As this blood returns, it picks up carbon dioxide. The carbon dioxide is carried back to your heart and then pumped to your lungs where you exhale these carbon dioxide waste products. Your heart has four sections called chambers. Between each chamber is a valve that acts like a control gate to keep blood flowing through your heart in the right direction. These four valves are made of thin, but very strong, flaps of tissue that open and close as the heart pumps.
Heart valves function like one-way gates, allowing the blood to move in only one direction.
A normal heart valve is flexible enough to open and permit blood to flow through it, yet strong enough to hold back the flow when it is closed. Heart valves may not always work as well as they should because of problems caused by disease, aging, or a birth defect. Diseases of the heart valves are classified according to the specific valve involved and the type of valve defect. Any problem with a valve makes your heart work harder. To make up for this extra workload your heart may get larger.