Only dermis is vascularized. Nutrients reach epidermis by diffusing through the tissue from the blood vessels. Underneath dermis is hypodermis (superficial fascia), also called subcutaneous tissue which is composed of loose connective tissue (mostly areolar and adipose).
A collagen dressing is a type of wound dressing that is made with a form of collagen to aid in the body's healing processes. Collagen is a category of structural proteins that are naturally present in almost every part of the human body and are especially common in connective tissue.
Collagen and Silicone Dressings. Collagen is the main protein involved in the connectuve tissues found in animals. It is most common in areas such as tendons, ligaments, and skin. These dressings contain collagen and, when in contact with the skin, attract cells to the wound which aid in new tissue formation, thus healing the wound faster.