1. 2 Support and Movement Fundamentals of Anatomy & Physiology Unit
Frederic H. Martini
PowerPoint® Lecture Slides prepared by Professor Albia Dugger, Miami–Dade College, Miami, FL
Professor Robert R. Speed, Ph.D., Wallace Community College, Dothan, AL
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

2. Chapter 5: The Integumentary System

3. What are the structures and functions of the integumentary system?

4. Size of the Integument
The integument is the largest system of the body:
16% of body weight
1.5 to 2 m2 in area

5. Parts of the Integument
The integument is made up of
2 parts:
cutaneous membrane (skin)
accessory structures

6. Parts of the Integumentary System
Figure 5–1

7. Parts of the Cutaneous Membrane
Outer epidermis:
superficial epithelium (epithelial tissues)
Inner dermis:
connective tissues

8. Accessory Structures Originate in the dermis
Extend through the epidermis to skin surface:
hair
nails
multicellular exocrine glands

9. Connections Circulatory system: Nervous system:
blood vessels in the dermis
Nervous system:
sensory receptors for pain, touch, and temperature

10. What is the relationship between the integument and subcutaneous layer?

11. The Subcutaneous Layer
Subcutaneous layer (superficial fascia or hypodermis):
loose connective tissue
below the dermis
location of hypodermic injections

12. Functions of Skin Protects underlying tissues and organs
Excretes salts, water, and organic wastes (glands)
Maintains body temperature (insulation and evaporation)

13. Functions of Skin Synthesizes vitamin D3 Stores lipids
Detects touch, pressure, pain, and temperature

14. What are the main structures and functions of the epidermis?

15. Epidermis Avascular stratified squamous epithelium
Nutrients and oxygen diffuse from capillaries in the dermis

16. Organization of the Epidermis
Figure 5–2

17. Cells of the Epidermis Keratinocytes: contain large amounts of keratin
the most abundant cells in the epidermis

18. Thin Skin
Covers most of the body
Has 4 layers of keratinocytes

19. Thick Skin Covers the palms of the hands and soles of the feet
Has 5 layers of keratinocytes

20. Structures of the Epidermis
The 5 strata of keratinocytes in thick skin
Figure 5–3

21. Layers of the Epidermis
From basal lamina to free surface:
stratum germinativum
stratum spinosum
stratum granulosum
stratum lucidum
stratum corneum

22. Stratum Germinativum The “germinative layer”:
has many germinative (stem) cells or basal cells
is attached to basal lamina by hemidesmosomes
forms a strong bond between epidermis and dermis

23. Structures of Stratum Germinativum
Epidermal ridges (e.g., fingerprints)
Dermal papillae (tiny mounds):
increase the area of basal lamina
strengthen attachment between epidermis and dermis

24. Ridges and Ducts
Figure 5–4

25. Cells of Stratum Germinativum
Merkel cells:
found in hairless skin
respond to touch (trigger nervous system)
Melanocytes:
contain the pigment melanin
scattered throughout stratum germinativum

26. Stratum Spinosum The “spiny layer”:
produced by division of stratum germinosum
8–10 layers of keratinocytes bound by desmosomes
cells shrink until cytoskeletons stick out (spiny)

27. Cells of Stratum Spinosum
Continue to divide, increasing thickness of epithelium
Contain Langerhans cells, active in immune response

28. Stratum Granulosum The “grainy layer”
Stops dividing, starts producing:
keratin:
a tough, fibrous protein
makes up hair and nails
keratohyalin
dense granules
cross-link keratin fibers

29. Cells of Stratum Granulosum
Produce protein fibers
Dehydrate and die
Create tightly interlocked layer of keratin surrounded by keratohyalin

30. Stratum Lucidum The “clear layer”: found only in thick skin
covers stratum granulosum

31. Cells of Stratum Lucida
Flat
Dense
Filled with keratin

32. Stratum Corneum The “horn layer”: exposed surface of skin
15 to 30 layers of keratinized cells
water resistant
shed and replaced every 2 weeks

