Chapter 5: Integument System
Hair shaft
Epidermis
Papillary
layer
Dermis
Reticular
layer
Hypodermis
(superficial fascia)
Nervous structures
• Sensory nerve fiber
• Pacinian corpuscle
• Hair follicle receptor
(root hair plexus)
Dermal papillae
Subpapillary
vascular plexus
Pore
Appendages
of skin
• Eccrine sweat
gland
• Arrector pili
muscle
• Sebaceous
(oil) gland
• Hair follicle
• Hair root
Cutaneous vascular
plexus
Adipose tissue
Figure 5.1
Integument System
• Skin and its derivatives – sweat and oil glands,
hair, and nails
• Skin
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Covers entire body
1.2  2.2 square meters
~4 – 5 kg, 9-11 lbs
~ 75 of total body weight
Thickness varies – 1.5  4.0 mm thick
2 regions –
• dermis – tough, leathery material, vascularized fibrous
connective tissue
• Epidermis – epithelial cells, outermost protective shield
Skin
• Epidermis
• Dermis
• Hypodermis
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Also called superficial fascia
Not part of skin
But same protective feature
Mostly adipose tissue
Anchors skin to underlying structures
Loosely so that skin can slide freely over structures
Shock absorber/insulator
Thickens when gain weight
Women – accumulates in thighs and breasts first
Men – anterior abdomen “beer belly”
Hair shaft
Epidermis
Papillary
layer
Dermis
Reticular
layer
Hypodermis
(superficial fascia)
Nervous structures
• Sensory nerve fiber
• Pacinian corpuscle
• Hair follicle receptor
(root hair plexus)
Dermal papillae
Subpapillary
vascular plexus
Pore
Appendages
of skin
• Eccrine sweat
gland
• Arrector pili
muscle
• Sebaceous
(oil) gland
• Hair follicle
• Hair root
Cutaneous vascular
plexus
Adipose tissue
Figure 5.1
Epidermis
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Keratinized stratified squamous
4 distinct cell types
4 or 5 layers
Cells:
1.
2.
3.
4.
Keratinocytes
Melanocytes
Epidermal dendritic cells
Tactile cells
Keratinocytes
• Most common
• Produce keratin – fibrous protein that helps give
epidermis its protective function
• Arise from cell layer – stratum basale
• Continuous mitosis – epidermal growth factor
• Push cells upward by production of new cells
• By the time they reach the surface – dead, scale
like structures with a keratin filled plasma
membrane
Keratinocytes
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Millions of dead cells rub off everyday
Totally new epidermis every 25 – 45 days
Friction – hands and feet – accelerated
Persistent friction – causes thickening of
epidermis - callus
Melanocytes
• Spider shaped epithelial ells that synthesize
melanin
• Found in deepest layer of epidermis
• Melanin – made and accumulated in
membranous granules
• Melanosomes – moved to ends of melanocyte
processes, then taken up by keratinocytes
• Pigment – protects nucleus from damaging
effects of UV radiation
Epidermal Dendritic Cells
• Also called Langerhorn cells
• Arise from bone marrow and migrate to
epidermis
• Ingest foreign substances
• Key activators of the immune system
• Slender processes extend around
keratinocytes – forming continuous network
Tactile (Merkel) Cells
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Present in epidermal junction
Shaped like spiky hemisphere
Associated with disk like sensory nerve ending
Sensory receptor for touch
Layers of Epidermis
• Variation – thick or thin skin
• Thick skin – covers – palms, fingers, soles
• 5 layers or strata
– Stratum basale – DEEP
– Stratum spinosum
– Stratum granulosum
– Stratum lucidum
– Stratum corneum – superficial
(a)
Dermis
Stratum corneum
Most superficial layer; 20–30 layers of dead
cells represented only by flat membranous
sacs filled with keratin. Glycolipids in
extracellular space.
Stratum granulosum
Three to five layers of flattened cells,
organelles deteriorating; cytoplasm full of
lamellated granules (release lipids) and
keratohyaline granules.
Stratum spinosum
Several layers of keratinocytes unified by
desmosomes. Cells contain thick bundles of
intermediate filaments made of pre-keratin.
