Unlike the epidermis, which is composed mainly of cells, the dermis has few cells and is composed mainly of connective tissue fibers — collagen fibers and a small amount of elastic fibers. The dermis functions as the matrix to support the epidermis, both structurally through its collagen and elastic fibers and nutritionally through its abundant blood vessels.
Layers of the Dermis
The entire dermis ranges in thickness from 0.5 to 1.0 mm, and is subdivided into: papillary dermis, and reticular dermis, which is further subdivided into the upper reticular dermis, mid-dermis, and lower reticular dermis. The papillary dermis, which lies immediately below the epidermis, has vertically oriented connective tissue fibers and a rich supply of blood vessels.
Below the papillary dermis is the thicker, major layer of the dermis, the reticular dermis. It extends from the base of the papillary dermis to the subcutaneous fat layer and is composed of thick collagen bundles, elastic fibers that are densely packed and arranged mostly parallel to the skin surface and the glycosaminoglycans (GAGs) of the extracellular matrix. The reticular dermis is the layer that is responsible for the amazing strength and elasticity of the skin (see Table 1-1).
It is the junction of the papillary dermis with the underlying reticular dermis that is called the immediate reticular dermis (IRD) which represents the maximum depth for the Designed Blue Peel.
Dermal Components (Table 1-1)
| Fibroblasts | Key cells of the dermis producing collagen, elastin, and extracellular matrix |
| Collagen | Provides tensile strength and the firm “feel” of skin Elastic fiber network Provides normal skin tension (tightness) and elasticity (the “snap-back” of skin) |
| Extracellular matrix (GAGs) | High water-binding capacity produces tone and turgor (fullness) in tissues and resistance to compression; Helps in stretching ability |