Chapter 6Skin and Its Appendages

Structure of the Skin

Structure• Picture page 163 ( 197)• Integumentary system = skin• Skin is a thin relatively flat organ• Classified as a membrane: cutaneous

membrane• Cutaneous Membrane is divided into

epidermis and dermis

Epidermis• Outer, thinner epithelial layer.

• Develops from ectodermal germ layer, usually by the 17th week of gestation the baby’s has all the essential characteristics of the adult’s

• Avascular

Dermis• Inner, thicker connective layer

• Derived from the mesoderm

• Vascular

Dermal-epidermal junction

• Specialized area where cells of epidermis meet connective tissue of dermis

• characteristics of the adult structure by the 9th week of gestation

Subcutaneous Layer• Also called hypodermis

• Lies beneath the dermis

• Rich in fat and aerolar tissue

• Irregular connective tissue

Epidermis

Dermis

Subcutaneous layer (hypodermis)

Epidermis

Page 200 in home books

Cell Types• Epidermis is composed of several types of

epithelial cells• Keratinocytes

– Most important cell in the epidermis– Comprise over 90% of epidermal cells– Filled with tough, fibrous protein called keratin– principle structural element of outer skin

Cell Types• Melanocytes

– Contribute color to skin– Protect from UV light– Can be completely absent from skin in some

non-lethal conditions

Cell Types

Cell Types• Langerhans Cells

– Dendritic cells (immune cells)– Play a role in immune reactions that effect the

skin– Cells originate in the bone marrow but migrate

to deep cell layers of the epidermis early in life

Cell Layers of Epidermis

Strata

Page 200 in home books

Stratum basale• Base layer

• Single layer of columnar cells

• Only cells in this deepest layer of epithelium undergoes mitosis

• Cells migrate from this layer to other layers until they reach the surface and are shed off

Stratum Spinosum• Also called spiny layer• Stratum germinativum is used to describe the

stratum basale and Stratum Spinosum together• Formed from 8-10 layers of irregularly shaped

cells with very prominent intercellular bridge or desmosomes

• Desmosomes appear to pull points of the plasma membranes of adjoining cells toward one another. Gives spiny appearance

• Cells are rich in RNA making them well equipped to start protein synthesis needed for the production of keratin

Stratum Granulosum• Granular layer• Process of surface keratin formation begins• Sheet 2-4 layer deep filled with intensely staining

granules called keratohylin (required for surface keratin formation)

• Cells start to degenerate• High levels of lysosomal enzymes are present in

cytoplasm and nuclei are in the process of breaking down

• In thin skin this layer may not be visible

Stratum Lucidum• Clear layer

• Keratinocytes are very flat, closely packed and clear

• Nuclei are usually absent

• Dying cells are filled with eleidin which is eventually transformed to keratin

• Absent in thin skin

Stratum Corneum• Horny layer• Most superficial layer of epidermis• Composed of thin squamous cells• At surface cells are dead and continuously being

shed• Desmosomes holding together Keratinocytes

strengthen this layer• Keratinization: process in which cells from

deeper layers migrate, fill with keratin and move to surface

Stratum Corneum• Sometimes called barrier area of skin• Protects from water loss and environmental threats• Glycophospholipids cement keratin into water proof

barrier.• Glycophospholipids can be washed away by excessive

soaking. The keratin can then absorb water appearing puffy and wrinkled

• Diseases can cause layer to thicken• Hyperkeratosis: Thick, dry, scaly skin that is inelastic and

subject to painful fissures

Cell Layers

Thin and Thick Skin

Thin and Thick Skin• There are up to 5 layers of stratum or cell

layers. (stratum corneum, lucidum, granulosum, spinosum, basale)

• Epidermal tissue can be categorized thin or thick skin

• Most of the body surface is covered by thin skin

• Hairless skin covering palms, fingertips, soles of feet or other areas associated with friction has a covering of thick skin

Thick skin• Each of 5 strata of epidermis are

present and each stratum are generally several layers thick

• Hair not found in thick skin• Thick skin underlying dermal

papillae are raised in curving parallel friction ridges forming fingerprints or footprints

• Ridges allow us to pick up and manipulate small items and supplies slip resistance to the feet.

