8_The_Integumentary_System-schoolwires by qingyunliuliu


									               Ever Wonder?
   Why you stink when you sweat?
   How your hair or nails grow?
   How hair dye works?
   Why you get tan in the summer & lose it in the winter?
   If tanning booths are safer than laying out?
   What SPF is & how it helps prevent skin cancer?
   Why your hair stands up when you are scared or cold?
   Why your face gets red when you work out or become
   What a “zit” is?
The Integumentary System
                    Be able to
                    identify the basic
                    structures within &
                    layers of skin
                    Describe the
                    functions of the
                    parts & layers of

                    Cross-section of skin
   There are so many interesting, controversial & cutting-
    edge topics when it comes to the Integumentary System!

   In replacement of an Integumentary System Exam
    (60 pts), your group will be responsible for researching &
    presenting information in a Power Point presentation
    to the class later during this unit (day before Fall Break).
      You will have multiple quizzes throughout the unit & you
       will see the information in the lecture notes on your
       Semester Exam!
   Rubric that will be used…each criterion is worth 10 pts.
      Minimum of 10 NEAT, ORGANIZED & CLEAR Power
       Point slides
      MLA Format with Proper Citation
      Minimum of 5 graphics
      Define the topic using anatomical/Integumentary
       terminology & location
      Minimum of 2 statistical analyses via graph or raw
      All group members actively participated in the
               (Basic Characteristics)
   Waterproof
   Stretchable
   Washable
   Invisibly repairs small cuts, rips, and burns
   Guaranteed to last a lifetime with reasonable care
   Weighs on average between 9-11 lbs. (approx. 7%-15%
    of total body weight)
   Measures between 1.5-4 mm thick
   Thick skin – area where stratum corneum (layer of
    epidermis) is increased
          Does not have hair follicles or oil glands
   One last interesting FACTOID about skin:
       Every square centimeter of skin contains…
          70 cm of blood vessels,
          55 cm of nerves,
          100 sweat glands,
          15 oil glands,
          230 sensory receptors, and
          approximately 500,000 cells that are constantly dying and being
   Function:
       Protection
   Structure:
       Composed of two major regions: epidermis & dermis
 Composed of epithelial cells
  (stratified squamous)
 Outermost layer
 Not vascular
 Made up of 4 types of cells
 Consists of 4-5 distinct layers
 New epidermis is regenerated
  every 25-45 days
   4 Types of Cells:                        Cells of
            Produce keratin, the fibrous
             protein that helps give the
             epidermis its protective
       Melanocytes
            Synthesize pigment called
            Melanin picked up by
             keratinocytes &
             used to shade their nuclei
             from UV radiation
       Merkel cells
            Combo of Merkel cell &
             nerve ending (called Merkel
             disc) functions as a sensory
             receptor for touch
       Langerhans’ cells
            Macrophages that help to
             activate immune system
             Layers of Epidermis
   In thick skin (soles
    of feet & palms of
    hands) there are 5
    layers (strata);
    everywhere else
    has 4
   Deep to
       Stratum
       S. spinosum
       S. granulosum
       S. lucidum (only present in thick skin)
       S. corneum
            Strong, flexible connective
Dermis       tissue
            Cell types:
                Fibroblasts
                Macrophages
                Mast cells
                White blood cells
            Binds the entire body
                Your HIDE
            Innervated, vascularized
            Hair follicles, oil glands &
             sweat glands
            2 major layers:
                Papillary layer
                Reticular layer
Papillary Layer
 Highly vascularized
 Borders the stratum basale
  of epidermis
 Superior portion covered with
  dermal papillae, which house
  blood capillaries
 Touch & pain receptors
 On palms & soles, these
  papillae lie atop dermal ridges,
  which produce whorled
  epidermal ridges
               Reticular Layer
   Deep to papillary layer
     ~80%   of dermis
   Made up of dense irregular connective tissue
    (matrix consist of high quantities of collagen
     This high concentration helps dermis from being
      easily penetrated
 Collagen binds water, helping to hydrate the
 Elastin fibers give skin elasticity
Extreme  stretching of skin can tear
dermis (stretch marks) - striae
Short-term   trauma can cause a blister
to form (fluid sac that forms between
epidermis & dermis)
Flexure   lines – dermal folds that occur
at or near joints where dermis is tightly
attached to deeper underlying structures
              Known as subcutaneous
               tissue or superficial fascia
              Structure:
                    Has more adipose than dermis
                Functions:
                  Energy reservoir
                  Thermal insulation

                Hypodermic injections
                    Into subcutaneous tissue since
Hypodermis           highly vascular
Subcutaneous Fat Distribution
                             Mid-

                             Outer

                             Buttocks

                             Breasts
       Yellow-orange pigment
        found in certain plant
       Accumulates in stratum
        corneum & in adipose
        tissue of hypodermis
       Most obvious in palms &
        soles where S. cornuem
        is thickest
   Red pigment of red
    blood cells (RBCs)

