Integumentary System 2 PPT - The

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					The Integumentary System


 Anatomy and Physiology
       What are the major
    characteristics of the skin?
 Waterproof, stretchable,washable, and
  permanent-press, that automatically repairs
  small cuts, rips and burns and is guaranteed
  to last a lifetime.
 Surface area of up to 2.2 square meters
 11 pounds
 7% of total body weight
 Pliable yet tough
What are the 3 major layers of
          the skin?
   Epidermis (epi-upon)
    – Composed of epithelial tissue (stratified squamous)
    – Non-vascularized
   Dermis – underlies the epidermis
    – Tough leathery layer composed of fibrous connective
      tissue
    – Good supply of blood
   Hypodermis (not considered skin)
    – Made of adipose and areolar tissue
    – Stores fat, anchors skin, protects against blows
Epidermis




Dermis
            Basement membrane
Epidermis




 Dermis




Hypodermis
    What are the different types of
      cells in the epidermis?
   Keratinocytes
    – Produce a fibrous protein
        called keratin
    –   Are formed in the lowest
        levels of the epidermis.
    –   Pushed upward by the
        production of new cells
        beneath them.
    –   Become dead and scale-like
    –   Millions rub off everyday
What are the different types of
  cells in the epidermis?
   Melanocytes
    – Synthesizes the
      pigment melanin
    – Melan-black                      melanocyte
    – Can transfer melanin to
      keratinocytes             Melanin in
                                keratinocytes
    – Protects skin from
      ultraviolet light.
                                Epidermis
a. Keratinocytes – make keratin and divide rapidly.
b. melanocytes – spider shaped cells that synthesize melanin.
c. Langerhaus cells – arise from bone marrow and are macrophages
d merkel cells – at epidermal/dermal junction – spiky with disc-like nerve
ending (touch receptors)




