Final answer:
Lymphocytes are agranulocytes that include T cells and B cells as well as natural killer cells. They play key roles in the immune system by producing antibodies, attacking infected or abnormal cells, and forming immune memory. Lymphocytes are numerous, being the second most common leukocyte, and are primarily located in lymphoid tissues.
Step-by-step explanation:
The subject you are asking about is an agranulocyte known as a lymphocyte, which is a type of white blood cell crucial to the immune system. There are two main types of lymphocytes: B cells and T cells, which include killer cells. Lymphocytes are numerous, being the second most common type of leukocyte, making up about 20-30 percent of all leukocytes.
Lymphocytes have a distinctive appearance; their nucleus is large and spherical, staining purple, and they have a small amount of cytoplasm, which can appear as a light blue rim. They are primarily located in lymphoid tissues, such as lymph nodes and the spleen, though some circulate in the blood. B cells produce antibodies and T cells attack infected or abnormal cells. Furthermore, natural killer (NK) cells, a subtype of lymphocytes, play a critical role in attacking infected cells and tumor cells. These immune cells are integral for protecting the body against pathogens and maintaining immune memory for long-term immunity.