Papillary layer of dermis

Recommended video: Skin [38:23]

General histology of the skin.

The dermis is one of three layers of skin, along with the epidermis and hypodermis. The dermis also has two distinct layers: papillary and reticular layers. 

The papillary layer is a more superficial and significantly thinner layer of the dermis. It is mainly composed of areolar connective tissue and various types of cells that include fibroblasts, scattered mast cells, macrophages, and other leukocytes. The substance of this tissue consists mainly of type I and III collagen fibers. 

The papillary layer forms irregular projections known as the dermal papillae. They interlace with the epidermal ridges and contain small vessels organized in subpapillary vascular plexus. The papillae are less abundant and smaller in thin skin that has minimal mechanical stress, when compared to in areas of thicker skin (i.e., palms and soles) where they tend to form curved parallel lines.

The main function of the papillary layer is to provide the superficial dermal and epidermal layers with sufficient nutrients.