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

• Deeper of the two skin layers • Contains all major tissue types, plus – Sebaceous oil glands – Hair follicles and arrector pili muscles – Collagen, elastin, and nerve fibers – Blood ve

The Integumentary

System

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

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

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

– Hair follicles – Nails

– Skin glands

Skin is the body’s outer covering and its largest

Functions of the Integumentary System

regulation

– If too hot

surface so heat can escape

– If too cold

– Small amounts of waste products

are lost through perspiration

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!

• Mostly dead cells form an impermeable layer

• Deepest layer

• Cells constantly dividing and pushing older cells outward

Epidermis (cont.)

• Keratinocyte – most common

• Durable protein that makes the epidermis waterproof and resistant to pathogens

• Melanocyte

• Traps UV radiation and prevents damage to underlying layers of the skin

• Deeper of the two skin layers

• Contains all major tissue types, plus

– Sebaceous (oil) glands

– Hair follicles and arrector pili muscles

– Collagen, elastin, and nerve fibers

– Blood vessels

• Binds the epidermis to the

subcutaneous tissue

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

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!

Skin Color

of melanin in the

epidermis of skin

darker the skin color

– Range is from yellowish

to brownish

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

Apply Your Knowledge

What affects skin color?

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

Nice Job!

tumor

Skin Lesions (cont.)

Bulla A large blister or cluster of blisters

Cicatrix A scar, usually inside a wound or tissue

Ecchymosis A black-and-blue mark or bruise

Erosion A shallow area of skin worn away by

friction or pressureExcoriation A scratch; may be covered with dried

blood

Skin Lesions (cont.)

Fissure A crack in the skin’s surface

Macule A flat skin discoloration, such as a

freckle or a flat mole

Papule An elevated mass similar to but smaller

than a nodulePetechiae Pinpoint skin hemorrhages that result

from bleeding disorders

Skin Lesions (cont.)

Plaque A small, flat, scaly area of skin

Purpura Purple-red bruises usually due to

clotting abnormalitiesScale Thin plaques of epithelial tissue on

skin’s surfacePustule An elevated (infected) lesion containing

pus

Skin Lesions (cont.)

Apply Your Knowledge

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

• Sebaceous glands

– Produce sebum to keep hair soft

– Prevent bacteria from growing on skin

• Nails

– Protect the ends of fingers and toes

– Hard keratin

Accessory Organs (cont.)

– Located in the dermis of skin

Skin Healing (cont.)

• Inflammation promotes healing

– Extra blood to area

– Extra nutrients for skin repair

– Defensive cells

Injury occurs

Blood clot forms

Scab replaces

other dried tissue

Collagen fibers

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

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

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

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!

death in the U.S.

extent (coverage) of burn

– Extent of body surface area

– 11 body areas

Rule of Nines

Burn Severity

Back

Burns: Treatment

• Do not remove anything

sticking to the burn

• Do not apply butter, lotions,

Apply Your Knowledge

Using Figure 24-5, determine

burn extent for a patient who

has burnt his anterior face and

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

Basal Cell Carcinoma

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

legs of women– Itches or bleeds

• Treatment

– Surgery and biopsy– Removal of lymph nodes

– Chemotherapy and radiation therapy– Immunotherapy

Stages of Melanoma

Stage 0 Only found in epidermis

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

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

Cancer Warning Signs

Apply Your Knowledge

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

Melanomas are more aggressive.

Borders are irregular.

Common Skin Disorders

Common Skin Disorders (cont.)

– Oozing skin lesions

that eventually crust over

• Pediculosis

– Head lice– Body lice– Pubic lice

• Psoriasis

– Inherited autoimmune disorder

Common Skin Disorders (cont.)

• Warts

– Harmless growths caused by a virus

Apply Your Knowledge

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

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

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

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

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

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

We may have different religions, different

languages, different colored skin, but we all belong to one

human race.

End of Chapter 20