In the described path, what is the pressure at the venules?

• A. 0 mmHg
• B. 15 mmHg
• C. 110 mmHg
• D. 5 mmHg

Answer: (B)

The pressure in the microcirculation falls as blood moves through the capillary bed, from a higher value on the arterial side to a lower value on the venous side. By the time blood reaches the venular portion of the pathway, the capillary hydrostatic pressure is typically about 15 mmHg. This reflects the venous end of the capillary bed where pressures are low enough to help return blood toward the heart, yet are not zero. So, in the described path, the venules carry blood at roughly 15 mmHg.

Why the other numbers don’t fit here: 110 mmHg is arterial pressure and wouldn’t be present in venules; 0 mmHg would imply no driving pressure at all, which isn’t consistent with venular capillary pressures in the systemic bed; 5 mmHg is closer to central venous pressure and would not represent the venular end of capillaries in most descriptions of microcirculation.