Granulocyte

Granulocyte

Types of granulocytes

Granulocytes are a category of white blood cells characterized by the presence of granules in their cytoplasm. These granules contain enzymes that are released during infections, allergic reactions, and asthma. Granulocytes are part of the innate immune system and play a crucial role in the body's defense against pathogens.

Types of Granulocytes

Granulocytes are divided into three main types based on the staining properties of their granules:

• Neutrophils
• Eosinophils
• Basophils

Neutrophils

A neutrophil

Neutrophils are the most abundant type of granulocytes and the most abundant type of white blood cells in most mammals. They form an essential part of the innate immune system. Neutrophils are typically the first responders to microbial infection; their activity and death in large numbers form pus.

Eosinophils

Eosinophils are responsible for combating multicellular parasites and certain infections in vertebrates. They also control mechanisms associated with allergy and asthma. The granules of eosinophils contain a variety of enzymes and toxic proteins that are released upon activation.

Basophils

Basophils are the least common type of granulocyte and are involved in inflammatory reactions, particularly those that cause allergic symptoms. They contain large cytoplasmic granules which obscure the cell nucleus under the microscope when stained.

Function

Granulocytes are involved in the body's defense against pathogens. They are part of the innate immune system, which is the first line of defense against invading pathogens. Granulocytes are capable of phagocytosis, a process by which they engulf and digest microorganisms and cellular debris.

Development

Diagram of hematopoiesis

Granulocytes are derived from hematopoietic stem cells in the bone marrow. The process of granulocyte development is known as granulopoiesis. During this process, hematopoietic stem cells differentiate into myeloid progenitor cells, which then further differentiate into the various types of granulocytes.

Related Pages

• White blood cell
• Immune system
• Hematopoiesis
• Innate immune system

Illustration of granular leukocytes from 1907