Final answer:
Superficial capillaries are intact capillaries that disappear when the area is blanched, distinguishing them from petechiae. Fenestrated capillaries have pores that make them permeable to larger molecules, while petechiae are small spots on the skin caused by damaged vessels.
Step-by-step explanation:
Superficial capillaries are intact capillaries that are distinguished from petechiae if they disappear when the area is blanched. Fenestrated capillaries, on the other hand, have small pores in their endothelial lining that make them permeable to larger molecules, while petechiae are small red or purple spots on the skin that result from blood leaking out of damaged vessels. The disappearance of superficial capillaries when the area is blanched indicates that they are intact and functioning properly.