   Stratum basale (stratum germinativum)
    – Single layer of cuboidal to columnar cells
    – Stem cells that produce keratinocytes
    – Melanocytes - # the same for all races
    – Continually being replaced
What are the different types of
  cells in the epidermis?
   Langerhans’ cells
    – Formed in bone
                           Langerhans’
      marrow.
                           cell
    – Move to the skin
    – Macrophages
What are the different types of
  cells in the epidermis?
   Merkel Cells
    – Has a spiked
      appearance
    – Connected to nerve
      cells from dermis
    – Function as sensory
      receptors for touch.
     What are the layers of the
           epidermis?
 Stratum basale: deepest layer of the epidermis,
  undergoes rapid cell division.
 Stratum spinosum: intermediate layer, contain
  spiny shaped keratinocytes.
 Stratum corneum: outermost layer 20-30 cells
  thick of dead keratinized cells.
    – Dandruff
    – Average person shed 40 pounds of these cells in their
      lifetime.
    – Everything you see on a human is dead!
Stratum Spinosum (thorn-like,
          prickly)
What are the characteristics of
        the dermis?
 Made up of connective tissue
 Richly supplied with blood vessels and
  lymph vessels
 Has hair follicles, oil and sweat glands and
  sensory receptors
 Ridges formed from the papillary layer can
  form finger prints.
    Reticular layer of the dermis
 Filled with dense irregular fibrous
  connective tissue
 Matrix is filled with thick bundles of
  collagen fibers (give the skin strength)
 Less dense regions are called lines of
  cleavage or tension lines; surgeons use
  these to make incisions because they heal
  quicker.
      What causes the color of
              skin?
   3 pigments contribute to skin color
    – Melanin- protein pigment (natural sunscreen)
           Can range in color from yellow to reddish-brown to black
           Everyone has the same number of melanocytes but make
            varying amounts and colors (differences in skin color)
           Increased melanin production can caused by sunlight.
    – Carotene-yellow to orange pigment found in carrots.
           Most commonly found in the palms or soles. Most intense
            when large amounts of carotene-rich foods are eaten.
    – Hemoglobin- Red blood gives a pinkish hue to fair skin
      What are the major
    appendages of the skin?
 Sweat glands
 Sebaceous glands
 Hairs
 Nails
    What are the types of glands
        found in the skin?
   Sudoriferous Glands
    – Eccrine- common sweat glands
          Hot sweats vs. Cold sweats
    – Apocrine- produce sweat plus a milky or yellowish
      substance composed of fat and protein.
          Found in the arm pits and genitalia
          Thought to be scent glands.
    – Ceruminous- produce cerumen (ear wax)
    – Mammary glands- produce milk
   Sebaceous glands- oil glands (sebum)
    – Softens and lubricates hair and skin
    – Slows water loss and kills bacteria
      Why is hair useful?
 Senses insects that land on the skin.
 Hair on the head protects the head from a
  blow, sunlight and heat loss.
 Eyelashes shield the eye
 Nose hairs filter the air
             What are hairs?
 Made from hair follicles
 Made of dead keratinized skin cells
 Two parts shaft and root
 Shaft has 3 layers of cells
    – Medulla(central core)
    – Cortex (bulky layer)
    – Cuticle (heavily keratinized; protects hair)
 Matrix: the site of actively dividing
  epithelial cells. Highly vascularized.
 Root hair plexus: sensory nerve endings
  here - sense when hair is bent
 Layers: medulla surrounded by cortex
  surrounded by cuticle.
 Distribution: vellus: fine hairs everywhere
  except around the scalp and eyes until
  puberty.
 Terminal hairs: after puberty
Why do
humans
have
arrector pili
muscles?
    What are the parts of nails?
 A nail is a scalelike modification of the
  epidermis
 Made of tightly compressed keratinized
  cells
 Useful tools to pick up small objects or
  scratch an itch.
 Nail matrix is the region responsible for nail
  growth.
 Nail body: visible attached portion
 Cuticle or eponychium: proximal skin fold
  overlapping nail.
 Nail root: embedded in skin
 Nail matrix: thickened proximal portion of
  nail bed (actively growing)
 Lunula: Thickened nail matrix “white crescent
  moon
What are the primary functions of the
      Integumentary System?
   Protection: provides 3 types of barriers
    – Chemical barriers: low pH of skin secretions
      slows bacterial growth. Human defensin is an
      antibiotic that destroys bacteria (produced by
      human skin)
           Physical barriers
– Physical barriers: very few substance are able
  to enter the skin. Substances able to pass.
      Lipid-soluble substances: oxygen, carbon dioxide,
       some vitamins
      Oleoresins- poisons (poison ivy)
      Organic solvents- dry-cleaning fluid, paint thinner
      Salts of heavy metals- lead, mercury, nickel
      Penetration enhancers- drug agents that help
       substances into the body.
          Biological barriers
   Langerhans’ cells-
    act as macrophages
    police the
    epidermis for
    viruses and
    bacteria.
             Functions cont.
 Thermoregulation- skin contains sweat glands
  that secrete watery fluid, that when evaporated,
  cools the body.
 Sensation- Skin contains sensory receptors that
  detect cold, touch, and pain.
 Vitamin D synthesis- cholesterol in the skin is
  bombarded by sunlight and converted to vitamin
  D (calcium cannot be absorbed from digestive
  tract)
           Functions cont.
 Blood reservoir- blood will be moved from
  skin to muscles during strenuous activity.
 Excretion- Sweating is an important outlet
  for wastes such as salt and nitrogen
  containing compounds. (urine)
             Skin Cancer
 Benign tumors such as warts and moles are
  not serious.
 Malignant tumors can start on the skin and
  invade other body areas.
 Crucial risk factor- overexposure to UV
  radiation
         Types of Skin Cancer
   Basal cell carcinoma- most common, 30% of all
    white skin people get it.
    – Arises from the stratum basale layer of the skin
    – 99% curable if caught early
    – Dome shaped nodules that form an ulcer in the center.
   Squamous Cell carcinoma-
    – Arise from stratum spinosum
    – Grows rapidly and metastasizes if not removed
    – Small red rounded elevation on the skin
Deepest layer, columnar cells where mitosis continually takes place.
Firmly attached to dermis. Single row of keratinocytes with 10 - 25%

