The Integumentary System

The Integumentary System
23 The Integumentary System

Learning Outcomes (cont.)
23.1 Describe the functions of skin. 23.2 Describe the layers of skin and the characteristics of each layer. 23.3 Explain the factors that affect skin color. 23.4 Summarize types of common skin lesions.

Learning Outcomes (cont.)
23.5 Describe the accessory organs of skin along with their structures and functions. 23.6 Explain the process of skin healing, including scar production. 23.7 Describe the common diseases and disorders of the skin.

Introduction Integumentary system Skin Accessory organs:
Body’s outer covering Largest organ Accessory organs: Hair follicles Nails Skin glands Learning Outcome: 23.1 Describe the functions of skin. Your skin accounts for approximately 15% of body weight.

Functions of the Integumentary System
Protection First line of defense Bacteria Viruses Protects underlying structures UV radiation Dehydration Learning Outcome: 23.1 Describe the functions of skin. Protection First line of defense against bacteria and viruses. Protects underlying structures from ultraviolet (UV) radiation and dehydration.

Functions of the Integumentary System (cont.)
Body temperature regulation If too hot Dermal blood vessels dilate More blood to surface so heat escapes If too cold Dermal blood vessels constrict Prevents heat from escaping Learning Outcome: 23.1 Describe the functions of skin. When a person is hot, dermal blood vessels dilate, which is why a person’s skin becomes pinkish. Because the dermal blood vessels are dilated, more blood than normal passes through the skin. This is beneficial because blood carries a lot of the body’s heat. When the blood gets close to the body’s surface (to skin), the heat can escape. On the other hand, if a person is cold, the dermal blood vessels constrict, preventing the heat in blood from escaping.

Functions of the Integumentary System (cont.)
Vitamin D production Skin must have sunlight Needed for calcium absorption Sensation – receptors Excretion – perspiration Learning Outcome: 23.1 Describe the functions of skin. Vitamin D production – when exposed to sunlight, the skin produces a molecule that is turned into vitamin D. Sensation – the skin is packed with sensory receptors that can detect touch, heat, cold, and pain. Excretion Small amounts of waste products, such as water and salts, are lost through skin when a person perspires Hydration is important when exercising or during exposure to high temperatures As the amount of perspiration increases, higher amounts of water and salts are lost.

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. Learning Outcome: 23.1 Describe the functions of skin. Super!

Skin Structure Epidermis Dermis Hypodermis or subcutaneous layer
Learning Outcome: Describe the layers of skin and the characteristics of each layer. The skin is consists of two layers: the epidermis and the dermis. These skin layers sit on a third layer called the subcutaneous layer or hypodermis.

Epidermis Superficial layer of the skin Major layers Stratum corneum
Outermost layer Mostly dead cells form an impermeable layer Stratum basale Deepest layer Cells constantly dividing and pushing older cells outward Learning Outcome: Describe the layers of skin and the characteristics of each layer. Stratum corneum The most superficial layer of the epidermis. Most of the cells in this layer are dead and very flat. Because they have accumulated keratin, the cells in this layer stick together and form an impermeable layer for skin. Most bacteria, viruses, and water cannot penetrate the stratum corneum. Stratum basale Also known as the stratum germinativum The deepest layer of the epidermis. Cells in this layer are constantly dividing (or germinating), and push older cells up toward the stratum corneum. To Figure of Skin

Epidermis (cont.) Cell types Keratinocyte
Most common Makes and accumulates the protein keratin Melanocyte ~ makes the pigment melanin Learning Outcome: Describe the layers of skin and the characteristics of each layer. Keratinocyte The most common cell type in the epidermis. Makes and accumulates the protein keratin. Keratin is a durable protein that makes the epidermis waterproof and resistant to bacteria and viruses. Melanocyte Makes the pigment melanin. Melanin is deposited throughout the layers of the epidermis. This pigment absorbs UV radiation from sunlight and prevents the radiation from harming structures in the skin’s underlying layers.

