Red Blood Cell Structure

Red Blood Cell Structure
Red blood cells have a unique structure responsible for oxygen transport. Their flexible disc shape helps increase the surface area-to-volume ratio of these extremely small cells. This enables oxygen and carbon dioxide to diffuse across the red blood cell s plasma membrane more readily. Red cells in peripheral blood smears appear as rounded bright pink-stained cells, they are 6.5-8.5 µm in diameter and have a biconcave shape, appearing paler in the center and darker at the periphery. Red blood cells contain enormous amounts of a protein called hemoglobin. This iron containing molecule binds oxygen as oxygen molecules enter blood vessels in the lungs. Unlike other cells of the body, mature red blood cells do not contain a nucleus, mitochondria, or ribosomes. The absence of these cell structures leaves room for the hundreds of millions of hemoglobin molecules found in red blood cells.
A mutation in the hemoglobin gene can result in the development of sickle-shaped cells and lead to sickle cell disorder.
The blood s red color is due to the spectral properties of the hemic iron ions in hemoglobin. Each human red blood cell contains approximately 270 million of these hemoglobin molecules. Each hemoglobin molecule carries four hem groups; hemoglobin comprises about a third of the total cell volume. Hemoglobin is responsible for the transport of more than 98% of the oxygen in the body (the remaining oxygen is carried dissolved in the blood plasma)..