MICROANATOMY

Detailed explanation-1: -Blood first enters the heart’s right atrium. A muscle contraction forces the blood through the tricuspid valve into the right ventricle. When the right ventricle contracts, blood is forced through the pulmonary semilunar valve into the pulmonary artery. Then it travels to the lungs.

Detailed explanation-2: -When the ventricle is full, the mitral valve shuts. This prevents blood from flowing backward into the atrium while the ventricle contracts. As the ventricle contracts, blood leaves the heart through the aortic valve, into the aorta and to the body.

Detailed explanation-3: -Pulmonary circulation transports oxygen-poor blood from the right ventricle to the lungs, where blood picks up a new blood supply. Then it returns the oxygen-rich blood to the left atrium.