Dermis Deeper, more complex Contains all major tissues, plus
Sudoriferous glands Sebaceous glands Hair follicles and arrector pili muscles Collagen, elastin, and nerve fibers Blood vessels Learning Outcome: Describe the layers of skin and the characteristics of each layer. Deeper and most complex of the two skin layers. Contains all the major tissue types plus Sudoriferous (sweat) glands Sebaceous (oil) glands Hair follicles The arrector pili muscles Collagen fibers, elastin fibers, nerve fibers, and many blood vessels Binds the epidermis to the subcutaneous tissue. To Figure of Skin

Subcutaneous Layer Hypodermis Composed of
Adipose (fat) and loose connective tissue Blood vessels and nerves Learning Outcome: Describe the layers of skin and the characteristics of each layer. Subcutaneous layer – hypodermis Made up of adipose and loose connective tissue Contains blood vessels and nerves The adipose or fat tissue acts as a storage facility. It also cushions and insulates the underlying structures and organs. The amount of adipose tissue varies from body region to body region, and from person to person. To Figure of Skin

Skin Structure Sebaceous gland Stratum corneum Hair follicle
Stratum basale Arrector pili muscle Learning Outcome: Describe the layers of skin and the characteristics of each layer. The skin is consists of two layers: the epidermis and the dermis. These skin layers sit on a third layer called the subcutaneous layer or hypodermis. Adipose tissue Sudoriferous (Eccrine) gland Back

Excellent! Apply Your Knowledge
What are the layers of skin and what is their function? ANSWER: Epidermis – superficial outer layer; cells produce keratin which makes it waterproof and resistant to bacteria and viruses; and melanin which absorbs UV radiation. Dermis – most complex layer; contains all major tissue types; binds epidermis to subcutaneous tissue Subcutaneous layer – inner most layer of adipose and loose connective tissue; the adipose cushions and insulates underlying structures and organs. Learning Outcome: Describe the layers of skin and the characteristics of each layer. Excellent!

Skin Color Determined by amount of melanin and activity of melanocytes
Genetic trait Learning Outcome: Explain the factors that affect skin color. The amount of melanin in the skin’s epidermis is what most determines skin color. All people have about the same number of melanocytes, regardless of skin color. What varies is how active the melanocytes are in producing melanin. Sunlight, UV lamps, and X-rays stimulate melanin production. Skin color is directly related to the genes you received from your parents.

Skin Color (cont.) Oxygenated blood
Oxygen dissolved in the hemoglobin of the red blood cells Well-oxygenated blood ~ pink skin Poorly oxygenated blood ~ pale or bluish skin Learning Outcome: Explain the factors that affect skin color. Another factor that determines skin color is the amount of oxygenated blood in the skin’s dermis. Oxygen is carried by a pigment called hemoglobin in the red blood cells. Oxygenation refers to the amount of oxygen dissolved in the hemoglobin. Well-oxygenated hemoglobin is bright red in color. A person with a rich supply of oxygenated blood will have skin that is a pinkish hue. When the supply of oxygen in the blood is low, the skin looks rather pale or bluish. A bluish color of skin is called cyanosis.

Nice Job! Apply Your Knowledge What affects skin color?
ANSWER: The amount of melanin produced by the melanocytes and the oxygenation of the blood. Learning Outcome: Explain the factors that affect skin color. Nice Job!

Skin Lesions Any variation in the skin As simple as a freckle
As serious as a tumor Learning Outcome: Summarize types of common skin lesions.

Skin Lesions (cont.) Primary – originate from disease or body changes
Secondary – reaction to external trauma Vascular – anomalies of blood vessels Learning Outcome: Summarize types of common skin lesions. Classified in three major categories: primary, secondary, and vascular. Primary lesions like macules and vesicles, originate from disease or body changes. Secondary lesions, which include ulcers and keloids, are caused by a reaction to external traumas like scratching or rubbing, the healing process, or from primary lesions. Vascular lesions are anomalies of the blood vessels and include telangiectasia, which are small dilated blood vessels on the skin’s surface, and ecchymoses, commonly called bruises. Refer to Figure 23-2

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 Learning Outcome: 23.4 Summarize types of common skin lesions. Table 23-1 Common Skin Lesions and Descriptions

Skin Lesions (cont.) Lesion Name Description Excoriation
A scratch; may be covered with dried blood 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 Learning Outcome: 23.4 Summarize types of common skin lesions. Table 23-1 Common Skin Lesions and Descriptions

Skin Lesions (cont.) Lesion Name Description Papule
An elevated mass similar to but smaller than a nodule Petechiae Pinpoint skin hemorrhages that result from bleeding disorders Plaque A small, flat, scaly area of skin Purpura Purple-red bruises usually due to clotting abnormalities Pustule An elevated (infected) lesion containing pus Learning Outcome: 23.4 Summarize types of common skin lesions. Table 23-1 Common Skin Lesions and Descriptions

Skin Lesions (cont.) Lesion Name Description Scale
Thin plaques of epithelial tissue on skin’s surface Tumor A swelling of abnormal tissue growth Ulcer A wound that results from tissue loss Vesicle A blister Wheal Another term for hive Learning Outcome: 23.4 Summarize types of common skin lesions.

