What does the heart do?
The Ancient Egyptians believed that the heart was the source of emotions, wisdom, memories, and the personality. We now know this is not true, as the brain has control over most of these things. So what does the heart do? The heart is simply a well-designed "double pump" shunting blood to the lungs to pick up oxygen and pumping the oxygenated blood back out to the body. The heart does this by creating pressure differences in its four chambers. The heart is an integral part of the Circulatory System, working with the Pulmonary System (the lungs) and the systemic network of arteries, veins, and capillaries to circulate blood around the body. Blood also transports nutrients around the body and brings carbon dioxide to the lungs to be exhaled.
Structure
The heart is a muscle. However, cardiac muscle is different than skeletal muscle (the muscles we use to produce voluntary movement). When you want to raise your hand in class, your brain must first tell the muscles in your arm to do so. But you do not have to think about making your heart beat. This is because the heart is equipped with specialized cardiac fibers that create and relay electric impulses through the heart to signal contraction (squeezing). Cardiac muscle cells are connected by intercalated disks which help spread the rhythmic electrical impulses across the heart with little resistance. This allows the atria to contract at the same time, and then the ventricles at the same time.
Using the video and the diagram to the right, trace the blood flow through the heart starting with de-oxygenated blood in the Right Atrium.
Using the video and the diagram to the right, trace the blood flow through the heart starting with de-oxygenated blood in the Right Atrium.
Heart Disease
There are many different kinds of heart disease. The most common ones are Coronary Artery Disease (ischemic), Hypertensive Heart Disease, and Inflammatory Heart Disease. The risk factors for heart disease include:
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Which of these risk factors are modifiable and which are not? In other words, which of these can be changed and which ones cannot?