Thin skin• Number of cell layers in the epidermal

stratum are less than in thick

• One or more strata may be entirely absent

• Friction ridges are not present

Epidermal Growth and

Repair

Epidermal Growth and Repair• Turnover or regeneration time describes period

required for a cell population to mature and reproduce

• To maintain constant thickness, new cells must be formed at the same rate that old keratinized cells flake off from stratum corneum.

• Current research suggest regeneration time is about 35 days

• Abrasion can accelerate skin regeneration time. The result is an intense stimulation of mitotic activity in the stratum basale and shortened turnover period

• Continued abrasion can result in an abnormally thick stratum corneum, producing calluses at the point of abrasion.

Epidermal Growth and Repair• Callus formation is normal but there are several

skin diseases by abnormally high mitotic activity in the epidermis resulting in scales and lesions

• 10%-12% of cells in the stratum basale enter mitosis each day

• Cells migrating to surface proceed upward in vertical columns from groups of 8-10 of these basal cells undergoing mitosis

• Each group of active basal cells, with its vertical column of migrating keratinocytes is called epidermal proliferating unit (EPU)

Review• Identify two main layers of skin

• Terms thick and thin refer to which primary layer of skin

• How do thin and thick skin differ

• Identify two main cell types found in the epidermis

• List 5 layers of epidermis (strata)

Dermis

Page 200 in home books

Dermal-Epidermal Junction• Specialized area where cells of epidermis meet

connective tissue of dermis• characteristics of the adult structure by the 9th

week of gestation • lies between papillary layer and the stratum

basale• Combines basement membrane and includes

specialized fibrous elements and a polysaccharide gel

• cement the superficial epidermis to the dermis (glue the two layers together)

• Provides mechanical support for epidermis

Dermis• Also called the corium or “true skin”• Vascular• Composed of thin papillary layer and

thicker reticular layer• Much thicker than the epidermis• Serves a protection function against

mechanical injury

Dermis• Specialized network of nerves and nerve

endings called somatic sensory receptors process sensory information

• At various levels the dermis may contain muscle fibers, hair follicles, sweat and sebaceous glands and many blood vessels

• It is rich vascularity that plays an important role in temperature regulation (discussed later)

Papillary Layer• Thin superficial layer of the dermis• Forms bumps called dermal papillae on its

surface• Dermal-Epidermal Junction lies between

papillary layer and the stratum basale• Composed of loose connective tissue elements

along with thin collagenous and elastic fibers• Has characteristic ridges on surface due to

conforming tightly to dermal papillae • Fingerprints and footprints allow us to grip so we

can grasp small objects and walk upright on slippery surfaces (Friction Ridges)

Reticular Layer• Thicker layer of dermis

• More of the dense reticulum or network of fibers (most are collagenous) than in papillary layer

• Dense collagenous fibers in this layer is what produces leather in processed animal skins (these fibers also give skin toughness)

• Elastic fibers make skin stretchable

Reticular Layer• Serves as a point of

attachment for skeletal and smooth muscle fibers

• Most of the structures such as muscle fibers, hair follicles, sweat and sebaceous glands are located in reticular layer

• Several skeletal muscle are located in the skin of the face and scalp and permit various facial expressions

Reticular Layer• Distribution of smooth muscle is much

more extensive than skeletal• Each hair follicle has a small bundle of

involuntary muscle attached to it. Called arrector pili muscle

• Contraction of these muscles makes hair stand on end and raises skin around hair

• Goosebump• Have millions of somatic sensory

receptors

Dermal Growth and Repair• Unlike epidermis, dermis does not

continually shed and regenerate

• Rapid regeneration of connective tissue in dermis occur only unusual circumstances such as wound healing

