In a skeletal muscle capillary, the capillary hydrostatic pressure $\left(\mathrm{P}_{\mathrm{c}}\right)$ is $32 \mathrm{~mm} \mathrm{Hg}$, the capillary oncotic pressure $\left(\pi_{\mathrm{c}}\right)$ is $27 \mathrm{~mm} \mathrm{Hg}$, and the interstitial hydrostatic pressure $\left(\mathrm{P}_{\mathrm{i}}\right)$ is $2 \mathrm{~mm} \mathrm{Hg}$. Interstitial oncotic pressure $\left(\pi_{\mathrm{i}}\right)$ is negligible. What is the driving force across the capillary wall, and will it favor filtration or absorption?

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Quizplus · Accepted Answer

[Chapter 3, VII C]. The driving force is calculated from the Starling forces across the capillary wall. The net pressure $=\left(\mathrm{P}_{\mathrm{c}}-\mathrm{P}_{\mathrm{i}}\right)-\left(\pi_{\mathrm{c}}-\pi_{\mathrm{i}}\right)$. Therefore, net pressure $=$ $(32 \mathrm{~mm} \mathrm{Hg}-2 \mathrm{~mm} \mathrm{Hg})-(27 \mathrm{~mm} \mathrm{Hg})=+3 \mathrm{~mm} \mathrm{Hg}$. Because the sign of the net pressure is positive, filtration is favored.

In a Skeletal Muscle Capillary, the Capillary Hydrostatic Pressure (Pc)\left(\mathrm{P}_{\mathrm{c}}\right)(Pc​) Is 32 mmHg32 \mathrm{~mm} \mathrm{Hg}32 mmHg

In a Skeletal Muscle Capillary, the Capillary Hydrostatic Pressure $\left(\mathrm{P}_{\mathrm{c}}\right)$ Is $32 \mathrm{~mm} \mathrm{Hg}$