Final answer:
Facial flushing can be caused by the dilation of superficial arteries, increasing blood flow and warmth in the skin without affecting blood flow to the digestive system.
Step-by-step explanation:
One cause of facial flushing is the dilation of superficial arteries. When these arteries widen, increased blood flow warms the skin, causing a reddened appearance. This physiological reaction can also result in heat being dissipated into the air, which serves to regulate body temperature. Contrary to certain conditions where blood flow may be redirected, during facial flushing, the blood flow is not diverted away from the digestive system.
This can be seen as redness or a flushed appearance on the face. When the arteries dilate, more blood is brought to the skin's surface, causing the redness.