Apply Your Knowledge BRAVO! Match the following: ANSWER:
___ 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 ANSWER: C A BRAVO! E B F Learning Outcome: 23.4 Identify and describe common skin lesions. D

Accessory Organs Hair follicles
Tube-like depressions in the dermis of skin Generate hairs Alopecia – follicles die Arrector pili ~ muscles that pull on follicles Learning Outcome: Describe the accessory organs of skin along with their structures and functions. The skin’s accessory organs include hair follicles, sebaceous (oil) glands, nails, and sudoriferous (sweat) glands. Breasts are also an accessory organ but will be covered in a later chapter. Hair follicles are tube-like depressions in the skin’s dermis, which are made of epithelial tissue. They function to generate hairs. Root – portion of hair embedded in skin. Shaft – portion of hair extending from surface of skin. Hair follicle Keratinocytes – old cells stick together to produce a hair Melanocytes – produce and distribute pigments to produce hair color. If the hair follicle goes into a resting cycle, the hair falls out but will generally begin a growing cycle again. If hair follicles completely die, alopecia develops. Diagram

Accessory Organs (cont.)
Sudoriferous glands Eccrine glands Watery sweat Activated by heat Apocrine glands Thicker sweat Armpit and groin areas Activated by nervousness or stress Sebaceous glands Produce sebum to keep hair soft Prevent bacteria from growing on skin Learning Outcome: Describe the accessory organs of skin along with their structures and functions. Sudoriferous Glands (sweat glands) Located in the skin’s dermis with ducts open onto the skin’s epidermis. Eccrine glands Most numerous Produce a watery type of sweat Activated primarily by heat Apocrine glands Produce a thicker type of sweat that contains more proteins. Most concentrated in areas of skin with coarse hair, like the armpit and groin. Become active during puberty. Activated by nervousness, pain, or stress but can also be activated by heat. Bacteria break down the proteins in the sweat and release a foul-smelling waste product of body odor. Sebaceous Glands Oil glands – produce an oily substance called sebum. Sebum is secreted onto hairs to keep them soft and pliable, and it is eventually deposited onto skin to keep it soft as well. Sebum also prevents bacteria from growing on skin. Diagram

Accessory Organs Nails Protect the ends of fingers and toes
Epithelial cells with hard keratin Nail body Nail root Lunula Nail bed Learning Outcome: Describe the accessory organs of skin along with their structures and functions. Nails Function to protect the ends of the fingers and toes. Formed by epithelial cells with hard keratin Nail body – portion of a nail you can see. Nail root – portion of a nail embedded in skin. Lunula White half-moon-shaped area at base of nail Contains active keratinocytes. Nail bed Layer beneath each nail that holds the nail down to underlying skin Provides nutrients to the nail from the blood supply under the nail bed.

Apply Your Knowledge Perfect! ANSWER:
Matching: Sudoriferous glands Sebum Apocrine glands Hair follicles Nails Eccrine glands Alopecia Sebaceous glands Arrector pili tube-like depressions in the skin’s dermis; generate hairs baldness produce watery type of sweat muscles attached to hair follicles; cause “goose bumps” produce sweat produce sebum keeps hair soft and pliable protect the ends of fingers and toes become active during puberty D G F I A H Learning Outcome: Describe the accessory organs of skin along with their structures and functions. B E Perfect! C

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 Learning Outcome: Explain the process of skin healing, including scar production. When skin is injured, it becomes inflamed. Characteristics of inflammation Redness – nearby blood vessels dilate. Swelling – dilated blood vessels “leak” and fluids seep into spaces between cells Localized warmth Pain – excess fluid activates pain receptors

Scab replaces blood clot Collagen fibers replace scab
Skin Healing (cont.) Inflammation promotes healing Extra blood to area Extra nutrients Defensive cells Injury occurs Blood clot forms Clotted blood and other dried tissue Scab replaces blood clot Learning Outcome: Explain the process of skin healing, including scar production. Inflammation promotes healing because more blood travels to the area Carries more nutrients needed for skin repair. Carries defensive cells to clear up the cause of inflammation. Process A blood clot forms. A scab replaces the blood clot. A scab – clotted blood and other dried tissue fluids Collagen fibers eventually replace the scab Bind the edges of the wound together. Serve as the major component of scars. Scars can be a cosmetic nuisance or they can cause problems with underlying structures. Refer to CONNECT to see an animation about Inflammation Binds the edges of wound; scar may form Collagen fibers replace scab