Stratum basale
Deepest epidermal layer; one row of actively
mitotic stem cells; some newly formed cells
become part of the more superficial layers.
See occasional melanocytes and epidermal
dendritic cells.
Figure 5.2a
Layers of Epidermis
• Thin Skin – covers rest of body
• Stratum lucidum – absent
• Outer strata thinner
Stratum corneum
Most superficial layer; 20–30 layers of dead
cells represented only by flat membranous
sacs filled with keratin. Glycolipids in
extracellular space.
Stratum granulosum
Three to five layers of flattened cells,
organelles deteriorating; cytoplasm full of
lamellated granules (release lipids) and
keratohyaline granules.
Stratum spinosum
Several layers of keratinocytes unified by
desmosomes. Cells contain thick bundles of
intermediate filaments made of pre-keratin.
Stratum basale
Deepest epidermal layer; one row of actively
mitotic stem cells; some newly formed cells
become part of the more superficial layers. See
occasional melanocytes and epidermal
dendritic cells.
Desmosomes
Melanin granule
Melanocyte
(b)
Keratinocytes
Dermis
Sensory
nerve ending Epidermal
Tactile
dendritic cell
(Merkel) cell
Figure 5.2b
1. Stratum Basale
• Basal layer
• Also called stratum germinative ‘germinating
layer”
• Deepest epidermal layer
• Attached by wavy borderline
• Single row of stem cells
• Many mitotic nuclei
• 10- 25 % of cells – melanocytes
• Occasional tactile cells
2. Stratum Spinosum
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Prickle layer
Several cell layers thick
Web like system of intermediate filaments
Tension resisting bundles of pre-keratin filaments
Span cytosol and attach to desomones
Keratinocytes – have spines – called prickle cells
Artifacts that arise during tissue prep
Scattered are melanin granules and epidermal
dendritic cells
3. Stratum Granulosum
• Granular layer
• 3 to 5 cell layers in which keratinocytes – appearance
changes
• Keratinization – cells fill with protein keratin
• Cells flatten, nuclei and organelles begin to disinigrate
• Accumulate 2 types of granules:
– Keratohylane granules – help to form granules
– Lamellated granules – water resistant glycolipids, slow
water loss across epidermis
• Plasma membrane thickens as cytosol proteins bind
• Lipids released – coat outer surface
• Make more resistant to destruction
4. Stratum Lucidum
• Clear layer
• Appears – thin translucent
• 2 or 3 rows of clear, flat, dead keratinocytes
with distinct boundaries
• Arrogate in large, cable like parallel arrays
• Visible in only thick skin
5. Stratum Corneum
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Horney layer
Broad zone of 20-30 cell layers thick
¾ of total thickness
Keratin and thickened plasma membrane of cells – protect
skin against abrasion and penetration
Glycolipids – water proof
Durable overcoat
Protects deeper cells from – air, water-loss, and chemical,
biological, and physiological assaults
Layer of dead cells – play many roles
Remnants – cornified or horney cells
Average person – sheds 18 kg in lifetime
Outer skin we see - DEAD
Dermis
• 2nd major skin region
• Strong, flexible connective tissue
• Connective tissue proper cells – fibroblasts,
macrophages, mast cells, and WBCs
• Semi fluid matrix – binds together like a stocking
• “hide” – like animal hide
• Richly supplied with nerve fibers, blood, and
lymphatic vessels
• Major portion of hair follicles, sweat, and oil
glands found here
Dermis
• 2 layers –
1. Papillary layer –
- thin, superficial areolar connective tissue
- Fine, interlacing collagen and elastic fibers from
loosely woven mat
- Numerous small blood vessels
- Dermal papillae – superior surface
- Peg like projections
- Indent overlying epidermis
- House fee nerve endings - pain receptors
- touch receptors – Meissner’s Corpuscles
Dermis
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Papillary layer – cont
Palms of the hands and soles of the feet
Papillae lie atop larger mounds – dermal ridges
Turn overlying epidermis into epidermal ridged
(mounds)
Friction ridges – increased friction and enhanced
