Ch. 5 Notes: Integumentary System

5.1 STRUCTURE OF THE SKINIntroduction-Also known as the cutaneous membrane or integument-Largest organ in human body- about 1.8 square metersTwo regions: epidermis and dermis-Hypodermis or subcutaneous tissue (under the skin)is found between skin and underlying structures like muscle.

Epidermis-Outer and thinner region of the skin. -Made up of stratified squamous cells divided into 5 distinct layers

Stratum Basale (base) or Stratum G erminativum (grow) 1. Located superficial to the dermis2. Epidermal stem cells produce new cells that are pushed to surface every 2-4 weeks.3. These cells will eventually die and slough off4. Keratinocytes- produce and store waterproof keratin, enlarge when move into stratum spinosum5. Langerhans cells- macrophages (leukocyte / WBC) that phagocytize microbes and stimulate immune system reactions6. Melanocytes- produce melanin, pigment responsible for skin color

a. Serves to protect skin from uv radiationb. How freckles and tanning results from more melanin productionc. Albinism- lack the ability to produce melanin

7. Free nerve endings- supply pain and temperature sensation8. Tactile cells (Merkel cells)- signal the brain that an object has touched the skin

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Stratum Spinosum and Stratum Granulosum1.Stratum spinosum (spine)

a. Above stratum basale- provide strength and flexibilityb. Cells reproduce by mitosisc. Spiny appearance from keratin filaments

2.Stratum granulosum (grain)a. Above stratum spinosumb. Flattened cells with dark-staining protein granules found in cytoplasmc. Tightly form together to make an effective barrier

Stratum Lucidum (clear)1.Layer above the stratum granulosum2.Found in thick skin: palms of hands, soles of feet, elbows3. Provides protection from constant frictionStratum Corneum (horn-like)1.Layer above the stratum lucidum2.Cells are flat, hard, and tough by keratinization of entire cell. 3.Keratinization is greater where layers of stratum lucidum are present 4. Provides protection from constant friction, moisture barrier, and protects from microbes

Dermis1.Denser, thicker region composed of dense irregular connective tissue2. Upper layer has fingerlike projections called dermal papillae which project into and anchor the epidermis

a. Fingerprints- ridges caused in the overlying epidermis3.Collagen fibers- flexible, great resistance to overstretching; prevent skin from tearing4.Elastic fibers- stretch to allow movement of underlying muscles and joints; normal skin tension5.Blood vessels that supply oxygen and nutrients

a. Palor (white) - decrease blood flow to skinb. Cyanotic (blue)- inadequate supply of oxygen to blood

6. Sensory nerves that carry signals to and from accessory organsDermal Layers

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Hypodermis (Subcutaneous tissue)1. Loose connective tissue and 2. Adipose (fat) tissue- serves for long-term energy storage and insulation and protection

MEDICAL FOCUS - Decubitus ulcers-Caused by constant unrelieved pressure that blocks blood flow to the dermis

Stages of decubitusStage 1 Pressure Injury: Non-blanchable erythema of intact skin1.Skin is intact, redness (erythema) does not blanch on palpation. 2. May have changes in sensation, temperature, or firmness

Stage 2 Pressure Injury: Partial-thickness skin loss with exposed dermis1.Exposed dermis layer. Wound is pink or red, moist2.May be an intact or ruptured clear (serum) filled blister.3.Common in pelvis and heel from shear force4.Adipose and deeper tissues are not visible

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Stage 3 Pressure Injury: Full-thickness skin loss1. Adipose is present and granulation tissue (reddish connective tissue that forms on the surface of a wound when the wound is healing) may be present2. Epibole may be present- to rolled or curled-under closed wound edges that may be dry or callused 3. Slough or eschar (black,dead tissue) may be visible; tunneling may occur4. Depth of tissue damage varies based on anatomical location

Stage 4 Pressure Injury: Full-thickness skin and tissue loss1. Full-thickness skin and tissue loss with exposed muscle, tendon, ligament, cartilage or bone in the ulcer. 2. Slough and/or eschar may be visible. Epibole (rolled edges), undermining and/or tunneling often occur.3. Depth varies by anatomical location.4. If slough or eschar obscures the extent of tissue loss this is an Unstageable Pressure Injury.

5.2 ACCESSORY STRUCTURES OF THE SKINHair1. Not found on palms, soles, lips, & nipples.2. Hair follicle- form from epidermal cells located in the dermis3. Hair matrix-at base of hair where new hair cells are produced

a. Hair cells are fed by dermal blood vessels, but as pushed farther from nutrients become keratinized.

