A Level Biology Practice Exam

Where do T lymphocytes mature in the body?

1. Spleen

2. Bone marrow

3. Thymus gland

4. Lymph nodes

The correct answer is: Thymus gland

T lymphocytes, or T cells, mature in the thymus gland. The thymus is essential for the development and maturation of these cells, where they undergo a process that enables them to recognize and respond to specific antigens. During their maturation in the thymus, T cells also learn to differentiate between self and non-self, which is crucial for them to function properly in the immune system and avoid attacking the body's own cells. In contrast, the spleen, bone marrow, and lymph nodes play different roles in the immune system. The bone marrow is where T cells originate from their precursor cells before they migrate to the thymus for maturation. The spleen filters blood and helps mount immune responses to blood-borne pathogens, while lymph nodes act as sites for immune cell activation and proliferation, primarily for B cells. Thus, the thymus gland is distinctly recognized as the site for T cell maturation.