INTEGUMENTARY SYSTEM

• Integumentary System


  Organ consisting of skin and accessory structures
• Accessory Skin Structures


  • Hair
  • Nails
  • Sweat Glands

  
• Hair


  Composed of dead keratinized cells, provides insulation and UV protection
• Hair Structure


  1. Shaft (visible)

  2. Root (below)

  3. Follicle (supports hair and growth)

  4. Bulb (produces hair from matrix cells, connected to blood supply)

  
• Hair Color


  Melanocytes in hair bulb produce varying amounts and types of melanin (black-brown and red)
• Hair Muscles


  Arrector pili (smooth muscle), contraction causes hair to "stand on end"
• what does the nail consist of ?

  Consist of nail root and body, grow continuously unlike hair

  
• Nail Matrix


  Cells that give rise to the nail

  
• Sebaceous Glands


  Exocrine glands that secrete oily/waxy sebum to prevent drying and inhibit bacteria
• Exceptions for sebaceous glands

  • Lips
  • Glands of eyelids
  • Genitalia
  • Hands
  • Feet

  
• Eccrine Sweat Glands


  Open directly onto skin surface, produce isotonic fluid for temperature regulation

  
• Apocrine Sweat Glands


  Usually open into hair follicles, secrete organic compounds that become odiferous when acted on by bacteria

  
• Ceruminous Glands


  Produce earwax (cerumen) to prevent dirt/insects and keep eardrum supple
• Mammary Glands


  Modified apocrine sweat glands that produce milk to feed young
• Integumentary system has many functions and is vital in maintaining homeostasis, linking with other systems
• Temperature Regulation


  1. Hypothalamus monitors and controls temperature

  2. Arterioles in dermis change diameter to regulate blood flow and temperature

  
• Vitamin D


  Can be acquired from diet or produced photochemically from cholesterol in skin, controlled by parathyroid hormone (PTH)
• Vitamin D and Calcium Functions

  • Control calcium levels
  • Bone formation, growth, repair
  • Clotting
  • Nerve and muscle function
• Vitamin D deficiency can lead to softening of bones and increased risk of fractures (rickets, osteomalacia, osteoporosis)
• Effects of Aging on Integumentary System

  • Skin more easily damaged
  • Wrinkling occurs
  • Skin becomes drier
  • Skin infections more likely
  • Sunlight ages skin more rapidly
  • Decrease in blood supply causes poor temperature regulation
  • Changes in melanocyte function causes age spots
• Skin Cancer Types


  • Basal cell cancer
  • Squamous cell cancer
  • Melanoma
• Basal and squamous cell cancers are often caught early and rarely fatal, while melanoma can progress rapidly and is responsible for 75% of skin cancer deaths
• ABCDE Assessment of Melanoma

  • A=Asymmetrical
  • B=Borders
  • C=Color (variegated)
  • D=Diameter
  • E=Evolving (any change)