Final answer:
White blood cells (WBCs) consist of granulocytes and agranulocytes, each with specialized functions in the immune system. They differ from red blood cells by having nuclei and lacking hemoglobin. Knowing the various WBC types and their counts is crucial for diagnosing and understanding different medical conditions.
Step-by-step explanation:
White Blood Cells and Their Functions
White blood cells (WBCs), or leukocytes, are essential components of the immune system and play a critical role in defending the body against infections and diseases. Unlike red blood cells, they have nuclei and do not contain hemoglobin. There are two main groups of WBCs: granulocytes and agranulocytes.
Granulocytes, named for the granules in their cytoplasm which are visible under a microscope, include three types of cells: neutrophils, which primarily fight bacteria; eosinophils, which combat parasites and have a role in allergic reactions; and basophils, which are involved in allergic responses. Agranulocytes do not contain visible granules and consist of monocytes, which differentiate into macrophages and help break down bacteria, and lymphocytes, which are pivotal in the immune response to infectious microorganisms and foreign substances.
The relative percentages of these different types of WBCs in the blood can give important clues about a person's health. For instance, an elevated white blood cell count can indicate an infection, inflammation, or leukemia, among other conditions. Conversely, a reduced count may suggest a compromised immune system, potentially due to conditions such as HIV/AIDS or chemotherapy treatment.