Integumentary

• Integumentary System

  • Skin and Its Appendages
  • Skin (cutaneous membrane)
  • Skin derivatives: Sweat glands, Oil glands, Hairs, Nails
  • Skin, hair, and nails
• Skin Structure

  • Epidermis – outer layer, Stratified squamous epithelium, Often keratinized (hardened by keratin)
  • Dermis, Dense connective tissue
  • Deep to dermis is the hypodermis, Not part of the skin, Anchors skin to underlying organs, Composed mostly of adipose tissue
• Skin Functions

  • Protects deeper tissues from: Mechanical damage, Chemical damage, Bacterial damage, Thermal damage, Ultraviolet radiation, Desiccation
  • Aids in heat regulation
  • Aids in excretion of urea and uric acid
  • Synthesizes vitamin D
• Function of body membranes

  1. Line or cover body surfaces

  2. Protect body surfaces

  3. Lubricate body surfaces
• Melanin


  Pigment (melanin) produced by melanocytes, Color is yellow to brown to black, Melanocytes are mostly in the stratum basale, Amount of melanin produced depends upon genetics and exposure to sunlight
• Dermis

  Two layers: Papillary layer (Projections called dermal papillae, Pain receptors, Capillary loops), Reticular layer (Blood vessels, Glands, Nerve receptors)
• Normal Skin Color Determinants

  • Melanin (Yellow, brown or black pigments), Carotene (Orange-yellow pigment from some vegetables), Hemoglobin (Red coloring from blood cells in dermis capillaries, Oxygen content determines red coloring)
• Appendages of the Skin

  • Sebaceous glands (Produce oil: Lubricant for skin; Kills bacteria, Ducts that empty into hair follicles, Glands activated at puberty, Acne – infection of sebaceous glands)
  • Sweat glands (Widely distributed in skin, Two types: Eccrine - Open via duct to pore on skin surface, Apocrine - Ducts empty into hair follicles)
  • Hair (Produced by hair bulb, hard keratinized epithelial cells, Melanocytes can provide pigment for color)
• Sweat and Its Function

  Mostly water, Some metabolic waste (urea, uric acid), Fatty acids and proteins (apocrine only), dissipate excess heat, Excretes waste products, Acidic nature inhibits bacteria growth, Odor is from associated bacteria, not fluid!
• Hair Anatomy

  Central medulla, Cortex surrounds medulla, Cuticle on outside of cortex, Most heavily keratinized
• Associated Hair Structures

  Hair follicle
• Hair


  • Produced by hair bulb
  • Hard keratinized epithelial cells
  • Melanocytes can provide pigment for color
• Only epidermis is damaged in burns, skin is red and swollen
• Severity of Burns:
• Associated Hair Structures

  • Hair follicle
  • Dermal and epidermal sheath surround hair root
  • Arrector pili
  • Sebaceous gland
  • Sweat gland
• Hair Anatomy

  • Central medulla
  • Cortex surrounds medulla
  • Cuticle on outside of cortex
  • Most heavily keratinized
• Burns

  1. Tissue damage & cell death

  2. Caused by heat, electricity, UV radiation, or chemicals

  3. Associated dangers: Dehydration, Electrolyte imbalance, Circulatory shock
• Skin Homeostatic Imbalances

  • Athlete's foot - caused by fungal infection
  • Boils and carbuncles - caused by bacterial infection
  • Cold sores - caused by virus
  • Allergies
  • Contact dermatitis - exposure cause allergic reaction
  • Impetigo - bacterial infection
  • Psoriasis - Cause unknown, Triggered by trauma, infection, stress
• Nails


  • Scale-like modifications of epidermis
  • Heavily keratinized
  • Lack of pigment makes them colorless
• Appendages of the Skin

  • Hair
  • Nails
• Apocrine sweat glands

  1. Dissipate excess heat

  2. Excretes waste products

  3. Acidic nature inhibits bacteria growth

  4. Odor is from associated bacteria, not fluid!
• 2nd degree burn: Epidermis and upper dermis are damaged, skin is red with blisters
• Critical Burns are considered if: >25% of body has 2nd degree burns, >10% of the body has 3rd degree burns, 3rd degree burns of the face, hands, or feet
• Skin Cancer is an abnormal cell mass, with Benign type not spreading and Malignant type metastasizing to other parts of the body. Skin cancer is the most common type of cancer
• 3rd degree burn: Destroys entire skin layer, burn is gray-white or black
• Malignant Melanoma is the most deadly of skin cancers, cancer of melanocytes, metastasizes rapidly to lymph and blood vessels, and detection uses the ABCD rule
• Basal Cell Carcinoma is the least malignant, most common, metastasizes to lymph nodes, and early removal allows a good chance of cure