The Integumentary System

1
The Integumentary System

• Chapter 6

2
The Integumentary System

• Functions of the skin and subcutaneous tissue
• epidermis and dermis
• hypodermis
• thick and thin skin
• skin color
• skin markings
• Hair and nails
• Cutaneous glands
• Skin disorders

3
Overview

• Largest organ (15 of body weight)
• Epidermis
• __________________________________________
• _______________________________
• connective tissue layer
• Hypodermis
• Thickness varies, normally 1-2 mm dermis up to 6
  mm
• _____________________________________________

4
Functions of the Skin

• _______________________
• keratin and desmosomes
• _______________________
• Barrier to ultraviolet light
• _______________________
• Sensory receptors
• Thermoregulation sweating
• Nonverbal communication

5
Cells of the Epidermis

• Stem cells
• undifferentiated cells
• __________________________________
• Melanocytes
• synthesize pigment melanin
• __________________________________
• ___________________________________
• _________________________________
• macrophages guard against pathogens

6
_______________

• Single layer cells ?
• basement membrane
• Cell types in this layer
• keratinocytes
• Mitotic, replace epidermis
• ______________________________
• distribute melanin to keratinocytes
• merkel cells ? ___________________
• form Merkel disc

7
Stratum Spinosum

• Layers of keratinocytes
• appear spiny
• ________________ ________________
• _______________
• protect body against pathogens

8
Stratum Granulosum

• ___________________ ___________________
• Contain keratin
• ___________________ ___________________
• Barrier between surface and deeper layers
• Cuts off surface from nutrients

9
_____________

• ________________ _________________
  _________________
• Cells have no nucleus or organelles

10
____________ __________

• ____________________________ ______________
  ______________
• surface cells flake off (exfoliate)

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________

• Thickness 0.6mm to 3mm
• Composition
• collagen, elastic reticular fibers, fibroblasts
• ___________________________ - extensions of
  dermis into the epidermis
• form the ridges of the fingerprints
• Layers
• ________________________________
• ________________________________

12
___________

• Subcutaneous tissue/ superficial fascia
• ______________________
• Functions
• _______________________
• _______________________
• Hypodermic injections (subQ)
• _______________________

13
Skin Colors (Pigmentation)

• _____________ red pigment of red blood cells
• ______________________ yellow pigment
• ______________________________________
• ______________ yellow, brown, and black hues
• pigment synthesis stimulated by UV radiation

14
Abnormal Skin Colors

• _________________ ? deficiency of oxygen in the
  blood (cold weather)
• _________________ ? dilated cutaneous vessels
  (anger, sunburn, embarrassment)
• ____________________ __________________ ? excess
  of bilirubin in blood (liver disease)

15
Abnormal Skin Colors

• Bronzing golden-brown color of _______________
  (deficiency of glucocorticoid hormone)
• Pallor pale color ? lack of blood flow
• __________________ a genetic lack of melanin
• _____________ a bruise (visible clotted blood)

One person in 17,000 has some type of albinism.
Albinism affects people from all races. Most
children with albinism are born to parents who
have normal hair and eye color for their
particular ethnic backgrounds. Often people do
not recognize that they have albinism.
16
Skin Markings

• ____________________________
• discoloration caused by benign tumors of
  capillaries (strawberry birthmarks disappear in
  childhood -- port wine birthmarks last for life)
• Freckles and moles ____________________________
• freckles are flat moles are elevated
• Friction ridges leave fingerprints
• unique pattern formed during development
• _____________________ form after birth by
  repeated closing of the hand
• Flexion lines form in wrist and elbow areas

17
Characteristics of Human Hair

• Hair (composed of hard keratin)
• Hair found almost everywhere
• 3 different body hair types
• ____________ -- fine, unpigmented fetal hair
• _____________ -- fine, unpigmented hair of
  children and women
• terminal hair -- _______ ____________________
  ____________________

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Hair Follicle

• Hair filament of keratinized cells
• shaft ________________
• __________ within follicle
• Follicle tube in skin
• ______________________
• vascular tissue (papilla) in bulb provides
  nutrients
• Texture and shape of hair
• straight hair round, wavy oval
• Hair color pigment in cells of cortex

19
Structure of Hair Follicle

• Root sheath
• Hair receptors wrap each follicle
• _________________
• goose bumps

20
Hair Growth and Loss

• Thinning or baldness __________________
• Pattern baldness ______________________
• sex-influenced trait(dominant in males, recessive
  in females) expressed with high testosterone
  levels
• ____________ excessive hair growth
• hormone imbalance (ovary or adrenal cortex
  problem)

21
Functions of Hair

• Body hair
• __________________________________
• Scalp hair
• heat retention and sunburn cover
• Beard, pubic and axillary hair indicate sexual
  maturity
• Guard hairs and eyelashes
• _______________________________________
  _______________________________________
• Expression of emotions with eyebrows

22
Fingernail Structure
Growth rate is 1 mm per week. New cells added by
mitosis in the nail matrix. Nail plate is visible
part of nail. Medical diagnosis of iron
deficiency concave nails
23
Sweat Glands

• _____________ and waste products
• 500 ml of insensible perspiration/day
• sweating with visible wetness ?diaphoresis
• ____________________________
• millions of them help cool the body
• ________________ produce sweat with fatty acids
• found near hair follicles respond to stress and
  sex
• ______________is body odor produced by bacterial
  action on fatty acids

24
Sebaceous Glands

• Oily secretion called _____________ that contains
  broken-down cells
• lanolin in skin creams is sheep sebum
• Flask-shaped gland with duct that opens into hair
  follicle

25
Ceruminous Glands

• ______________________________
• Their secretion combines with sebum to produce
  earwax
• ________________________________
• ________________________________

26
Skin Cancer

• Induced by UV rays
• ____________________ (least dangerous)
• Cells from stratum basale invade dermis
• squamous cell carcinoma
• from keratinocytes in _____________
  ____________________________
• metastasis to the lymph nodes can be lethal
• _______________________ (most deadly)
• ________________________________
  ________________________________
• ABCD--asymmetry, border irregular, color, mixed
  and diameter over 6 mm
• Result of oncogene BRAF in men

27
UVA, UVB and Sunscreens

• UVA and UVB both initiate skin cancer
• As sale of sunscreens has risen so has skin
  cancer
• those who use have higher incidence of basal cell
• chemical in sunscreen damage DNA and generate
  harmful free radicals
• PABA, zinc oxide and titanium dioxide

28
Burns

• Hot water, sunlight, radiation, electric shock or
  acids and bases
• Degrees of burns
• ___________________________ ______________________
  _____ ___________________________
• 2nd-degree _______________ _____________________
  ______ ___________________________
• regeneration from hair follicles and sweat glands
• 3rd-degree ________________ ____________________
  _______
• requires grafts fibrosis and disfigurement may
  occur
• Death from fluid loss and infection
• Treatment IV nutrition and fluid replacement,
  debreedement and infection control

29
Skin Grafts and Artificial Skin

• Third-degree burns require skin grafts
• Graft options
• ________________ -- tissue from patient
• isograft -- tissue from identical twin
• cultured keratinocyte patches
• Temporary grafts (immune system)
• ____________ (____________) -- from unrelated
  person
• heterograft (________) -- from another species
• amnion from afterbirth
• artificial skin from silicone and collagen