Final answer:
The transport of oxygen from the lungs to the body's cells is primarily facilitated by hemoglobin within erythrocytes (red blood cells). Oxygen binds to hemoglobin in the alveoli, and the oxygen-rich blood returns to the heart and is distributed to the body.
Step-by-step explanation:
The component of blood responsible for transporting oxygen from the air in the lungs to the body's cells is hemoglobin, which is found within erythrocytes (red blood cells). In the process of external respiration, oxygen enters the bloodstream from the alveoli, small sacs in the lungs. The deoxygenated blood, carried to the lungs via the pulmonary artery, reaches the alveoli and the surrounding capillaries where oxygen diffuses into the blood due to a higher concentration of oxygen in the alveoli compared to the blood.
Oxygen then binds to the metalloprotein hemoglobin inside the red blood cells. Each hemoglobin molecule can carry up to four oxygen molecules, which allows for the efficient transportation of oxygen throughout the body. Oxygenated blood, bright red in color due to the presence of oxygen-bound hemoglobin, then returns to the heart through the pulmonary veins and is pumped into the systemic circulation to deliver oxygen to various tissues and organs.
Simultaneously, carbon dioxide, a waste product from the body's cells, diffuses from the blood into the alveoli to be exhaled. This gas exchange is a continuous process that sustains cellular respiration and is essential to life.