gripping ability
Genetically determined and unique to each
Sweat pores – open at crest
Sweat = fingerprints
Friction ridges
Openings of
sweat gland ducts
(a)
Figure 5.4a
Dermis
2. Reticular Layer – deeper
- 80 % of thickness of dermis
- Coarse, irregularly arranged
- Dense fibrous connective tissue
- Cutaneous plexus – network of blood vessels
- Extracellular matrix – adipose cells
- Thick bundles of collagen fibers
Dermis
2. Reticular Layer – deeper
(cont)
- Less dense regions –
cleavage or tension lines
- Incisions made parallel to
lines – skin gapes less and
heals better
- Gives skin strength
- Keeps skin hydrated
- Stretch recoil properties
- Flexure lines – dermal folds –
occur near joints
Skin Color
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3 pigments – melanin, carotene, and hemoglobin
Only melanin – made in skin
Melanin – polymer of tyrosine amino acids
2 forms
Range in color from yellow tan and reddish
brown  black
• Synthesis depends on enzyme – tyrosine
• Pigment found only in deeper layer of epidermis
Melanin
• Humans – differ in skin color
• Not random –
– Darker – near equator, need greater amount of
protection from the sun
– Lighter – closer to poles, need less protection
• Melanocytes of darker skinned people produce
more and darker melanocytes
• Freckles and pigmented nevu (moles) – local
accumulation of melanin
Melanin
• Prolonged sun exposure – substantial melanin
buildup
• Protects skin from UV radiation
• Excessive sun – damages skin
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Clumping of elastic fibers – leathery skin
Temporary depresses immune system
Alters DNA of skin cells – leads to skin cancer
UV radiation – also destroys folic acid stores – can be
harmful if pregnant – impaired development of fetal
NS
Carotine
• Yellowish – orange pigment
• Found in certain plant products – carrots
• Accumulates in stratum corneum and fatty
tissue of hypodermis
• Converted to vitamin A – essential for normal
vision
• Infants - orangey
Hemoglobin
• Pinkish hew
• Caucasian – small amounts of melanin –
hemoglobin color shows through
• Cyanosis – blue skin – hemoglobin poorly
oxygenated
– Heart failure and severe respiratory disorders
– Darker skin – melanin masks, but can be seen in
mucus membranes and nail beds
Alterations in Skin Color
• Redness – erythema – embarrassment, fever,
hypertension, inflammation or allergy
• Pallor – blanching – fear, anger, also signifies anemia or
a decrease in BP
• Jaundice – yellow – liver disorder, yellow bile pigments
accumulate in blood, deposited in body tissues
• Bronzing – Addison's Disease, adrenal cortex –
inadequate amounts of steroid hormones, sign of
pituitary gland tumor
• Black and Blue – burses, blood escaped circulation and
clotted beneath skin, hematomas – blood swelling
Appendages of Skin
• Nails, sweat glands, sebaceous (oil) glands,
hair follicles and hair
• Forming – appendages
• Epithelial bud – formation
• Stimulated by reduced production of cell
adhesion factor (cadherin)
• Cell-cell attractions – broken, cells move and
rearrange themselves
Sweat (Sudoriferous) Glands
• Distributed over entire skin surface except
nipples, and parts of external genitalia (tip of
penis)
• Up to 3 million per person
• 2 types – eccrine and apocrine
• Myoepithelial cells – specialized cells –
contract when stimulated by NS
• Contraction forces sweat into and through
duct system to surface
Eccrine Sweat Glands
• Merocrine sweat glands
• Numerous
• Most abundant in palms, soles of feet, and
forehead
• Simple coiled tubular gland
• Secretory part in dermis
• Duct –open in a funnel shaped pore on skin
surface
Sweat pore
Eccrine
gland
Sebaceous
gland
Duct
Dermal connective
tissue
Secretory cells
(b) Photomicrograph of a
sectioned eccrine gland (220x)
Figure 5.5b
Eccrine Sweat Glands
• Secretion – sweat
• Hypertonic filtrate of the blood
• Released by exocytosis
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99 % water
Some salts (NaCl)
Vitamin C
Antibodies
Microbe killing peptide – dermcidin