Correct 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. Learning Outcome: Explain the process of skin healing, including scar production. Correct

Common Diseases and Disorders of the Skin
Burns Extent of body surface area and degree of a burn Rule of nines is used to determine extent of burn Estimate body surface area 11 body areas Learning Outcome: Describe the common diseases and disorders of the skin. The skin is prone to burns. In fact, burns are a leading cause of accidental death in the United States. The extent of the affected body surface area and the severity (degree) of a burn are the most important factors in predicting the risk of death associated with burn injuries. The rule of nines A quick way to estimate the extent of body surface area affected by burns. Divides the body into 11 areas, each accounting for 9% of the total body surface. The genital area accounts for 1%

Burns Head and neck 9% Posterior trunk and buttocks Anterior trunk
Arms, hands, and shoulders 18% 4½% Perineum 1% Anterior legs and feet Posterior legs and feet Anterior trunk Posterior trunk and buttocks 4½% 4½% Learning Outcome: Describe the common diseases and disorders of the skin. Head 9% (front and back, 4.5% each) Right arm 9% (front and back, 4.5% each) Left arm 9% (front and back, 4.5% each) Front of right leg 9% Front of left leg 9% Back of right leg 9% Back of left leg 9% Front of body 18% (both areas) trunk is two areas Back of body 18% (both areas) trunk is two areas Genital area 1% Total body area = 100% Back

Burns (cont.) Full-thickness Superficial Partial-thickness
All layers of skin and often underlying structures Skin appears charred Always requires medical attention Superficial Epidermis only Pain, redness, swelling Partial-thickness Epidermis and dermis Pain, redness, swelling, blisters Learning Outcome: Describe the common diseases and disorders of the skin. Superficial (first-degree) Involves only the epidermis Characterized by pain, redness, and swelling. Generally do not require medical attention and usually heal well. Partial-thickness (second-degree) Involves the epidermis and dermis. Characterized by pain, redness, swelling, and blisters. Any partial-thickness burn that affects 1% or more of the body surface should receive medical treatment. Shock is likely to develop if 9% or more of the body surface is affected. These burns can be life-threatening. Full-thickness (third-degree). Involves all layers of skin and often underlying structures Skin frequently looks black or charred, which is known as eschar. Always require medical attention regardless of the extent or the size of the burn area. Burns

1st Degree 2nd Degree 3rd Degree
Partial thickness Full thickness Learning Outcome: Describe the common diseases and disorders of the skin. Back

Burns (cont.) General guidelines for treatment
Do not remove anything sticking to the burn Do not apply butter, lotions, or ointments Cool with large amounts of water Learning Outcome: Describe the common diseases and disorders of the skin. General guidelines for treating burns Anything sticking to the burn should be left in place. Butter, lotions, or ointments should not be applied to the burn. Only ointments prescribed by a doctor or recommended by a pharmacist should be used. The burn should be cooled with large amounts of cool water. Ice or extremely cold water should be avoided.

Burns (cont.) General guidelines for treatment
Cover with sterile sheet or plastic bag Contact emergency services Check airways for swelling Learning Outcome: Describe the common diseases and disorders of the skin. General guidelines for treating burns (cont.) The burn should be covered with a sterile sheet or plastic bag. Burns to the face, however, should not be covered. Emergency medical personnel should be contacted for serious burns. In burns to the mouth and throat, the airways should be checked for swelling. Burns to the head are always more serious than burns to other body parts. They almost always require emergency medical treatment.

Skin Cancer and Common Skin Disorders
Skin – vulnerable due to exposure Skin cancer Epidermis Excessive exposure to sunlight Types Basal cell and squamous cell carcinoma Malignant melanoma Learning Outcome: Describe the common diseases and disorders of the skin. Skin is vulnerable to many disorders because it is the most exposed of all body organs. Skin cancer Develops from cells in the skin’s epidermis More common in people who have light-colored skin and who have had excessive exposure to sunlight. The two most common types of skin cancer Basal cell carcinoma Squamous cell carcinoma The most deadly type is malignant melanoma

