A & P 1 Integumentary System

Consists of

  • Cutaneous membrane
  • Epidermis and Dermis
  • Accessory structures
  • Subcutaneous layer

Functions of the skin

  1. Protection
  2. Excretion – sweat and sebum
  3. Temperature maintenance – sweating and shivering
  4. Nutrient storage
  5. Vitamin D3 synthesis – from the sun
  6. Sensory detection – sensations from the outside world

Integumentary System Components.

Epidermis – composed of layers of keratinocytes

  • Thin skin – four layers (strata)
  • Thick skin – five layers

Layers of the Epidermis

  • Stratum Corneum
  • Stratum lucidum
  • Stratun granulosum
  • Stratum Spinosum
  • Stratum germinativum – basale

The structure of the Epidermis

  • Keratinocyte , Cells accumulate keratin and eventually are she
  • Epidermal ridges are interlocked with dermal papillae
  • Fingerprints and improves gripping ability
  • Langerhans cells (immunity) in s. spinosum
  • Merkel cells (sensitivity) is s. germinativum (basale)

Skin color depends on

  • Blood supply
  • Carotene (from fruits) and melanin
  • Melanocytes produce melanin and protect from UV radiation.
  • Epidermal pigmentation
  • Interrupted blood supply leads to cyanosis

Stretch Marks

  • Caused by excessive stretching of the dermis
  • Patterns of collagen and elastic fibers from lines of cleavage

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