Q.Given below are some human organs. Identify one primary and one secondary lymphoid organ. Explain its role. Liver, thymus, stomach, thyroid, tonsils

Step 1. Liver, stomach and thyroid are not lymphoid organs at all — they are digestive/endocrine organs, so they can be set aside.

Step 2. The thymus is a primary (central) lymphoid organ: it provides the protected environment in which immature T cells (thymocytes) mature into immunocompetent T cells, driven by the hormone thymosin.

Step 3. The tonsils are a secondary (peripheral) lymphoid organ: as paired tissue masses at the back of the throat, they are part of the lymphatic system that traps and fights invading bacteria and viruses entering through the mouth and throat. …

Classify each listed organ as lymphoid or non-lymphoid, then sort the lymphoid ones i …

• Mistaking the thyroid (an endocrine gland) for a lymphoid organ because the name sounds similar to 'thymus' …