Integumentary System Is Comprised of the Skin

Integumentary system is comprised of the skin and skin derivatives including hair, nails, glands and receptors. Skin, glands and receptors have many important functions that will be described in this paper (The integumentary system (skin)):

Protects the body's internal living tissues and organs

Protects against invasion by infectious organisms

Protects the body from dehydration

Acts as a receptor for touch, pressure, pain, heat and cold

Protects the body against abrupt changes in temperature

Stores water, fat, and vitamin D

Helps dispose of waste materials

However, hair and nails serve little purpose for humans and will not be discussed (Introduction to Anatomy and Physiology).

The skins keeps the inside structures in and outside substances out (Introduction to Anatomy and Physiology). Its strength and pliability make it very tough to outside physical forces. Keratin is a protein in skin cells that makes skin water repellant thereby providing resistance to many chemicals. Acidic skin secretions also help resist chemical damage and prevent bacterial growth. And, the skin protects the body from ultraviolet radiation damage. Coloration cells in the skin are called melanocytes. Exposure to sunlight increases the production of the pigment melanin in the Epidermis (thin outer layer of skin), creating a suntan. This darkening of the skin helps shield the cell nucleus from ultraviolet damage. Sebum, secreted by the skin prevents our bodies from evaporating too much water through the skin and helps prevent dehydration.

Because the skin contains several types of sensory receptors, it serves as the gateway through which sensations such as pressure, heat, cold, and pain are transmitted to the nervous system (Integumentary system). When the body temperature rises, the hypothalamus sends a nerve signal to the sweat-producing skin glands, causing them to release one to two liters of water per hour to cool the body. The hypothalamus also causes dilation of the blood vessels of the skin which allows more blood to flow into those areas, causing heat to be convected away from the skin surface to also cool the body. In contrast, when body temperature falls, the sweat glands constrict and sweat production decreases. If the body temperature continues to fall to a certain point, the body will engage in thermiogenesis, or heat generation, by raising the body's metabolic rate and by shivering. Deeper within the skin than heat and cold receptors are Meissner's corpuscles, which are especially common in the tips of the fingers and lips, and are very sensitive to touch. Pacinian corpuscles respond to pressure.

The metabolism of Vitamin D, a vitamin essential for proper bone growth and normal cell growth, is yet another important function of the skin (Introduction to Anatomy and Physiology). When the skin is exposed to ultraviolet rays in sunlight, a form of cholesterol is eventually transformed into Vitamin D Vitamin D is the only vitamin that can be produced by the body.