The integumentary system ppt

April 21, 2012 | By | Reply More

The integumentary  system ppt

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Subject : Anatomy
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The integumentary  system

  • Protection
  • Thermoregulation
  • Indicator of health
    • Hypoxia
    • Rashes
    • Disorders of the skin

Functions of  the skin

  • Regulation of body  temperature
  • Large blood supply (associated with thermoregulation)
  • Protection
  • Sensation (cutaneous receptors)
  • Excretion and absorption
  • Vitamin D synthesis

Largest organ  of the body


  • Keratinocytes
  • Melanocytes
    • Melanin protects against UV
  • Langerhans cells
    • Immune cells
  • Merkel cells
    • touch

Epithelial layers  (strata)

  • Stratum basale (stratum  germinativum) new cell formation; keratinocytes
  • Stratum spinosum “spiny”
  • Stratum granulosum- cells are dying; producing keratin and lipid
  • Stratum lucidum- only in thick skin. Lots of keratin
  • Stratum corneum- many layers of dead cells; water repellent


  • Contains lots of  collagen and elastic fibers
  • Papillary region (areolar)
    • Meissner corpuscles (touch)
    • Free nerve endings
  • Reticular region (dense)
    • variety of cells and glands
  • Epidermal ridges form fingerprints

Lines of cleavage  indicate orientation of collagen

Skin color

  • People have same  number of melanocytes but different amount  of melanin
  • Carotene- yellowish tint
  • Hemoglobin-reddish tint
  • Albinism- no melanin
  • Vitiligo- irregular loss of melanin
  • Changes in skin tone may be significant
    • Cyanosis
    • Jaundice
    • Rash

Accessory structures  of skin


  • Dead, keratinized  cells
  • Medulla, cortex, cuticle
  • Shaft is what you see
  • Bulb is base of hair follicle
    • Papilla contains blood vessels
    • Matrix source of new cells

Hair growth  is cyclical

  • Lanugo formed (and  lost) before birth
  • Vellus hairs (“peach fuzz”)
  • Terminal hairs
    • Head, eyebrow, lashes, pubic
    • More terminal hair on body in males than females
    • Hair color, balding patterns are inherited

Glands of the  skin


Earwax is produced  by modified sweat glands!

  • Ceruminous glands
  • Secrete into external auditory meatus
  • Helps protect ear from foreign objects


  • Freeedge, nail body,  nail root
  • Hyponychium holds nail onto fingertip
  • Eponychium is cuticle

Skin is not  uniform over the body

  • Thin hair is  hairy
    • No stratum lucidum
    • Few epidermal ridges
    • Hair follicles present
    • Many sebaceous, fewer sudoriferous glands
  • Thick skin is hairless
    • More sensory receptors, more sweat glands

Blood supply  to integumentary system

  • None to epidermis
  • Some plexuses supply blood to dermis; usually offshoot of supply to muscle
    • Cutaneous plexus between dermis and subQ
    • Papillary plexus extends into dermis

Developmental aspects  of integument

  • Epidermis formed  from ectoderm, dermis from mesoderm
  • See Figure 5.8 for sequence
  • Effects of aging usually occur in dermis
    • Collagen and elastic fibers break down
  • Immune function decreases
  • Glands secrete less

Disorders of,  damage to skin

Damage to skin  may be diagnostic

  • Wheal (hives)
  • Vesicles (viral infections)
  • Dermatitis, pruritis (allergic reaction)
  • Type of rash may help diagnose infectious disease
  • Condition of nails or hair may indicate disease
  • Contact dermatitis

Introducing material  to skin (barrier properties of skin)

  • Intradermal- within  dermis
    • TB tests
    • Allergy tests
    • Economical way to give vaccines?
  • Subcutaneous
    • Little blood supply
    • Slow absorption, e.g. insulin
  • Intramuscular
    • Large doses
    • Rapid absorption
  • Transdermal
    • Timed release
    • No needles!


  • Skin protects the  internal structures
  • Skin helps maintain body temperature
  • Storage (of fat) secretion (of salts, water and wastes) and synthesis (of vitamin D) are important features
  • Many different types of nerve endings allow distinction of touch, pressure, pain and temperature.

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