4. Hair root- portion of hair within the follicle5. Hair shaft- portion of the hair that extends beyond the skin.6. Hair shedding and regrowth

a. Scalp hair lasts 3-4 years while eyelashes last 3-4 monthsb.Alopecia- hair loss

1) Androgenic Alopecia- male pattern baldness 2) Alopocia areata- sudden onset of patchy hair loss7. Arrector pili- smooth muscle that attaches to the follicle, causes hair to stand up causing “goose bumps”

Hair and Nail

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Nails1. Nail root- epithelial cells from which the nail grows2. Nail body- visible portion of the nail 3. Cells become keratinized as they grow over the nail bed.4. Cuticle- a fold of skin that hides the nail root.5. Average nail growth is 1mm per week.6. Pink color comes from vascularized dermal tissue; 7. White half-moon shape or lunula is a thicker layer of rapid reproducing cells.

Glands-Specialized groups of cells to produce and secrete substances into ducts

Sweat Glands (sudoriferous glands)1. Range from 90 to 400 glands per square cm; more in palms and soles, fingertips. 2. Tubule shape, more active when person stressed3. Function by exocytosis

a. Apocrine glands1. Open into the hair follicle2. Located in anal region, groin, and armpit3. Part of sweat secretion may be a sex attractant

b. Eccrine glands1. Open onto the surface of the skin2. Produce sweat that consists of water, salt, & urea (waste).3. Allows for cooling of body when hot

c. Ceruminous glands1. Line the external ear canal2. Produce cerumen, or earwax.

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Sebaceous Glands1. Most are associated with hair follicles2. Sebum- oily substance flows into hair follicle and onto the skin.

a. Lubricates hair and skin, waterproofs, and weakens or kills bacteria3. White heads or black heads- pimples caused when fail to discharge sebum and collects in pore. 4. Boil / pimple- when pus-inducing bacteria are present5. Acne vulgaris – inflammation of the sebaceous glands; usually caused by hormonal changes in puberty

Mammary Glands1. Modified apocrine glands that produce milk after puberty

5.3 DISORDERS OF THE SKIN

Various Skin Disorders

Skin Cancer1. Basal cell carcinoma

a. Caused by UV radiation affects epidermal basal cellsb. Signs: open sore that will not heal, recurring reddish patch, smooth circular growth with raised

edges; a shiny bum, or a pale markc. Easily cured by surgical removal, may reoccur

2. Squamous cell carcinomaa. Caused by UV radiation - found in the superficial cells of the epidermisb. Same signs as basal cell or look like a wart or scaly growth that bleeds and scabsc. More likely to spread than basal cell

3. Melanomaa. Starts in the melanocytes and looks like an unusual mole. b. Warning signs of melanoma

1. Asymmetrical2. Borders- irregular and have notches or indentation in them3. Color- is uneven and several colors may be present (black, brown, tan, or red)4. Diameter- greater than 6mm (larger than a pencil eraser)5. Evolving- mole has changed in size, shape, or color

4.Skin protectiona. Broad-spectrum sunscreen at least SPF 15b. Wear protective clothing- hats, long-sleevesc. Sunglasses that reflect both forms of UV radiationd. Avoid peak sun times from 10am-3pm.

Wound Healing1. Tissue is injured

a. Injury causes inflammation with redness, swelling, heat, and pain. b. Deep wounds rupture blood vessels and blood fills the wounds.c. Chemical signals released from damaged tissue

2. Blood clot and scab formation6

a. Prevent toxins and pathogens from spreading to other tissuesb. Clot exposed to air will harden and form a scabc. WBC help to fight infection and fibroblasts pull wound edges together

3.New epidermis formsa. Fibroblasts promote tissue regenerationb. Basal layer of the epidermis promotes new cells at faster ratec. Fibroblasts begin scar formation

4.Scar formationa. Tissue that composed of many collagen fibers to provide maximum strengthb. No accessory organs of the skin; loss of sensationc. Epidermis and dermis are now healed.

