Hematology is the medical specialty that pertains to the anatomy, physiology, pathology, symptomatology and therapeutics related to the blood and blood forming tissues.
Blood supplies oxygen and nutrients to all of the parts of the body, and it carries away waste products, such as carbon dioxide (CO2), from cells. The blood vessels serve as the transportation pathways in the body for the flow of fluid, blood cells, platelets, gases, waste products, nutrients, lipids, sugars, amino acids, vitamins, proteins, hormones, electrolytes, and other substances. Blood contains all of these elements, and scientists have suggested that space flight causes changes in them. Scientists attempt to characterize the general nature of blood and how this nature is changed when a human enters the microgravity environment.
Exposure to the microgravity environment and the associated headward fluid shift that accompanies it, result in a series of compensatory mechanisms. Several of these mechanisms are thought to affect the physiology of the blood, specifically, plasma volume, red blood cell mass and production, red cell metabolism, blood proteins and hemoglobin concentration. Since the most significant hematologic changes resulting from space flight are reductions in plasma volume and red blood cell mass, many space flight investigations are specific to these issues.
Hematologic investigations have been conducted on US space flight missions since the early Gemini flights and continue on the Shuttle flights today.
Metabolism of Red Blood Cells
Red Blood Cell Mass and Survival
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Page last updated: 07/16/1999