Your heart muscle receives a rich blood supply from the coronary arteries. If the coronary arteries become blocked, it can result in coronary heart disease, angina, heart attack or congestive heart failure. Learn how these conditions get started.
The heart consists of four chambers that are continuously bathed in blood.
This blood is pumped through the heart every second of every day. But if the heart muscle itself is not getting a sufficient blood supply, serious health problems can arise. In this lesson, you will learn about some common heart conditions and diseases.So, you might be wondering how the heart muscle could ever be short of blood.
After all, the entire blood supply circulates through the heart chambers numerous times a day. However, the blood inside the heart does not nourish the heart muscle. This is the job of the coronary arteries.
We can’t have a conversation about heart disease without mentioning the right and left coronary arteries. We previously learned that these arteries are the arteries that supply blood to the heart muscle. We can recall this term by remembering that the word ‘coronary’ refers to the heart. Proper function of the heart muscle is essential to life, so your circulatory system wastes no time supplying it with oxygen-rich blood straight off of the aorta as we see in this picture.
The coronary arteries are relatively narrow, and because they lie directly on the heart, 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.
One problem that can affect any artery in your body is plaque buildup. This is a condition called atherosclerosis, which is 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 this 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. It is kind of like a traffic jam that is caused by road construction. If one lane of a highway is blocked due to road construction, all of the traffic must travel in one lane around the construction. This is inefficient, and less traffic is going to get through. It’s the same with a clogged artery.
Coronary Heart Disease
Atherosclerosis can affect any artery in your body. If it affects the coronary arteries, it takes on a special name and becomes coronary heart disease or coronary artery disease. We define this condition as a narrowing of the coronary arteries due to the buildup of plaque. As we mentioned, this plaque takes up space and this obstructs the flow of oxygen-rich blood to the heart muscle. When the heart muscle is deprived of oxygen, a person can experience angina, which is 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 as we mentioned, the coronary arteries are able to 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. You may have heard that the drug nitroglycerin can be used to decrease angina. This works because nitroglycerin stimulates vasodilation (which, we remember, causes the blood vessels to dilate, or increase in size), and this allows more blood to flow through the coronary arteries.
Over time, plaque within the coronary arteries can build to a point 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, which is defined as the blockage of blood flow to the heart muscle resulting in damage or death of the heart cells. An interesting way to remember this is to note that the medical term for a heart attack is myocardial infarction. The term ‘myocardial’ means heart muscle, and the term ‘infarction’ means death of tissue due to lack of oxygen, so a myocardial infarction (or a heart attack) 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. But 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.
This condition is called congestive heart failure. It 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.We know that blood follows a one-way path through the heart. It 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.
We see that the heart pumps blood to two different areas. One side of the heart pumps blood to the lungs, and the other side pumps blood to the body. Because the heart is a double pump, each side of the heart can weaken independent of the other side. 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. The result is that blood gets backed up and stays 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. This leads to swelling in the feet, ankles and legs.
Let’s review.Any artery in your body can accumulate plaque within its inner wall.
This condition is called atherosclerosis and is defined as hardening and narrowing of the arteries due to plaque buildup. We know that the heart is a vital organ and that the coronary arteries have the important job to supply blood to the heart muscle. If we see plaque buildup in the coronary arteries, we give this condition a special name: coronary heart disease.
This plaque takes up space, which can obstruct the flow of blood to the heart muscle. This can result in angina, which is chest pain caused by a lack of blood flow to the heart. If blood flow to the heart is stopped, a heart attack could result. We define a heart attack as the blockage of blood flow to the heart muscle resulting in damage or death of the heart cells.If the heart muscle becomes weak due to damage from a heart attack or prolonged conditions such as coronary heart disease or high blood pressure, the heart may become an inefficient pump. This results in congestive heart failure, a condition in which the heart can’t pump enough blood to meet the body’s needs.
Because we know that the heart is a double pump, each side of the heart can weaken independent of the other side. If the left side of the heart does not pump blood out of the heart, blood will back up in the lungs, making it difficult for the person to breathe. If the right side of the heart does not pump blood efficiently, blood will pool up in the body, leading to swelling in the lower extremities.
After watching this lesson, you should be ready to:
- Define coronary arteries
- Summarize the causes and symptoms of atherosclerosis, coronary heart disease, angina, heart attack and congestive heart failure