The integument or skin constitutes an organ system with a variety of important functions.

Consisting of dermal and epidermal layers, the skin protects the body from various kinds of mechanical injury and constitutes the first line of defense against invasion of foreign organisms. With the various epidermal appendages (hair, nails, sweat glands, and sebaceous glands, skin is critical for maintaining the body's temperature and preventing desiccation.

The skin also contains many receptors for various kinds of sensory stimuli and represents the direct site of interaction between the body and the environment. In addition, skin has various metabolic functions, such as synthesis of vitamin D by cells of epidermis.

The protective, sensory, thermoregulatory and artistic platform functions of the integument are reflected in its complex morphology.

Learning Objectives:

• Understand the major layers and tissue components of skin and their functional significance.
• Recognize the different histological layers within the epidermis and how these relate to the process of keratinization and epidermal function.
• Understand the formation and function of various epidermal appendages such as hair and nails

The morphology of thick skin.