Science

• Integumentary System


  A barrier that protects the internal structure of the body from injury and infection
• The integumentary system includes the skin and accessory structures such as nails, hair, and glands that perform important functions in the body
• Skin


  • Largest organ of the body, weighing twice the brain
  • Serves as protective cover for almost all of the body surface
• Layers of skin


  • Epidermis (outermost layer)
  • Dermis (middle layer)
  • Subcutaneous (innermost layer)
• Epidermis


  Outermost layer of the skin, appears scaly due to layers of flat and dead cells
• The epidermis, hair, and nails are made up of keratin
• The skin has tiny openings called pores through which sweat and oil leave the body
• Melanin


  Pigment found at the bottom of the epidermis that determines the color of the skin and protects it by absorbing ultraviolet rays from the sun
• People with darker complexions have more melanin and therefore have more protection from the sun
• Dermis


  Layer found below the epidermis, contains sweat glands, oil glands, hair follicles, and blood vessels
• Nerves


  Found in the dermis, essential for sensations such as touch, pain, heat, and pressure through the skin
• Sweat glands


  Function in perspiration
• Oil glands


  Function in the production of sebum
• Subcutaneous layer


  Layer of fat below the dermis, contains larger blood vessels and nerves, serves as storage for fat and insulation of heat
• The thickness of the subcutaneous layer differs from person to person and varies depending on its location in the body
• Hair


  Made up of keratin, most of the hair is dead and keratinized, only the hair bulb at the bottom is living
• Functions of hair


  • Filters dust particles in the nose and ears
  • Deflects sweat to protect the eyes
  • Reduces the skin's exposure to UV rays
  • Protects the head and skull from abrasion
• Melanin


  Determines the color of the hair, more melanin results in darker hair color
• As people grow older, less melanin is produced, resulting in gray and white hair
• Nails


  Also made of keratin, formed from the root of the epidermis, protect the sensitive fingertips and toes from injury and help in sensing the environment
• Sweat glands


  Help in the excretion of wastes by releasing excess water and salts, also function in the regulation of body temperature
• Oil glands (sebaceous glands)


  Secrete an oily substance called sebum that lubricates and waterproofs the surface of the skin and hair
• Too much production of sebum may clog the pores and produce organisms that may lead to infection, resulting in pimples and blemishes
• Ways to take care of the skin

  • Bathing regularly to keep the skin healthy and clear
  • Eating the right kinds of food to preserve the integrity of the skin and promote general wellness
  • Staying away from harmful substances
• Sunburns and skin cancer may be prevented by wearing protective clothing such as hats and by appropriately applying sunscreen