Metabolic wastes (urea, uric acid, and ammonia)
Small amounts of ingested drugs
• Acidic pH 4.0-6.0
Eccrine Sweat Glands
• Sweating –
• Regulated by sympathetic part of Autonomic
NS
• Major role – prevent from overheating
• Heat induced sweat begins at head and
spreads
• Emotionally induced stress – begins at palms,
soles, and armpits
Sweat pore
Eccrine
gland
Sebaceous
gland
Duct
Dermal connective
tissue
Secretory cells
(b) Photomicrograph of a
sectioned eccrine gland (220x)
Figure 5.5b
Apocrine Sweat Glands
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Approximately – 2000 of them
Confined to auxiliary asnd anogential areas
Exocytosis
Larger than eccrine
Lie deeper in dermis and sometimes hypodermis
Ducts empty into hair follicles
Same basic components of sweat plus some fatty
substances and proteins
• Viscous
• Milky/yellowish color
• When organic molecules are decomposed by bacteria –
body odor
Apocrine Sweat Glands
• Begin functioning at puberty
• Little role in thermoregulation, function not
yet known
• Through of as the human equivalent of scent
glands
• Increased activity during foreplay
• Enlarge and recede with menstrual cycle
Apocrine Sweat Glands
• Ceruminous glands – modified apocrine
glands
• Lining of internal ear canal
• Secretion mixes with sebum
• Sticky bitter substance – cerumen – earwax
• Thought to deter insects and block entry of
foreign material
Apocrine Sweat Glands
• Mammary Glands – specialized sweat glands
• Secret milk
Sebaceous (oil) Glands
• Oil glands
• Simple branched alveolar glands
• Found all over body except thick skin of palms
and soles
• Small amounts on body trunk and limbs
• Numerous on face, neck, and upper chest
• Secrete – sebum- oily substances
Sweat
pore
Dermal
connective
tissue
Sebaceous
gland
Sebaceous
gland duct
Eccrine
gland
Hair in
hair follicle
Secretory cells
(a) Photomicrograph of a sectioned
sebaceous gland (220x)
Figure 5.5a
Sebaceous (oil) Glands
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Central cells – accumulate oil lipids
Engorged – burst
Holocrine glands
Develop from hair follicles
Sebum secreted into follicle – softens and
lubricates hair and skin
– Slows water loss from skin
– Bactericidal- bacteria killing
• Secretion - stimulated by hormones (androgens)
activated during puberty
Sebaceous (oil) Glands
• When blocked – white head
• When material inside oxidizes – becomes a
blackhead
• Acne – active inflammation of sebaceous glands
• Bacterial infection – staphylococcus
• Cradle cap – infants – seborrhea – fast flowing
sebum
Hair and Hair Follicles
• Millions on skin except – palms, soles, nipples,
and external genitalia (some parts)
• Warmth – mammals - ours less luxuriant and
useful
• Main function – sense insects
• Hair on scalp – prevent physical trauma, heat
loss, and sunlight
• Eyelashes – shield eyes
• Nose Hairs – filter large particles
Structure
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Hair (pili)
Flexible strands
Produced by hair follicles
Consist largely of dead keratinized cells
Hard keratin
– 2 advantages
1. Tougher and more durables
2. Individual cells do not flake off
Follicle wall
Hair shaft
Arrector
pili
Sebaceous
gland
Hair root
• Connective tissue
root sheath
• Glassy membrane
• External epithelial
root sheath
• Internal epithelial
root sheath
Hair
• Cuticle
• Cortex
• Medulla
(a) Diagram of a cross section of
a hair within its follicle
Hair bulb
Figure 5.6a
Follicle wall
• Connective tissue
root sheath
• Glassy membrane
• External epithelial
root sheath
• Internal epithelial
root sheath
Hair
Hair shaft
Arrector
pili
Sebaceous
gland
Hair root
• Cuticle
• Cortex
• Medulla
(b) Photomicrograph of a cross
section of a hair and hair
follicle (250x)
Hair bulb
Figure 5.6b
Structure - Hair
• Regions
1. Shaft – portion in which keratinization is
complete, extends halfway into skin
2. Root – keratinization ongoing, portion of hair
deep in follicle
- Shape
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Flat ribbon-like – hair kinky
Oval – silky and wavy
Perfectly round – straight and coarse
