9. Leukocytes (white blood cells), their functions . Total and differential white blood cells count.

Leukocytes, also known as white blood cells (WBCs), are an essential component of the immune system. They play a crucial role in defending the body against infections and diseases. There are several types of leukocytes, each with specific functions:<br /><br />1. **Neutrophils**: These are the most abundant type of white blood cells in the body. They are phagocytic, meaning they can engulf and destroy bacteria and other pathogens. Neutrophils are also involved in the inflammatory response and help to clear damaged tissues.<br /><br />2. **Lymphocytes**: There are two main types of lymphocytes: B cells and T cells. B cells produce antibodies that help to neutralize pathogens, while T cells directly attack infected cells. Lymphocytes also play a role in the adaptive immune response, which provides long-term immunity against specific pathogens.<br /><br />3. **Monocytes**: These cells are phagocytic and can differentiate into macrophages or dendritic cells. Macrophages help to clear dead cells and debris, while dendritic cells present antigens to T cells to initiate an immune response.<br /><br />4. **Eosinophils**: These cells are involved in the response to parasitic infections and allergic reactions. Eosinophils release toxic granules that can kill parasites and modulate inflammatory responses.<br /><br />5. **Basophils**: These cells are involved in the release of histamine and other mediators that contribute to inflammation and allergic reactions. Basophils also play a role in the defense against parasites.<br /><br />The total white blood cell count (WBC) is a measure of the number of white blood cells in a given volume of blood. It is an important indicator of the body's immune response and can be used to diagnose and monitor various medical conditions.<br /><br />The differential white blood cell count is a more detailed analysis of the different types of white blood cells present in the blood. It provides information on the relative proportions of each type of leukocyte and can help identify specific patterns associated with certain diseases or infections.<br /><br />In summary, leukocytes play a vital role in the immune system, and their functions and counts are important indicators of the body's overall health and immune response.