• Fibroblasts quickly reproduce and begin forming a dense mass of new connective tissue that will either be replaced by normal tissue or become a scar

Dermal Growth and Repair• Dense white bundles of collagenous fibers orient

themselves in patterns called cleavage lines or Langer’s Lines. Page 167 (203)

• Surgical incisions are made parallel to cleavage lines the resulting wound has less tendency of gaping open and will tend to heal with a less noticeable scar

• When elastic fibers are stretched too much (pregnancy) Fibers weaken and tear and initially resulting in pinkish or slightly bluish depressed furrows with jagged edges

• When they heal and lose color they remaining furrows appear as glistening silver-white scar lines (stretch marks)

Hypodermis

Hypodermis• Called subcutaneous layer, subQ or

superficial fascia

• Not part of the skin but usually discussed with the skin

• Forms connection between skin and underlying structures of the body

• Made up mostly of loose fibrous tissue and adipose tissue

• Carries major vessels and nerves to skin above

Review• What is the name of the layer separating

the dermis from the epidermis?

• Which layer of the dermis forms the bumps that produce the ridges on palms and soles?

• Which layer is vascular? Dermis or epidermis

• What is the main function of the hypodermis?

Skin Color

Melanin• Main determinant of skin color is the

quantity of melanin deposited in the epidermis cells

• Melanin (pigment) is produced by melanocytes

• Melanocytes scattered throughout the stratum basale is roughly the same amount for everyone

• It is the amount and type of melanin pigment that melanocytes produce that account for skin color variations

Melanin• Two groups of melanin

– Eumelanin – Pheomelanin

• Eumelanin– “true Black”– Very dark brown, sometimes

nearly black– Dark skinned and dark haired

produce large quantities– Absorbs more UV radiation

than pheomelanin

Melanin• Pheomelanin

– “dusky black”– Hints at lighter reddish and orange colors– Very light skinned with reddish orange

freckles and red hair produce large quantities and very little of eumelanin

Melanin• Only melanocytes have ability to routinely

convert the amino acid tyrosine into melanin pigments

• These pigment granules release tiny melanosomes

• Melanosomes form a cap over the nucleus in keratinocytes protecting it from UV damage

• The enzyme tyrosinase regulate the pigment producing process

Melanin• 4-6 pairs of genes exert primary control of

the amount of melanin formed by melanocytes

• Albinism can result if the enzyme tyrosinase is absent from birth

• Heredity determines how dark or light one’s skin color will be

• Prolonged UV exposure in light skinned people causes melanocytes to increase melanin production

Melanin• Prolonged UV exposure in light skinned

people causes melanocytes to increase melanin production

• Increasing age may influence melanocyte activity

• Melanin production can be stimulated by excess secretion of adrenocorticotropic hormone (ACTH)

Other Pigment or Color Changing Factors

• Beta-carotene: yellow pigment– Can be converted by body into vitamin A

(important nutrient for skin growth)– High consumptions of carrot juice or sweet

potatoes can cause yellowing of the skin (especially in infants)

– Jaundice caused by bile pigments

Other Pigment or Color Changing Factors

• Blood Flow– Hemoglobin (reddish pigment)– Increased flow causes skin to temporally be

redder– Blood vessels dilate during blushing– When blood vessels constrict the skin

becomes paler

Other Pigment or Color Changing Factors

• Hemoglobin– Low in O2 and high in CO2 can appear bluish

or cyanotic – Hemoglobin changes from bright red to deep

maroon-red as it loses oxygen– Light reflects from maroon-red and is diffused

by skin fibers may appear blue – The darker the skin the greater amount of

unoxygenated skin must be present before cyanosis (condition of blueness)

