Which component carries oxygen in the blood?

The component that carries oxygen in the blood is hemoglobin. Hemoglobin is a protein found in red blood cells, and its primary function is to bind oxygen in the lungs and transport it to tissues and organs throughout the body. When you inhale, oxygen diffuses from the alveoli, the tiny air sacs in the lungs, into the bloodstream. In this stage, hemoglobin in red blood cells picks up the oxygen to form oxyhemoglobin.

Once the red blood cells circulate to various tissues, hemoglobin releases the oxygen for use by the cells in cellular respiration. Additionally, hemoglobin helps transport carbon dioxide, a waste product of metabolism, back to the lungs for exhalation, although its main role is in the transport of oxygen.

While alveoli and bronchi are parts of the respiratory system involved in the process of gas exchange and airflow, respectively, they do not carry oxygen themselves. Bicarbonate is involved in blood pH regulation and the transport of carbon dioxide rather than the direct transport of oxygen. Therefore, hemoglobin is the definitive component responsible for the transport of oxygen in the blood.