Definition of Leukocyte – White Blood Cells

LeukocyteA white blood cell, also referred to as a WBC.

Leukocytes are the foundation of the body’s immune response and are phagocytic-that is, they have the ability to consume other cells.

They circulate in the blood and the lymph as well as reside in tissues throughout the body. There are three basic types of leukocytes: granulocytes, monocytes, and lymphocytes. Each type has several subtypes.

The spleen and lymph tissues produce monocytes and lymphocytes; the red bone marrow produces granulocytes.

Health Conditions that Affect Leukocyte Counts

A substantial increase overall in leukocyte count may indicate a cancer of the bone marrow such as leukemia or lymphoma. The ratio between erythrocytes (red blood cells) and leukocytes in the blood is also an important diagnostic indicator.

A healthy adult has between 5,000 and 10,000 leukocytes per microliter of blood, with granulocytes accounting for about 70 percent. Increases in certain subtypes of leukocytes suggest particular health conditions.

HEALTH CONDITIONS THAT AFFECT LEUKOCYTE COUNTS
Allergy ResponseAsthma
Autoimmune DisordersChemotherapy
Environmental toxin exposureHypersensitivity Reaction
InfectionInflammation
LeukemiaLeukopenia
LymphocytopeniaLymphoma
Many cancersMedication side effects
Mononucleosis, infectiousRadiation therapy
SurgeryVitamin B12 deficiency

Types of Leukocytes

LEUKOCYTES
Type of LeukocyteSubtypesOrgan that Produces
granulocytesbasophils, eosinophils, neutrophilsRed Bone Marrow
monocytesmacrophages (reside in the tissues)Spleen, lymph nodes
lymphocytesT-cell lymphocytes
cytotoxic T-cells
helper T-cells
memory T-cells
suppressor T-cells
spleen, lymph nodes, thymus
B-cell lymphocytes
memory B-cells
PLASMA cells

For further discussion of blood and lymph structure and function please see the overview section “The Blood and Lymph.”

See also B-CELL LYMPHOCYTECELL STRUCTURE AND FUNCTIONERYTHROCYTEHEMATOPOIESISPHAGOCYTOSIS; PLASMA; PLATELET; SIDE EFFECTTHYMUS.

How did you like this article?

Page last reviewed:

About Us