Jibmit intestines for food, glands for hormones) and delivered to the cells that need them. They are pretty small -- about 5 um in diameter. out of the capillary equal flows into and out of the capillary Capillaries Arteriole Venule 1 point Now consider a capillary inside a muscle. The muscle has done work and used up its oxygen. The concentration of oxygen inside the capillary is 1 million molecules per cubic micrometer, and the concentration of oxygen in the fluid surrounding the muscle is 0.3 million molecules per cubic micrometer. Which way will be the net flow of oxygen across the muscle tissue membrane? into the capillary Artery Tissue cells Vein capillaries out of the capillary O equal flows into and out of the capillary One of the interesting questions about this process is: how do oxygen molecules know where to go? For example, Wikipedia says that red blood cells "take up oxygen in the lungs or gills and release it while squeezing through the body's 1 point capillaries". In order to consider this, let's make a simplified model in which oxygen Suppose the membrane of the alveolus is 8.0 nm thick, and the diffusion constant diffuses into the blood stream in the lungs and is carried by fluid flow out to the for oxygen through the membrane is 6.4 x 10-3 um2/s. Using the concentrations cells where it diffuses out. (In reality, the oxygen is bound to hemoglobin, carried, given above, calculate the particle flux of oxygen through the membrane of the and released, but the beginning and end processes are as described here.) alveolus in units of number of molecules per square micrometer per second. Type your