PlasmaPlasma is a straw-colored fluid that makes up 55% of blood. It is composed of 90% water. Plasma also contains nutrients, electrolytes, hormones, and proteins. Proteins include:
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Red Blood CellsRed blood cells (RBC's) are also know as erythrocytes. They make up 99.9% of the formed elements and have a red color. This color is due to the pigment hemoglobin which transports oxygen and carbon dioxide. RBC's are made in the red bone marrow of long bones when the protein erythopoietin is released. Erythopoietin is released when a person is in low oxygen conditions (such as high altitudes), has respiratory channel damage, or is anemic. Special characteristics of RBC's include:
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White Blood CellsWhite blood cells (WBC's) are also called leukocytes. They make up less than .1% of formed elements. They contain nuclei and other organelles, but do not have hemoglobin. They move like amoebas and squeeze between the walls of the blood vessel to leave the bloodstream. They are only present in the blood when they are attracted by chemical stimuli such as damaged tissue. There are five kinds of WBC's: neutrophils, lymphocytes, monocytes, eosinophils, and basophils. WBC's serve several functions:
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