Integumentary System

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Chapter 5

• Integumentary System

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Overview of the Integumentary System

• Structures that are part of the integument
• Overview of Functions

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Skin

• 
  Superficial layer of epithelial tissue.
• Dermis Deep layer of
• Not part of skin
• 
  that connects skin to underlying structures

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Epidermis

• Avascular
• Composed of cells arranged into layers or
  .
• Separated from dermis by

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Epidermal Cells

• Cell types
• Desquamate cells of the deeper layers undergo
  mitosis as they move toward the surface, older
  cells slough off
• Keratinization as cells move outward through the
  layers they fill with keratin, die, and serve as
  a layer that resists abrasion and forms
  permeability layer

Cell Type Description
Keratinocyte
Contribute to skin color. Melanin. Same number in all people
Langerhans Cells
Merkers Cells
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Epidermal Strata
Stratum Description
Basale (germinitivum
Limited cell division. Desmosomes. Lamellar bodies and additional keratin fibers
Contains keratohyalin. In superficial layers nucleus and other organelles degenerate and cell dies
Lucidum
Corneum
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Epidermal Layers and Keratinization
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Thick and Thin Skin

• Thick skin
• Has
• Found in areas subject to
• Palms of hands, fingertips, soles of feet
• Fingerprints and footprints. Papillae of
  underlying dermis in parallel rows
• Thin skin
• More flexible than thick skin
• Covers rest of body
• Callus. Increase in number of layers in
  . When this occurs over a bony
  prominence, a forms.

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Skin Color

• Determined by 3 factors
• Pigments
• Melanin provides ________________________________
  __________________________________________________
  _________________
• - _______________________ deficiency or absence
  of pigment.
• ______________________ yellow pigment. From
  vegetables.
• Blood circulating through the skin
• reddish hue increases during _____________________
  ___________________________
• __________________________________________________
  _ blue color caused by decrease in blood oxygen
  content
• Thickness of stratum corneum can cause yellow
  skin color

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Dermis

• _________________________________________________.
  C.T. with many fibers, fibroblasts, macrophages.
  Some adipocytes and blood vessels.
• Contains _________________________________________
  _________________________________________________
  __________________________________________________
  _________
• Sensory functions _______________________________
  _________________________________________________
  ____________________

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Two Layers of the Dermis

• Papillary. ________________________(outer)
  _________. Fingerprints. Whorls of ridges. Touch
  receptors (Meissners), free nerve endings
  sensing pain
• Reticular ____________________(inner)________.
  Collagen and elastic fibers. Some adipose, hair
  follicles, nerves, oil glands, ducts of sweat
  glands, heat sensors.

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Cleavage (Tension) Lines and Striae

• _________________________________________
  elastin and collagen fibers oriented in some
  directions more than in others
• Important in surgery
• If incision parallel to lines, there is less
  gapping, faster healing, less scar tissue
• If skin is ____________________,
  _____________________(stretch marks) occur

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Hypodermis

• _________________to skin
• Consists of ________________________with
  __________________________________________________
  ____________
• Types of cells
• Also called
• Subcutaneous tissue
• Superficial fascia
• Contains about one-half of bodys fat. Functions
  as

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Accessory Skin Structures Hair

• Not found on _____________________________________
  __________________________________________________
  ____________________________
• Shaft protrudes above skin surface
• Root located below surface base of root is the
  hair bulb
• Has 3 concentric layers

Layer Function
Medulla
Forms bulk of hair
Cuticle
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• Hair Growth
• Cycles
• Growth and resting stages
• Growth cells added at ________________and hair
  elongates. Average rate is ______________________
  ______________
• Rest follicle _________________and holds hair in
  place. Rest, then hair falls out of follicle. New
  hair begins.
• Regular hair loss means hair is being
  ______________________________.
• Permanent hair loss _____________________________
  ___most common cause
• Hair Color. Caused by varying amounts and types
  of _______________. Can be black-brown and red
• Muscles. _________________________. Type of
  smooth muscle.
• Muscle ________________________causes hair to
  stand on end
• Skin pushed up by movement of hair follicle

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Accessory Skin Structures Glands

• _____________________
• _____________________ (death of secretory cells)
• Oily secretion
• Prevents drying and may inhibit bacteria
• Most empty into hair follicle
• Exceptions lips, meibomian glands of eyelids,
  genitalia

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Accessory Skin Structures Glands

• _______________________________________
• _________________________or _____________________.
  Most common.
• Open directly onto surface of skin. Have own
  pores.
• Coiled part in ________________, duct exiting
  through ______________.
• Produces ______________________________.
• Numerous in palms and soles.
• _____________________________. Active at puberty.
  
• Usually open into hair follicles superficial to
  opening of sebaceous gland.
• Secretion odorless organic compounds, become
  odiferous when acted on by bacteria
• Found in axillae, genitalia (external labia,
  scrotum), around anus.

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Accessory Skin Structures Glands

• ________________________________ modified
  merocrine sweat glands, external auditory meatus.
• Earwax (cerumen).
• Function- In combination with hairs,
  ___________________________________________. Also
  keep eardrum supple.
• ___________________________________ modified
  apocrine sweat glands.

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Accessory Skin Structures Nails

• Anatomy
• Nail body ________________
• ________________________or cuticle is corneum
  superficial to nail body, ______________________is
  corneum beneath the free edge
• Matrix and nail bed _____________________________
  _____________________
• Nail root extends
• Growth
• Grow ______________unlike hair
• Fingernails grow ___________________ faster than
  toenails

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Burns

• Classifications
• First-degree
• Second-degree
• Third-degree
• Skin Grafts
• Split skin
• Artificial skin
• Cadavers or pigs

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The Rule of Nines

• Used to estimate amount of body that is burned.
• Note differing proportions in adult and child.

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Effects of Aging on the Integumentary System

• Skin more easily damaged because epidermis thins
  and amount of collagen decreases
• Skin infections more likely
• Wrinkling due to decrease in elastic fibers
• Skin becomes drier
• Decrease in blood supply causes poor ability to
  regulate body temperature
• Functioning melanocytes decrease or increase age
  spots
• Sunlight ages skin more rapidly