Chapter 4 Skin and Body Membranes Pathology Essentials of Human Anatomy & Physiology, 7th ed. by Elaine N. Marieb

Skin and Body Membranes: Integumentary System, Pathology Pathology – the study of disease; any deviation from a healthy, normal, or efficient condition. (pathos=suffering, logos=to study)

Pathologies of the Integumentary System: Skin and Body Membranes: Integumentary System, Pathology Pathologies of the Integumentary System: 1. Skin Color Abnormalities 2. Acne 3. Skin Abnormalities: ringworm, boils, cold sores, warts, contact dermatitis, pityriasis rosea, psoriasis, eczema, decubitis ulcers (bedsores) 4. Burns 5. Hypothermia 6. Heat exhaustion/heat stroke 7. Tissue repair 8. Skin cancer

Skin and Body Membranes: Integumentary System, Skin Color Abnormalities Cyanosis If hemoglobin is poorly oxygenated, blood and skin appears blue Most apparent in areas of thin skin (lips or beneath nails) Common during heart failure and severe breathing disorders Response to extreme cold

Skin and Body Membranes: Integumentary System, Cyanosis

Skin and Body Membranes: Integumentary System, Skin Color Abnormalities Erythema (redness): may indicate embarrassment (blushing), fever, hypertension, inflammation, skin injury, infection, or allergy

Skin and Body Membranes: Integumentary System, Skin Color Abnormalities Pallor (AKA Blanching) (pale): may indicate emotional stress (fear, anger), anemia, low blood pressure, or impaired blood flow into the area

Skin and Body Membranes: Integumentary System, Skin Color Abnormalities Jaundice (yellow cast): usually signifies a liver disorder in which excess bile pigments are deposited in body tissues because the liver is unable to excrete bile normally.

Skin and Body Membranes: Integumentary System, Skin Color Abnormalities Contusions (bruises): reveal sites where blood has clotted in tissue spaces; clots are called hematomas.

Skin and Body Membranes: Integumentary System, Skin Color Abnormalities Vitiligo: the immune system malfunctions, and antibodies attack normal melanocytes; person has patches of irregular white spots on their skin

Skin and Body Membranes: Integumentary System, Acne Acne: an active infection of the sebaceous glands with “pimples.” Can be mild or severe, resulting in permanent scarring.

Skin and Body Membranes: Integumentary System, Acne Whitehead: forms when a sebaceous gland’s duct becomes blocked with sebum Blackhead: forms when blocked sebum oxidizes and dries

Ringworm Caused by fungal infection Beard: tinea barbae (folliculitis) Skin and Body Membranes: Integumentary System, Skin Abnormalities Ringworm Caused by fungal infection Beard: tinea barbae (folliculitis) Body: tinea corporis Feet: tinea pedis (Athlete’s foot) Groin: tinea cruris (jock itch) Scalp: tinea capitis Easily communicable (skin, combs, unwashed clothing, shower and pool surfaces) Pets can transmit disease, too (esp. cats)

Tenia corporis Tenia pedis Tenia barbae

Caused by bacterial infection Skin and Body Membranes: Integumentary System, Skin Abnormalities Boils and carbuncles Caused by bacterial infection

Caused by herpes simplex virus Skin and Body Membranes: Integumentary System, Skin Abnormalities Cold sores Caused by herpes simplex virus

Skin and Body Membranes: Integumentary System, Skin Abnormalities Warts Caused by a virus (usually some subspecies of human papillomavirus, HPV) Warts are contagious, and usually infect the skin through areas of broken epidermis. They typically persist for months, but can last for years, and often recur.

Exposure to allergen or irritant causes reaction Skin and Body Membranes: Integumentary System, Skin Abnormalities Contact dermatitis Exposure to allergen or irritant causes reaction

Pityriasis rosea Common among young adults Skin and Body Membranes: Integumentary System, Skin Abnormalities Pityriasis rosea Common among young adults Believed to be caused by a virus Not thought to be contagious Most often last 4-8 weeks. (3-12 weeks) The rash starts with a single large patch called a herald patch. After several days, more skin rashes will appear on the chest, back, arms, and legs. Usually oval shaped patches. (Sun exposure helps.)

