The upper chambers receive incoming blood and the lower chambers are more muscular, and pump blood out of your heart.

The two upper cavities of the heart are called atria (plural for atrium). Deoxygenated blood is received into the right atrium, and the left atrium receives oxygenated blood..

Blood from the right atrium enters the right ventricle and pumps it into the lungs, and blood from the left atrium enters the left ventricle where it gets pumped into the circulatory system.

The aorta carries oxygenated blood from the heart to all the tissues in the body.

The average adult body has about 10 billion capillaries, which connect arteries and veins.

It is estimated that the volume of blood in a human body is roughly 7 percent of body weight.

Heart disease is a term that encompasses all types of heart-related infections, irregularities, and birth defects including heart failure, coronary artery disease, arrhythmias, and angina .

Each year, 1 in every 4 deaths in the United States is due to heart disease.

High cholesterol, high blood pressure, and diabetes can also increase your risk for developing heart disease.

The coronary artery is important for supplying the heart with blood. If it is blocked or narrowed, coronary artery disease can occur. This is the most common cause of heart disease.

Damage to the lining of the blood vessel by high blood pressure, smoking, or high cholesterol can lead to the formation of plaques in your arteries that can clog the way for blood.

Plaques start as a fatty streak on the inside of the blood vessel, and can progress to a calcified plaque.

Also called hypertension, high blood pressure is defined as a blood pressure above 140/90. A healthy blood pressure is generally considered at or below 120/80.

Arrhythmia refers to any change in the electrical impulses of the heart that deviate from the normal sequence. This can lead to the inability of the heart to pump blood efficiently.

Peripheral artery disease most commonly occurs in the legs.

A stroke is a kind of "brain attack" - the cells of the brain can die because if blood flow is cut off, then the cells do not receive oxygen and cannot survive.

A type of ischemic stroke resulting from a blockage in the blood vessels that supply blood to the brain is called a cerebral infarction.

The word "cyan" comes from the Greek word for blue: kyanós.

There are two types of heart failure, diastolic and systolic.

In diastolic heart failure, the muscle of the left ventricle has become stiff and cannot relax, resulting in an inability to fill with blood properly.

In systolic heart failure, the left ventricle cannot contract normally, so enough blood cannot get pushed into circulation and maintain a healthy body.

Angina is chest pain caused by a lack of oxygen-rich blood flow to the heart. It can feel like pressure in your chest or indigestion.

The myocardium is the muscular tissue of the heart, and an infarction is the obstruction of the blood supply.

Aneurysms can occur in any blood vessel, and carry a risk of life-threatening rupture.

Studies have shown that people who live alone are twice as likely to have a heart attack compared to people who live with others.

Cardiac arrest occurs when the heart suddenly stops pumping as a result of an electrical problem in the heart. This is different from a myocardial infarction (heart attack).

Congenital means present from birth, and can be inherited or acquired.

Nitrates, commonly taken in the form of nitroglycerin, are used to relieve symptoms of angina, such as chest pain or pressure.

Cardiac myocytes (the cells of your heart muscle) are dependent on the blood and electrical supply to coordinate the contractions of cells to make your heart pump properly.

Low-energy electrical pulses generated by a pacemaker will prompt the heart to beat at a normal rate.

Lipids are naturally occurring molecules that function to store energy and acting as structural components of cell membranes, among other things.

It is important to make healthy diet choices and increase exercise to start lowering your high cholesterol.

Exercise and moderate consumption of alcohol raise your HDL levels (which stands for high density lipoprotein), whereas obesity and smoking decrease your HDL levels.

LDL, which stands for low density lipoprotein, mobilizes and deposits cholesterol to the tissue, where it can contribute to plaque formation and progress to heart disease.

Omega-3 fatty acids are abundant in fish oils and are beneficial, whereas (trans)unsaturated fats produced by artificial hydrogenation of polyunsaturated oils (used in baked goods and margarine) adversely affect cholesterol profiles.