B,O AB - A,B,AB,O O- O AB - universal receiver O - universal donor Rh factor - protein found in the blood. The Rh factor may have a harmful effect on a baby, being carried by a mother, if an Rh- mother is carrying an Rh+ baby. Rh antibodies from the mother may enter the blood of the baby and destroy the baby’s red blood cells. Cardiovascular Problems Some cardiovascular problems involve the heart and blood vessels, while other problems affect the blood. Smoking, high levels of cholesterol in blood, stress, heredity and other factors can cause cardiovascular problems. 1. Atherosclerosis: It is the leading cause of death in the United States. Atherosclerosis occurs when fatty materials, such as cholesterol, build up on the inside of blood vessels. When a major artery becomes blocked, a person has a heart attack, and part of the heart could die. 2. Hypertension: It is also known as high blood pressure. Hypertension is dangerous because it overworks the heart and can weaken vessels and make them rupture. If a blood vessel in the brain becomes clogged or ruptures, certain parts of the brain will not receive oxygen and may die. This is called a stroke.