Physiology

• Integumentary system


  Protective barrier
• Protein


  Basic building block for body tissues
• Appendages


  • Hair
  • Nails
  • Sweat glands
  • Oil glands
• Everyone has the same number of melanocytes
• Epidermis is thinner than the dermis
• Scar tissue lacks hair and sweat glands
• Characteristics of healthy skin

  • Moist
  • Soft
  • Smooth
  • Somewhat Acidic
• Functions of the skin

  • Sensation
  • Heating & Cooling (Temperature Regulation)
  • Absorption
  • Protection
  • Excretion
  • Secretion
• Sensation


  Perceive changes in our environment, such as heat, cold, touch, pain, and pressure
• Sensory nerve fibers are most abundant in the fingertips and are designed to be one of the most sensitive parts of the body
• Protection


  The barrier function is the skins mechanism that's protects us from irritation and transepidermal water loss
• Transepidermal water loss


  Water loss caused by evaporation on the skins surface
• Hydrolipidic Film


  Film to protect the skin from drying out and from exposure to external factors that could damage it
• Acid Mantle


  Has an average PH of 5.5
• Epidermal growth Factor


  Stimulate skin cells to reproduce and heal
• Heat Regulation


  Maintains thermoregulation through evaporation, perspiration, radiation and insulation
• Average body temp of 98.6 F or 37 C
• When cold


  1. Arrector pili muscles attached to hair follicles contract and cause "goosebumps"

  2. Shivering: automatic response to cold and a way to warm up the body
• Excretion


  Sudoriferous Glands (sweat glands) serve to prevent the body from over heating
• Secretion


  Sebum is an oily substance that protects the surface of skin and lubricate both the skin and hair
• Sebaceous Glands


  Oil gland, appendage to the skin
• Absorption


  Absorption of chemicals, hormones, moisture, and oxygen is need for healthy skin
• Vitamin D synthesize and produce upon skin exposure
• Smaller Molecular size can penetrate the skin
• Subcutaneous Tissue


  Also known as hypodermis or superficial fascia
• Subcutaneous layer


  • Composed of loose connective tissue or subcutis tissue
  • Made of 80% fat
• Dermis


  Also called the Derma, corium, cutis or true skin
• Dermis


  • Support layer of connective tissue above the hypodermis
  • Made of collagen protein and elastin fibers
  • 25 times thicker than epidermis
• Reticular Layer


  Denser and deeper layer of the dermis, made of mainly collagen and elastin
• Papillary Layer


  Connects dermis to epidermis
• Dermal papillae


  • Membranes of ridges and grooves that attach to the epidermis
• Hair papillae


  Small cone shaped structures at the bottom of the hair follicle
• Collagen


  Protein substance of complex fibers that gives Strength and is necessary for wound healing
• Collagen makes up 70% of the dermis
• Fibroblast cells


  Produce proteins and aid in the production of collagen and elastin
• Elastin


  Fibrous protein that forms elastic tissue and gives skin its elasticity
• Glycosaminoglycans (GAG)


  Large protein molecules and water binding substances found between the fibers of the dermis
• Hyaluronic Acid


  Hydrating fluid that are part of dermal substance and is a glycosaminoglycan
• Lymph vessels


  Remove waste products, bacteria, and excess fluid
• Cells found in the dermis

  • Fibroblasts (call stimulators)
  • Lymphocytes (infection fighters)
  • Langerhans cells (guard cells)
  • Mast cells (involved in allergic reactions)
  • Leukocytes (white blood cells to fight off infection)