Final answer:
The movement of fluids into and out of capillaries is facilitated by bulk flow, which involves filtration and reabsorption. Hydrostatic pressure and osmotic pressure interact to promote the movement of fluid along the length of the capillary.
Step-by-step explanation:
The movement of fluids into and out of capillaries is facilitated by bulk flow, which is driven by two pressure-driven mechanisms: filtration and reabsorption. Filtration occurs when fluid moves from an area of higher hydrostatic pressure in the capillary bed to an area of lower pressure in the tissues. Reabsorption, on the other hand, happens when fluid moves from an area of higher pressure in the tissues into an area of lower pressure in the capillaries.
The interaction of hydrostatic pressure and osmotic pressure is crucial in driving the movement of fluid. Hydrostatic pressure, also known as capillary blood pressure, is higher than the osmotic pressure at the arteriolar end of the capillary. This pressure forces plasma and nutrients out of the capillaries and into the surrounding tissues. At the venule end of the capillary, the hydrostatic pressure is lower than the osmotic pressure, causing the movement of fluid and cellular wastes from the tissues into the capillaries.