Integumentary System and Body Temperature (Chap. 7)

  1. Integumentary System
    • Skin
    • Accessory structures (sweat and oil glands, hair and nails)
    • subcutaneous tissue
  2. Integumentary Functions
    • Two-way mechanical barrier
    • Protects internal structures and organs
    • Secretes important fluids
    • Houses sensory receptors
    • Temperature regulation
    • Immune response
    • Acts as a gland by synthesizing vitamin D
  3. Cutaneous Membrane
    • Skin=Largest Organ in the body
    • Two Layers: Epidermis (outer/surface layer) and Dermis (inner layer anchored to subcutaneous layer)
  4. Epidermis
    • Thin outer layer of the skin
    • Composed of stratified squamous epithelium
    • Avascular
    • Five layers
  5. Stratum Germinativum
    • lies on top of the dermis
    • has access to blood supply
    • layer in which cell division takes place (2 layers)
  6. Keratin
    • A tough protein
    • Hardens and flattens the cells as they move toward the surface of the skin
    • Waterproofing
  7. Stratum Corneum
    • Surface layer of epidermis
    • 30 layers of dead cells
  8. Dermis
    • Lies on the subcutaneous tissue under the epidermis
    • Largest portion of the skin
    • Composed of dense fibrous tissue
    • Contains collagen and elastic fibers (skin stretches)
    • Thickness depends on where its located in body
    • accessory structures (hair, nails, glands, blood vessels, nerves and muscle tissue)
  9. Herpes Zoster
    an inflammation of nerves caused by the chickenpox virus develops painful skin lesions along the path of the nerve
  10. Subcutaneous Layer
    • NOT considered part of the skin, it lies under the skin (Hypodermis)
    • Composed of loose connective and adipose tissue
    • Acts as insulator, (Prevents heat loss)
    • Anchors the dermis to underlying structures
  11. Skin Color
    • Determined by many factors (genetic, physiologic, disease)
    • Melanin causes skin to darken (melanocytes)
    • Carotene causes skin to appear yellow
    • Amount of blood in the skin affects color (e.g. flushing)
    • Cyanosis skin turns blue due to poor oxygenated
    • Jaundice usually seen in babies (yellow skin) too much bilirubin
  12. Vitilgo and Albinism
    • Vitilgo; loss of pigment (melanin) in certain areas of the skin, patches of white skin
    • Albinism; melanocytes completely fail to secrete melanin, leaving hair, eyes, and skin white
  13. Hair
    • Unevenly distributed (sparse) over the skin
    • Main function of sparseness: sense insects on the skin before they can sting us
    • Somebody parts are hairless (palms of hands, soles of feet, lips, etc.)
    • Eyelashes and eyebrows protect eyes from dust and perspiration
    • Nasal hairs trap dust and prevent it from being inhaled into the lungs
    • Hair on scalp keeps us warm
  14. Hair growth and color
    • Growth is influenced by sex hormones: estrogen and testosterone
    • Color is determined by: the amount and type of melanin
  15. Hair shaft and root
    • Chief parts of hair
    • Shaft; part above the surface of the skin
    • Shaft shape also determines hair shape (flat shaft-curly, oval shaft-wavy, round shaft-straight)
    • Root; extends from the dermis to the surface
  16. Arrector Pili
    • Group of smooth muscles attached to the end of a hair follicle
    • Contraction of these muscles causes the hair to stand on the end
    • Goosebumps
  17. Hair Loss
    • Alopecia; loss of hair
    • Hereditary condition
    • Toxins
  18. Nails
    • Thin plates of stratified squamous epithelial cells that contain keratin
    • Structures include: free edge, nail body, and nail root.
  19. Glands
    • Two major exocrine glands
    • Sebaceous- oil glands, associated with hair follicles, secrete sebum
    • Sebum lubricates and helps waterproof the hair and skin and inhibits growth of bacteria on surface 
    • Sudoriferous-Sweat glands, located in the dermis, secrets sweat.
    • Apocrine sweat secreted by hair follicles and axillary/genital areas. 
    • Eccrine sweat glands located throughout the body but not associated with hair follicles
  20. Body Temperature
    • Normal body temp: 98.6°F (97-100°F okay)
    • Maintained by balancing (thermoregulation) heat production and heat loss.
  21. Heat production
    • produced by metabolizing cells
    • produced by muscles and the liver
  22. Heat Loss
    • 80% of heat is lost through the skin
    • Radiation-heat is lost from a warm object (body) to cooler air surrounding it.
    • Conduction- loss of heat from warm object to a cooler object when it comes in contact
    • Convection-loss of heat by air currents moving over the surface of the skin
    • Evaporation-when a liquid becomes a gas (ex. sweat)
  23. Heat regulation
    • Normal body temp. is set by body thermostat in the hypothalamus.
    • Heat is lost through sweating and vasodilation
    • Heat is conserved by vasoconstriction and produced by shivering
  24. Burned Skin
    • Classification: Thickness of burn, Partial (first and second degree) and Full (third degree) burns. Rule of nines to evaluate burns (%)
    • Short term effects: fluid and electrolyte losses, shock, inability to regulate body
    • Long term effects: scarring-loss of function
  25. Eschar
    • Dead burned tissue, forms a thick, inflexible, scablike layer over burned surface
    • Breeding ground for bacteria
    • Escharotomy
  26. Aging Skin
    • Thinning epidermis
    • Melanocytes decrease
    • Dermis becomes thinner
    • Skin becomes more fragile
    • Subcutaneous tissue circulation decreases
    • Adipose tissue decreases in subcutaneous layer.
Card Set
Integumentary System and Body Temperature (Chap. 7)
NURS151 Chapter 7