They constitute the second largest group of leukocytes in a blood count, right after the neutrophils. There are several subtypes of lymphocyte however they can be distinguished in routine histological sections only after using special techniques, such as immunocytochemistry.
Among other functions, the lymphocytes are responsible for the specific recognition of antigens, production of immunoglobulins (antibodies), and triggering and controling immune responses.
They are spherical and small, measuring about 7 µm in diameter. Lymphocytes are mononuclear leukocytes, thus their nuclei are non-lobulated. They are spherical and occupy most of the cell. A thin layer of cytoplasm may be seen surrounding their heavily stained nucleus. Hence, the lymphocytes are usually recognized in sections as well as in blood smears by their characteristic nuclei.
Two lymphocytes are seen in the figure. Observe their round, strongly stained nuclei. In both lymphocytes, a delicate thin rim of cytoplasm can be seen surrounding the nuclei.
More lymphocytes in the next pages as well as in pages 12-14 and 12-15 by clicking on the links page 12-14 and page 12-15.
