Question

Explain why a superficial skin scrape (such as a paper cut) doesn't blood. why don't you bleed when a hair is pulled out?

Answer 1

Answer:

Because they are avascular.

Explanation:

Superficial skin does not have adequate blood supply so it does not bleed and this is reason why a cut on the superficial skin or when a hair is  pulled dose not results in bleeding.

It involves the epidermal part of the skin which is not properly supplied with blood vessels. So any cut or hair pulling from this region has no bleeding.

Answer 2

Basically because your skin has several layers to it (see link, below), and the layer that has the blood vessels capable of bleeding in it is further down than a superficial scrape would affect.