The Integumentary System

• Integumentary system


  Set of organs that forms the external covering of the body, includes the hair, nails and skin
• Integumentary system


  • Communication - sensory receptors notify the brain
  • Secretion - skin provides moisture
  • Protection - from harmful micro-organisms and chemicals
• Epidermis


  • Tough layer - flat dead cells
  • Clear layer - flat dead cells
  • Granular layer - Granular cells
  • Spiny layer - Keratinocytes make cells hard
  • Base - Alive cells
• Epidermis


  • Keratinocytes - epidermal cells that undergo keratinization (hardening process)
  • Melanocytes - specialized cells that produce melanin
• Factors affecting skin color

  • Melanin - more melanin, darker skin color
  • Carotenoid - olive tint
  • Hemoglobin - reddish or pinkish tint

  
• Skin conditions


  • Freckles - uneven distribution of melanin
  • Mole - localized concentration of melanin
  • Albino - an individual that cannot produce melanin
• Dermis


  • Sweat gland - produces sweat
  • Pores - openings
  • Sweat ducts - tubes
  • Sebaceous gland - produces sebum
  • Blackheads - excess oil
  • Arrector pili - "goose-bumps"
  • Hair follicle - manufactures hair
  • Nerve endings - sense pain, touch, pressure, and temperature
• Subcutaneous layer


  • Fatty tissue
  • Binds the skin in underlying organs
  • Insulator and shock absorber
• Tanning results from increased melanin production to protect the skin from harmful UV rays
• Sunburn is a painful inflammation due to too much exposure to sunlight