Components of blood

Author: Scott A. Sheffield MS

Last update:

General Composition of Blood:

Human blood is primarily composed of plasma, red blood cells (erythrocytes), and white blood cells (leukocytes).

  1. If a tube of blood is left standing or spun briefly in a centrifuge, the components will image descriptionseparate into layers, based on their density.

Blood seperation animation slide 1
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Blood seperation animation slide 10
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Blood seperation animation slide 32
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Standing glass tube containing whole blood
  1. The bottom, red-colored layer is made up of image descriptionred blood cells  (RBCs or erythrocytes). Red blood cells normally occupy about 45% of the total blood volume (females = 37-48% & males = 45-52%).
Blood seperation animation slide 39
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Animation slide showing the 45% or red blood cells in whole blood.
Standing glass tube containing whole blood - red blood cells.
  1. Above the RBCs is the image descriptionbuffy coat. This narrow, white band is composed of white blood cells (WBCs or leukocytes) and cell fragments called platelets (thrombocytes). Approximately 1% of the blood volume is occupied by these components.

Want to learn more about blood cells? Don’t miss these free fill-in-the-blank histology identification quizzes!

Animation slide showing the 45% or red blood cells in whole blood.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Standing glass tube containing whole blood - buffy coat.
  • Together, the RBCs, WBCs, and platelets are referred to as the blood’s formed elements.
  1. On top of the formed elements is the blood image descriptionplasma. This straw-colored fluid makes up approximately 55% of the total blood volume.
Animation showing the elements of the buffy coat: white blood cells and platelets.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Animation showing the elements of the plasma: water, proteins, and other solutes.
Standing glass tube containing whole blood - plasma.
  • By weight, the composition of plasma is about 91.5% water and 8.5% dissolved solutes. Most of the dissolved solutes are proteins. The remaining solutes are a mixture of nutrients, electrolytes, nitrogenous wastes, respiratory gases, and regulatory compounds.
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