Download The Skin - Cloudfront.net

The Skin
Homeostatic Imbalances
Tattoos
• Needle is used to deposit pigment within
the dermis
• Risks:
– One ugly tattoo
– Dyes w/cancer causing agents
– Hepatitis C
• Removal:
– Dermabrasion, cryosurgery, caustic chemicals,
laser based technology
Excessive Sun exposure
• Damages skin
• Elastic fibers clump -> leathery skin
• Chance for herpes (aka cold sore)
increases
• Alter DNA of skin cells -> skin cancer
– inc melanin in black ppl dec chance for skin
cancer
Decubitus Ulcer
• Restriction of normal blood supply to skin
• Causes cell death
• Occurs often in bedridden patients who are
no turned regularly or who are dragged or
pulled repeatedly across bed
– Blood supply restricted -> blanching
– Skin reddens when pressure released
– Cracks appear in skin @ compressed
– areas
Infections and
Allergies
• Athlete’s Foot
– Itchy, red, peeling
– between toes
– Fungal infection: fungus grows on or in the top
layer of the skin
– Easily transferred
– Can be caught walking near
swimming pools and lockers
Infections and Allergies
• Boils and carbuncles
– Boils: inflammation of hair follicles and
sebaceous glands
– Carbuncles: boils caused by bacterial infection
Infections and Allergies
• Cold Sores
– Small, fluid-filled blisters
– Itch and sting
– Caused by herpes simplex infection
– Virus localizes in cutaneous nerve
– Dormant until activated by emotional upset,
fever, or UV
Infections and Allergies
• Contact dermatitis
– Itching, redness, swelling of skin, blistering
– Caused by exposure of skin to chemicals
– i.e. poison ivy
Infections and Allergies
• Impetigo
– Pink, water-filled, raised lesions
– Develops yellow crust and ruptures
– Caused by staphylococcus infection
– Common in elementary children
Infections and Allergies
• Psoriasis
– Reddened epidermal lesion
– Dry, silvery scales
– May be disfiguring
Burns
• Tissue damage and cell death caused by
intense heat, electricity, UV, or chemicals
• Two life-threatening problems:
– Body loses supply of fluids containing proteins
and electrolytes
– Dehydration and electrolyte loss = shutdown of
kidneys and circulatory shock
• Lost fluids must be replaced immediately!
Burns
• Rule of nines:
– Divides body into 11 area, each accounting for
9% of total body surface (plus 1% for genital)
• Infection leading cause of death in burn
victims
• Burned skin sterile for 24 hours
• Patient’s immune system depressed
Burns
• First degree
– Only epidermis damaged
– Area red and swollen
– Not serious
– Heals in two to three days
– i.e. sunburn
Burns
• Second degree
– Injury to epidermis and upper dermis
– Red, painful, and blisters present
– Enough epithelial present for regeneration
– No permanent scars result if taken care of
• First and second degree burns are called
partial-thickness burns
Burns
• Third degree
– Destroys entire thickness of skin
– aka full-thickness burn
– Burned area is blanched or blackened
– Nerve endings destroyed = no pain
– Regeneration not painful
– Skin grafting
• Fourth Degree Burn
– a burn that extends deeply into the
subcutaneous tissue, completely destroying
the skin, subcutaneous tendons, underlying
tendons, involving muscle, fascia, or bone
16
Burns
• Considered critical if:
– 25% has second degree burns
– 10% has third degree burns
– Third degree burns of face, hands, or feet
• Dangerous because burned respiratory
passageways
• Swells and causes suffocation
Skin Cancer
• Single most common type of cancer in
humans
• Most important risk factor is UV radiation
Skin Cancer
• Basal cell carcinoma
– Least malignant
– Most common type (usu. On face)
– Cells in stratum basale cannot form keratin and
no longer honors boundary between epidermis
and dermis
– Appears shiny, dome-shaped nodules that
develop an ulcer
– Slow-growing
– curable
Skin Cancer
• Squamous Cell Carcinoma
– Lesion appears scaly, reddened papules
– Gradually forms ulcer
– Usu on scalp, ears, dorsum of hands, lower lip
– Grows rapidly and into lymph nodes if not
removed
– Curable surgically or w/radiation therapy
Skin Cancer
• Malignant melanoma
– Cancer of melanocytes
– Accounts for 5% of skin cancers
– Usu. Appears as spreading brown to black
patch
– Grows into lymph and blood vessels
– Survival is 50%
– Treatment is wide surgical excision with
immunotherapy
Malignant melanoma
• Use ABCD on new moles or pigmented
spots to recognize
– Asymmetry: two sides of spot do not match
– Border irregularity: borders of lesion are not
smooth and have indentations
– Color: spot contains areas of different colors
– Diameter: spot is larger than 6 mm in diameter
AGE
• Newborn: skin is thin and blood vessels are
visible
– Skin thickens with age
• Adolescence: skin and hair become oily
• Adulthood (twenties and thirties): skin
reaches optimal appearance
– Environmental affects: abrasion, chemicals,
wind, sun, and other irritants clog pores with
pollutants and bacteria
– dermatitis (skin inflammation), pimples, scales
occur
• Old Age: subcutaneous tissue decreases, skin
is drier, skin thins, decreased elasticity
• FRECKLES: Concentration of Melanin in a
certain area
• HAIR:
– By 50, # of follicles dec by 1/3
– Bald men have hair in “bald areas”
• degenerated follicles develop colorless and tiny hair
– Graying: dec in amount of melanin deposited in the
hair
• emotional crisis, anxiety, protein deficiency,
chemotherapy, radiation, excessive vitamin A, fungal
diseases, genetics