Other Pigment or Color Changing Factors

• Bruising– Damage to blood vessels permits release of

RBC – These RBC produce the bluish colors

discussed earlier– As blood clots it may appear darker blue or

even black– Macrophages break down hgb into iron

containing hemosiderin (brownish pigment) and several iron free bile pigments (yellow and green)

Functions of the Skin

Function of the Skin• Protection• Sensation• Permits movement and growth• Endocrine (Vitamin D production)• Excretion• Immunity• Temperature regulation

• Page 171(207) for skin functions chart

Protection• Barrier for underlying tissue against

microorganisms, chemicals and mechanical injury

• Protects from dehydration of body fluids and entry of excessive fluids from external environment

• The pigment melanin protects us from overexposure to UV light

Surface Film• Mechanical barrier

• Produced by mixing residue from sweat and sebaceous glands with cast off epithelial cells (shedding of epithelial cells is called desquamation)

• Has antibacterial and antifungal properties

• Lubricates and hydrates skin surface

• Buffers caustic irritants and blocks toxic agents

Surface Film• Chemical composition include:

– Amino acids, sterols and complex phospholipids

– Fatty acids, triglycerides, and waxes– Water, ammonia, lactic acid, urea and uric

acid

• Chemical composition varies from area to area

Sensation

Flexibility

• Skin must be elastic and supple to allow movement of the body without injury

• It grows as we grow

Vitamin D ProductionExposure to UV light

Taken to liver and kidney by blood

Active form of vitamin D

Too much melanin in skin can keep bodies from synthesizing vitamin D

Excretion

• Plays minor role in the excretion of body waste

• Excretes urea, uric acid and ammonia (sweat)

Immunity

• Specialized cells attach to and attack microorganisms in the skin

• Langerhan’s cells function with helper T cells to trigger helpful immune reaction to certain diseases.

Temperature Regulation• Humans usually maintain a constant core

body temperature (aprox 37°C)

• Certain chemical reactions must take place at specific temperatures

• Body must balance amount of heat it produces with the amount of heat it loses

• Skin plays an important role in this balance

Body Temperature Regulation

Heat Production• Heat is produced by

– metabolism of food

• Muscle and glands are the most active, they metabolize more and produce more heat

• During exercise and shivering heat production is increased

• During sleep metabolism and heat production slow

Heat Loss• 80% of heat transfer occurs through the

skin

• Heat loss can be regulated by altering the flow of blood in the skin

• If heat must be conserved blood vessels constrict keeping warm blood flow deeper in the body

• If heat lost must be increased vessels dilate to increase flow to out tissue where it is released into enviroment

Evaporation• Heat energy must be expanded to

evaporate fluid

• Important in high environmental temperatures

• Humid atmosphere retards evaporation and lessens the cooling effect

Radiation

• Transfer of heat from the surface of one object to another without actual contact

• Heat radiates to nearby objects that are cooler

• Radiation accounts for a greater percentage of heat loss than conduction and evaporation do

Conduction• Transfer of heat to any substance in actual

contact with body (jewelry, clothing, food, etc)

• Accounts for relatively small amount of heat loss

Convection

• Transfer of body heat by movement of heated air

Homeostatic Regulation of Heat Loss• Heat loss in skin is controlled by negative

feedback loop Page 174 (211)

• Hypothalamus has receptors that detect body temperature changes

• Hypothalamus acts as integrator sending signal to sweat glands and blood vessels (effectors)

• they respond to promote heat loss

http://www.youtube.com/watch?v=H2CEhWLFfUc

Review

• What is the one means of heat production in the body?

• In what organs do most heat production occur?

