What are the two upper chambers of the heart called? Cardiac septum Atria Valves Pericardium

## Step 1<br />The heart is a vital organ in the human body that pumps blood throughout the body. It is divided into four chambers: two upper chambers and two lower chambers.<br />## Step 2<br />The two upper chambers of the heart are called the atria. They receive blood returning to the heart from the body and lungs.<br />## Step 3<br />The two lower chambers of the heart are called the ventricles. They pump blood out of the heart to the body and lungs.<br />## Step 4<br />The cardiac septum is a wall that separates the left and right sides of the heart.<br />## Step 5<br />The valves are structures within the heart that ensure blood flows in the right direction.<br />## Step 6<br />The pericardium is a double-walled sac containing the heart and the roots of the great vessels.