Coronary Arteries and Atherosclerosis

• The heart consists of four chambers that are continuously bathed in blood, which is pumped through the heart every second of every day.
• Serious health problems can arise if the heart muscle does not receive a sufficient blood supply.

Coronary Arteries

• The blood inside the heart does not nourish the heart muscle; this is the job of the coronary arteries.
• The right and left coronary arteries supply blood to the heart muscle.
• The word 'coronary' refers to the heart.
• Proper heart muscle function is essential to life.
• The circulatory system supplies it with oxygen-rich blood straight off of the aorta.
• The coronary arteries extend into the heart from the aorta.
• The coronary arteries are relatively narrow.
• They tend to compress when the ventricles contract and fill when the heart relaxes.
• These facts do not cause problems with normal, healthy coronary arteries, but it can become a factor if there is a problem with the arteries.

Atherosclerosis

• Plaque buildup can affect any artery in the body; this condition is called atherosclerosis, defined as hardening and narrowing of the arteries due to plaque buildup.
• Atherosclerosis usually begins because the delicate inner layer of the arteries becomes damaged due to such things as smoking or high blood pressure.
• This makes the inside of the artery rough and allows fatty materials, such as cholesterol, to stick to the inside of the arteries and grow over time.
• As plaque grows, it takes up space, leaving less space for blood to travel through the artery and feed the organ or muscle that it is leading to.

Coronary Heart Disease

• Atherosclerosis can affect any artery in the body.
• If it affects the coronary arteries, it becomes coronary heart disease or coronary artery disease, defined as a narrowing of the coronary arteries due to plaque buildup.
• Plaque obstructs the flow of oxygen-rich blood to the heart muscle.
• When the heart muscle is deprived of oxygen, a person can experience angina, chest pain caused by a lack of blood flow to the heart muscle.
• A person prone to angina might not have chest pain when he or she is resting because the coronary arteries can fill during the relaxation periods of the heartbeat.
• If the person exercises or becomes stressed, the relaxation periods are shortened because the heart pounds more frequently.
• Nitroglycerin can decrease angina because it stimulates vasodilation, which causes the blood vessels to dilate or increase in size, and allows more blood to flow through the coronary arteries.

Heart Attack

• Plaque within the coronary arteries can build to where the artery is completely blocked, or the plaque can break off of the artery wall and become stuck in smaller arteries.
• This can stop blood flow to the heart muscle and can result in a heart attack, defined as the blockage of blood flow to the heart muscle, resulting in damage or death of the heart cells.
• The medical term for a heart attack is myocardial infarction.
• The term 'myocardial' means heart muscle, and 'infarction' means death of tissue due to lack of oxygen, so a myocardial infarction is literally the death of the heart muscle.

Congestive Heart Failure

• The cardiovascular system of a healthy individual maintains a balance between the amount of blood pumped out of the heart and the amount of blood that circulates back to the heart.
• If the pumping efficiency of the heart is diminished due to conditions such as coronary heart disease, damage from a heart attack, or conditions that overwork the heart, like high blood pressure, the cardiovascular system can become congested and inefficient.
• Congestive heart failure is defined as a condition in which the heart can't pump enough blood to meet the body's needs.
• Congestive heart failure is a progressive condition that worsens over time due to a weakening of the heart muscle.
• Blood enters the right side of the heart and is then pumped into the lungs.
• After visiting the lungs, blood returns to the left side of the heart before being pumped out to the body.
• If the left side of the heart fails, blood will not be pumped out to the body efficiently and will get backed up, almost like a traffic jam inside your heart, causing blood to get backed up and stay in the lungs, and this congestion in the lungs makes it difficult to breathe.
• If the right side of the heart fails, blood will get backed up in the body because blood will not be able to move through the right ventricle efficiently, leading to swelling in the feet, ankles, and legs.