They let blood flow from the atria to the ventricles. Two of the heart valves are the mitral (say: MY-trul) valve and the tricuspid (say: try-KUS-pid) valve.The door shuts behind you and keeps you from going backward. A valve lets something in and keeps it there by closing - think of walking through a door. Your blood relies on four special valves inside the heart. So when the blood gets pumped, how does it know which way to go? What Do the Heart Valves Do? While the ventricles are squeezing, the atria refill and get ready for the next contraction. The ventricles then squeeze, pumping blood out of the heart. The atria and ventricles work as a team - the atria fill with blood, then dump it into the ventricles. The septum's job is to separate the left side and the right side of the heart. Running down the middle of the heart is a thick wall of muscle called the septum (say: SEP-tum). The ventricles are the chambers that pump out the blood to the body and lungs. If you're talking only about one, call it an atrium. The atria are the chambers that fill with the blood returning to the heart from the body and lungs. What Are the Atria? And What's An Atrium? The two chambers on the bottom are called the ventricles (say: VEN-trih-kulz). The heart has a left ventricle and a right ventricle.The two chambers on top are called the atria (say: AY-tree-uh). The heart has a left atrium and a right atrium.One chamber is on the top and one chamber is on the bottom. There are two chambers on each side of the heart. The heart is made up of four different blood-filled areas, and each of these areas is called a chamber. The heart is one hard worker! What Are the Parts of the Heart? Your heart does this all day and all night, all the time. That's sort of like what your heart does so it can pump the blood. When the heart contracts, it squeezes - try squeezing your hand into a fist. Then it contracts to pump the blood along. The systemic circulation then transports oxygen to the body and returns carbon dioxide and relatively deoxygenated blood to the heart for transfer to the lungs.Before each beat, your heart fills with blood. Blood in the pulmonary circulation exchanges carbon dioxide for oxygen in the lungs through the process of respiration. This circulation consists of the systemic circulation to and from the body and the pulmonary circulation to and from the lungs.

The heart functions as a pump in the circulatory system to provide a continuous flow of blood throughout the body. These are surrounded by a double-membraned sac called the pericardium. The left heart has two chambers: the left atrium, and the left ventricle, separated by the mitral valve.The heart wall is made up of three layers: the inner endocardium, middle myocardium and outer epicardium. The right heart consists of two chambers, the right atrium and the right ventricle, separated by a valve, the tricuspid valve. The wall of the heart is made up of three layers: epicardium, myocardium, and endocardium. The heart is enclosed in a protective sac, the pericardium, which also contains a small amount of fluid. Commonly the right atrium and ventricle are referred together as the right heart and their left counterparts as the left heart.] Fish, in contrast, have two chambers, an atrium and a ventricle, while reptiles have three chambers.In a healthy heart blood flows one way through the heart due to heart valves, which prevent backflow. In humans, other mammals, and birds, the heart is divided into four chambers: upper left and right atria and lower left and right ventricles. In humans, the heart is located between the lungs, in the middle compartment of the chest. Blood provides the body with oxygen and nutrients, as well as assists in the removal of metabolic wastes. The heart is a muscular organ in humans and other animals, which pumps blood through the blood vessels of the circulatory system.

Heart blood flow diagram worksheet