Integumentary System Bozeman science

• Integumentary system


  Skin, hair, and nails
• Functions of the integumentary system


  • Offers protection
  • Keeps bacteria and foreign objects out
  • Allows sensations like touch and pain
  • Allows thermoregulation
• Skin is the largest organ in the body
• Epidermis


  The top layer of skin
• Tattoo placement


  Ink must be placed underneath the epidermis
• Layers of the epidermis


  • Stratum basale
  • Stratum spinosum
  • Stratum granulosum
  • Stratum lucidum
  • Stratum corneum
• Stratum basale


  Where mitosis occurs to create new cells that migrate upwards
• Stratum spinosum


  Contains melanocytes that produce melanin
• Stratum granulosum


  Cells become compressed as they move upwards
• Stratum lucidum


  Only found in thick skin like palms and soles
• Stratum corneum


  Layer of dead cells that are constantly replaced from below
• Dermis


  Layer below the epidermis, contains blood vessels, glands, and receptors
• Structures in the dermis


  • Capillaries
  • Sweat glands
  • Sebaceous glands
  • Nerve receptors
• Hypodermis


  Layer below the dermis, contains connective tissue and fat cells
• Accessory structures


  • Hair
  • Nails
• Hair formation


  1. Capillaries in the papilla

  2. Matrix of cells constantly producing new hair

  3. Hair made of dead keratin-filled cells
• Nail formation


  1. Matrix of cells at the base producing new nail

  2. Nail made of keratin-filled dead cells

  3. Eponychium forms the cuticle
• Nails evolved from claws in other organisms
• Layers of the skin


  • Epidermis
  • Dermis
  • Hypodermis
• The integumentary system has four-fold importance