Triggered by trauma, infection, stress Skin and Body Membranes: Integumentary System, Skin Abnormalities Psoriasis Cause is unknown Scaly patches Not contagious Triggered by trauma, infection, stress

Usually occurs during first 5 years of life (90%) Skin and Body Membranes: Integumentary System, Skin Abnormalities Eczema Immediate hypersensitivity response that results in “weeping” skin lesions and intense itching Usually occurs during first 5 years of life (90%) Familial predisposition

Decubitus ulcers (AKA Bedsores) Skin and Body Membranes: Integumentary System, Skin Abnormalities Decubitus ulcers (AKA Bedsores) Occur when people lay in the same position for extended periods of time. Blood flow is cut off from skin under pressure Skin bacteria eat away at skin without bloodflow (no white blood cells!)

Skin and Body Membranes: Integumentary System, Burns Tissue damage and cell death caused by heat, electricity, UV radiation, or chemicals Associated dangers Dehydration Electrolyte imbalance Circulatory shock

First-degree burns Second degree burns Third-degree burns Skin and Body Membranes: Integumentary System, Burns First-degree burns Only epidermis is damaged Skin is red and swollen Second degree burns Epidermis and upper dermis are damaged Skin is red with blisters Third-degree burns Destroys entire skin layer Burn is gray-white or black Often painless, as sensory nerves in dermis are destroyed

1st Degree Burn (superficial) 2nd Degree Burn (partial thickness) 3rd Degree Burn (full thickness)

Burns are considered critical if: Skin and Body Membranes: Integumentary System, Burns Burns are considered critical if: Over 25% of body has second degree burns Over 10% of the body has third degree burns There are third degree burns of the face, hands, or feet Burns complicated with musculoskeletal injuries Circumferential burns

Rule of Nines Rule of Palm Way to determine the extent of burns Skin and Body Membranes: Integumentary System, Severity of Burns Rule of Nines Way to determine the extent of burns Body is divided into 11 areas for quick estimation Each area represents about 9% Rule of Palm Alternate way to determine extent of burns Patient’s palm is ~1% of body

Skin and Body Membranes: Integumentary System, Rule of Nines

Treatment of Burns Stop the burning process! Evaluate type of burn Skin and Body Membranes: Integumentary System, Treatment of Burns Treatment of Burns Stop the burning process! Evaluate type of burn Flame: Wet down, smother, then remove clothing Semi-solid (e.g. wax, grease, tar): cool with water. Do not remove substance Water-based chemical burns: Flush with water for 15 minutes Organic chemical burns: Flush with alcohol initially, followed by water (15 min.) Dry chemical burns: Brush off remaining chemical, followed by water (15 min.)

Treatment of Burns 3. Remove clothing and jewelry Skin and Body Membranes: Integumentary System, Treatment of Burns Treatment of Burns 3. Remove clothing and jewelry 4. Wrap with dry, sterile dressing 5. Burns to eyes If chemical burn, flush eyes with water for at least 20 minutes If thermal burn, don’t try to open eyelids. Cover both eyes with sterile, dry gauze pads.

Skin Response to Extreme Temperature Skin and Body Membranes: Integumentary System, Pathology Skin Response to Extreme Temperature Hypothermia – cold Skin response: vasocontriction Hyperthermia – hot Skin response: vasodilation

Hypothermia Core Body Temperature Symptoms 99-96oF 96-91oF 91-86oF Skin and Body Membranes: Integumentary System, Hypothermia Hypothermia Core Body Temperature Symptoms 99-96oF Shivering, vasoconstriction, skin appears pale, cyanosis 96-91oF Intense shivering, difficulty speaking 91-86oF Shivering replaced by strong muscular rigidity, muscle coordination is affected, thinking is less clear, possible total amnesia 86-81oF Loss of contact with environment, stuporous state, muscle rigidity, pulse and respirations are slow 81-78oF Loss of consciousness, most reflexes fail, heart slows until cardiac arrest

