Final answer:
Continuous drainage during injection is called closed-circuit drainage; it is not related to the biological processes of capillary osmosis, passive drainage, or gravity drainage.
Step-by-step explanation:
Continuous drainage during injection is referred to as closed-circuit drainage. This process occurs in the medical field, particularly in surgeries where fluids need to be continuously removed from the body to prevent accumulation. None of the other options provided—capillary osmosis, passive drainage, or gravity drainage—accurately describe this process. Closed-circuit drainage systems typically utilize mechanical means to ensure the constant removal of fluids, maintaining a safe and controlled environment during medical procedures. It's important to differentiate this from the concept of osmotic pressure, which is the net pressure driving reabsorption of fluid from the interstitial fluid back into the capillaries, influenced by the solute-to-water concentration gradients in the blood and tissue fluid. The key pressures in capillary exchange are hydrostatic pressure, driving fluid out, and osmotic pressure, drawing fluid back in.