   Since Caucasian people
    contain relatively small
    amounts of melanin,
    their skin is nearly
    transparent which
    allows hemoglobin’s
    color to shine through
   Appendages of the Skin
 Sweat  glands
 Oil glands
 Hair
 Nails
          Sweat Glands
 Exist all over skin except
  nipples & part of external
  genitalia (more than 2.5
 2 types:
       Eccrine & apocrine
Eccrine Sweat Glands
           Much more numerous
           Most abundant on
            palms, soles & forehead
           Structurally simple:
               Coiled tubular gland
               Secretory part lies coiled
                in dermis
               Duct opens in pore at
                skin’s surface
Eccrine Sweat Glands
         What   is sweat?
           99%   water, with some
            salts, vitamin C,
            antibodies, traces of
            urea, uric acid, ammonia
           Also contains lactic acid,
            which is the chemical
            that attracts mosquitoes
           Normally of pH 4-6
Apocrine Sweat Glands
            Most common in armpit &
             anogenital regions
            Larger than eccrine glands
            Ducts empty into hair follicles
            Apocrine secretion has generally
             same composition as normal
             sweat, however it has fatty
             acids & proteins which makes it
             more viscous
            Odorless, however, when
             decomposed by bacteria on skin
             a “Body Odor” is created
         Ceruminous Glands
 Modified apocrine
  glands found in the
  lining of external ear
 Secrete sticky cerumen
       Thought to deter insects
        (bitter flavor) & block
        entry of foreign particles
Mammary Glands
      Specialized apocrine sweat gland that
       secretes milk
      Exist in both men & women
          Males – little mammary tissue
             Male lactation – most commonly caused
              by hormonal treatments given to men
              suffering from prostate cancer
             Female hormones are used to slow
              production of cancerous tissue
          Females – milk develops with increase of
           hormones when pregnant & after birth
             Prolactin
             Progesterone
             Estrogen
            Sebaceous (Oil) Glands
   Found all over the body
    EXCEPT palms & soles
     Small – body trunk & limbs
     Large – face, neck & upper chest

 They secrete oily secretion
  called sebum
 Sebum softens & lubricates the
  hair & skin
     Prevents them from becoming
     Slows water loss from skin
    Sebaceous Glands
 Sebum kills bacteria
 If a sebaceous gland duct
  becomes blocked by accumulated sebum, a
  whitehead forms
 If this material oxidizes & dries,
  it turns into a blackhead
 Acne is an active inflammation of
  sebaceous glands accompanied
  by pimples (pustules) on the skin
       Usually caused by bacterial infection
              Hairs & Hair Follicles
   Main functions of our body
    hair = sensory reception
    and protection
   Main functions of hair on
    scalp = protect head from
    physical trauma, heat loss,
   Eyelashes = protect eyes
   Nosehair = filter
                   Characteristics of
                    Human Hair
                  Hair found almost everywhere
                   on the body
richard.har           Differences between sexes or
e.dsl.pipex.           individuals = texture & color of hair
                  ~100,000 hairs in human head
                  Lack hair: lips, nipples, thick
                   skin & parts of the internal
                  Hair growth & density are
                   determined by nutrition &
                  Average growth rate:
                   2 mm/day
  One Last Chunk of Hair
 Hair   grows fastest from teen years to 40s
   Hairs   are no longer replaced as quickly as shed
 Alopechia (balding in both sexes) usually
 begins at the anterior hairline
 Male   pattern baldness
   Genetically  determined, sex-influenced condition
   Follicular hair cycles become so short that the
    hairs never emerge from the scalp before being
         Structure of Hair
   Hairs (pili) – strands produced by hair follicles that consist mostly
    of keratinized cells
   Shaft – portion that projects from skin
      Shape of shaft determines texture
          Flat & ribbonlike in cross section =
           very wavy
          Oval = smooth & silky
          Perfectly round = straight & coarse
   Root – portion embedded in skin
   Cuticle – outermost layer formed from
    a single layer of overlapping cells
      Subjected to most abrasion
      Wears away at tip of hair shaft
      Allows keratin fibrils to frizz out,
        creating “split ends”
    Structure of a Hair Follicle
   Extends into dermis
       In scalp extend into hypodermis
   Sensory nerves (root hair plexus) wraps around each
   A papilla containing capillaries
    protrudes into bulb & supplies growing
    hair with nutrients
   Hair bulge – just above bulb, contains
    chemical receptors to send reproductive
    cells to begin producing new hair cells
   Arrector pili – a muscle attached to
    each follicle
       Contraction pulls follicle into upright
        position, producing “goose bumps”
    Modification of epidermis
    Corresponds to hoofs or claws
    of other animals
   Contain hard keratin (like hairs)
   Clear, hard derivative of stratum
   Growth rate is 1 mm/week
   Structure:
        Nail bed – skin on which nail plate
        Matrix – only living part
           Behind & underneath nail fold
           Produces keratin of nail plate
           Damage affects growth of nail
        Eponychium – dead skin that forms around cuticle
        Hyponychium – attachment between nail plate & nail bed that lies
         underneath free edge
        Cuticle – where nail meets skin
        Nail plate – hard, translucent part of nail composed of layers of keratin

To top