MICROANATOMY

Detailed explanation-1: -After the blood gets oxygen in the lungs, it is called oxygen-rich blood. Oxygen-rich blood flows from the lungs back into the left atrium (LA), or the left upper chamber of the heart, through four pulmonary veins.

Detailed explanation-2: -The pulmonary artery then carries the oxygen-poor blood from your heart to the lungs. Your lungs add oxygen to your blood. The oxygen-rich blood returns to your heart through the pulmonary veins.

Detailed explanation-3: -This is called the pulmonary circulation. From your pulmonic valve, blood travels to the pulmonary arteries and eventually to tiny capillary vessels in the lungs. Here, oxygen travels from the tiny air sacs in the lungs, through the walls of the capillaries, into the blood.