sir tamonan ppt

• 5 functions of the integumentary system

  > protection

  > sensation

  > temperature regulation

  > vitamin d production

  > excretion
• epidermis


  outermost region / resists abrasion / reduces water loss
• dermis 


  middle region / bulk of skin / responsible for the structural strength of the skin / produces leather (animal)
• hypodermis 


  subcutaneous tissue / deepest region / not really a part of the skin / connects the skin to muscle or bone
• epidermis 


  composed of five or four strata / produces vitamin D / gives rise to hair, nails, and glands
• stratum corneum


  superficial layer / 25 or more layers of dead squamous cells
• stratum lucidum


  3 - 5 layers of dead cells / appears transparent
• stratum granulosum 


  flattened diamond shaped cells / release of lipids
• stratum spinosum


  production of keratin fibers / formation of lamellar bodies
• stratum basale 


  single layer of cuboidal or columnar cells / attaches to dermis / production of cells of the stratum corneum
• dermis


  responsible for the structural strength and flexibility of the skin / composed of 2 layers

  1. papillary
  2. reticular
• papillary layer


  loose connective tissue
• reticular layer 


  dense irregular connective tissue / forms cleavage lines
• subcutaneous tissue 


  not part of the skin / loose connective tissue with abundant fat deposits
• keratinocytes 


  most abundant cell type / produces keratin / protects skin
• melanocytes 


  produces melanin / found in deepest layer of epidermis
• langerhans' cells 


  epidermal macrophages / help activate the immune system
• merkel cells 


  touch receptors
• stratum basale


  firmly attached to the dermis / consists of youngest keratinocytes / undergo mitotic divisions every 19 days / 10-25% are melanocytes
• stratum spinosum 


  melanin granules and langerhan's cells are abundant here
• stratum granulosum


  drastic changes in keratinocyte appearance / keratohyaline and lamellated bodies (waterproofing) accumulate / epithelial cells die above this layer because they are too far from the dermis
• stratum lucidum


  thin, transparent band / flat, dead keratinocytes / only in thick skin
• stratum corneum


  3/4 of the thickness of the epidermis / 20-30 layers thick, all dead cells / millions rub off everyday / totally new every 25-45 days
• thick skin have all five strata (true or false)


  true
• thin skin does not have stratum lucidum (t or f)


  true
• hair is only found in ________ skin?

  thin
• melanocytes produce melanin inside melanosomes
• erythema


  red skin color due to increased blood flow
• cyanosis


  bluish color
• carotene 


  can cause the skin to appear yellow
• dermis


  cell types include fibroblasts, adipose cells, and macrophages / composed of 2 layers
• papillary layer

  contains peg-like projections (dermal papillae) / contains blood vessels
• dermal papillae


  genetically determined / responsible for fingerprints and footprints
• reticular layer


  accounts for 80% of the thickness of the skin / striae are caused when skin is overstretched / produces cleavage or tension lines /
• striae 


  stretch marks
• subcutaneous tissue 


  deep / mostly adipose tissue / not really part of the skin / connects skin to muscles or bones / increases greatly as you gain weight
• lanugo 


  fetal hair
• terminal hairs


  thick, coarse hair on scalp, eyelids, eyebrows
• vellus hairs


  peach fuzz / thin, fine hair and shorter than terminal hair
• at puberty, vellus hairs can be replaced with

  terminal hairs