Skin Cancer and Common Skin Disorders (cont.)
Basal Cell Signs / symptoms Growth or sore that will not heal Waxy, smooth, red, pale, flat, or lumpy Treatment Curettage and electrodessication Mohs surgery Cryosurgery Laser therapy Learning Outcome: Describe the common diseases and disorders of the skin. Basal cell carcinoma Accounts for approximately 90% of all skin cancers in the United States. It progresses slowly and rarely spreads to other body parts. It is derived from cells of the stratum basale of the epidermis. Treatment Curettage and electrodessication. In curettage, a sharp instrument is used to scoop out the cancerous lesion. Electrodessication uses electrical currents to minimize bleeding as well as to kill any remaining cancer cells. Mohs surgery The cancerous lesion is shaved off one layer at a time. Each layer is sent to the histology lab for evaluation until no tumor is detected in the last layer removed. Cryosurgery – freezing is used to kill cancer cells. Laser Therapy – a beam of light destroys cancer cells.

Squamous Cell Less common than basal cell Flat cells of the epidermis Found on face, lips, ears, and backs of hands Signs and symptoms and treatments are the same as for basal cell carcinoma Learning Outcome: Describe the common diseases and disorders of the skin. Squamous cell carcinoma Much less common than basal cell carcinoma More likely to spread to surrounding tissues. It arises from flat cells of the epidermis.

Malignant Melanoma Signs / symptoms Mole that itches or bleeds ABCDE rule Treatment Surgery Determination if cancer has spread Chemotherapy and radiation therapy Immunotherapy Learning Outcome: Describe the common diseases and disorders of the skin. Melanoma is the most aggressive type of skin cancer. Fastest growing – rates increasing 5% to 7% per year; lifetime incidence 1/75 More prevalent in females – on arms and legs Males have poorer prognosis – appear on trunk, head, and neck Can occur anywhere on the body Arises from melanocytes. Signs and symptoms A mole that itches or bleeds is a common symptom. New moles may develop near it or it may change to have any signs of the ABCDE rule (next slide) Treatment – will depend on the staging of this cancer. Surgery to remove the melanoma. Lymph node biopsy to determine if the cancer has spread. Removal of cancerous lymph nodes. Chemotherapy for advanced stages of cancer. Radiation therapy for advanced stages of cancer. Immunotherapy to boost the patient’s immune system.

Asymmetry – a mole should not become asymmetrical. Border – a mole should not have irregular borders and edges should not blur into normal tissue. Color – a mole should not change or become mixture of colors. Learning Outcome: Describe the common diseases and disorders of the skin. Assymmetry –it should look equal in size from side to side. Color – it should have even coloring.

Diameter – a mole should not grow larger than the diameter of a pencil eraser (6 mm.) Evolving – a mole that has been changing in size, color and appearance, or growing in an area of previously normal skin Learning Outcome: Describe the common diseases and disorders of the skin. Evolving In an existing mole, the texture of the mole may change and become hard, lumpy, or scaly. Although the skin may feel different and may itch, ooze, or bleed, melanoma usually does not cause pain.

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 and may be ulcerated Stage III Spread to one or more nearby lymph nodes Stage IV Spread to other body organs or lymph nodes far from original melanoma Learning Outcome: Describe the common diseases and disorders of the skin.

Common Skin and Hair Disorders
Alopecia Hair loss Heredity Cellulitis Inflammation of connective tissue in skin Red, tight, painful skin Dermatitis Inflammation of skin or a rash Eczema ~ chronic dermatitis Folliculitis Swimmer’s rash Inflammation of hair follicles Learning Outcome: Describe the common diseases and disorders of the skin. Alopecia – baldness Most often inherited, incurable Loss or lack of hair on the scalp or other areas of the body Cellulitis – caused by staphylococcal and streptococcal bacteria. Dermatitis Many causes; a common type is contact dermatitis Eczema – one type of chronic dermatitis that has acute phases characterized by a blistered rash that itches severely. Folliculitis Causes – shaving or excess rubbing of skin areas; may also be caused by bacteria and fungi; leaving a wet swimsuit on too long Follicles become red and itchy and often look like pimples.

