Lecture Medical assisting: Administrative and clinical procedures with anatomy and physiology (4e) – Chapter 20

CHAPTER

20
The Integumentary
System

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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.

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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.
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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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Functions of the Integumentary System

20-7

(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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Functions of the Integumentary System

20-8

(cont.)

•

Vitamin D production
– Needed for calcium absorption

•

Sensation
– Sensory receptors

•

Excretion
– Small amounts of waste products
are lost through perspiration
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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

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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)

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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

Scale

Thin plaques of epithelial tissue on
skin’s surface

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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