INTEGUMENTARY SYSTEM

• What does integumentary mean?

  - COVERING
• FUNCTIONS:

  1. Protection
  2. Sensation
  3. Temperature regulation
  4. Excretion
  5. Vitamin D production
• PROTECTION - water loss, microbes, UV light
• SENSATION - hot, cold, pain pressure
• TEMPERATURE REGULATION - helps maintain homeostasis
• EXCRETION -removes waste
• VITAMIN D PRODUCTION - UV light stimulates production
• SKIN FACTS

  • weighs 9 lbs.
  • Used to determine body fat
  • 2 main regions: EPIDERMIS and DERMIS
• EPIDERMIS

  • 1st major skin region (outside)
  • Composed of stratified squamous epithelial
• KERATINIZATION

  • Process in which new cells (with keratin) push old cells to surface
  • 40-56 days for new cells to reach surface
• STRATA OF EPIDERMIS

  1. Stratum corneum
  2. callus
  3. Stratum basale
• STRATUM CORNEUM

  • outermost layer of epidermis
  • 20-30 layes of dead squamous cells filled with keratin
  • accounts for 75% of epidermal thickness
• DANDRUFF - is this layer flaking off scalp
• CALLUS - froms when stratum corneum has frequent friction
• STRATUM BASALE

  • deepest layer of epidermis
  • single layer of cells
  • firmly attached to dermis
• DERMIS

  • 2nd major skin region
  • dense connective tissue
  • contains collagen and elastic fibers
  • contains fibroblasts, nerve endings, smooth muscle, glands, blood vessels, and hair follicles
• CLEAVAGE LINES

  • area ehre skin is most resistant to stretching
  • important in scarring
• LAYERS OF DERMIS

  1. Papillary layer
  2. Dermal papillae
  3. Reticular layer
• PAPILLARY LAYER - thin connective tissue layer that contains blood vessels
• DERMAL PAPILLAE

  • projections that extend up into epidermis
  • remove waste and help regulate body temp.
  • ridged on hands and feet (fingerprints)
  • pattern is genetically determine
• RETICULAR LAYER

  • deppest layer of dermis
  • accounts for 80% of dermis
• HYPODERMIS - Subqutaneous Glands

  • below dermis
  • foundation of skin
  • attaches skin to underlying muscle and bone
  • Contains 1/2 of body's fat
  • BOdy fat for females 20-23%, males 13-25%
• SKIN COLOR AND VARIATIONS

  Determined by:

  • pigments
  • genetics
  • blood circulation
  • thickness of stratum corneum
• SKIN PIGMENTS

  MELANIN:

  • produced by MELANOCYTES
  • ranges from yellow to reddish-brown to black
  • responsible for hair and eye color
  • albinism is absence of melanin
• CAROTENE - yellow-range pigment found in plants

  accumulates in stratum corneum
• HEMOGLOBIN

  • gives pinkish-red color
  • found in RBC
• SKIN COLOR AND DISEASE

  REDNESS - fever, hypertension, inflammation, allergies

  PALLOR - anemia or low blood pressure

  JAUNDICE - liver disorder (yellow)

  BRONZING - Addison's diseae (kidney disease)

  BRUISING - broken blood vessels
• VITILIGO - loss of melanocytes
• ALBINISM - lack of melanin production
• NEVI/MOLES - benign tumors of melanocytes
• MELASMA - dark patches on face due to hormonal changes
• ECZEMA - chronic skin condition characterized by dryness, redness, itching, and flaky patches of skin.
• MELANOCYTIC NEVI - brown to black spots on skin
• DERMATOSIS HERPETIFORMIS - autoimmune skin condition that causes itchy blisters on the face, scalp, arms, legs, and torso.
• ROSACEA - redness caused by dilation of capillaries
• PSORIASIS - scaly lesions on the scalp, elbows, knees, and trunk
• ACNE - common skin condition caused by excess oil and bacteria leading to pimples, blackheads, and whiteheads.
• HAIR COMPONENTS

  1. Hair/shaft
  2. Root
  3. Hair Bulb
  4. Hair Follicle
• HAIR/SHAFT - flexible strand of keratinized cells
• ROOT - below skin scalp