23 - Membrane Transport in Red Blood Cells

Abstract

This chapter focuses on the plasma membrane and underlying cytoskeleton. It is mentioned that the availability, structural and metabolic simplicity, and ease of manipulating the intracellular as well as the extra cellular solutions of red blood cells have made them a popular subject for the study of membrane transport. The chapter discusses several concepts related to red blood cells—membrane and cytoskeleton, intracellular environment, metabolism and life span, membrane transporters in red blood cells, ionic and osmotic equilibrium and cell volume regulation, anion exchange and conductance, and cytotoxic calcium cascade. The chapter includes an illustration of electrogenic potential of the Na+ -K+ pump in human red blood cells, as monitored with the oxonol dye WW781.The life spans of red blood cells from various mammalian species correlate with body mass, suggesting the existence of a biological clock that is obviously independent of gene transcription or translation in the mature non-nucleated cells. Mammalian red blood cells are highly differentiated for their primary function of oxygen and carbon dioxide transport, and from a structural point of view are the simplest of all eukaryotic cells. Most mammalian red blood cells normally exhibit a biconcave discoidal shape. The red-cell membrane and associated cytoskeleton enclose a viscous cytoplasmic solution of the oxygen–binding pigment called hemoglobin. The metabolism and life span vary from mammal to mammal. Membrane transporters in red blood cells have been explained in detail. Human red blood cells contain 66% water. Characteristics of human blood cells have been described. The transport of carbon dioxide from the peripheral tissues to the lungs is facilitated by the production of bicarbonate by red blood cells in a cyclic reaction scheme known as the Jacobs-Stewart cycle, which has been illustrated. The effect of excess cytotoxic calcium on red blood cell has been described. It is mentioned that red blood cells are prototypical of more complicated cells and have long been a popular object of study for cellular physiologists.