Learning the Heart

When you're learning the path blood takes through the heart, start with blood leaving the left ventricle. This makes more conceptual sense and will help you get things straight. Learning the heart is like learning anything else in medicine, it is not hard or complicated, but it can quickly become overwhelming if you don't have a good  framework to put information into. So here's a broad framework for understanding the heart and the blood-flow through it.

The heart is one of the most important organs of the body. All organs have a function, all are important, but the heart and the brain are the two most important because without them everything else dies. And the body knows this. When a patient is really sick or losing a lot of blood, the body will start cutting off its own blood-flow to the parts of the body that it thinks are less important for immediate survival like the arms and the legs. This happens so that there is more blood for the heart and brain to use. 

The reason the heart is important is because of its one function: to deliver oxygen to the rest of the body. To digress a moment:

• oxygen is needed for every cell (which is the building block of every part of our body) to make energy to function (this energy is called ATP)

• if the oxygen supply is cut off, even for a brief amount of time, cells start to die which means our body starts to die

• so getting a constant supply of oxygen to every part of our body is required for us to live (oxygen is to the body what oil is to the world's economy: if oil were cut off, even for one day, we'd be screwed. Same goes for oxygen except we're talking seconds to minutes)

• Red Blood Cells is the part of our blood that carries oxygen from our lungs to the rest of our body; this is it's only important function. RBC = oxygen.

So again, the heart's one major function is to pump blood which contains the oxygen to the rest of the body. This happens when the left ventricle fills with blood just back from the lungs and shoots it out into the aorta and beyond. This is mission accomplished for the heart.

So the blood goes to different organs and your fingers and wherever and drops off the oxygen. It then returns to the heart to pick up more oxygen. The blood collects in the right side of the heart, is squeezed through the lungs where it picks up more oxygen, and again collects in the left ventricle, ready to get shot out again to carry more oxygen. Our body, like our economy, is very demanding for its natural resources. 

Get this broad concept down and think about blood flow through the heart as starting with expulsion from the left ventricle (oxygenated blood = mission accomplished) and follow it from there. It's a small thing but in my experience helps keep the later details straight.