24-1
The Integumentary System
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-2
Learning Outcomes
24.1 List the functions of skin.
24.2 Explain the role of skin in regulating body
temperature.
24.3 Describe the layers of skin and the characteristics
of each layer.
24.4 Explain the factors that affect skin color.
24.5 Identify and describe common skin lesions.
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-3
Learning Outcomes (cont.)
24.6 List the accessory organs of skin and describe
their structures and functions.
24.7 Explain the process of skin healing, including scar
production.
24.8 Describe the effects of aging on skin.
24.9 List the different types of burns and describe their
appearances and treatments.
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-4
Learning Outcomes (cont.)
24.10 Describe the causes, signs and symptoms, and
treatments of various types of skin cancer.
24.11 Describe the causes, signs and symptoms, and
treatments of common skin disorders.
24.12 Explain the ABCD rule and its use in evaluating
melanoma.
24.13 Using the acronym CAUTION, list the seven
warning signs of cancer.
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-5
Introduction

Integumentary
system consists of
skin and its
accessory organs

Accessory organs:



Hair follicles
Nails
Skin glands
Skin is the body’s outer covering and its
largest organ.
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24-6
Functions of the Integumentary
System

Protection

First line of defense against



Bacteria
Viruses
Protects underlying
structures from


Ultraviolet (UV) radiation
Dehydration
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24-7
Functions of the Integumentary
System (cont.)

Body temperature regulation

If too hot



Dermal blood vessels dilate
Vessels carry more blood to
surface so heat can escape
If too cold


Dermal blood vessels constrict
Prevents heat from escaping
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24-8
Functions of the Integumentary
System (cont.)

Vitamin D production


Sensation


Needed for calcium absorption
Sensory receptors
Excretion

Small amounts of waste products
are lost through perspiration
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-9
Apply Your Knowledge
What are the functions of the integumentary system?
ANSWER: The functions of the integumentary system are
protection, regulation of body temperature, vitamin D
production, sensation, and excretion.
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-10
Structure of Skin

Epidermis

Dermis

Hypodermis
or subcutaneous
layer
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24-11
Skin Structure: Epidermis


Most superficial layer
Two parts

Stratum corneum



Outermost layer
Mostly dead cells form an impermeable layer
Stratum basale (stratum germinativum)


Deepest layer
Cells constantly dividing and pushing older cells
outward
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24-12
Skin Structure: Epidermis (cont.)

Keratinocyte – most common

Makes and accumulates keratin


Durable protein that makes the epidermis waterproof
and resistant to pathogens
Melanocyte

Makes the pigment melanin

Traps UV radiation and prevents damage to
underlying layers of the skin
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24-13
Skin Structure: Dermis


Deeper of the two skin layers
Contains all major tissue types, plus






Sudoriferous (sweat) glands
Sebaceous (oil) glands
Hair follicles and arrector pili muscles
Collagen, elastic, and nerve fibers
Blood vessels
Binds the epidermis to the
subcutaneous tissue
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24-14
Skin Structure: Subcutaneous Layer


Hypodermis
Composed of



Adipose (fat) and loose connective tissue
Blood vessels and nerves
Functions


Storage in adipose tissue
Cushions and insulates underlying
structures
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-15
Apply Your Knowledge
Where are melanocytes and keratinocytes, and what is
their function?
ANSWER: Both are located in the epidermis of the skin.
Keratinocytes make and accumulate keratin, which is a
durable protein that makes the epidermis waterproof and
resistant to pathogens.
Melanocytes make the pigment melanin, which traps UV
radiation and prevents damage to underlying layers of the
skin.
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-16
Skin Color

Determined by amount
of melanin in the
epidermis of skin

The more melanin, the
darker the skin color

Range is from yellowish
to brownish
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24-17
Skin Color (cont.)

