Which of the following statements is FALSE? Antibodies mark antigens for destruction. Only lymph nodes filter lymph. T lymphocytes originate from the red bone marrow. The thymus consists mainly of lymphoid tissue.
The Correct Answer and Explanation is:
The FALSE statement is: “Only lymph nodes filter lymph.”
Explanation:
- Antibodies mark antigens for destruction: This is true. Antibodies are proteins produced by B lymphocytes (a type of white blood cell) that specifically bind to antigens (foreign molecules) like bacteria, viruses, or toxins. By binding to these antigens, antibodies tag them for destruction by other immune cells, such as macrophages or killer T cells. This is part of the body’s adaptive immune response.
- Only lymph nodes filter lymph: This is false. Lymph nodes are not the only structures that filter lymph. While lymph nodes play a major role in filtering lymph and trapping pathogens or foreign particles, other lymphoid tissues such as the spleen and mucosa-associated lymphoid tissues (MALT) (e.g., tonsils, Peyer’s patches) also filter lymph or related bodily fluids. The spleen, for example, filters blood and removes damaged cells and pathogens, while MALT is involved in mucosal immunity.
- T lymphocytes originate from the red bone marrow: This is true. T lymphocytes, or T cells, originate in the red bone marrow from hematopoietic stem cells. However, they mature in the thymus where they undergo a selection process to ensure they can recognize foreign antigens without attacking the body’s own tissues.
- The thymus consists mainly of lymphoid tissue: This is true. The thymus is an organ that is primarily composed of lymphoid tissue, which plays a critical role in the development of T lymphocytes. It is located just behind the sternum and is crucial for immune function during childhood and adolescence.
In summary, lymph nodes are important for filtering lymph, but they are not the only structures with this function. The spleen and MALT also contribute to immune surveillance.