33. Keratinization
The formation of a layer of dead, protective cells filled with keratin
Occurs on all exposed skin surfaces except eyes

34. Skin Life Cycle
It takes 15–30 days for a cell to move from stratum germinosum to stratum corneum

35. Perspiration Insensible perspiration: Sensible perspiration:
interstitial fluid lost by evaporation through the stratum corneum
Sensible perspiration:
water excreted by sweat glands

36. Water Loss Through Skin
Dehydration results:
from damage to stratum corneum, e.g., burns and blisters (insensible perspiration)
from immersion in hypertonic solution, e.g., seawater (osmosis)

37. Water Gain Through Skin
Hydration:
results from immersion in hypotonic solution, e.g., freshwater (osmosis)
causes stretching and wrinkling skin

38. What causes different skin colors?

39. Skin Color Skin color depends on: the pigments carotene and melanin
blood circulation (red cells)

40. Carotene Orange-yellow pigment Found in orange vegetables
Accumulates in epidermal cells and fatty tissues of the dermis
Can be converted to vitamin A

41. Melanin Yellow-brown or black pigment
Produced by melanocytes in stratum germinativum
Stored in transport vesicles (melanosomes)
Transferred to keratinocytes

42. Function of Melanocytes
Melanin protects skin from sun damage
Ultraviolet (UV) radiation:
causes DNA mutations and burns which lead to cancer and wrinkles

43. Melanocytes
Figure 5–5

44. Melanocytes
Skin color depends on melanin production, not number of melanocytes

45. Capillaries and Skin Color
Oxygenated red blood contributes to skin color:
blood vessels dilate from heat, skin reddens
blood flow decreases, skin pales

46. Cyanosis Bluish skin tint
Caused by severe reduction in blood flow or oxygenation

47. Illness and Skin Color Jaundice: Addison’s disease:
buildup of bile produced by liver
yellow color
Addison’s disease:
and other diseases of pituitary gland
skin darkening

48. Illness and Skin Color
Vitiglio:
loss of melanocytes
loss of color

49. Vitamin D Epidermal cells produce cholecalciferol (vitamin D3):
in the presence of UV radiation
Liver and kidneys convert vitamin D into calcitriol:
to aid absorption of calcium and phosphorus

50. Vitamin D
Insufficient vitamin D:
can cause rickets

51. Epidermal Growth Factor (EGF)
Is a powerful peptide growth factor
Is produced by glands (salivary and duodenum)
Is used in laboratories to grow skin grafts

52. Functions of EGF Promotes division of germinative cells
Accelerates keratin production
Stimulates epidermal repair
Stimulates glandular secretion

53. KEY CONCEPT The epidermis:
is a multilayered, flexible, self-repairing barrier
prevents fluid loss
protects from UV radiation
produces vitamin D3
resists abrasion, chemicals, and pathogens

54. What are the structures and functions of the dermis?

55. The Dermis Is located between epidermis and subcutaneous layer
Anchors epidermal accessory structures (hair follicles, sweat glands)
Has 2 components:
outer papillary layer
deep reticular layer

56. The Papillary Layer Consists of areolar tissue
Contains smaller capillaries, lymphatics, and sensory neurons
Has dermal papillae projecting between epidermal ridges

57. The Reticular Layer Consists of dense irregular connective tissue
Contains larger blood vessels, lymph vessels, and nerve fibers
Contains collagen and elastic fibers
Contains connective tissue proper

58. Dermatitis An inflammation of the papillary layer
Caused by infection, radiation, mechanical irritation, or chemicals (e.g., poison ivy)
Characterized by itch or pain

59. Characteristics of Dermis
Strong, due to collagen fibers
Elastic, due to elastic fibers
Flexible (skin turgor)

60. Skin Damage
Sagging and wrinkles (reduced skin elasticity) are caused by:
dehydration
age
hormonal changes
UV exposure

61. Skin Cancer
Figure 5–6

62. Stretch Marks Thickened tissue resulting from:
excessive stretching of skin due to:
pregnancy
weight gain

63. Lines of Cleavage Collagen and elastic fibers in the dermis:
are arranged in parallel bundles
resist force in a specific direction

