The Ins and Outs of the Heart

Your heart is about the size of your fist.

The Human Heart

When most peeps think of the word "heart" they think of love, romance and all that mushy stuff. Those things are great and all, but let's also give your heart props for what it really is - an amazingly powerful life-sustaining organ.

Pump Up the Oxygen

To put it simply, your heart is a pump. Much like that gizmo in your fish tank, your heart moves liquid from one place to another. In the process, the heart re-oxygenates the blood moving through it with the oxygen you breathe in. This is an essential process cuz your blood supplies oxygen to your entire body. If you don't get oxygen for more than a few minutes, you'll die.

Basic Anatomy

Your heart is a cone-shaped muscle in the middle of your chest, right between your lungs. The average adult heart weighs between 9 - 10.5 ounces (255 - 298 grams) and it pumps about 1,900 gallons (7,200 liters) of blood every day. The heart has three layers: the endocardium (outside layer), the myocardium (middle layer) and the pericardium (the fluid sack that surrounds the heart). The heart is also divided up into four chambers, which each have a valve that allows blood to flow in, but prevents blood from flowing backwards.

In Action

The heart squeezes blood out and into the rest of the circulatory system when it contracts. When it expands, it sucks in poorly oxygenated blood and pushes through the chambers and into the pulmonary artery, where it is re-oxygenated. Then the blood makes its way out of the heart via the aorta and back into the body where it provides your cells with oxygen.