Which system returns interstitial fluid to the circulatory system and supports immune function?

Which system returns interstitial fluid to the circulatory system and supports immune function?

• A. Circulatory system
• B. Nervous system
• C. Lymphatic system
• D. Endocrine system

Answer: (C)

The lymphatic system is responsible for returning excess interstitial fluid to the circulatory system and supporting immune function. Interstitial fluid, which bathes tissues, is mostly reabsorbed by blood capillaries, but a portion enters lymphatic capillaries as lymph. This lymph travels through progressively larger lymphatic vessels, is filtered by lymph nodes where immune cells can detect and respond to pathogens, and then returns to the bloodstream, emptying into the subclavian veins via the thoracic duct (and the right lymphatic duct on the right). Lymphoid organs like the spleen and thymus coordinate immune responses, while lymph carries immune cells and antigens to monitor for invaders. The lymphatic system also helps absorb fats from the digestive tract through lacteals.

The lymphatic system is responsible for returning excess interstitial fluid to the circulatory system and supporting immune function. Interstitial fluid, which bathes tissues, is mostly reabsorbed by blood capillaries, but a portion enters lymphatic capillaries as lymph. This lymph travels through progressively larger lymphatic vessels, is filtered by lymph nodes where immune cells can detect and respond to pathogens, and then returns to the bloodstream, emptying into the subclavian veins via the thoracic duct (and the right lymphatic duct on the right). Lymphoid organs like the spleen and thymus coordinate immune responses, while lymph carries immune cells and antigens to monitor for invaders. The lymphatic system also helps absorb fats from the digestive tract through lacteals.