64. Clinical Importance Lines of cleavage establish important patterns:
a parallel cut remains shut, heals well
a cut across (right angle) pulls open and scars

65. Lines of Cleavage
Figure 5–7

66. Dermal Circulation
Figure 5–8

67. Arteries Cutaneous plexus: Papillary plexus:
a network of arteries along the reticular layer
Papillary plexus:
capillary network from small arteries in papillary layer

68. Veins Venous plexus: Contusion:
capillary return deep to the papillary plexus
Contusion:
damage to blood vessels resulting in “black and blue” bruising

69. Nerves Nerve fibers in skin control:
blood flow
gland secretions
sensory receptors
Tactile disks monitor Merkel cells

70. KEY CONCEPT The dermis:
provides mechanical strength, flexibility and protection
is highly vascularized
contains many types of sensory receptors

71. What are the structures and functions of the subcutaneous layer?

72. The Hypodermis The subcutaneous layer or hypodermis:
lies below the integument
stabilizes the skin
allows separate movement

73. Structure of the Hypodermis
The subcutaneous layer is:
made of elastic areolar and adipose tissues
connected to the reticular layer of integument by connective tissue fibers

74. Clinical Importance Subcutaneous layer:
has few capillaries and no vital organs
is the site of subcutaneous injections using hypodermic needles

75. Adipose Tissue Deposits of subcutaneous fat:
have distribution pattern determined by hormones
are reduced by cosmetic liposuction

76. Integumentary Accessory Structures
Hair, hair follicles, sebaceous glands, sweat glands, and nails:
are derived from embryonic epidermis
are located in dermis
project through the skin surface

77. What determines hair growth, texture, and color?

78. Location of Hair The human body is covered with hair, except: palms
soles
lips
portions of external genitalia

79. Functions of Hair Protects and insulates
Guards openings against particles and insects
Is sensitive to very light touch

80. The Hair Follicle Is located deep in dermis Produces nonliving hairs
Is wrapped in a dense connective-tissue sheath
Base is surrounded by sensory nerves (root hair plexus)

81. Structures of Hair and Follicles
Figure 5–9a

82. Accessory Structures of Hair
Arrector pili:
involuntary smooth muscle
causes hairs to stand up
produces “goose bumps”
Sebaceous glands:
lubricate the hair
control bacteria

83. Regions of the Hair Hair root: Hair shaft: lower part of the hair
attached to the integument
Hair shaft:
upper part of the hair
not attached to the integument

84. Inside the Follicle
Figure 5–9b

85. Keratin As hair is produced, it is keratinized:
medulla contains flexible soft keratin
cortex and cuticle contain stiff hard keratin

86. Hair Growth Cycle Growing hair: Club hair:
is firmly attached to matrix
Club hair:
is not growing
is attached to an inactive follicle

87. Hair Growth Cycle New hair growth cycle: follicle becomes active
produces new hair
club hair is shed

88. Types of Hairs Vellus hairs: Terminal hairs: soft, fine
cover body surface
Terminal hairs:
heavy, pigmented
head and eyebrows
other parts of body after puberty

89. Hair Color Produced by melanocytes at the hair papilla
Determined by genes

90. What are the skin glands and secretions?

91. Exocrine Glands Sebaceous glands (oil glands): Sweat glands:
holocrine glands
secrete sebum
Sweat glands:
merocrine glands
watery secretions

92. Types of Sebaceous Glands
Simple branched alveolar glands:
associated with hair follicles
Sebaceous follicles:
discharge directly onto skin surface

93. Sebaceous Glands
Figure 5–10

94. Sebum Contains lipids and other ingredients
Lubricates and protects the epidermis
Inhibits bacteria

95. What are the functions of sweat glands?

96. Types of Sweat Glands Apocrine: Merocrine:
found in armpits, around nipples, and groin
Merocrine:
widely distributed on body surface
especially on palms and soles