Common Skin Disorders (cont.)
Herpes simplex Type 1 Cold sores Spread through saliva Type 2 – genital Genital Sexually transmitted No cure Herpes zoster Shingles Chicken pox virus lies dormant Symptomatic treatment Vaccine Learning Outcome: Describe the common diseases and disorders of the skin. Herpes simplex Types 1 and 2 are the most common types of herpes simplex. Cause –a virus Herpes simplex type 1 is very contagious and is spread through saliva. Herpes simplex type 2 is sexually transmitted. Signs and symptoms Herpes simplex type 1 causes painful sores on the lips, mouth, and face. Herpes simplex type 2 normally causes painful sores on genital areas. Herpes zoster – shingles Caused by the Varicella virus, the same one that causes chickenpox. A painful blistering rash usually on one side of the body. Follows the dermatome – the skin area along the pathway of affected nerve root. The vaccine Zostavax® by Merck Pharmaceuticals is a preventive alternative to reducing the risk of developing shingles.

Impetigo Oozing skin lesions that eventually crust over Highly contagious Pediculosis Capitus ~ head lice Corporis ~ body lice Pubis ~ pubic lice Psoriasis – chronic, inflammatory skin condition Learning Outcome: Describe the common diseases and disorders of the skin. Impetigo Spreads by contact with the lesions or the exudates. Caused by staphylococcal and streptococcal bacteria. Crust is a distinctive honey-color. Pediculosis Caused by parasitic lice. Associated with overcrowded conditions and poor hygiene. Pubic lice are also spread by sexual contact. Psoriasis Most likely an inherited autoimmune disorder. Presents as recurring episodes of itching and redness with outbreaks of distinctive silvery, scaly skin lesions; may also have joint pain

Ringworm Three types Tinea corporis Tinea capitis Tinea pedis Dermatophytes Antifungal agents Rosacea Dilation of small facial blood vessels Not curable Learning Outcome: Describe the common diseases and disorders of the skin. Ringworm is a fungal skin infection Three forms Tinea corporis (body) Tinea capitis (scalp) Tinea pedis (feet), which is commonly known as athlete's foot. Caused by fungi called dermatophytes. Flat, circular lesions that may be dry and scaly or moist and crusty. Tinea capitis is characterized by small papules that may cause small, patchy areas of baldness. Rosacea Appears as facial redness, predominantly over the cheeks and nose. Redness and acne-like symptoms.

Scabies Contagious skin condition caused by mites Redness and itching Treat entire family Warts Harmless growths caused by a virus Vary in appearance OTC medications Learning Outcome: Describe the common diseases and disorders of the skin. Scabies Highly contagious Cause – an itch mite that burrows beneath skin and lays its eggs. Signs and symptoms – redness and severe itching, especially at night Treatment Prescription medications Antipyretic or steroid creams may control the itching. Warts (verrucae) Growths can appear almost anywhere on the body surface but most commonly occur on the hands, feet, and face. Cause – a virus Signs and symptoms - warts vary greatly in appearance; they can be smooth, flat, rough, raised, dark, small, or large. Removed with OTC medications Also be treated through surgery, lasers, freezing, or burning.

Apply Your Knowledge Good Job! ANSWER: 1. 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. F Melanomas are more aggressive. T T Learning Outcome: Describe the common diseases and disorders of the skin. F Borders are irregular. T Good Job!

It all adds up to a right answer!
Apply Your Knowledge Using Figure for Rule of Nines, determine burn extent for a patient who has burns to his anterior face and both arms. Click for Rule of Nines ANSWER: Face = 4.5% Both arms, hands, and shoulders = 18% 4.5% + 18% = 22.5% Learning Outcome: Describe the common diseases and disorders of the skin. It all adds up to a right answer!

In Summary 23.1 The functions of skin include: protection, body temperature regulation, vitamin D production, sensation, and excretion. 23.2 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. 23.3 The amount of melanin affects and determines skin color. The amount of oxygen-carrying hemoglobin in the blood also affects skin color.

In Summary (cont.) 23.4 Skin lesions are split among three main types: primary lesions such as macules and vesicles; secondary lesions, which include ulcers and keloids; and vascular lesions, which involve blood vessels and include telangiectasias and ecchymoses The accessory organs of skin include: hair follicles, arrector pili muscles, sebaceous glands, sudoriferous glands, and keratin-filled nails.

In Summary (cont.) 23.6 Injured skin becomes inflamed from dilating blood vessels that 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. 23.7 Common diseases and disorders of the skin include alopecia, cellulitis, dermatitis, eczema, folliculitis, herpes simplex, herpes zoster, impetigo, pedicuosis, psoriasis, ringworm, rosacea, scabies, and warts.

End of Chapter 23 We may have different religions, different languages, different colored skin, but we all belong to one human race. ~ Kofi Annan

The Integumentary System

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