In a capillary, $\mathrm{P}_{\mathrm{c}}$ is $30 \mathrm{~mm} \mathrm{Hg}, \mathrm{P}_{\mathrm{i}}$ is $-2 \mathrm{~mm} \mathrm{Hg}$, $\pi_{\mathrm{c}}$ is $25 \mathrm{~mm} \mathrm{Hg}$, and $\pi_{\mathrm{i}}$ is $2 \mathrm{~mm} \mathrm{Hg}$.
-What is the direction of fluid movement and the net driving force?

Question

Quizplus · Accepted Answer

[VII C 1]. The net driving force can be calculated with the Starling equation
$$\begin{aligned}
\text { Net pressure } & =\left(\mathrm{P}_{\mathrm{c}}-\mathrm{P}_{\mathrm{i}}\right)-\left(\pi_{\mathrm{c}}-\pi_{\mathrm{i}}\right) \
& =[(30-(-2))-(25-2)] \mathrm{mm} \mathrm{Hg} \
& =32 \mathrm{~mm} \mathrm{Hg}-23 \mathrm{~mm} \mathrm{Hg} \
& =+9 \mathrm{~mm} \mathrm{Hg}
\end{aligned}$$
Because the net pressure is positive, filtration out of the capillary will occur.

In a Capillary Pc\mathrm{P}_{\mathrm{c}}Pc​ Is 30 mmHg,Pi30 \mathrm{~mm} \mathrm{Hg}, \mathrm{P}_{\mathrm{i}}30 mmHg,Pi​ Is −2 mmHg-2 \mathrm{~mm} \mathrm{Hg}−2 mmHg

In a Capillary $\mathrm{P}_{\mathrm{c}}$ Is $30 \mathrm{~mm} \mathrm{Hg}, \mathrm{P}_{\mathrm{i}}$ Is $-2 \mathrm{~mm} \mathrm{Hg}$