                            melanocytes

          Basal cell carcinoma: typically localized




       http://www.nebraskin.com/basal.htm
Basal Cell Carcinoma
        Squamous cell carcinoma




                                                 http://www.southcoastmedc
                                                 enter.com/content/services/l
http://missinglink.ucsf.edu/lm/DermatologyGlos   ab/skin_cancer.asp
sary/squamous_cell_carcinoma.html
Squamous cell carcinoma
      Skin Cancer Types cont.
   Melanoma
    – Cancer of melanocytes (very dangerous)
    – 5% of skin cancers but rising fast
    – Can arise from preexisting moles
    – Appears as a spreading brown or black patch
    – Chance of survival is poor if the lesion is
      greater than 4 mm thick
Melanoma
     What is the ABCD rule?
 Used for recognizing melanoma
 A-Asymmetry: two sides of the pigmented
  mole do not match
 B-Border irregularity: borders are not
  smooth
 C- Color: lesion has a multiple of colors
 D- Diameter the spot is larger than 6 mm in
  diameter (size of a pencil eraser)
     What are the 3 types of
            burns?
 First-degree burns: only the epidermis is
  damaged. Redness, swelling and pain are
  common. (sunburn) 2-3 days to heal
 Second-degree burns: epidermis and upper
  layers of dermis. Blistering can occur. 3-4
  weeks to heal.
 Third-degree burns: involves the entire
  thickness of the skin. (pg. 164-165)
      Second-degree burns




Third-degree burn
Skin Grafts
           Decubitus Ulcers
   Epidermis is destroyed: pressure
    compresses blood flow – over a period of
    time, tissue looses oxygen supply – ulcer
    forms and can become gangrene. This can
    be fatal.
Decubitus Ulcers
progression
 Contusion: bruise: blood vessels ruptures.
  As the bruise ages and moves toward the
  surface, it changes from black/blue to
  green/yellow.
 Cyanosis: bluish skin caused by vessel
  constriction – lack of blood flow to skin
  from either cold, or lack of oxygen, so the
  body conserves it for the vital organs by
  constricting its flow to the skin.
   Wrinkles: collagen fibers align themselves
    more and more as they are pulled in the
    same direction: smile, frown
    – Skin sags because the body makes less elastin.
      Pinch your grandma’s skin. Does it bounce or
      ooze back?
    – Face lift
    – Creams?????? They can’t fix the collagen
      problem. Its like thinking you can clean your
      skin by washing your jacket (while its on you.
   Botox: deadly poison that paralyzes the
    muscles so they sag.
    – Releases the tension and relaxes the skin line.
    – Lasts only 3 months and then the muscle cells
      grow so the wrinkles come back.
 Collagen injections: Collagen injected into
  hypodermis (lasts a couple of years)
 Moisturizer creams: main ingredient is
  water. Superficial affect. Increased water in
  corneum causes expansion and hides
  wrinkles temporarily.
What about stretch marks and
          tatoos?

                Stretch marks – tear in
                dermis
                (silvery white in color)
          Self tanning lotions: contain
    dihydroxyacetone - colorless sugar that
      interacts with dead cells. (5-7 days)
   Bath pruning: keratin softened water soaks in. Dead cells
    don’t perform active transport - thicker skin = more
    pruning. Surface cells expand do to osmosis but attached
    to dermis that doesn’t = wrinkles.


 Caroteen - yellow orange pigment of plant
  products accumulates in the corneum and
  hypodermal fat.
 Blister - separation between dermis and epidermis.
Some other skin disorders:
ACNE

				
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