• Name three processes heat is lost from the body and explain

Appendages of the Skin

Appendages of Skin

• Hair

• Nails

• Glands

Hair• Tubular pockets called hair follicles develop in

parts of the skin many months before birth• By 6th month fetus is covered with fine, soft hair

called lanugo, which is uasually lost before birth• When lanugo hair is lost it is replaced by vellus

hair (stronger, fine less pigmented)• Course pubic and axillary hair that develops at

puberty is called terminal hair• In adult male terminal hair replaces 80-90% of

the vellus hair on chest, extremities and beard

Hair Growth• Cells of epidermis spread down into

dermis to form small tube or follicle

• Follicle consists of two primary layers– Outer dermal root sheath– Epithelial root sheath

• Stratum germinativum develops into follicle’s innermost layer and at bottom of follicle forms a cap-shaped cluster of cells known as germinal matrix

Hair Growth• Protruding into germinal matrix is small

mound of dermis called hair papilla• Hair papilla contained blood capillaries

that nourish germinal matrix• Cells of germinal matrix are responsible

for forming hairs• These cells undergo repeated mitosis,

push upward in follicle and become keratinized to form hair

• As long as germinal matrix remains alive, hair will regenerate

Hair Growth• The root lies hidden in the

follicle

• The visible part of the hair is called the shaft.

• Inner core is known as the medulla

• Superficial portion around is called the cortex

• Covering layer is called cuticle

Hair Growth• Hair alternates between periods growth

and rest

• Hair on head grows approximately ½” per month

• Hair lives about 2-6 years before dying and being shedded

• New hair normally replace lost ones

• Cutting or shaving does not stimulate hair growth and does not continue to grow after death

Appearance of Hair• Deposits in the hair is varying amounts of

melanins. Amount, type and distribution determines hair color

• Varying amounts of eumelanin in the cortex or medulla can produce shades of blond and brunette hair

• Pheomelanin give hair a reddish tint• Advancing age can produce white (containing no

pigment at all)• White hair results from failure to maintain

melanocytes in hair follicle

Appearance of Hair• Shape of shaft determines if hair is straight or

wavy• Straight hair has round, cylindrical shaft • Wavy hair has a flat shaft that is not as strong• Two or more sebaceous glands secret sebum,

(oily substance) into hair follicle• Sebum lubricates and conditions hair to keep it

from becoming dry and brittle (lipid containing conditioners help reduce damage also)

Appearance of Hair• Genes for baldness are inherited

• Common or male pattern baldness can occur when gene is inherited and testosterone is present

• The drug minoxidil can slow or even stop baldness but the drug is expensive and must be continued for life and it does not always produced dramatic effect hopped for

Nails• Heavily keratinized epidermal cells• Visible part is called nail body• The rest of nail or root lie hidden by a fold

of skin bordered by the cuticle.• The white crescent-shaped area is called

lunula• Under nail is a layer of epithelium called

nail bed• Nail bed contains abundant blood vessels

and thus appears pink through nail

Nails• Cyanosis will appear at the nail bed first so

nail beds are monitored during surgery in case of a sudden drop in oxygenation

• Nails grow by mitosis in the stratum germinativum beneath the lunula

• Nails grow an average 0.5 mm a week (fingernails grow faster than toenails)

• Nails grow faster in the summer than in the winter

Skin Glands

• 3 types of microscopic glands

–Sweat

–Sebaceous

–ceruminous

Skin GlandsSweat Glands

• Also called sudoriferous glands

• Most numerous skin gland

• Can be classified as eccrine or apocrine

• Eccrine– Most numerous, important and widespread– Distributed over total body surface with the

exception of lips, ear canal, glans penis and nail beds

– Simple, coiled, tubular type of gland

Skin GlandsSweat Glands

• Eccrine– Most numerous, important and widespread– Distributed over total body surface with the

exception of lips, ear canal, glans penis and nail beds

– Simple, coiled, tubular type of gland– Produce perspiration or sweat rich in salts,

ammonia, uric acid, urea and other waste products

Skin GlandsSweat Glands

• Eccrine– Besides eliminating waste sweat helps

maintain core temperature– Histologists estimate that a single square inch

of skin on the palms contain about 3000 sweat glands

– Actual secretory portion is in the subcutaneous layer but the ducts travel through dermis and epidermis to open to the outside

