Download The Integumentary System

CHAPTER
20
The Integumentary
System
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
20-2
Learning Outcomes
20.1 List the functions of skin.
20.2 Explain the role of skin in regulating body
temperature.
20.3 Describe the layers of skin and the
characteristics of each layer.
20.4 Explain the factors that affect skin color.
20.5 Identify and describe common skin lesions.
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
20-3
Learning Outcomes (cont.)
20.6 List the accessory organs of skin and
describe their structures and functions.
20.7 Explain the process of skin healing, including
scar production.
20.8 Describe the effects of aging on skin.
20.9 List the different types of burns and describe
their appearances and treatments.
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20-4
Learning Outcomes (cont.)
20.10 Describe the causes, signs and symptoms,
and treatments of various types of skin
cancer.
20.11 Describe the causes, signs and symptoms,
and treatments of common skin disorders.
20.12 Explain the ABCDE rule and its use in
evaluating melanoma.
20.13 Using the acronym CAUTION, list the seven
warning signs of cancer.
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
20-5
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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20-6
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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20-7
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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20-8
Functions of the Integumentary System
(cont.)
•
Vitamin D production
–Needed for calcium absorption
•
Sensation
–Sensory receptors
•
Excretion
– Small amounts of waste products
are lost through perspiration
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
20-9
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.
Super!
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20-11
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
To Figure of Skin
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20-12
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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20-13
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, elastin, and nerve fibers
– Blood vessels
• Binds the epidermis to the
subcutaneous tissue
To Figure of Skin
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20-14
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
To Figure of Skin
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
20-15
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.
Excellent!
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20-16
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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20-17
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)
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
20-18
Apply Your Knowledge
What affects skin color?
ANSWER: The amount of melanin produced by the
melanocytes and the oxygenation of the blood.
Nice Job!
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20-19
Skin Lesions
• Any variation in the
skin
– As simple as a
freckle
– As serious as a
tumor
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20-20
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
Excoriation
A scratch; may be covered with dried
blood
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20-21
Skin Lesions (cont.)
Lesion Name
Description
Fissure
A crack in the skin’s surface
Keloid
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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20-22
Skin Lesions (cont.)
Lesion Name
Description
Plaque
A small, flat, scaly area of skin
Purpura
Purple-red bruises usually due to
clotting abnormalities
Thin plaques of epithelial tissue on
skin’s surface
Scale
Pustule
An elevated (infected) lesion containing
pus
Tumor
A swelling of abnormal tissue growth
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20-23
Skin Lesions (cont.)
Lesion Name
Description
Ulcer
A wound that results from tissue loss
Vesicle
A blister
Wheal
Another term for hive
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20-24
Apply Your Knowledge
Match the following:
C Keloid
___
ANSWER:
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
___
E. Dried blood or pus on the skin
D Plaque
___
F. A wound that results from tissue loss
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20-25
Accessory Organs
•
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
Diagram
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20-26
Accessory Organs (cont.)
•
Sudoriferous (sweat) glands
– Located in the dermis of skin
– Types
•
Eccrine gland
– Produce watery type of sweat
– Activated by heat
•
Apocrine gland
– Produce thicker type of sweat with more
proteins
– Concentrated in armpit and groin areas
– Activated by nervousness or stress
Diagram
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20-28
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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20-29
Skin Healing (cont.)
• Inflammation promotes healing
– Extra blood to area
Injury occurs
– Extra nutrients for skin repair
– Defensive cells
Blood clot
forms
Scab replaces
blood clot
Collagen fibers
replace scab
Clotted blood and
other dried tissue
Bind the edges of wound;
major component of scars
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
20-30
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.
Correct
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20-31
Skin and Aging
• Skin loses firmness due to
– Loss of elastin 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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20-32
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
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
20-33
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.
Very Good!
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20-34
Burns
•
Second leading cause of accidental
death in the U.S.
•
Rule of nines is used to determine
extent (coverage) of burn
– Extent of body surface area
– 11 body areas
Rule of Nines
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20-35
Back
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20-36
Burn Severity

Superficial – first-degree



Partial-thickness – second-degree



Epidermis only
Pain, redness, swelling
Epidermis and dermis
Pain, redness, swelling, blisters
Full-thickness – third-degree



