Integumentary

• What does integument mean?

  • covering
• Components of integumentary system:

  • skin
  • hair
  • nails
  • glands
• Functions of integumentary system:

  • Protection
  • Sensation
  • Temperature regulation
  • Excretion
  • Vitamin D production
• Skin weighs 9 lbs
• 2 Main regions of skin:

  • epidermis
  • dermis
• Epidermis - 1st major skin region (outside)
• Epidermis - skin region that is composed of stratified squamous epithelium
• Keratinization: process in which new cells (with keratin) push old cells to surface
• In keratinization, it takes 40-56 days for new cells to reach surface
• Layers of Epidermis:

  • Stratum corneum
  • Stratum lucideum
  • Stratum granulosum
  • Stratum spinosum
  • Stratum basale
• Stratum corneum:

  • outermost layer of epidermis
• Stratum corneum accounts for 75% of epidermal thickness
• Stratum corneum: this layer of epidermis is flaking off scalp called dandruff
• Callus: forms when stratum corneum has frequent friction
• Stratum basale: deepest layer of epidermis that has single layer and is firmly attached to dermis
• Dermis - 2nd major skin region
• Dermis:

  • Dense connective tissue
  • Contains collagen and elastic fibers
  • Contains fibroblasts, nerve endings, smooth muscle, glands, blood
• Cleavage lines:

  • area where skin is most resistant to stretching due to orientation of collagen fibers
  • important in scarring
• Layers of Dermis:

  • Papillary layer
  • Reticular layer
• Papillary layer: thin connective tissue layer that contains blood vessels
• Dermal papillae are the tiny projections on the epidermis that is ridged on hands and feet (fingerprints)
• Reticular layer: deepest layer of dermis and accounts for 80% of dermis
• Hypodermis - the layer of fatty tissue beneath the dermis
• Hypodermis: layer of skin that attaches skin to underlying muscle and bone
• Hypodermis contains loose and adipose tissue
• Body fat for females 20-23%, males 13-25%
• Skin Color and Variations is determined by:

  • pigments
  • genetics
  • blood circulation
  • thickness of stratum corneum
• All races have same number of melanocytes
• Melanin: produced by melanocytes
• albinism is absence of melanin
• melanin responsible for hair and eye color
• Carotene:

  yellow-orange pigment found in plants

  • accumulates in stratum corneum
• Hemoglobin:

  gives pinkish-red color

  • found in red blood cells
• Redness is a skin color caused by fever, hypertension, inflammation, allergies
• Pallor is a skin color caused by anemia or low blood pressure
• Jaundice is a skin color caused by liver disorder (yellow)
• Bronzing is a skin color caused by Addison’s disease (kidney disease)
• Bruising is a skin color caused by broken blood vessels
• Hair/shaft: flexible strands of keratinized cells
• Root: hair component that is below skin (scalp)