Layer 2 - The Dermis
The dermis also varies in thickness depending on the location of the skin. It is .3 mm on the eyelid and 3.0 mm on the back. The dermis is composed of three types of tissue that are present throughout - not in layers.
The types of tissue are:
- Collagen
- Elastic tissue
- Reticular fibers
The two layers of the dermis are the papillary and reticular layers.
- The upper, papillary layer, contains a thin arrangement of collagen fibers.
- The lower, reticular layer, is thicker and made of thick collagen fibers that are arranged parallel to the surface of the skin.
The dermis contains many specialized cells and structures.
- The hair follicles are situated here with the erector pili muscle that attaches to each follicle.
- Sebaceous (oil) glands and apocrine (scent) glands are associated with the follicle.
- This layer also contains eccrine (sweat) glands, but they are not associated with hair follicles.
- Blood vessels and nerves course through this layer. The nerves transmit sensations of pain, itch, and temperature.
- There are also specialized nerve cells called Meissner's and Vater-Pacini corpuscles that transmit the sensations of touch and pressure.