What to do for hypothermia: Skin and Body Membranes: Integumentary System, Hypothermia What to do for hypothermia: Passive rewarming: remove any wet clothing, put on dry clothing, wrap in dry, warm blankets, do not massage extremities Active rewarming: same as passive rewarming plus: apply heat to body by way of heat packs, hot water bottles, electric heating pads, warm air, even body heat, drink warm fluids (but no stimulants)…Do not warm too quickly! Cold, stagnant blood from the extremities will circulate to the core, dropping core body temperature. This could cause cardiac arrest. Central rewarming: apply heat to lateral chest, neck, armpits, and groin. –Do not apply heat to extremities.

Localized cold injuries – affecting only particular parts of the body Skin and Body Membranes: Integumentary System, Hypothermia Localized cold injuries – affecting only particular parts of the body Most commonly affects the ears, nose, face, fingers/hands, toes/feet Early = superficial Brought on by direct contact with cold air, water or cold object. Skin appears red (if light-skinned) or lighter in color (if dark-skinned). In more advanced instances, the skin takes on a grey/white blotchy appearance.

What to do for hypothermia: Superficial Local Hypothermia Skin and Body Membranes: Integumentary System, Hypothermia What to do for hypothermia: Superficial Local Hypothermia Warm affected area: Obtain a container of warm water (~100-105oF). It should feel comfortably warm. Immerse entire affected area into water until sensation and skin color return to normal. Do not rub or massage.

Localized cold injuries – affecting only particular parts of the body Skin and Body Membranes: Integumentary System, Hypothermia Localized cold injuries – affecting only particular parts of the body Most commonly affects the ears, nose, face, fingers/hands, toes/feet Late = deep Skin becomes numb, due to reduced circulation. Continued exposure to cold leads to all loss of sensation, and the skin becomes dead white with a waxy appearance.

What to do for hypothermia: Deep Local Hypothermia Skin and Body Membranes: Integumentary System, Hypothermia What to do for hypothermia: Deep Local Hypothermia Only if you cannot get to a hospital should you warm the affected area: Obtain a container of warm water (~100-105oF). It should feel comfortably warm. Immerse entire affected area into water until sensation and skin color return to normal. Do not rub or massage. Ice crystals may have formed in the affected tissue. Agitation could further damage cells.

Skin and Body Membranes: Integumentary System, Hyperthermia Normal body temperature ranges from about 97-99.5oF. Any temperature above that is considered hyperthermic. If body temperature rises above 104oF, it considered life-threatening – seek medical attention! Core temperature can rise due to exercise, fever, or prolonged exposure to a hot environment. Hyperthermia follows two stages: Heat Exhaustion Heat Stroke

Characteristics of Heat Exhaustion: Skin and Body Membranes: Integumentary System, Hyperthermia Characteristics of Heat Exhaustion: 1. Skin appears moist, red (if light-skinned) or darker (if dark-skinned), and normal-cool to the touch 2. Heavy perspiration 3. Rapid, shallow breathing 4. Normal-weak pulse 5. Weakness and/or dizziness 6. Muscular cramps (usually in legs and abdomen)

What to do for Heat Exhaustion Skin and Body Membranes: Integumentary System, Hyperthermia What to do for Heat Exhaustion Get to a cool environment, cool passively 2. Lie down on your back with legs elevated 3. Apply moist towels over cramps 4. Drink water (not too cold) if not nauseated

Characteristics of Heat Stroke: Skin and Body Membranes: Integumentary System, Hyperthermia Characteristics of Heat Stroke: Skin appears moist or dry, pale, and hot to the touch Little or no perspiration Weakness and/or dizziness, possibly unconscious No muscular cramps, but possibly seizures Rapid, shallow breathing Full, rapid pulse Dilated pupils

