AP BIOLOGY

Detailed explanation-1: -Lymphocytes are mature, infection-fighting cells that develop from lymphoblasts, a type of blood stem cell in the bone marrow. Lymphocytes are the main cells that make up lymphoid tissue, a major part of the immune system. Lymphoid tissue is found in lymph nodes, the thymus gland, the spleen, the tonsils, and adenoids.

Detailed explanation-2: -B lymphocytes originate in the bone marrow; their goal is to recognize an antigen. Each of them responds to the antigen in a specific way, as it expresses specific antibodies on the membrane (IgM, CD79a, and CD79b).

Detailed explanation-3: -Red bone marrow produces all red blood cells and platelets and around 60–70% of lymphocytes in human adults. Other lymphocytes begin life in red bone marrow and become fully formed in the lymphatic tissues, including the thymus, spleen, and lymph nodes.

Detailed explanation-4: -B cells (sometimes called B-lymphocytes and often named on lab reports as CD19 or CD20 cells) are specialized cells of the immune system whose major function is to produce antibodies (also known as immunoglobulins or gamma-globulins). B cells develop in the bone marrow from stem cells.

Detailed explanation-5: -Lymphocytes include natural killer cells (which function in cell-mediated, cytotoxic innate immunity), T cells (for cell-mediated, cytotoxic adaptive immunity), and B cells (for humoral, antibody-driven adaptive immunity). They are the main type of cell found in lymph, which prompted the name “lymphocyte".