The Integumentary System

1
The Integumentary System

• Chapter 6

2
The Integumentary System

• Functions of the skin and subcutaneous tissue
• Divisions (_______________________
  _____________________)
• Skin color and markings
• Hair and nails
• __________________
• Skin disorders

3
Overview

• Largest organ (15 of body weight)
• Epidermis
• ____________________________________
• ____________
• connective tissue layer
• _____________________
• Thickness variable, normally 1-2 mm dermis up to
  6 mm
• _________________ layer increased
• calluses on hands and feet

4
Functions of the Skin

• Resistance to trauma and infection
• keratin and linked by desmosomes
• acid mantle (pH 4-6)
• __________________________
• __________________________
• __________________________
• Thermoreceptors through sweating
• Nonverbal communication

5
Cells of the Epidermis

• Stem cells
• undifferentiated cells
• ________________ most of the skin cells
• ________________
• synthesize pigment that shield UV
• Tactile (merkel) cells
• ______________________________________
• Dendritic (langerhans) cells
• macrophages guard against pathogens

6
Stratum ________

• Single layer cells on
• basement membrane
• Cell types in this layer
• keratinocytes
• ________________________
• ____________________
• distribute melanin to keratinocytes
• merkel cells ? touch receptors
• form Merkel disc

7
Stratum Spinosum

• Layers of keratinocytes
• appear spiny from shrinkageduring preparation
• Dendritic (Langerhans) cells
• ________________ ________________
• 800 cells/millimeter2
• protect body against pathogens

8
Stratum Granulosum

• 3 to 5 layers flat keratinocytes
• Contain keratinohyalin granules
• combine with filaments of cytoskeleton to form
  _________________
• ________________________ ________________________
• barrier between surface cellsand deeper layers
  of the epidermis
• _____________________________ ____________________
  _________

9
Stratum ________

• Thin translucent zone seen only in
  _________________
• Keratinocytes contain eleidin, a precursor to
  keratin
• does not stain well
• __________________ __________________

10
Stratum _____________

• Up to 30 layers of dead, scaly,keratinized cells
• surface cells flake off (exfoliate)

11
Dermis

• Thickness 0.6mm to 3mm
• Composition
• collagen, elastic reticular fibers, fibroblasts
• __________________ - extensions of the dermis
  into the epidermis
• _____________________________ ____________________
  _________
• Layers
• ___________________________
• reticular layer is deeper part of dermis

12
Hypodermis

• ___________________________________
• Mostly ___________________
• Functions
• _______________________
• thermal insulation
• Hypodermic injections (subQ)
• highly vascular

13
Skin Colors (Pigmentation)

• Hemoglobin red pigment of red blood cells
• ________________________ yellow pigment
• concentrates in stratum corneum and fat
• _____________ yellow, brown, and black hues
• pigment synthesis stimulated by UV radiation

14
Abnormal Skin Colors

• ___________ blueness ? deficiency of oxygen in
  the blood (cold weather)
• Erythema __________ ? dilated cutaneous vessels
  (anger, sunburn, embarrassment)
• ____________ yellowing of skin and sclera ?
  excess of bilirubin in blood (liver disease)

15
Abnormal Skin Colors

• _____________ golden-brown color of Addison
  disease (deficiency of glucocorticoid hormone)
• Pallor pale color ? lack of blood flow
• Albinism ____________ ______________________
• _____________ 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

• _____________________ (birthmarks)
• discolored skin caused by benign tumors of
  capillaries (strawberry birthmarks disappear in
  childhood -- port wine birthmarks last for life)
• Freckles and moles aggregates of melanocytes
• ______________________________________
• Friction ridges leave oily fingerprints on
  touched surfaces
• unique pattern formed during fetal 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 -- coarse, long, pigmented hair of
  scalp

18
Hair Follicle

• Hair filament of keratinized cells
• ______________ above skin
• ______________ within follicle
• in cross section medulla, cortex and cuticle
• Follicle tube in skin
• bulb where hair originates
• 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

• ____________
• Hair receptors entwine each follicle
• __________ muscle
• goose bumps

20
Hair Growth and Loss

• Thinning or baldness alopecia
• ___________________ genetic and hormonal
• _________________________ 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
• ____________________________________
• _____________________
• heat retention and sunburn cover
• Beard, pubic and axillary hair indicate sexual
  maturity
• Guard hairs and eyelashes
• prevent foreign objects from getting into
  nostrils, ear canals or eyes
• __________________________________

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

• Filtrate of plasma and waste products
• ____________ of insensible perspiration/day
• sweating with visible wetness ?diaphoresis
• Merocrine glands
• _________________________
• ________________ produce sweat with fatty acids
• found near hair follicles respond to stress and
  sex
• bromhidrosis is body odor produced by bacterial
  action on fatty acids

24
____________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
_____________Glands

• Found only in external ear canal
• Their secretion combines with sebum to produce
  earwax
• waterproof keeps eardrum flexible
• bitterness repel mites and other pests

26
Skin Cancer

• Induced by UV rays of the sun
• ___________ carcinoma (least dangerous)
• from _________________ and invades dermis
• ______________________ cell carcinoma
• from keratinocytes in _______________
  _______________________
• metastasis to the lymph nodes _______
  __________________________
• ____________________________________
• from ___________of a preexisting mole
• 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 are both thought to initiate skin
  cancer
• Thymidene dimers
• As sale of sunscreens has risen so has skin
  cancer
• those who use have higher incidence of basal cell
• chemical in sunscreen damages 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
• 1st-degree _______________ (red, painful and
  edema)
• 2nd-degree epidermis and part of dermis
  (____________)
• regeneration from hair follicles and sweat glands
• _____________ epidermis, dermis and more is
  destroyed
• often requires grafts fibrosis and disfigurement
  may occur
• ____________________________________
• Treatment IV nutrition and fluid replacement,
  debreedement and infection control

29
Skin Grafts and Artificial Skin

• Third-degree burns require skin grafts
• Graft options
• ______________ -- from self
• ______________ -- from identical twin
• cultured keratinocyte patches
• Temporary grafts (immune system)
• homograft (_____________) -- from unrelated
  person
• heterograft (____________) -- from another
  species
• amnion from afterbirth
• artificial skin from silicone and collagen