Leukotsüüte

Leukotsüüte, commonly known as white blood cells or leukocytes, are an essential part of the immune system. They are produced in the bone marrow and circulate in the blood and lymph fluid. Their primary function is to defend the body against infection and disease. Leukocytes are a diverse group of cells, each with specific roles in identifying and eliminating pathogens such as bacteria, viruses, and fungi, as well as abnormal cells like cancer cells.

There are several types of leukocytes, each distinguished by their appearance and function. Granulocytes, including neutrophils, eosinophils, and basophils, are characterized by the presence of granules in their cytoplasm. Neutrophils are the most abundant type and are crucial for combating bacterial infections. Eosinophils play a role in allergic reactions and defense against parasites. Basophils release histamine, contributing to inflammatory responses.

Agranulocytes, which lack prominent granules, include lymphocytes and monocytes. Lymphocytes are key players in adaptive immunity; B lymphocytes produce antibodies, while T lymphocytes directly kill infected cells or regulate immune responses. Monocytes are large cells that differentiate into macrophages in tissues, where they engulf and digest cellular debris, foreign substances, microbes, and cancer cells.

The number of leukocytes in the blood can vary depending on physiological conditions. An elevated white blood cell count, known as leukocytosis, often indicates an infection or inflammatory process. Conversely, a low white blood cell count, leukopenia, can result from various medical conditions or treatments, leaving the body more vulnerable to infection. Monitoring leukocyte levels is a common diagnostic tool in medicine.