White Blood Cells

Whitestripes

White blood cells (WBCs), also known as leukocytes, are cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders. All white blood cells are produced and derived from multipotent cells in the bone marrow known as hematopoietic stem cells. Leukocytes are found throughout the body, including the blood and lymphatic system.

Types

There are several different types of white blood cells, each with distinct functions:

• Neutrophils: The most abundant type of white blood cells, essential for fighting bacterial infections.
• Lymphocytes: Includes B cells, T cells, and natural killer cells, crucial for the adaptive immune response.
• Monocytes: Differentiate into macrophages and dendritic cells to phagocytize pathogens and present antigens.
• Eosinophils: Combat multicellular parasites and certain infections; also involved in allergic reactions.
• Basophils: Release histamine for inflammatory responses and play a role in allergic reactions.

Function

White blood cells are part of the body's immune system and help the body fight infection and other diseases. They move through the blood and tissue looking for foreign invaders such as bacteria, viruses, and fungi, which they destroy.

Clinical Significance

The number of white blood cells in the blood is often an indicator of disease. A high white blood cell count, known as leukocytosis, can indicate an infection, inflammation, trauma, or other conditions. A low white blood cell count, known as leukopenia, can indicate bone marrow problems, autoimmune conditions, or the effects of certain medications.

Related Pages

• Immune system
• Hematopoiesis
• Bone marrow
• Lymphatic system
• Blood
• Infection
• Inflammation
• Leukocytosis
• Leukopenia

See Also

• Red blood cell
• Platelet
• Complete blood count