where does diffusion take place in our body
Diffusion An example of a situation in which bulk motion and diffusion can be differentiated is the mechanism by which oxygen enters the body during external respiration known as breathing. The lungs are located in the thoracic cavity, which expands as the first step in external respiration. This expansion leads to an increase in volume of the alveoli in the lungs, which causes a decrease in pressure in the alveoli. This creates a pressure gradient between the air outside the body at relatively high pressure and the alveoli at relatively low pressure. The air moves down the pressure gradient through the airways of the lungs and into the alveoli until the pressure of the air and that in the alveoli are equal i.e. the movement of air by bulk flow stops once there is no longer a pressure gradient.
Cellular waste product H2O also diffuses out of the cell into the blood stream, from where it is excreted in the form of perspiration, water vapor in breath, or urine from the kidneys. Water, along with some dissolved solutes, are removed from blood circulation in the nephrons of the kidney and eventually excreted as urine.[12]