Florida State Paramedic Practice Exam

What is the term for the movement of water and dissolved substances from an area of high pressure to low pressure?

1. Diffusion

2. Osmosis

3. Filtration

4. Reabsorption

The correct answer is: Filtration

The term for the movement of water and dissolved substances from an area of high pressure to low pressure is filtration. This process occurs when a fluid moves through a semi-permeable membrane or porous material, allowing for the separation of substances based on pressure gradients. Filtration is a critical physiological process, particularly in the kidneys, where it plays a vital role in urine formation. Blood pressure in the glomeruli facilitates the filtration of water and solutes into the tubules, effectively removing waste products from the bloodstream while retaining cells and large proteins. In contrast, diffusion refers to the movement of molecules from an area of higher concentration to an area of lower concentration, which is more about concentration gradients rather than pressure gradients. Osmosis specifically deals with the movement of water through a selectively permeable membrane, driven by differences in solute concentration rather than pressure. Reabsorption is the process by which substances are taken back into the bloodstream after being filtered, which does not inherently address the movement driven by pressure differences. By understanding filtration, one can appreciate its significance in maintaining homeostasis and the body's ability to regulate various substances effectively.