tubular passage of mucous membrane and muscle extending about 8.3 meters from mouth to anus; functions in digestion and elimination

tubular passage of mucous membrane and muscle extending about 8.3 meters from mouth to anus; functions in digestion and elimination

tubular passage of mucous membrane and muscle extending about 8.3 meters from mouth to anus; functions in digestion and elimination

tubular passage of mucous membrane and muscle extending about 8.3 meters from mouth to anus; functions in digestion and elimination

transport of a substance (as a protein or drug) across a cell membrane against the concentration gradient; requires an expenditure of energy

transport of a substance (as a protein or drug) across a cell membrane against the concentration gradient; requires an expenditure of energy

transport of a substance (as a protein or drug) across a cell membrane against the concentration gradient; requires an expenditure of energy

either of the passages in the outer ear from the auricle to the tympanic membrane

receptors postulated to exist on nerve cell membranes of the sympathetic nervous system in order to explain the specificity of certain agents that affect only some sympathetic activities (such as vasoconstriction and relaxation of intestinal muscles and contraction of smooth muscles)

receptors postulated to exist on nerve cell membranes of the sympathetic nervous system in order to explain the specificity of certain agents that affect only some sympathetic activities (such as vasoconstriction and relaxation of intestinal muscles and contraction of smooth muscles)