Which leukocytes are considered nongranular?

Lymphocytes and monocytes are classified as nongranular leukocytes, also referred to as agranulocytes. This classification is based on the presence or absence of visible granules in their cytoplasm when viewed under a microscope after staining.

Lymphocytes play a crucial role in the immune response, with subtypes such as B cells and T cells involved in antibody production and cellular immunity, respectively. Monocytes are important as they differentiate into macrophages and dendritic cells when they migrate into tissues, where they help in phagocytosis and antigen presentation.

In contrast, the other leukocytes listed, such as neutrophils, eosinophils, and basophils, are granular leukocytes. Neutrophils are the most abundant white blood cells and are vital for innate immunity, especially in responding to bacterial infections. Eosinophils are involved in combating multicellular parasites and allergic reactions, while basophils play a role in inflammatory responses and the release of histamine. Thus, recognizing that lymphocytes and monocytes are the nongranular leukocytes highlights their fundamental roles in the immune system.