Q.Distinguish between: Blood and lymph.

The lymphatic system consists of lymph, lymphatic vessels, and associated lymphoid organs/tissue. Lymph is a fluid connective tissue much like blood plasma but without RBCs, platelets and some larger plasma proteins; it forms when interstitial fluid from the tissue spaces enters blind-ended lymphatic capillaries, travels through progressively larger lymphatic vessels (filtered along the way by lymph nodes), and finally drains back into the blood via the thoracic duct and right lymphatic duct, both emptying into the subclavian vein.

Lymphoid tissue and lymph nodes are spread widely through the body — the thymus gland, tonsils and cervical nodes near the head/neck, axillary nodes under the arms, the appendix, spleen, red bone marrow, and inguinal/popliteal nodes in the groin/behind the knee. Tonsils (normally five, in the pharyngeal region) intercept inhaled/ingested foreign material; their inflammation (tonsillitis, viral or bacterial) causes sore throat, fever, swollen nodes, congestion and difficulty swallowing, treated with antibiotics if bacterial or, if unresponsive, ton …