The uptake is the acquisition or entrance of a substance from the environment into the body, into an organ, into a tissue, into a cell, or into the body fluids by passage through a membrane or by other means as a result of any active or passive process - such as by respiration, ingestion, or absorbing it through the epidermis - without regard to its subsequent storage, metabolism, and excretion by that organism.

For more details see: absorption.