Homeostasis The body's process of maintaining a relatively constant internal environment, which is essential to survival. Osmotic pressure The force generated by a liquid against the wall of a vessel. Acid A substance that dissociates in solution and releases hydrogen ions. Buffer A substance that dissociates in solution and accepts hydrogen ions from the solution. Body fluids Any water-based liquids within the body. Base A substance that can stabilize the pH of a solution. Hydrostatic pressure The pressure needed to stop the flow of solvent across the selectively permeable membrane between two compartments. Electrolyte Compounds that dissociates in solution and form ions such as sodium, potassium, and calcium. ers Request Answer