Oxygenated blood

Amount of oxygen dissolved in the hemoglobin
of the red blood cells

Hemoglobin – a pigment in the RBCs

If blood is well-oxygenated, skin will be pink

If oxygen level in blood is low, skin will be pale
or have a bluish color (cyanosis)
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-18
Apply Your Knowledge
What affects skin color?
ANSWER: The amount of melanin produced by the
melanocytes and the oxygenation of the blood.
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-19
Skin Lesions

Any variation in the
skin

As simple as a freckle

As serious as a tumor
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24-20
Skin Lesions (cont.)
Lesion Name
Description
Bulla
A large blister or cluster of blisters
Cicatrix
A scar, usually inside a wound or tissue
Crust
Dried blood or pus on the skin
Ecchymosis
A black-and-blue mark or bruise
Erosion
A shallow area of skin worn away by
friction or pressure
A scratch; may be covered with dried blood
Excoriation
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24-21
Skin Lesions (cont.)
Lesion Name
Description
Fissure
Keloid
A crack in the skin’s surface
An overgrowth of scar tissue
Macule
A flat skin discoloration, such as a freckle or
a flat mole
Nodule
A large pimple or small node
Papule
An elevated mass similar to but smaller than
a nodule
Petechiae
Pinpoint skin hemorrhages that result from
bleeding disorders
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24-22
Skin Lesions (cont.)
Lesion Name
Description
Plaque
A small, flat, scaly area of skin
Purpura
Purple-red bruises usually due to clotting
abnormalities
Scale
Thin plaques of epithelial tissue on skin’s
surface
Pustule
An elevated (infected) lesion containing pus
Tumor
A swelling of abnormal tissue growth
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-23
Skin Lesions (cont.)
Lesion Name
Description
Ulcer
A wound that results from tissue loss
Vesicle
A blister
Wheal
Another term for hive
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-24
Apply Your Knowledge
Match the following:
ANSWER:
C Keloid
___
A. A blister
A Vesicle
___
B. A crack in the skin’s surface
E Crust
___
C. An overgrowth of scar tissue
B Fissure
___
D. A small, flat scaly area of skin
F Ulcer
___
D Plaque
___
E. Dried blood or pus on the skin
F. A wound that results from tissue loss
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-25
Accessory Organs (cont.)

Hair follicles




Tube-like depressions
in the dermis of skin
Generate hairs
Alopecia (baldness)
occurs when follicles
die
Arrector pili muscles
attached to follicles
cause goose bumps

Sebaceous glands



Produce sebum to keep
hair soft
Prevent bacteria from
growing on skin
Nails


Protect the ends of
fingers and toes
Hard keratin
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-26
Accessory Organs (cont.)

Sudoriferous (sweat) glands


Located in the dermis of skin
Types

Eccrine



Produce watery type of sweat
Activated by heat
Apocrine



Produce thicker type of sweat with more proteins
Concentrated in armpit and groin areas
Activated by nervousness or stress
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24-27
Accessory Organs
Sebaceous gland
Hair follicle
Sudoriferous gland
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24-28
Skin Healing

Injury  inflammation

Redness due to dilation of nearby
blood vessels

Swelling because vessels leak
fluid into spaces between cells

Pain because excess fluid
activates pain receptors
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24-29
Skin Healing (cont.)

Inflammation promotes healing
Extra blood to area
Injury occurs
 Extra nutrients for skin repair
Blood clot
 Defensive cells
forms
Scab replaces
Clotted blood and
blood clot
other dried tissue
Collagen fibers
replace scab
Bind the edges of wound;

major component of scars
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-30
Apply Your Knowledge
How does inflammation promote healing of the skin?
ANSWER: Inflammation promotes healing by bringing
extra blood, nutrients for skin repair, and defensive cells to
the area of injury.
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-31
Skin and Aging

Skin loses firmness due to



Loss of elastic and collagen
fibers in dermis
Loss and shifting of underlying
adipose tissues
Skin color changes


Dermis becomes thinner and more transparent
Paler due to decrease in circulation
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24-32
Skin and Aging (cont.)

