AP BIOLOGY

Detailed explanation-1: -When the right ventricle contracts, blood is forced through the pulmonary semilunar valve into the pulmonary artery. Then it travels to the lungs. In the lungs, the blood receives oxygen then leaves through the pulmonary veins. It returns to the heart and enters the left atrium.

Detailed explanation-2: -Blood comes into the right atrium from the body, moves into the right ventricle and is pushed into the pulmonary arteries in the lungs. After picking up oxygen, the blood travels back to the heart through the pulmonary veins into the left atrium, to the left ventricle and out to the body’s tissues through the aorta.

Detailed explanation-3: -The lung veins sometimes referred to as the pulmonary veins, are blood vessels that transfer freshly oxygenated blood from the lungs to the left atria of the heart.