1. Oxygen and Carbon Dioxide Exchange in the Lungs: This is a prime example of diffusion. Oxygen from the inhaled air diffuses across the thin membrane of the alveoli (tiny air sacs in the lungs) into the bloodstream, while carbon dioxide from the blood diffuses into the alveoli to be exhaled. This difference in concentration drives the movement of these gases.
2. Nutrient Absorption in the Small Intestine: Once food is broken down, nutrients like glucose and amino acids need to move from the small intestine into the bloodstream. This happens primarily through diffusion. The concentration of these nutrients is higher in the small intestine than in the blood, so they move across the intestinal lining and into the bloodstream to be carried to the body's cells.
3. Waste Removal in the Kidneys: The kidneys filter waste products from the blood, and some of this waste removal involves osmosis. Water, for example, moves from the blood into the tubules of the kidneys, following the concentration gradient of solutes (like waste products). This process helps to regulate the volume and composition of our blood.
