When a person is lying flat, venous pressure is generally at its:

When a person is lying flat, venous pressure is generally at its:

• A. Highest
• B. Lowest
• C. Moderate
• D. Variable

Answer: (B)

When lying flat, gravity’s effect on the venous system is minimized, so the hydrostatic pressure that blood experiences along the veins is at its smallest. This means the pressure in the venous system, including central veins near the heart, is at its lowest. If you were standing, a vertical column of blood would place a larger hydrostatic load on the leg veins, raising their venous pressure and promoting pooling. So the supine position yields the lowest venous pressure, with higher pressures occurring as you move upright.

When lying flat, gravity’s effect on the venous system is minimized, so the hydrostatic pressure that blood experiences along the veins is at its smallest. This means the pressure in the venous system, including central veins near the heart, is at its lowest. If you were standing, a vertical column of blood would place a larger hydrostatic load on the leg veins, raising their venous pressure and promoting pooling. So the supine position yields the lowest venous pressure, with higher pressures occurring as you move upright.