What is the fluid that bathes and nourishes the cells of the body tissue called?

• A. Interstitial
• B. Lymphatic
• C. Thymus
• D. Plasma

Answer: (A)

The fluid that bathes and nourishes the cells is interstitial fluid. This fluid fills the spaces between cells, forming part of the extracellular fluid that surrounds body tissues. It originates mainly from plasma that filters out of capillaries, and its composition is similar to plasma but with fewer large proteins. Interstitial fluid delivers oxygen and nutrients to cells and provides a medium through which waste products can diffuse away to be removed. It also helps maintain tissue hydration and the small pressure gradients that support microcirculation. When interstitial fluid drains into lymphatic vessels, it becomes lymph and is returned to the bloodstream, but it’s the interstitial fluid in the tissue spaces that directly nourishes cells. The other options aren’t the fluid bathing tissues: plasma stays within blood vessels, lymph is the fluid once interstitial fluid enters the lymphatic system, thymus is an organ, and lymphatic is a drainage system rather than the fluid that directly nourishes cells.