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Overview of Blood Disorders

By

David J. Kuter

, MD, DPhil, Harvard Medical School

Last full review/revision Jun 2021| Content last modified Jun 2021
Click here for the Professional Version

Some blood disorders cause the number of cells in the blood to decrease:

Other blood disorders cause the numbers of blood cells to increase:

Blood flows to every cell in the body and is important to the health and function of all of the body's organs.

Blood cells are produced in the bone marrow, and many blood proteins are made in the liver or the blood cells themselves. Blood cells and blood proteins provide the following functions:

  • Red blood cells contain hemoglobin, which carries oxygen to every part of the body.

  • White blood cells and antibodies fight infections and cancers.

  • Platelets and blood clotting factors make bleeding stop or prevent bleeding from occurring.

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