INTEGUMENTARY SYSTEM THE FUNCTIONS

SEVEN FUNCTIONS OF THE SKIN 1. Protection 2. Regulation of body temperature 3. Manufactures vitamin D 4. Sensory perception 5. Storage 6. Sun screen 7. Absorption

1. PROTECTION Intact skin is the best protection Skin generally too dry for microbial growth Most skin bacteria associated with hair follicles or sweat glands Best way to prevent the spread of disease is handwashing

2. BODY TEMPERATURE Regulates temperature by controlling the amount of heat loss Evaporation of water from the skin, in the form of perspiration, helps rid the body of excess heat

3. VITAMIN D Ultraviolet light from the sun onto the skin is necessary for the first stages of vitamin D formation

4. SENSORY PERCEPTION Skin is the site of many nerve endings A square inch of skin contains about 72 feet of nerves and hundreds of receptors Look at figure 5-1 on page 72

5. STORAGE Skin has tissues for the temporary storage of fat, glucose, water, and salts Most of these substances are later absorbed by the blood and transported to other parts of the body

6. SUN SCREEN Skin is designed to screen out harmful UV radiation contained in sunlight

7. ABSORPTION Skin has special properties to absorb certain drugs and other chemical substances Allows us to apply drugs locally (such as applying hydrocortisone for rashes) or we can apply medications that can be absorbed through the skin and have a general effect on the body (such as Nitro-Bid paste or Nitro patch) Question: what does Nitro-Bid or a Nitro patch do?

GLANDS Sudoriferous/Sweat Glands Perspiration is 99% water with only small quantities of salt and organic materials (waste products) Distributed over the entire skin surface Large numbers under the arms, and on the palms of the hands, soles of the feet, and forehead Perspiration is excreted through the pores Activated by heat, pain, fever, and nervousness and other factors Underarm odor: caused by bacteria mixed with sweat Lose an average of 500mL of water a day through the skin (but varies according to exercise and environmental temperature)

Sebaceous/Oil Sebum: thick, oily substance that protects the skin; lubricates the skin, keeping it soft and pliable Sebum is secreted by the sebaceous glands Sebum contains amino acids, lactic acids, lipids, salt, and urea