Structure - Hairs
• 3 layers –
1. Medulla– central core
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Large cells, air spaces
Contains soft keratin
2. Cortex – bulky layer
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Surrounding medulla
Several layers of flattened cells
3. Cuticle – outer layer
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Single layer of cells that overlap each other
Most heavily keratinized
Tends to wear away at tip – keratin fibrils – frizz out, spilt
ends
Hair Pigment
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Made by melanocytes
Transferred to cortical cells
Different colors – yellow, rust, brown, black
Red hair – colored by iron containing pigment
– trichosiderin
• Gray or white – decrease in melanin in
production
Structure of Hair Follicle
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Folded down from epithelial surface into dermis
May extend to hypodermis
~ 4 mm below skin
Hair – bulb – expanded region at base
Hair follicle receptor – (hair plexus)
Wraps around bulb
Hair papilla – dermal tissue that protruded into hair
bulb
Knots of capillaries – supply blood
Wall – connective tissue root sheath
Thickened basement membrane – glassy membrane
Epithelial root sheath – invagination of epidermis
Hair shaft
Arrector
pili
Sebaceous
gland
Hair root
Hair bulb
Follicle wall
• Connective tissue root sheath
• Glassy membrane
• External epithelial root sheath
• Internal epithelial root sheath
Hair root
• Cuticle
• Cortex
• Medulla
Hair matrix
Hair papilla
Melanocyte
Subcutaneous adipose tissue
(c) Diagram of a longitudinal view of the expanded hair
bulb of the follicle, which encloses the matrix
Figure 5.6c
Structure of Hair Follicle
• Hair Matrix – actively dividing area of hair
bulb
• Originate in hair bulb
• New cells produced, older cells pushed out
• Arrector pili – smooth muscle
• Contraction pulls hair upright
• Dimples skin – goose bumps
Follicle wall
• Connective
tissue root sheath
• Glassy membrane
• External epithelial
root sheath
• Internal epithelial
root sheath
Hair root
• Cuticle
• Cortex
• Medulla
Hair matrix
Hair papilla
Subcutaneous
adipose tissue
Hair shaft
Arrector
pili
Sebaceous
gland
Hair root
Hair bulb
(d) Photomicrograph of longitudinal view
of the hair bulb in the follicle (160x)
Figure 5.6d
Types of Hair
• Vellus hair – pale, fine hair
– body hair of children and women
• Terminal Hair – coarse, long hair
– Eyebrows and scalp
– Puberty – terminal appear is auxiliary and pubic
regions (both sexes), face and chest (male)
Hair Growth
• Dependent on - Nutrition and hormones
• Poor nutrition = poor hair growth
• Increased dermal blood flow – chronic physical
irritation = increased hair growth
• Undesired Hair growth – eliminated by
electrolysis
• Excessive hairiness in women – Hirsutism – can
be from adrenal gland or ovarian tumor that
secretes large amounts of androgens
Rate of Growth
• Varies
• Average ~ 2.5 mm/week
• Growth cycles –
1. Active phase
2. Regressive phase
3. Resting phase
Rate of Growth
• Scalp – active 6 – 10 years before inactive for a
few months
• Average – 90 hairs lost a day
• Eyebrows are only active for ~ 3-4 months
Hair Thinning/Baldness
• Growth fastest – teens  40 years old - then slows
• Hairs not replaced as fast as they are shed – Alopecia
• True or frank baldness – Male pattern baldness –
genetically determined, sex influenced condition
• Delayed action gene and changes in response of hair
follicles to DHT
• Follicular growth very short
• Minoxidial – drug that reduces BP, found to stimulate
hair growth
• Finasteride – pill – must take everyday or new hair falls
out
Hair Thinning/Baldness
• Thinning – can be caused by:
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High fever
Surgery
Emotional trauma
Drugs – excessive vitamin A
• Antidepressants
• Anabolic steroids
• Chemotherapy drugs
– Also protein deficiency or lactation
– Alopecia Areata – condition where immune system
attaches follicles and hair falls out
– Burns and radiation – can also cause permanent hair
loss
Nails