What to do for Heat Stroke: Skin and Body Membranes: Integumentary System, Hyperthermia What to do for Heat Stroke: Get to a cool environment, cool actively Lie down on your back with legs elevated Remove clothes and place cool packs to neck, groin, and armpits. If you cannot get to a hospital, immerse your entire body in cool water. Drink water (not too cold) if not nauseated

Tissue Repair

Nearby capillaries dilate and become leaky. Skin and Body Membranes: Tissue Repair When continuous tissues like the skin, mucosae, and blood vessels are broken, the body initiates the inflammatory response. Injured cells and certain white blood cells release inflammatory hormones (e.g. histamines). Nearby capillaries dilate and become leaky. Clotting proteins in the blood form a scaffold that traps platelets, leading to a clot. (stops bleeding and isolates pathogens) White blood cells attack pathogens, dead cells, and other debris.

Fibrosis = Repair by dense fibrous connective tissue (scar tissue) Skin and Body Membranes: Tissue Repair Even as the clot is forming, tissue repair begins immediately. Depending on the tissue, and severity of injury, tissues will regenerate or be replaced by scar tissue (or both). Regeneration = Replacement of destroyed tissue by the same kind of cells Fibrosis = Repair by dense fibrous connective tissue (scar tissue) Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Blood clot is replaced by granulation tissue. Skin and Body Membranes: Tissue Repair Tissue Regeneration Blood clot is replaced by granulation tissue. Capillaries grow in from nearby areas, forming new capillary bed. Fibroblasts produce growth factors (encourage mitosis) and collagen fibers. Some fibroblasts even help to pull the wound together. Large white blood cells digest clot. Granulation tissue is replaced either by original tissue type. Fibrosis Same as above, except granulation tissue is replaced by fibrous connective tissue. Always occurs in cuts, scrapes, punctures, burns to some extent. May be visible at surface or not. Over time scar tissue might be replaced by original tissue type. Pure infections rarely lead to fibrosis. (only occurs in destructive infections)

Tissues that regenerate easily: Skin and Body Membranes: Tissue Repair Tissues that regenerate easily: Epithelial tissue, fibrous connective tissue, areolar tissue, bone, blood-forming tissue Tissues that regenerate moderately: Smooth muscle, dense regular connective tissue Tissues that regenerate poorly: Skeletal muscle, cartilage Tissues that are replaced largely with scar tissue: Cardiac muscle, nervous tissue within the brain and spinal cord

Skin and Body Membranes: Tissue Repair Sometimes, the body goes overboard with tissue repair. This can lead to hypertrophic scars AKA keloids.

Skin Cancer Skin cancer is the most common type of cancer Skin and Body Membranes: Integumentary System, Skin Cancer Skin Cancer Skin cancer is the most common type of cancer Biggest risk factor is overexposure to UV radiation in sunlight Graph of skin cancer rates?

Basal cell carcinoma Least malignant Most common type Skin and Body Membranes: Integumentary System, Skin Cancer Basal cell carcinoma Least malignant Most common type Arises from statum basale

Squamous cell carcinoma Skin and Body Membranes: Integumentary System, Skin Cancer Squamous cell carcinoma Arises from stratum spinosum Metastasizes to lymph nodes Early removal allows a good chance of cure

Malignant melanoma Most deadly of skin cancers Cancer of melanocytes Skin and Body Membranes: Integumentary System, Skin Cancer Malignant melanoma Most deadly of skin cancers Cancer of melanocytes Metastasizes rapidly to lymph and blood vessels Detection uses ABCD rule

ABCD Rule A = Asymmetry B = Border irregularity C = Color D = Diameter Skin and Body Membranes: Integumentary System, Skin Cancer ABCD Rule A = Asymmetry Two sides of pigmented mole do not match B = Border irregularity Borders of mole are not smooth C = Color Different colors in pigmented area D = Diameter Spot is larger than 6 mm in diameter

So what can I do to take care of my skin?