Capillary permeability affects the rate of distribution such that...

Capillary permeability affects the rate of distribution such that...

• A. Higher permeability slows distribution
• B. Lower permeability speeds distribution
• C. Lower permeability lowers rate of distribution
• D. No effect of permeability on distribution rate

Answer: (C)

Capillary walls determine how easily a drug can move from blood into tissue. The rate at which distribution happens depends on this ease of crossing, described by a permeability factor in diffusion. The more permeable the capillary walls, the faster the drug can diffuse into the interstitium; the less permeable, the slower the distribution. So when permeability is reduced, the rate of distribution decreases, which is why lowering permeability lowers the distribution rate. This concept sits alongside other factors like blood flow, but permeability specifically sets how quickly the drug can cross the capillary barrier.

Capillary walls determine how easily a drug can move from blood into tissue. The rate at which distribution happens depends on this ease of crossing, described by a permeability factor in diffusion. The more permeable the capillary walls, the faster the drug can diffuse into the interstitium; the less permeable, the slower the distribution. So when permeability is reduced, the rate of distribution decreases, which is why lowering permeability lowers the distribution rate. This concept sits alongside other factors like blood flow, but permeability specifically sets how quickly the drug can cross the capillary barrier.