Skin GlandsSweat Glands

• Apocrine – Larger than eccrine glands– Located deep in subcutaneous in axilla (armpit),

areola of the breast and pigmented area around anus– Connected with hair follicles– Classified as simple, branched tubular glands– Enlarge and begin to function at puberty. In females,

secretions changes are linked to menstrual cycle– Produce more viscous and colored secretion than

eccrine glands– Odor is linked to bacteria on the skin

Skin GlandsSebaceous Glands

• Secrete oil (sebum) for hair and skin• Helps prevent excessive water loss from skin• Rich in triglycerides, waxes, fatty acids and

cholesterols • Sebum has antifungal properties• Secretions increase during adolescence due to

increase in blood levels of sex hormones • Pimples are accumulated sebum in enlarged

sebaceous gland ducts • Oxidation causes sebum to darken in a

blackhead

Skin GlandsCeruminous Glands

• Modified apocrine glands

• Simple coiled tubular glands with excretory ducts that open to surface skin of external ear canal

• Secretion form a brown waxy substance called cerumen

• Protects skin from dehydrations but can harden, causing blockage which can result in hearing loss

Review

• Identify pigment that determines hair color

• Appendages of skin

• Two types of sweat glands

• Function of sebum

Skin Disorders

Skin Disorders

• Any disorder of the skin can be called dermatosis (skin conditions)

• Inflammation of the skin is called dermatitis

Skin Infections

Impetigo• Highly contagious bacterial infection

• Caused by staphylococcus or streptococcus

• Occurs most often in young children

• Starts as reddish discoloration (erythema) but soon develops into blisters and yellowish crust

• Can be systemic

Tinea• Fungal infection of the skin

• Include ringworm, jock itch, and athlete’s foot

• Signs include erythema, scaling and crusting

• Typically forms a round rash that heals in the center to form a ring

• Treated with antifungal

• Requires moist environment to grow

Warts• Caused by papillomavirus

• Nipple like neoplasm of the skin

• Most are benign but can transform to malignant

• Can be passed on by contact

• Can be removed by freezing, drying, laser or chemicals

Boils• Also called furuncles

• Local staphylococcus infection

• Large, inflamed, pus-filled lesion

• Group of untreated boils can fuse into larger carbuncle

Skin Cancer

Skin Cancer• Most common form of cancer• Two forms basal cell carcinoma and

squamous cell carcinoma account for 95% of reported skin cancer cases

• Very responsive to therapy• Very seldom metastasize• If left untreated can cause significant

damage to adjacent tissue• Malignant melanoma has tendency to

spread

Basal Cell Carcinoma• Most common form of skin cancer

• Begins in cells at the base of the epidermis– Basale Stratum

• Most often appears on nose or face

• Can appear at any age but increase after age 40

• Rarely metastasize but can cause severe damage to adjacent normal tissue

Squamous Cell Carcinoma• Slow growing

• Arises from the epidermis

• Occurs more frequently in middle-age or elderly

• Typically found on sun exposed areas – Forehead, back of hands, scalp, top of ears

Malignant Melanoma• Most deadly of all skin cancers

• Shown steady increase in the last 20 years

• Highest incidence found in older individuals with light skin, eyes and hairs, does not tan well and have suffered from severe sunburns

• Sometimes develops from pigmented nevus (mole)

Malignant Melanoma• Moles must be checked periodically (use

“ABCD” rule of self exam)• Asymmetry

– Benign moles are usually symmetrical

• Border– Benign moles have distinct border

• Color– Benign moles tend to be evenly colored

• Diameter– When exhibiting “ABC” changes a malignant mole is

usually larger than 6mm or ¼ “

Malignant Melanoma• Vaccines are currently being tested

• The main cause is UV radiation

• UV radiation damages DNA in skin cells causing mutations or mistakes in mitosis

