IMMUNOLOGY

Detailed explanation-1: -The thymus gland is the primary lymphoid organ for lymphocyte development. The red bone marrow produces B-lymphocytes (B cells) and T lymphocytes (T cells). B cells achieve immunocompetence (ability to recognize a specific antigen) in bone marrow. T cells migrate to the thymus gland, where they become immunocompetent.

Detailed explanation-2: -These lymphocytes develop immunocompetence in the primary lymphoid organs: thymus, for the T lymphocytes and bursa of Fabricius (in birds), on its equivalent (in mammals), for B lymphocytes.

Detailed explanation-3: -The primary function of the thymus gland is to train special white blood cells called T-lymphocytes or T-cells. White blood cells (lymphocytes) travel from your bone marrow to your thymus. The lymphocytes mature and become specialized T-cells in your thymus. After the T-cells have matured, they enter your bloodstream.

Detailed explanation-4: -T cells comprise the largest percentage of lymphocytes. These cells originate in the bone marrow, and then migrate to the thymus to become immunocompetent, or activated. When properly stimulated, T cells differentiate into several different cell types that will attack antigens and increase the body’s immune response.

Detailed explanation-5: -T lymphocytes develop from a common lymphoid progenitor in the bone marrow that also gives rise to B lymphocytes, but those progeny destined to give rise to T cells leave the bone marrow and migrate to the thymus (see Fig. 7.2). This is the reason they are called thymus-dependent (T) lymphocytes or T cells.