Skin Disorders and Diseases

Skin

• Accounts for 15% of body weight

• Largest organ - 21ft2

Homeostatic Imbalances of the Skin

• Can develop more than 1000 conditions

• Most common

– Bacterial

– Viral

– Yeast infections

• Less common…more damaging

– Cancer

– Burns

InfectionsAthletes foot

Caused by fungal infection

Boils and carbuncles

Caused by bacterial infection

Cold sores

Caused by virus

Ring Worm

Caused by fungal infection

Infections and allergies

Decubitus Ulcer (Bed Sore)

Pressure/infection

Contact dermatitis

Exposures cause allergic reaction

Urticaria

Hives

Caused by stress or allergin

Impetigo

Caused by bacterial infection

Psoriasis

Cause is unknown

Triggered by trauma, infection, stress

What Does It Look Like?

• Find a spot (mole, beauty mark, etc…) somewhere on your body

• Draw what it looks like on your paper, including the color

• Describe the texture

• Measure in mm

Skin CancerCancer – abnormal cell mass

Two types

Benign

Does not spread (encapsulated)

Malignant

Metastasized (moves) to other parts of the body

Skin cancer is the most common type of cancer

Overexposure to UV radiation – disables tumor suppressor gene (p53)

Basal Cell Carcinoma• Most common & least malignant

• Occurs in stratum basale

• Slow growing

• Cells proliferate & invade the dermis and hypodermis

• Usually appear on sun-exposed face

• Symptoms

– pale marks, reddish patches that recur, sores that don’t heal, shiny bumps, round & smooth growths with a raised edge

Squamous Cell Carcinoma• Next most common

• Arises from keratinocytes of the stratum spinosum

• Tends to grow rapidly & metastasize to lymph nodes if not removed

• Early removal allows a good chance of cure

• This kind can recur, so avoid sun and follow-up visits

• Symptoms

– similar to basal, bleeding wart, scaly reddened elevation, appears on scalp, ears, and lower lip

Melanoma• Most dangerous – cancer of the melanocytes

• Metastasizes rapidly to lymph and blood vessels

• Resistant to chemotherapy

• Appear spontaneously OR preexisting mole

• Appears as a spreading brown to black patch –moves to surrounding lymph & blood vessels

• Key – EARLY DETECTION!

Detection Uses ABCD ruleA = 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 then 6 mm in diameter

Using your Chromebook answer the question at the following link:

http://pollev.com/andreaferris121

Answer: Contact Dermatitis

Eczema = Atopic Dermatitis

Objectives

• Students will be able to distinguish between a hand full of genetic defects of the Integumentary System.

• Students will be able to identify the characteristics of the 3 types of burns, as well as use the rule of nines to determine the severity of a burn.

• Students will be able to describe the stages of skin development.

Genetic Disorders

• Vitiligo

– Loss of pigment

– White patches

• Albinism

– Defect in melanin production

– Fair complection & traits

• Porphyria

– Vampire Disease

– Build up of chemicals

– Heme production altered

• Mongolian Spot

– Entrapment of melanocytes during migration = more dark pigment

Genetic Disorders

• Epidermolysis Bullosa

– Severe blisters

– Fusion of parts

Striae AKA Stretch Marks

• Silvery, white scars • Dermis is torn or stretched

Skin Homeostatic Imbalances

Slide 4.25

Burns

Tissue damage and cell death caused by heat, electricity, UV radiation, or chemicals

Associated dangers

Dehydration

Electrolyte imbalance

Circulatory shock

Could lead to renal failure

Burns• Immediate threat – catastrophic loss of body

fluids containing proteins & electrolytes

• Must replace lost fluids immediately!!!

• Leading cause of death in burn victims –

infection (once initial crisis had passed)

• Use rule of nines for extent of the burns

Rules of Nines

Slide 4.26

Way to determine the extent of burns

Body is divided into 11 areas for quick estimation

Each area represents about 9%

Rule of Nines

Severity of Burns

Slide 4.27

First-degree burns

Only epidermis is damaged

Skin is red and swollen

Symptoms

localized redness, swelling, & pain, NO blisters

Heals in 2-3 days

Example: sunburn

Severity of Burns

Slide 4.27

Second degree burns

Epidermis and upper dermis are damaged

Skin is red with blisters

Heals in 3 – 4 weeks, minimal scarring

Third-degree burns

Destroys entire skin layer

Burn is gray-white , cherry red, or black

Area is not painful - why???

Infection is common because cells of the immune system can’t get to the tissue (no blood vessels)

• Skin grafting is usually necessary

– 1. remove burned skin

– 2. flood area with antibiotics and cover the burned area

– 3. healthy skin is transplanted to the burned site

Critical Burns

Slide 4.28

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

There are burns in the genital area.

Development of Skin

• Epidermis develops from ectoderm

• Dermis & Hypodermis – mesoderm

• By end of 4th month – skin is well formed.

• During the 5th & 6th month – fetus is covered

in downy coat = lanugo coat

• Lanugo coat is shed by 7th month

• When born – covered in vernix caseosa =

white, cheesy-looking substance produced by

sebaceous glands

Tell Your Classmate!!!

• Turn to a classmate and tell him or her the most interesting thing you learned today.

• Make sure to explain why you thought it to be interesting!

READ ON YOUR OWN

• Make sure to read pages 124-128 in your textbook.

• Look for study guide answers on Twitter.

• Bring all your foldables to class on Wednesday/Thursday.