Melanocytes decrease



Those remaining gather  “age” spots
Hair grays and becomes thinner
Decreased tolerance to temperature changes

Sudoriferous glands decrease in number


Decreased perspiration, hard to adjust to high
temperatures
Loss in adipose tissue and decreased circulation

Increased sensitivity to cold
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-33
Apply Your Knowledge
What happens to the skin in the elderly?
ANSWER: As a person ages, the skin loses firmness, skin
color changes, melanocytes decrease, and tolerance to
temperature changes decreases due to a loss of adipose
tissue and sweat glands.
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
Skin Cancer-The most common type of cancer


Cancer – abnormal cell mass
Two types of tumors:


Benign – cells are not able to metastisize (move to
new location)
Malignant – cancerous cells that can metastisize
Risks:
1.
Skin type
2.
Sun exposure
3.
Family history
4.
Age
5.
Immunological status
http://science.nationalgeographic.com/science/health
-and-human-body/human-body/skin-article/
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
Skin Cancer Types

Basal cell carcinoma – least malignant and most
common

bump with pearly edge, rarely metastisizes, surgery
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Skin Cancer Continued

Squamous cell carcinoma – rapid growth,
metastisizes to lymph nodes


Scaly, red areas forming an ulcer, common on scalp, ears,
hands & lower lip
Surgery + radiation
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
Skin Cancer Continued

Malignant melanoma – cancer of melanocytes,
spreads rapidly, often deadly

5% of skin cancer is this type, often from pigmented mole
Normal mole
Malignant Melanoma
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24-38
Skin Cancer: summarized

Basal cell carcinoma – progresses slowly and
rarely spreads to other body parts

Squamous cell carcinoma – more likely to
spread to surrounding tissues

Malignant melanoma – more aggressive and
occurs anywhere
 Most arise from melanocytes
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-39
Skin Cancer: Basal Cell Carcinoma

Signs and symptoms




New growth or sore that will not heal
Waxy, smooth, red, pale, flat, or lumpy
May or may not bleed
Treatment:


Curettage and electrodessication
Mohs’ surgery
 Cryosurgery
 Laser therapy
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-40
Skin Cancer: Squamous Cell Carcinoma

Less common than basal cell carcinoma

Found on face, lips, ears, and backs of hands

Signs and symptoms and
treatments are the same
as for basal cell carcinoma
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24-41
Skin Cancer: Malignant Melanoma

Signs and Symptoms




From melanocytes
Appear on trunk, head,
neck of men
Appear on arms and
legs of women
Itches or bleeds

Treatment




Surgery and biopsy
Removal of lymph
nodes
Chemotherapy and
radiation therapy
Immunotherapy
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24-42
Skin Cancer: Stages of Melanoma
Stage 0
Only found in epidermis
Stage I
Stage II
Spread to epidermis and dermis (1 to 2 mm
thick)
2 to 4 mm thick plus ulceration
Stage III
Spread to one or more lymph nodes
Stage IV Spread to other body organs or lymph nodes
far from original melanoma
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
ABCD Rule –for recognizing melanoma

A = Asymmetry – sides of mole do not match

B = Border irregularity – no smooth borders

C = Color – different colors, reds, tans, black, brown

D = Diameter – larger than 6 mm

You want moles to be symmetrical, smooth borders,
one color and small!!
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-44
Skin Cancer: ABCD Rule
A
B
C
D
Asymmetry: The mole should not become
asymmetrical
Border should not become irregular
Color should not change or become
mixture of colors
Diameter should not grow larger than the
diameter of a pencil eraser
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24-45
Cancer Warning Signs
C–
A–
U–
T–
I –
O–
N–
Change in bowel or bladder habits
A sore that will not heal
Unusual bleeding or discharge
Thickening or lump
Indigestion or difficulty swallowing
Obvious change in wart or mole
Nagging cough or hoarseness
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-46
Apply Your Knowledge
True or False:
ANSWER:
Melanomas are more aggressive .
F Basal cell carcinoma is the most aggressive form of skin
___
cancer and can form anywhere.
___
T Squamous cell carcinoma is more likely to spread to
surrounding tissues.
___
T Lesions of melanoma appear on trunk, head, neck of men and
on arms and legs of women.
Borders are irregular.
F The borders of skin cancers are usually regular.
___
___
T Basal cell carcinoma progresses slowly and rarely spreads to
other body parts.
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-47
Common Skin Disorders