In Case of Emergency – Burns

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Causes of Burns1. Heat (thermal) - occur when hot metals, scalding liquids, steam, or flames come in contact with the skin2. Electrical- exposure to electrical current or lightning strikes3. Chemical- contact with caustic chemicals4. Radiation- exposure to the sun's ultraviolet rays, other sources of radiation like tanning booths

Risk factors for Burns-Wood stoves, exposed heating sources, or electrical cords-Unsafe storage of flammable or caustic materials-Careless smoking-Child abuse-Hot water heater set above 130°F (54.4°C)-Heated foods and containers-Too much exposure to the sun

Burn Prevention-Installing smoke detectors-Teaching children about fire and burn prevention in schools-Stopping smoking and heavy alcohol use-Wearing flame retardant clothes -Planning emergency exit routes in the home, school, and workplace-Practicing fire drills

Burn TypesName Histology Appearance Sensation Healing time Skin

GraftingFirst degree (superficial)

Epidermis only -Erythema-Blanches easily-No blistering

-Intact-Mild to moderate pain

3-6 days-without scarring

No

Superficial second-degree (partial thickness)

Epidermis and superficial dermis; skin appendages intact

-Erythema-Blanches with pressure-Wet appearance-Blistering typical

-Intact-Severe pain

1-3 weeks-scarring unusual

No

Deep second degree (partial thickness)

Epidermis and most of dermis; most skin appendages destroyed

-Wet appearance-Does not easily blanch-Blistering typical

-Decreased-Less painful

-Greater than 3 weeks-often scarring and contractures

Yes

Third degree (full-thickness)

Epidermis and all of dermis; all skin appendages destroyed

-Variable erythema-White, charred, tan-Dry, leathery

-Loss of sensation-Pain around second degree edges

-does not heal-severe scarring and contractures

Yes

Fourth degree Into underlying fat, muscle and bone

-Black, charred, dry, crisp

-Painless; nerve endings destroyed

-Excision or amputaton needed; death may result

No

See Clinical Pictures

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Critical Burns and the Rule of 9’sCritical Burns1. Has trouble breathing; has burns covering more than one body part or a large surface area2. Has suspected burns to airway, burns to nose or mouth may be a sign3. Burns to head, neck, hands, feet, or genitals4. Has full thickness burn & is younger than 5 or older than 605. Burns were caused by chemicals, explosion, or electricity6. Body surface area: greater than 25% in 2nd degree; greater than 10% in 3rd degree; any 4th degree

Body Surface Area and Rule of 9’s1. Body surface area is the amount of skin that covers the entire body2. Average BSA in men is 1.9m2 and women Is 1.6m2 ; 12 year old is 1.33m2 and infant is 0.3 m2

3. Rule of 9’s- way to divide the body into regions when assessing the extent of burns. Different values for children and adults4. This allows HCP to then determine volume replacement needs

Assessment:Calculate total BSA (burn surface area)

Patient #1- An 21 year old female fell asleep by the pool for 5 hours. She has bright red burns from on her neck down to her ankles. ____%

Patient #2- A 23 year old male has partial thickness burns to his anterior thighs and full thickness burns to his perineum. ___%

Patient #3- A three year old patient has second degree burns covering the upper portion of the chest and lower portion of the face. _____%

First Aid: Caring for Burns

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Thermal burns1. Stop the burning by removing the person from the source if the scene is safe2. Check for life threatening conditions, cool the burn with large amounts of cold running water3. Cover the burn loosely with a sterile dressing; prevent infection, takes steps to minimize shock4. Keep the person comfortable and avoid chilling or overheated.DO NOT-Apply ice or water except on a small, superficial burn for no more than 10 minutes-Touch a burn with anything except a clean covering-Remove pieces of clothing that stick to burns; try to clean a severe burn-Break blisters; use any kind of ointment on a severe burn

Chemical Burns Will continue to burn until the chemical has been removed1. Burn from dry chemicals, brush off the chemicals using a gloved hand before flushing with tap water2. Flush the burn with cool running water for 20 minutes or until EMS arrive3. If an eye is affected, flush the eye until EMS arrives by tipping the head so the affected eye is lower than the unaffected eye4. If possible, have the person remove contaminated clothes5. Be aware that chemicals can be inhaled and damage airways

Electrical Burns1. Never go near the person until you are sure they are not in contact with the power source2. Call 9-1-1 for high-voltage electrocution like downed power lines3. Turn off the power at its source and care for any life-threatening conditions4. Be prepared to give CPR and defibrillation from cardiac arrest5. Care for shock & thermal burns

Radiation1. Care for the sunburn as other burns; cool the burn and get out of the sunlight

Complications from burns1. ABC- Airway, breathing, and circulation- watch for respiratory distress and shock 2. Fluid loss – usually given IV fluids3. Heat loss- place burn patient in warm environment with blankets as possible4. Bacterial infections-apply antibacterial dressings and medications

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