• Can be genetic

Kaposi Sarcoma• Rarer skin cancer

• Appears in cases of AIDS or other immune deficiencies

• First appears as purple papules and quickly spreads to lymph nodes and internal organs

• Believed to be caused by a virus

Vascular and Inflammatory

Skin Disorders

Skin Disorders• Decubitus Ulcer: Pressure sore (bed sore)

– Caused be irritation to skin form lying still or being bed ridden

• Uticaria or hives (allergic reaction)

•Raised red lesions called wheals

•Caused by leakage of fluid from skin’s blood vessels

•Severe itching

Skin Disorders• Scleroderma

– Means “hard skin”– Autoimmune disease that effects blood

vessels and connective skin tissue– Starts as mild inflammation and then develops

into patch of yellow hardened skin (usually localized)

• Psoriasis– Chronic inflammatory disorder– Cutaneous inflammation– Silver colored scaly lesion

Skin Disorders• Eczema

– Most common inflammatory disorder of the skin

– Bumps, blisters and crust– Not disease but a symptom of underlying

problem– Can be caused by allergic reaction– Poison Ivy can cause

Abnormal Body Temperature

Fever• Unusually high body temp (systemic

inflammatory response)

• Chemicals called pyrogens causes thermostatic control of hypothalmus to produce fevers

• Chills

• Enhance body immune response

• Best to let fever break on own

Malignant Hyperthermia• Inherited condition

• Abnormally increased body temp (hyperthermia)

• Muscles get rigid when exposed to certain anesthetics or muscle relaxants

• Drug dantrolene prevents or relieves condition by inhibiting heat producing muscle contractions

Heat Exhaustion

• Occurs when body loses large amount of fluid from heat mechanisms

• Loss of water and electrolytes can cause weakness, dizziness, nausea, muscle cramps and possibly loss of consciousness

• Treated with rest in cool place and fluid replacement

Heat Stroke/Sunstroke• Severe, sometimes fatal

• Inability of body to maintain normal temp in warm environment

• Factors include age, disease, and drugs

• 105° or higher, tachycardia, headache, hot dry skin, confusions, convulsions or loss of consciousness

• Body must be cooled and fluids replaced immediately

Hypothermia

• Inability of body to maintain normal temp in extremely cold environments

• 95° or lower, shallow slow respirations, faint slow pulse

• Treated by slowly warming body

Frostbite• Local damage to tissue from extreme cold

• Damage results fro formation of ice crystals and reduction in local blood flow

• Necrosis (tissue death) and gangrene (decay of dead tissue) can result

Burns

Body Surface Estimation• Severity of burn is determined by depth

and coverage of burn

• Determined by “Rule of Palms” or “Rule of Nines”

• Using the rule of palms, the surface of the patient's palm represents approx 1% of body surface area.

Body Surface Estimation• “Rule of Nine”

– Body divided into 11 areas of 9%– Area around genitals (perineum) representing

additional 1% of body – Small children use Lund-Browder chart

http://www.doereport.com/enlargeexhibit.php?ID=1971

Age in years 0 1 5 10 15 Adult

A-head (back or front) 9½

8½

6½

5½

4½

3½

B-1 thigh (back or front)

2¾

3¼

4 4¼

4½

4¾

C-1 leg (back or front) 2½

2½

2¾

3 3¼

3½

1st Degree Burn

• Can peel but no blistering

•Tissue damage in minimum

•Minor irritation

•Also called partial thickness burn

2nd Degree Burn

• Can damage glands and hair follicles

•Scaring is common

•Can have white charred skin

•Can produce shock

3Rd Degree Burn

• Tissue death extends below hair follicles and glands

•Fourth degree involves muscle and bone

•Pain may not be apparent due nerve damage

•Scaring is a serious problem

• http://video.google.com/videoplay?docid=1856678610844928019&ei=bEbiStjMO5-arAKNz7DoDA&q=skin+tissue&hl=en#