Human lymphatic system MCQ - Practice Questions with Answers

Human lymphatic system  

• When blood flows through the capillaries, some blood oozes out and this is known as Tissue fluid (Interstitial fluid)
• Tissue fluid is colourless fluid and contains white blood cells
• This fluid is collected by the Lymphatic system and returned to the Blood circulation
• Thus tissue fluid as it enters the Lympatic system is termed as Lymph (Lymph is clear fluid)
• Thus the movement of lymph in body is facilitated by lymphatic system
• Lymphatic system of humans comprises of lymphatic capillaries, lymphatic vessels, lymphatic ducts and lymphatic nodes

1. Lymphatic capillaries

• These capillaries are thin-walled, small and are composed of a single layer of endothelial cells
• Lymphatic capillaries lie close to blood capillaries
• The lymphatic capillaries of intestinal regions, which absorb the digested fats are called lacteals.

2. Lymphatic vessels

• Lymphatic capillaries unite to form a larger lymphatic vessels.
• Lymphatic vessels are composed of an outer coat of fibrous tissue, middle coat of muscular tissue and an inner lining of endothelial cells
• The lymphatic vessels have numerous valves

3. Lymphatic ducts

• Lymph vessels of left and right side of the body combines to form left lymphatic duct and right lymphatic duct respectively
• The left lymphatic duct discharges its lymph into the left subclavian vein and right lymphatic duct discharges its lymph into right subclavian duct

4. Lymphatic tissues

• Lymph nodes and Lymph organs are Lymphatic tissues
• Lymph nodes are oval or bean shaped structures located along the length of lymphatic vessels.
• Lymphatic nodes are 1-25 mm long and are covered by a capsule of dense connective tissue
• Lymph filters through the lymph nodes
• Lymph nodes also contain phagocytic WBCs and macrophages which consume microorganisms and foreign particles from the lymph
• Thymus, Spleen and Tonsils are Lymphatic organs and these also help to filter out pathogens

Movement of lymph

• Lymph moves slowly from lymphatic vessels, lymphatic ducts to venous system
• Blockage in the movement of lymph causes edema or swelling.
• Lymph movements are facilitated via muscular movements