Chapter 26 The Integumentary System. Copyright ©2012 Delmar, Cengage Learning. All rights reserved....

Chapter 26

The Integumentary System

Copyright ©2012 Delmar, Cengage Learning. All rights reserved.

The Skin

Functions of the Skin

• Protection– Against invasion by bacteria– Underlying tissue from injury– Against loss of body fluid

• Perception– Works with the nervous system to provide a sense

of touch– Registers pain, heat, cold, and pressure



• Absorption– Skin can absorb moisture and medication as well

as some vital vitamins and minerals through the hair follicles and glands.

• Excretion– Skin eliminates water, salt, and waste.




• Temperature control– When the temperature control center in the brain

senses that the body is too warm, blood vessels dilate so that heat escapes through the skin surface.

– When it is cold, the vessels constrict to prevent heat loss from the skin surface.


Structures of the Skin

• In 1 square centimeter of skin, there are:– 3 million cells– 24 sensory apparatuses for heat and cold– 200 nerve endings– 25 pressure apparatuses– 4 yards of nerves– 3,000 sensory cells – 700 sweat glands– 1 yard of blood vessels– 15 sebaceous glands


How the Body Cools Its Surface

• The skin contains sweat glands that produces moisture when the body is too hot.

• This moisture evaporates from the skin surface to provide a cooling effect.

The Three Layers of Skin Tissue

Epidermis– Top layer

Dermis– Middle layer– Filled with fat, blood vessels,

sweat and oil glands, and nerves

Subcutaneous– Inner layer – Contains blood vessels,

nerves, and hair follicles



4 Appendages of the Skin

Sweat glands– Produce moisture to cool the skin surface

Oils glands– Produce oils to prevent hair and skin from

becoming dry and brittle

HairNails



The Process That Causes Wrinkles

• With age, the elastic fiber in the dermis increases in size, and collagen in the dermis degenerates.

• The support for the epidermis is decreased and wrinkles develop.



What Causes a Suntan to Develop

• When the skin is exposed to the sun, it may become reddened because of superficial blood vessel dilation.

• The melanin pigment increases and moves to the surface to protect the underlying tissue.

• A brownish coloration or suntan appears.



Basal Cell Carcinoma

• Slow-growing, locally destructive skin tumor; also called skin cancer

• Usually occurs in areas where there are abundant sebaceous follicles

• More common in persons over 40, especially those who are blond and fair skinned



Squamous Cell Carcinoma

• Invasive tumor that has metastatic potential• Usually occurs in Caucasian men over the age

of 60• Working outdoors and smoking increases the

risk for developing this cancer.


Ordinary Moles versus Melanoma

• Shape• Border• Color• Diameter• Development


Factors that Contribute to the Development of Melanoma

• Intense exposure to ultraviolet (UV) rays from sunlight

• Blond or red hair• Fair skin with tendency to sunburn• Blue eyes


Blushing

• The skin has a rich supply of blood vessels.• When we blush, the vessels dilate and cause

reddening of the skin.


Birthmarks and Moles

• Birthmarks can be caused by coloration from a collection of blood vessels or from patches of skin pigment.

• Moles are pigmented patches of skin.


Albinism

• Persons who have little or no skin pigment to give it color are identified as albinos.

• The hair is pale yellow or white.• The eyes appear red and are very sensitive to

light.


Alopecia• Loss of hair that usually occurs in the scalp• Physiologic alopecia

– Temporary hair loss• Alopecia areata

– Limited to small patches of hair loss• Male pattern baldness

– Most common form of hair loss– Affects men over age 30


Cellulitis

• Acute diffuse or spreading inflammation of the skin and subcutaneous tissue

• Causes localized swelling, pain, heat, and redness

• Usually the result of a streptococcus or Staphylococcus infection


Eczema

• Acute or chronic skin disorder that results in dry, red, itchy, and scaly skin

• Eczema can be irritated by diet, cosmetics, clothing, medications, soaps, and environmental elements, as well as emotional stress.

Dermatitis and Folliculitis

• Dermatitis– Inflammation of the skin – Can refer to any form of skin condition such as

seborrhea, eczema, contact dermatitis, exfoliative dermatitis, or stasis

• Folliculitis– Infection of the hair follicle with the formation of

a pustule



Furuncles and Carbuncles

• Furuncles– Hard, painful nodules that develop over time and

then rupture and release pus and dead cells through a drainage point

– May develop from folliculitis• Carbuncles

– Began as a nodule, then enlarge and have multiple drainage points


Herpes

• Viral infection that causes groups of small, painful, clear vesicles

• Type I: Lesions appear in the mouth and nasal area.

• Type II: Lesions appear in the genitals.


Herpes Zoster

• Also called shingles• Acute infectious process from the same virus

that causes chickenpox• Results in fever, malaise, and usually unilateral

eruption of vesicles on the back, chest, or neck

Hirsutism and Impetigo

• Hirsutism– Excessive development of body hair that could be

hereditary or the result of an endocrine system disorder

• Impetigo– Contagious skin infection with macules and

vesicles that erupt and form a characteristic yellow crust



Keloids and Lyme Disease

• Keloids– Scars that develop excess dense tissue as they

heal• Lyme disease

– Tick-borne disease that is generally the result of a spirochete-infested deer tick


Pediculosis

• The infestation of parasitic lice• Pediculosis capitis

– Head lice• Pediculosis corpus

– Body lice• Pediculosis pubis

– Lice attached to pubic hair; commonly called crabs


Poison Ivy and Psoriasis

• Poison ivy– Dermatitis that results from contact with the

poison ivy plant• Psoriasis

– Chronic inflammatory skin condition that causes red papules covered with silvery scales


Rosacea and Ringworm

• Rosacea– Chronic skin eruption that makes the face,

especially the nose and cheeks, look flushed• Ringworm

– Fungal infection that causes flat lesions that may be dry and scaly or moist and crusty


Scabies and Urticaria

• Scabies– Skin infection caused by a skin mite; results in

intense itching• Urticaria

– Also called hives; a self-limiting reaction to allergens that results in distinct wheals surrounded by reddened areas


Verrucae

• Also called warts; a benign viral infection of the skin that results in rough, elevated, rounded areas on the skin surfaces

Chapter 26 The Integumentary System. Copyright ©2012 Delmar, Cengage Learning. All rights reserved....

Documents

Transcript of Chapter 26 The Integumentary System. Copyright ©2012 Delmar, Cengage Learning. All rights reserved....