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Scale like modification of epidermis
Clear protective covering
Correspond to hooves/claws of other animals
Tools – pick up and scratch
Hard keratin
Free edge, body, and root
Lateral
nail fold
Lunule
(a)
Free edge Body
of nail
of nail
Eponychium
(cuticle)
Nail bed
Proximal
nail fold
Root of nail
Nail
matrix
(b)
Hyponychium
Phalanx (bone of fingertip)
Figure 5.7
Nails
• Nail bed – epidermis below nail
• Nail Matrix – proximal part of nail bed,
responsible for nail growth
• Pink – because of capillaries under dermis
• Lunule – little moon – white crescent
• Borders – overlapped by skin folds
• Cuticle (eponychium) – proximal fold
• Hyponychium – region below free nail,
accumulates dirt
Nails
• Yellow nails – indicate a respiratory or thyroid
disorder
• Thickening and yellow – fungal infection
• Outward concavity – iron deficiency
• Horizontal lines – beaus lines – malnutrction
Functions of Integument System
• Protection
• 3 types
1. Chemical Barrier – skin secretions and melanin
- Low pH – acid mantle – retards bacteria growth
- Seat/bacterialcide substances kill bacteria
- Defensins – natural antibiotics secreted by skin
- Cathelicidins – wounded skin secretes to prevent
infection
- Melanin – protects against UV radiation
Functions of Integument System
• Protection
2. Physical/Mechanical barriers – continuity of
skin
- Hardness of keratinized cells
- Water resistant – glycolipids – block diffusion
of water
Functions of Integument System
• Protection
2. Physical/Mechanical barriers (cont)
- Some substances can penetrate skin –
1.
2.
3.
4.
5.
6.
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Lipid soluble – oxygen, carbon dioxide, vitamin A, D, E, & K. and
steroids
Oleoresins - poison ivy/poison oak
Organic solvents – acetone, paint thinner, etc.
Salts of heavy metals – lead and mercury
Selected drugs – nitroglycerine and nicotine
Drug agents – penetration enhancers, ferry other drugs into body
Enhanced by alcoholic drinks
Metals and organic solvents – can be lethal and can cause kidneys
to shut down
Also brain damage
Lead – anemia and neurological affects
Functions of Integument System
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Protection
Biological Barriers –
Dendritic cells – present antigens to WBCs
Macrophages – attack viruses and bacteria
DNA – chemical sunscreen, electrons absorb
UV radiation, convert it to harmless heat
Functions of Integument System
• Body temperature Regulation –
• 31- 32 C – external
– Sweat glands will produce ~ 500 ml of sweat a day
- Insensible perspiration
• Body temperature increase – NS stimulates
blood vessels to dilate and sweat glands to
secrete
– Loss can be up to 12 L/day – sensible perspiration
Functions of Integument System
• Cutaneous Secretion –
• Cutaneous sensory receptors –
• Exteroceptors – respond to stimuli outside the
body
• Meissners Corpsules and tactile discs – feel of
clothing
• Pacinian or purcles – bumps/contact involving
deeper pressure
• Free nerve endings – painful stimuli, irritating
chemicals or extreme heat or cold
Functions of Integument System
• Metabolic Functions –
• Sunlight – vitamin D precursor – converted to
vitamin D, role in calcium metabolism
• Keratinocyte Enzymes –
1. ‘disarm” cancer causing chemicals
2. Convert chemicals to carcinogens
3. Activate steroid hormones: cortisol 
hydroxycortisone
- Skin makes biologically important proteins collagenase
Functions of Integument System
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Blood reservoir –
Extensive and can hold large amounts of blood
~ 5% of total blood volume
Constriction – moves blood to other organs
that need it
Functions of Integument System
• Excretion –
• Limited amounts of nitrogen containing
wastes – ammonia, uric acid, urea
• Perfect sweating – water and salt
Homeostatic Imbalances
• More than 1000 different conditions and
aliments
• Bacterial, viral or yeast infections
• Cancer and burns
Homeostatic Imbalances
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Skin Cancer –
