The chemical composition of blood is primarily controlled by the kidneys through filtration, secretion and adsorption of components between the organ and the blood. when the kidneys do not function properly, the blood has to be regulated artificially. dialysis machines are used to filter blood externally, by taking blood from the body, and sending it through a series of semi-permeable membranes. these membranes have a molecular cut-off range that allows solutes to pass out of the blood without proteins and cells. substances in the blood move from an area of high concentration to an area of low concentration. as blood flows across one side of a semi-permeable membrane, a dialysate flows on the opposite side in the opposite direction to attract and collect solutes as they pass the membrane. assume the in-flow of blood has a stable solute concentration and that the dialysate is constantly refreshed. a. designing a model consider a simplified, focused region in the dialysis machine, where we are only concerned with diffusion of solutes from one portion of a cylindrical tube transporting blood. assume this tube a semi-permeable membrane. 1. first, draw a sketch of your model with appropriate labels. include a coordinate axis and appropriate labels for variables. 2. write down at least 3 assumptions for your model. 3. develop a conservation law for the system (begin with a given equation; cancel out variables until it is describes the simplified system you have developed above). 4. what are the boundary conditions for your model? 5. what are the extensive properties to be accounted for in this regulatory process?