MIDTERM- INTEGUMENTARY

• PARTS OF THE SKIN

  Epidermis

  Dermis
• EPIDERMIS - outermost layer of the skin, composed of keratinized stratified squamous epithelium.
• Epidermis four principal cells


  keratinocytes (90%)

  melanocytes (8%)

  intraepidermal macrophages

  tactile epithelial tissue
• layers of epidermis

  stratum Basale

  stratum spinosum

  stratum granulosum

  stratum lucidum

  stratum corneum
• stratum basale


  Deepest layer, composed of single row of cuboidal or columnar keratinocytes that contain scattered keratin intermediate filaments (tonofilaments); stem cells undergo cell division to produce new keratinocytes; melanocytes and tactile epithelial cells associated with tactile discs are scattered among keratinocytes
• stratum spinosum

  Eight to ten rows of many-sided keratinocytes with bundles of keratin intermediate filaments; contains projections of melanocytes and intraepidermal macrophages
• stratum granulosum

  Three to five rows of flattened keratinocytes, in which organelles are beginning to degenerate; cells contain the protein keratohyalin (converts keratin intermediate filaments into keratin) and lamellar granules (release lipid-rich, water-repellent secretion).
• stratum lucidum


  Present only in skin of fingertips, palms, and soles; consists of four to six rows of clear, flat, dead keratinocytes with large amounts of keratin
• stratum corneum


  Few to fifty or more rows of dead, flat keratinocytes that contain mostly keratin
• keratinization


  Newly formed cells in the stratum Basale are slowly pushed to the surface and accumulate more and more keratin
• epidermal growth factor


  Regulates growth and skin cell division
• regions of dermis

  papillary region

  reticular region
• papillary region


  Superficial portion of dermis (about one-fifth); consists of areolar connective tissue with thin collagen and fine elastic fibers; contains dermal ridges that house blood capillaries, corpuscles of touch, and free nerve endings
• reticular region


  Deeper portion of dermis (about four-fifths); consists of dense irregular connective tissue with bundles of thick collagen and some coarse elastic fibers. Spaces between fibers contain some adipose cells, hair follicles, nerves, sebaceous glands, and sudoriferous glands
• skin receptors


  free nerve ending

  pacinian corpuscles

  merkel's corpuscles

  meisnner's corpuscles

  krausse end-bulb

  ruffini's corpuscles
• accessory organs of the skin

  hair

  skin glands

  nails
• types of hair

  lanugo-fetal hair

  terminal hairs

  vellus hair
• color of hair

  eumelanin

  pheomelanin

  few melanin

  no melanin
• skin glands

  sebaceous gland

  sudoiferous gland

  ceruminous gland
• nails

  nail matrix

  nail root

  eponychium or cuticle

  lunula

  nail bed

  nail body

  free edge

  hyponychium
• nail matrix


  production of new cells in nails
• eponychium


  stratum corneum of epidermis
• nail bed

  skin below the nail bed
• nail body


  contains hard keratin
• free edge


  extension of the nail
• hyponychium


  secures nail to the fingertips
• maintenance of homeostasis

  epidermal wound healing

  deep wound healing
• epidermal wound healing

  • Division in the stratum Basale and migration
  • Thickening of epidermis
  • Healing is halted if stratum Basale is damage
• deep wound healing

  inflammatory phase

  proliferative phase

  maturation phase
• Skin graft

  • Autograft
  • Allograft
  • Xenograft
• Autograft


  Skin grafting from the patient himself
• Allograft

  Skin graft from dead body or from another body
• Allograft


  Skin graft taken from a dead body