IMMUNOLOGY

Detailed explanation-1: -Primary lymphoid organs: These organs include the bone marrow and the thymus. They create special immune system cells called lymphocytes. Secondary lymphoid organs: These organs include the lymph nodes, the spleen, the tonsils and certain tissue in various mucous membrane layers in the body (for instance in the bowel).

Detailed explanation-2: -The tissues and organs that produce, store, and carry white blood cells that fight infections and other diseases. This system includes the bone marrow, spleen, thymus, lymph nodes, and lymphatic vessels (a network of thin tubes that carry lymph and white blood cells).

Detailed explanation-3: -Since the function of the lymphoid organs is to filter and trap invading pathogens and present them to immune competent cells, the high levels of viremia seen following primary infection presumably lead to an efficient infection of the lymphoid tissue with HIV or SIV.

Detailed explanation-4: -There are three major types of lymphoid cells: B-cells, T-cells, and Natural Killer (NK) cells.

Detailed explanation-5: -The lymphoid organs in the human body include the spleen, lymph nodes, bone marrow, thymus and lymph tissue. Lymph nodes-These are small, bean-shaped structures which produce and store cells, specialized in fighting infections. They are a part of the lymphatic system.

Detailed explanation-6: -The spleen is the largest lymphatic organ in the body.