What type of pressure tends to push water out of blood vessels?

Hydrostatic pressure is the correct answer because it refers to the force exerted by the fluid within the blood vessels against the vessel walls. This pressure plays a crucial role in the movement of fluids; specifically, it pushes water and solutes out of the blood and into the interstitial space surrounding cells. This process is essential for nutrient delivery and waste removal at the capillary level.

In contrast, osmotic pressure primarily governs the movement of water into blood vessels rather than out of them, as it relates to the concentration of solutes in the blood. Atmospheric pressure is the weight of the air around us and does not directly influence fluid movement out of blood vessels. Intrathoracic pressure is related to the pressure within the thoracic cavity and primarily affects breathing and circulation mechanics rather than fluid exchange across capillary walls. Thus, hydrodynamic forces are primarily responsible for pushing fluid out from thevascular system, with hydrostatic pressure playing a major role in this process.