CHAPTER © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20 The Integumentary System

CHAPTER

© 2011 The McGraw-Hill Companies, Inc. All rights reserved.

20The Integumentary

System


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.


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.


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.


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.


20-6

Functions of the Integumentary System

• Protection– First line of defense against

• Bacteria • Viruses

– Protects underlying structures from

• Ultraviolet (UV) radiation • Dehydration


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


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


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!


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


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


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


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


20-15


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!


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


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)


20-18


What affects skin color?

ANSWER: The amount of melanin produced by the melanocytes and the oxygenation of the blood.

Nice Job!


20-19

Skin Lesions

• Any variation in the skin– As simple as a

freckle

– As serious as a tumor


20-20

Skin Lesions (cont.)

Lesion Name DescriptionBulla 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


20-21


Lesion Name DescriptionFissure 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


20-22


Lesion Name DescriptionPlaque 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


20-23


Lesion Name DescriptionUlcer A wound that results from tissue loss

Vesicle A blister

Wheal Another term for hive


20-24


Match the following:

___ Keloid A. A blister

___ Vesicle B. A crack in the skin’s surface

___ Crust C. An overgrowth of scar tissue

___ Fissure D. A small, flat scaly area of skin

___ Ulcer E. Dried blood or pus on the skin

___ Plaque F. A wound that results from tissue loss

A

E

B

F

D

C

ANSWER:


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


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


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


20-29

Skin Healing (cont.)

• Inflammation promotes healing – Extra blood to area– Extra nutrients for skin repair– Defensive cells

Injury occurs

Blood clot forms

Scab replaces blood clot Clotted blood and

other dried tissueCollagen fibers

replace scab Bind the edges of wound; major component of scars


20-30


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


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


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


20-33


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!


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


20-35

Back


20-36

Burn Severity

Burns


20-37

1st Degree 2nd Degree 3rd Degree

Back


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


20-39


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: Head = 9%

Both arms, hands, and shoulders = 18% + 18%

9% + 18% + 18% = 45%

It all adds up to a right answer!


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


20-41

Basal Cell Carcinoma


20-4220-42

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


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


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


20-45

ABCDE Rule

A Asymmetry – a mole should not become asymmetrical. It should look equal in size from side to side.

B Border – a mole should not have irregular borders and edges should not blur into normal tissue.

C Color – a mole should not change or become mixture of colors. It should have even coloring.

D Diameter – a mole should not grow larger than the diameter of a pencil eraser (6 mm.)

E Evolving – a mole that has been changing in size, color and appearance, or growing in an area of previously normal skin


20-4624-46

Cancer Warning Signs

C – Change in bowel or bladder habitsA – A sore that will not healU – Unusual bleeding or discharge T – Thickening or lumpI – Indigestion or difficulty swallowingO – Obvious change in wart or moleN – Nagging cough or hoarseness


20-47


True or False:

___ Basal cell carcinoma is the most aggressive form of skin

cancer and can form anywhere.

___ Squamous cell carcinoma is more likely to spread to surrounding tissues.

___ Lesions of melanoma appear on trunk, head, neck of men and on arms and legs of women.

___ The borders of skin cancers are usually regular.

___ Basal cell carcinoma progresses slowly and rarely spreads to other body parts.

ANSWER:

F

T

T

F

T

Melanomas are more aggressive.

Borders are irregular.


20-48

Common Skin Disorders• Alopecia

– Results in hair loss

• Cellulitis

– Inflammation of connective tissue in skin

Dermatitis Inflammation of skin

or a rash

Eczema Chronic dermatitis

Folliculitis Inflammation of hair

follicles


20-49

Common Skin Disorders (cont.)

• Herpes simplex – Type 1 – cold sores– Type 2 – genital

• Herpes zoster– Shingles

• Impetigo – Oozing skin lesions

that eventually crust over

• Pediculosis– Head lice– Body lice– Pubic lice

• Psoriasis – Inherited autoimmune

disorder


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


20-51


Match the following:

___ Alopecia A. Dilation of small facial blood

vessels

___ Folliculitis B. Inherited autoimmune disorder

___ Impetigo C. Hair loss

___ Psoriasis D. Growths caused by a virus

___ Rosacea E. Inflammation of hair follicles

___ Warts F. Oozing skin lesions

ANSWER:

C

F

A

B

D

E

Right!


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.


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.


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.


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.

20.10There 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.


20-56

In Summary (cont.)

20.11Common skin disorders: the signs, symptoms, and treatments for these conditions are found in the Pathophysiology section at the end of the chapter.

20.12ABCDE 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.

20.13The seven warning signs of cancer are: C = Change, A = A sore, U = Unusual, T = Thickening, I = Indigestion, O = Obvious change, and N = Nagging cough.


20-57

We may have different religions, different languages, different colored skin, but we all belong to one human race.

~ Kofi Annan

End of Chapter 20

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CHAPTER © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20 The Integumentary System