AP BIOLOGY

Detailed explanation-1: -The extracellular fluid, in particular the interstitial fluid, constitutes the body’s internal environment that bathes all of the cells in the body.

Detailed explanation-2: -Interstitial fluid, or simply tissue fluid, is a mixture of water, ions, and small solutes that are forced out of the blood plasma by the systolic pressure created when the heart pumps.

Detailed explanation-3: -Extracellular fluid (ECF) surrounds all cells in the body. Extracellular fluid has two primary constituents: the fluid component of the blood (called plasma) and the interstitial fluid (IF) that surrounds all cells not in the blood (Figure 2).

Detailed explanation-4: -Composition. Interstitial fluid consists of a water solvent containing amino acids, sugars, fatty acids, coenzymes, hormones, neurotransmitters, salts, as well as waste products from the cells. The composition of tissue fluid depends upon the exchanges between the cells in the tissue and the blood.