IMMUNOLOGY

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.

Detailed explanation-2: -The tricuspid heart valve separates the right atrium from the right ventricle and allows deoxygenated blood to flow between them. Once blood has cycled through the body, it is returned to the right atrium, which is located on the right side of the heart.

Detailed explanation-3: -Blood enters the right atrium and passes through the right ventricle. The right ventricle pumps the blood to the lungs where it becomes oxygenated. The oxygenated blood is brought back to the heart by the pulmonary veins which enter the left atrium. From the left atrium blood flows into the left ventricle.