Which of the following favors filtration at the arteriolar end of the capillary bed?
**Core Concept**
Filtration at the arteriolar end of the capillary bed is influenced by hydrostatic pressure and oncotic pressure. The arteriolar end of the capillary bed has higher hydrostatic pressure due to the influx of blood from the arteriole, which favors filtration.
**Why the Correct Answer is Right**
Filtration occurs when the hydrostatic pressure (pushing fluid out of the capillary) exceeds the oncotic pressure (pulling fluid into the capillary). At the arteriolar end of the capillary bed, the high hydrostatic pressure, generated by the resistance in the arteriole, pushes fluid out of the capillary into the interstitial space. This is a critical mechanism for the exchange of nutrients and waste products between the blood and the tissues.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not relevant to the question. The question is asking about the arteriolar end of the capillary bed, not the venous end.
* **Option B:** This option is incorrect because the arteriolar end of the capillary bed has higher hydrostatic pressure, which favors filtration, not the venous end which has higher oncotic pressure.
* **Option D:** This option is incorrect because the myogenic response is a mechanism that regulates arteriolar diameter in response to changes in blood pressure, but it does not directly influence filtration at the arteriolar end of the capillary bed.
**Clinical Pearl / High-Yield Fact**
The Starling forces, which include hydrostatic and oncotic pressures, play a crucial role in the regulation of fluid exchange between the capillary and the interstitial space. Understanding these forces is essential for appreciating the pathophysiology of edema and other fluid balance disorders.
**Correct Answer:** C.