97. Apocrine Sweat Gland
Figure 5–11a

98. Apocrine Sweat Glands Merocrine secretions, not apocrine
Associated with hair follicles
Produce sticky, cloudy secretions
Break down and cause odors

99. Merocrine Sweat Glands
Also called eccrine glands:
coiled, tubular glands
discharge directly onto skin surface
sensible perspiration
water, salts, and organic compounds

100. Merocrine Sweat Gland
Figure 5–11b

101. Functions of Merocrine Sweat
Cools skin
Excretes water and electrolytes
Flushes microorganisms and harmful chemicals from skin

102. Other Integumentary Glands
Mammary glands:
produce milk
Ceruminous glands:
protect the eardrum
produce cerumen (earwax)

103. Homeostasis Thermoregulation:
is the main function of sensible perspiration
works with cardiovascular system
regulates body temperature

104. KEY CONCEPT Skin plays a major role in controlling body temperature:
acts as a radiator
removes heat from dermal circulation
works by evaporation of sensible perspiration

105. What is the structure of nails, and how do they grow?

106. Nail Functions Nails protect fingers and toes:
made of dead cells packed with keratin
metabolic disorders can change nail structure

107. Structure of a Nail
Figure 5–12

108. How does injured skin respond and repair itself?

109. Repair of Localized Injuries to the Skin: Step 1
Bleeding occurs
Mast cells trigger inflammatory response
Figure 5–13 (Step 1)

110. Repair of Localized Injuries to the Skin: Step 2
A scab stabilizes and protects the area
Figure 5–13 (Step 2)

111. The Inflammatory Response
Germinative cells migrate around the wound
Macrophages clean the area
Fibroblasts and endothelial cells move in, producing granulation tissue

112. Repair of Localized Injuries to the Skin: Step 3
Fibroblasts produce scar tissue
Inflammation decreases, clot disintegrates
Figure 5–13 (Step 3)

113. Repair of Localized Injuries to the Skin: Step 4
Fibroblasts strengthen scar tissue
A raised keloid forms
PLAY
Integumentary Repair
Figure 5–13 (Step 4)

114. Rule of Nines
To estimate burn damage, surface area is divided into multiples of 9
Figure 5–14

115. What are the effects of aging on the skin?

116. Effects of Aging Epidermal thinning
Decreased numbers of Langerhans cells
Decreased vitamin D3 production
Decreased melanocyte activity
Decreased glandular activity (sweat and oil glands)

117. Effects of Aging Reduced blood supply
Decreased function of hair follicles
Reduction of elastic fibers
Decreased hormone levels
Slower repair rate

118. How does the integumentary system work with other systems?

119. Importance of the Integumentary System
Protects and interacts with all organ systems
Changes in skin appearance are used to diagnose disorders in other systems

120. Interactions with the Integumentary System
Figure 5–15

121. SUMMARY (1 of 12) Division of: integument into epidermis and dermis
epidermis into thin skin and thick skin

122. SUMMARY (2 of 12) Layers of the epidermis: stratum germinosum
stratum spinosum
stratum lucidum
stratum corneum

123. SUMMARY (3 of 12)
Roles of epidermal ridges and dermal papillae

124. SUMMARY (4 of 12) Functions of specialized cells: Langerhans cells
Merkel cells

125. SUMMARY (5 of 12)
Skin pigments:
carotene
melanin

126. SUMMARY (6 of 12) Metabolic functions of epidermis: vitamin D3
epidermal growth factor

127. SUMMARY (7 of 12) Divisions of the dermis: papillary layer
reticular layer

128. SUMMARY (8 of 12) Mobility of the dermis: stretch marks
lines of cleavage

129. SUMMARY (9 of 12) Blood supply of the dermis: cutaneous plexus
papillary plexus

130. SUMMARY (10 of 12) Role of the subcutaneous layer
Structure of hair and hair follicles

131. SUMMARY (11 of 12)
Glands of the skin:
sebaceous
sweat
ceruminous

132. SUMMARY (12 of 12) Structure of nails
Processes of inflammation and regeneration
Effects of aging on the integument