All layers of skin and often underlying
structures
Skin appears charred
Always requires medical attention
Burns
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20-37
1st Degree
2nd Degree
3rd Degree
Back
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20-38
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
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
20-39
Apply Your Knowledge
Using Figure 24-5, determine
burn extent for a patient who
has burnt his anterior face and
both arms.
Click for Figure 24-5
Rule of Nines
ANSWER: Face = 4.5%
Both arms, hands, and shoulders = 18%
4.5% + 18% = 22.5%
It all adds up to a
right answer!
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
20-40
Skin Cancer
•
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
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20-41
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  Cryosurgery
Mohs’ surgery
 Laser therapy
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20-42
20-42
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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20-43
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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20-44
Stages of Melanoma
Stage 0
Only found in epidermis
Stage I
Spread to epidermis and dermis (1 to 2
mm thick)
Stage II
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
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20-45
ABCDE Rule
A
Asymmetry – a mole should not become asymmetrical.
It should look equal in size from side to side.
B
C
D
Border – a mole should not have irregular borders and
edges should not blur into normal tissue.
E
Evolving – a mole that has been changing in size, color
and appearance, or growing in an area of
previously normal skin
Color – a mole should not change or become mixture
of colors. It should have even coloring.
Diameter – a mole should not grow larger than the
diameter of a pencil eraser (6 mm.)
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20-46
24-46
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
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
20-47
Apply Your Knowledge
True or False:
ANSWER:
F Basal cell carcinoma is the most aggressive form of skin
___
cancer and can form anywhere.
Melanomas are more aggressive.
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.
F The borders of skin cancers are usually regular.
___
Borders are irregular.
T Basal cell carcinoma progresses slowly and rarely
___
spreads to other body parts.
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20-48
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
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20-49
Common Skin Disorders (cont.)
•
Herpes simplex
•
– Type 1 – cold sores
– Type 2 – genital
•
– Head lice
– Body lice
– Pubic lice
Herpes zoster
– Shingles
•
Pediculosis
Impetigo
•
Psoriasis
– Inherited autoimmune
disorder
– Oozing skin lesions
that eventually crust
over
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20-50
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
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
20-51
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
Right!
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20-52
In Summary
20.1 The functions of skin include protection, body
temperature regulation, vitamin D production,
sensation, and excretion.
20.2 When the body is warm, the dermal blood vessels
dilate, allowing heat to escape and cool the body.
When the body is cool, the same vessels constrict,
preventing the heat carried by blood from escaping,
keeping the body warmer.
20.3 The topmost layer of the skin is the epidermis. The
dermis is the complex middle layer. The innermost
layer, attaching the skin to muscle, is the
subcutaneous layer.
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20-53
In Summary (cont.)
20.4 The amount of melanin affects and determines skin
color. The amount of oxygen-carrying hemoglobin in
our blood also affects skin color.
20.5 Skin lesions are split among three main types:
primary lesions such as macules and vesicles;
secondary lesions include ulcers and keloids;
vascular lesions involve blood vessels and include
telangiectasias and ecchymoses.
20.6 The accessory organs of skin include hair follicles,
arrector pili muscles, sebaceous glands, sudoriferous
glands, and keratin-filled nails.
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20-54
In Summary (cont.)
20.7 Injured skin becomes inflamed from dilating blood
vessels which leak and cause swelling. A blood clot is
formed, which is replaced by a scab, which is then
replaced by collagen fibers that produce scar tissue.
20.8 Skin loses elasticity with aging as well as the youthful
glow because of the loss of collagen and elastin
fibers. The loss of melanin also causes graying and
thinning of the hair. The loss of adipose tissue and
decreased number of sudoriferous glands makes it
difficult to readily adjust to temperature changes.
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20-55
In Summary (cont.)
20.9 First-degree burns affect only the epidermis and are
known as superficial burns. Second-degree burns or
partial thickness burns involve both the epidermis
and dermis. Third-degree or full-thickness burns
affect all skin layers and underlying structures,
including muscle and bone.
20.10 There are three types of skin cancer: basal cell,
squamous cell, and malignant melanoma. Signs of
skin cancer vary, as do the treatment methods for
each type.
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
20-56
In Summary (cont.)
20.11 Common skin disorders: the signs, symptoms, and
treatments for these conditions are found in the
Pathophysiology section at the end of the chapter.
20.12 ABCDE is the acronym used to remember the signs
of possible melanoma when looking at suspicious
moles on the body. A = Asymmetry, B = Border, C =
Color, D = Diameter, and E = Evolving.
20.13 The seven warning signs of cancer are: C = Change,
A = A sore, U = Unusual, T = Thickening, I =
Indigestion, O = Obvious change, and N = Nagging
cough.
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20-57
End of Chapter 20
We may have different
religions, different
languages, different
colored skin, but we all
belong to one human
race.
~ Kofi Annan
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.