1 in 5 Americans
Most are benign and do not spread
Wart – neoplasm caused by a virus
UV light – another risk factor
– Damages DNA bases
– Adjacent bases fuse, forming lesions – dimers
– Also disables tumor suppressor gene p 53
• Sunburn – increases production of Fas – a protein that causes
genetically damaged skin cells to commit suicide, skin pealing after
sunburn
– Damages DNA bases
– Adjacent bases fuse, forming lesions – dimers
– Also disables tumor suppressor gene p 53
Homeostatic Imbalances – Skin Cancer
• Skin lotions – fix damaged DNA before cells
develop into cancer cells
• Contain oily vesicles – liposomes – enzymes
that initiate repair of DNA mutation
Homeostatic Imbalances – Skin Cancer
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Basal Cell Carcinoma –
Least malignant
Most common
80 % of skin cancers
Stratum basal cells proliferate –
invade dermis and hypodermis
Lesions occur most often in face
Shinny dome shaped nodules
Later develop an ulcer
Slow growing
Surgical excision
Homeostatic Imbalances – Skin Cancer
• Squamous Cell Carcinoma
• 2nd most common
• Arises from keratinocytes
of stratum spinosium
• Scaly red papule
• Small, rounded elevation
• Most often on head and
hands
• Grows rapidly and
metastasize if not removed
Homeostatic Imbalances – Skin Cancer
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Melanoma –
Cancer of melanocytes
Most dangerous
Highly metastatic
Resistant to chemo
2 – 3 5 of all skin cancer
Increase rapidly
Most occur spontaneously
1/3 develop in persisting moles
Spreading brown to black patch
Early detection needed
If over 4 mm thick – survival poor
Surgical removal and
immunotherapy
Homeostatic Imbalances – Skin Cancer
• ABCD Rule –
• A. Asymmetry – 2 sides don’t match
• B. Border irregularity – borders exhibit
indentations
• C. Color – several colors – blacks, browns, tans,
blues, reds
• D. Diameter – larger than 6 mm in diameter –
pencil eraser
• Some want to add
• E. elevation – elevation above skin
Homeostatic Imbalances – Burns
• Burns –
• Tissue damage, inflicted by intense heat,
electricity, radiation, or certain chemicals
• Denatures cell proteins
• Causes cell death
• Immediate threat – loss of body fluids renal
shut down  shock
• Rules of 9s – body divided into 11 areas
– Each 9% of total area
– Genitals – remaining 1 %
Totals
4 1 /2 %
Anterior and posterior
head and neck, 9%
Anterior
4 1 /2 % trunk,
18%
Anterior and posterior
upper limbs, 18%
4 1 /2 %
Anterior and posterior
trunk, 36%
9% 9%
(Perineum, 1%)
Anterior and posterior
lower limbs, 36%
100%
Figure 5.9
Homeostatic Imbalances – Burns
• Supplement nutrients – extra calories to
replace damaged tissue
• After initial crisis passed – infection and sepsis
next threats
• Bacterial, viral, and fungal infections
Homeostatic Imbalances – Burns
• Classified according to severity:
1st degree burn – only epidermis is damaged.
- Localized redness, swelling, and pain
2nd degree burn – epidermis and upper regions of dermis
- blisters, red painful
3rd degree burn – full thickness of skin
- Gray white/cherry red/blackened
- Not painful – nerve endings destroyed
- Skin graft needed – living bandage
- Graft takes – extensive scar tissue
1st degree
burn
3rd
degree
burn
2nd degree
burn
(a) Skin bearing partial
thickness burn (1st and
2nd degree burns)
Skin bearing full
thickness burn
(3rd degree burn)
Homeostatic Imbalances – Burns
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•
•
•
Critical if –
Over 25 % of body – 2nd degree burns
Over 10 % - 3rd degree burns
3rd degree burns on head, face, and feet
Developmental Aspects of
Integumentary System
•
•
•
•
•
•
•
•
Epidermis develops from embryonic ectoderm
Dermis and hypodermis develop from mesoderm
By the end of the 4th month – skin fairly well formed
During 5th and 6th month fetus is covered with delicate
colorless hairs – lanugo coat
Shed by the 7th month, vellus hairs make appearance
Baby born – vernix caseosa – white substance
produced by sebaceous glands
Infancy and childhood – skin thickens
Older – skin thins