Anemia - Introduction

Introduction

Anemia is an abnormal reduction in red blood cells.

Anemia is not a single disease but a condition, like fever, with many possible causes and many forms. Causes of anemia include nutritional deficiencies, inherited genetic defects, medication-related side effects, and chronic disease. It can also occur because of blood loss from injury or internal bleeding, the destruction of red blood cells, or insufficient red blood cell production. The condition may be temporary or long-term, and can manifest in mild or severe forms.

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This report focuses on the most common forms of anemia:

• Iron deficiency anemia
• Anemia of chronic disease (ACD)
• Treatment-related anemia (chemotherapy, medication, radiation therapy)
• Megaloblastic anemia (caused by deficiencies in the B vitamins folate, vitamin B12, or both)

Blood

Blood has two major components:

• Plasma is a clear yellow liquid that contains proteins, nutrients, hormones, electrolytes, and other substances. It constitutes about 55% of blood.
• White and red blood cells and platelets make up the balance of blood. The white cells are the infection fighters for the body. Platelets are necessary for blood clotting. The important factors in anemia, however, are red blood cells.

Red blood cells (RBCs), also known as erythrocytes, carry oxygen throughout the body to nourish tissues and sustain life. Red blood cells are the most abundant cells in our bodies. On average, men have about 5.2 million red blood cells per cubic millimeter of blood, and women have about 4.7 million per cubic millimeter of blood.

Hemoglobin and Iron

Each red blood cell contains 280 million hemoglobin molecules. Hemoglobin is a complex molecule, and it is the most important component of red blood cells. It is composed of protein (globulin) and a molecule (heme), which binds to iron.

In the lungs, the heme component binds to oxygen in exchange for carbon dioxide. The oxygenated red blood cells are then transported to the body's tissues, where the hemoglobin releases the oxygen in exchange for carbon dioxide, and the cycle repeats. The oxygen is used in the mitochondria, the power source within all cells.