MICROANATOMY

Detailed explanation-1: -A typical heart has two upper and two lower chambers. The upper chambers, the right and left atria, receive incoming blood. The lower chambers, the more muscular right and left ventricles, pump blood out of the heart.

Detailed explanation-2: -The upper two chambers are called atria (singular: atrium) and the lower two are known as ventricles (singular: ventricle). Muscular walls, called septa or septum, divide the heart into two sides.

Detailed explanation-3: -The atrium was formerly called the ‘auricle’. That term is still used to describe this chamber in some other animals, such as the Mollusca.

Detailed explanation-4: -The two atria are thin-walled chambers that receive blood from the veins. The two ventricles are thick-walled chambers that forcefully pump blood out of the heart.

Detailed explanation-5: -The top chambers of the heart are called the left atrium and right atrium. The bottom chambers of the heart are the left ventricle and right ventricle, which have thicker walls.