Consider the following statements regarding the human lymphatic system: 1. The thoracic duct is the main vessel of the lymphatic system that drains lymph from the lower limbs, abdomen, and left side of the thorax. 2. The spleen acts as a primary lymphoid organ where B-lymphocytes undergo maturation and clonal selection. Which of the statements given above is/are correct?

💡 Solution & Explanation

The thoracic duct collects lymph from the lower body and the entire left upper quadrant, emptying it into the left subclavian vein, making the first statement accurate. The spleen is a secondary lymphoid organ, not a primary one; bone marrow and the thymus serve as primary lymphoid organs where lymphocytes originate and mature. Secondary lymphoid organs such as lymph nodes, spleen, and mucosa-associated lymphoid tissue provide sites for interaction between antigens and immunocompetent lymphocytes. Understanding lymphatic drainage pathways is essential for comprehending metastasis routes in clinical pathology.