Alopecia



Results in hair loss
Dermatitis

Cellulitis

Inflammation of
connective tissue
in skin

Eczema


Inflammation of skin
or a rash
Chronic dermatitis
Folliculitis

Inflammation of hair
follicles
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-48
Common Skin Disorders (cont.)

Herpes simplex



Type 1 – cold sores
Type 2 – genital
Pediculosis




Herpes zoster

Shingles

Psoriasis


Head lice
Body lice
Pubic lice
Impetigo

Inherited autoimmune
disorder
Oozing skin lesions that
eventually crust over
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-49
Common Skin Disorders (cont.)

Ringworm




Tinea corporis
Tinea capitis
Tinea pedis
Rosacea


Dilation of small facial
blood vessels
Scabies


Contagious skin
condition caused by
mites
Warts

Harmless growths
caused by a virus
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-50
Apply Your Knowledge
Match the following:
ANSWER:
C Alopecia
___
A. Dilation of small facial blood vessels
___
E Folliculitis
B. Inherited autoimmune disorder
___
F Impetigo
C. Hair loss
B Psoriasis
___
D. Growths caused by a virus
___
A Rosacea
E. Inflammation of hair follicles
___
D Warts
F. Oozing skin lesions
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
Skin Homeostatic Imbalances

BURNS:


Tissue damage and cell death caused
by heat, electricity, UV radiation, or
chemicals
Associated dangers
 Body loses supply of fluids
(proteins & electrolytes)
 Infection
• RULE OF NINES: 11 areas of the body with 9% value
each, + 1% perineum
•The higher the % the greater the risk of complications
and death.
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
Severity of Burns

FIRST-DEGREE BURNS – partial thickness burn, epidermis
damaged, red & swollen, 2-3 days to heal, “sunburn”

SECOND-DEGREE BURNS – partial thickness burn,
epidermis and papillary layer burned, red with blisters
 Regrowth usually occurs with little to no scarring

THIRD-DEGREE BURNS – full thickness burn, area is
blackened or gray/white, no pain (nerve endings burned off)
 Grafting must be done, scarring
Burns are considered critical if: over 25% of body has 2nd
degree burn, over 10% has 3rd degree burns or 3rd degree burns
on hands/face/feet

© 2009 The McGraw-Hill Companies, Inc. All rights reserved
http://www.youtube.com/watch?v=eXO_ApjKPaI&safe=active (the skin gun)
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-54
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-55
Burns: Treatment

Do not remove anything
sticking to the burn

Do not apply butter, lotions,
or ointments

Cool with large amounts of
water

Cover with sterile sheet or
plastic bag
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-56
Apply Your Knowledge
Using Figure 24-5, determine
burn severity for a patient who
has burnt his anterior face and
both arms.
ANSWER: Head = 9%
Both arms, hands, and shoulders = 18% + 18%
9% + 18% + 18% = 45%
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
Homeostatic Skin Imbalances
Directions: On a separate sheet of paper thoroughly
answer the question below. Use appropriate academic
vocabulary and clear and complete sentences.
Name FOUR homeostatic imbalances that can occur in
relation to the skin.
Describe each problem in detail along with the
underlying cause of each.
57
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
24-58
In Summary:


First line of defense for body
Protects the body from






Invading organisms
Chemicals
UV light
Water loss
Regulates body temperature
Understanding this system can help you be more
effective in your role
© 2009 The McGraw-Hill Companies, Inc. All rights reserved