By Billie Rubin, Hemoglobin’s Catabolic Cousin, reporting from the labs of Stanford Blood Center
Red blood cells are the taxi cabs of the cardio world. They can squeeze themselves into tiny capillaries or ride the big arterial highways like the aorta to different parts of the body. They are propelled by the currents created from the beats of the heart. They pick up oxygen molecule customers in the lungs and give it a ride to all the tissues of the body. The oxygen attaches itself to the iron at the center of the hemoglobin molecules (the taxi’s red-velvet interior inside the RBC) and gets off where it’s needed anywhere in the body.
The “empty” hemoglobin in the RBC then picks up another passenger in the tissues, a carbon dioxide molecule, and gives it a ride back to the lungs where the carbon dioxide gets off and is expelled through our breath. The “cab” works 24/7 for about three months until it’s worn out. It’s then removed from service and a new one takes its place. And that’s life in the fast lane.