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## Integumentary System **Connective Tissue** * Contains primarily collagen fibers, as well as elastic and reticular fibers. * Also contains motile cells called dendritic cells. * Contains blood vessels, sweat glands, sebaceous glands, hair follicles, nail roots, nerve endings and smooth muscle t...

## Integumentary System **Connective Tissue** * Contains primarily collagen fibers, as well as elastic and reticular fibers. * Also contains motile cells called dendritic cells. * Contains blood vessels, sweat glands, sebaceous glands, hair follicles, nail roots, nerve endings and smooth muscle tissue. **Two Major Regions** * *Superficial papillary layer* * *Deeper reticular layer* ### Papillary Layer * Superficial region of the dermis. * Composed of areolar connective tissue. * Contains projections called dermal papillae. * Dermal papillae interdigitate with epidermal ridges. * Dermal papillae contain capillaries that supply nutrients to the epidermis. * Contain sensory nerve endings that function as tactile receptors. ### Reticular Layer * Forms the deeper portion of the dermis. * Extends from papillary layer to the subcutaneous layer. * Composed of dense irregular connective tissue. * Contains collagen fibers that extend in all directions. * Collagen fibers are interwoven into a meshwork. * Surrounds structures such as hair follicles, sebaceous glands, sweat glands, nerves and blood vessels. **Learning Strategy 6.2** Use egg crate foam to understand how the epidermal ridges and dermal papillae interlock. One layer represents epidermal ridges, and another layer represents dermal papillae. Place the layers together so that the projections of one layer interlock with the depressions (valleys) of the other. ### Figure 6.6: Layers of the Dermis * Image (a) shows the dermis lying deep to the epidermis, with the papillary layer and reticular layer. ### Figure 6.6 Images * Image (b) shows an electron micrograph of the papillary layer. * Image (c) shows an electron micrograph of the reticular layer.