Where in the integumentary system are blood vessels found, and how do these vessels react when the body is cold? epidermis; the blood vessels contract. epidermis; the blood vessels dilate. dermis; the blood vessels dilate. dermis; the blood vessels contract?

In Integumentary system blood vessels are found in dermis and the blood vessels contract when the body is cold.
Dermis and epidermis are layers of the skin, dermis is the thick layer of tissues and it is present under the epidermis layer.
When we feel cold, our body supplies the warm blood to the skin. When contraction of blood vessels occurs, it reduces the flow of warm blood and reduces the heat loss. When we feel hot, blood vessels dilate.

This is the most closely resembles the model.