The Integumentary The Integumentary SystemSystem

The skin and its derivatives (hair, The skin and its derivatives (hair, nails, glands, ect…) which provide nails, glands, ect…) which provide the external protective covering of the external protective covering of

the body the body

FunctionsFunctions

1.1. ProtectionProtection: against abrasions, bacterial : against abrasions, bacterial invasion, UV light, dehydrationinvasion, UV light, dehydration

2.2. Stimulus perceptionStimulus perception: nerve endings in : nerve endings in dermis detect: temp, pressure and paindermis detect: temp, pressure and pain

3.3. ExcretionExcretion: perspiration releases body waste: perspiration releases body waste4.4. Regulates body TempRegulates body Temp: via perspiration: via perspiration5.5. Synthesis of vitamin DSynthesis of vitamin D: via exposure to : via exposure to

UV lightUV light6.6. Blood reservoirBlood reservoir: dermis holds large volume : dermis holds large volume

of blood until needed elsewhere of blood until needed elsewhere

3 Layers 3 Layers

1.1. EpidermisEpidermis: epithelial cells ( stratified : epithelial cells ( stratified squamous)squamous)

2.2. DermisDermis: dense irregular connective : dense irregular connective tissuetissue

3.3. Hypodermis:Hypodermis: areolar and adipose areolar and adipose

EpidermisEpidermis

► Made up of :Made up of :

a)a) stratified squamous epitheliumstratified squamous epithelium

b)b) karatinocytes ( produce keratin)karatinocytes ( produce keratin)

c)c) melanocytes ( produce melanin for melanocytes ( produce melanin for skin pigment)skin pigment)

d)d) langerhan’s cells and gransteid cells langerhan’s cells and gransteid cells ( for immunity.( for immunity.

Sublayers of epidermis ( called Sublayers of epidermis ( called strata) Starting with deepeststrata) Starting with deepest

1.1.Stratum basaleStratum basale: : mitotic layer, 1 cell thickmitotic layer, 1 cell thick► It continuously divides pushing the cells It continuously divides pushing the cells

above them toward the surface, above them toward the surface, ► they can change and slowly die before being they can change and slowly die before being

shedshed2.2.Stratum spinosum:Stratum spinosum: 8-10 rows of irregularly 8-10 rows of irregularly

shaped cells. shaped cells. ► Begin producing keratineBegin producing keratine3.3.Stratum granulosumStratum granulosum: 3-4 rows of darkly : 3-4 rows of darkly

stained cells.stained cells.► cell nuclei begin to degenerate as layers cell nuclei begin to degenerate as layers

receives less nourishmentreceives less nourishment

4.4. Stratum lucidumStratum lucidum: 2-3 rows of clearish cells only : 2-3 rows of clearish cells only found in thick skin of palms and solesfound in thick skin of palms and soles

5.5. Stratum corneumStratum corneum: 25 + rows of shingle-like : 25 + rows of shingle-like cells remnants. The protective waterproof layer cells remnants. The protective waterproof layer layerlayer

Epidermis: Epidermis: ► No blood vessels No blood vessels ► Nourished by diffusion ( does not make it to last 2 Nourished by diffusion ( does not make it to last 2

to 3 stratato 3 strata► Takes about 2 to 3 weeks to completely replace Takes about 2 to 3 weeks to completely replace

skin ( basale to corneum)skin ( basale to corneum)

DermisDermisThicker connective tissue layer Thicker connective tissue layer beneath epidermis, contains beneath epidermis, contains collagen and elastic fiberscollagen and elastic fibers

2 Regions of Dermis 2 Regions of Dermis

1.1. Papillary regionPapillary region

► Contains Contains dermal papilladermal papilla which are dermal which are dermal projections into epidermisprojections into epidermis

► Some papilla contain blood vessels and Some papilla contain blood vessels and pain receptors or touch receptors pain receptors or touch receptors ((meissner’s corpuscles)meissner’s corpuscles)

► The dermal papilla produces ridges and The dermal papilla produces ridges and valleys on the surface of epidermis valleys on the surface of epidermis ( increases friction for grip)( increases friction for grip)

► Sweat glands have glands that open at Sweat glands have glands that open at ridge peaks (making peaks sweaty) and ridge peaks (making peaks sweaty) and reason for over fingerprintsreason for over fingerprints

2 Regions of Dermis2 Regions of Dermis2.2. Reticular regionReticular region

► Contains:Contains:a.a. Dense irregular connective tissueDense irregular connective tissueb.b. Adipose tissue Adipose tissue c.c. Hair folliclesHair folliclesd.d. Oil and sweat glandsOil and sweat glands

► This region provides strength and elasticity to the This region provides strength and elasticity to the skinskin

► With age, elasticity lessensWith age, elasticity lessens

► Repeated stretched areas don’t bounce back… they Repeated stretched areas don’t bounce back… they wrinklewrinkle

► IF overstretched (pregnancy) they tear leaving IF overstretched (pregnancy) they tear leaving stretch marks (scars)stretch marks (scars)

HypodermisHypodermis

►Also called superficial fasciaAlso called superficial fascia►Composed of aereolar and adipose Composed of aereolar and adipose

connective tissue (usually muscle)connective tissue (usually muscle)►Acts as a shock absorber and insulator Acts as a shock absorber and insulator

due to fat and water contentdue to fat and water content►Contains Contains Pacinian corpusclesPacinian corpuscles (nerve (nerve

endings for pressure)endings for pressure)►Technically not part of integumentTechnically not part of integument

Skin colorSkin color

► Would be clear if not for 3 pigments: Would be clear if not for 3 pigments:

1.1. Melanin: Melanin:

2.2. CaroteneCarotene

3.3. HemoglobinHemoglobin

Melanin: Melanin:

►Range in color from orange to brown Range in color from orange to brown to dark brown,to dark brown,

►All people have it except albinosAll people have it except albinos►Amount produced is influenced by: Amount produced is influenced by:

genetics and exposure to UV light genetics and exposure to UV light

CaroteneCarotene

►Yellowish pigmentYellowish pigment►Collects in stratum corneum and Collects in stratum corneum and

adipose adipose

HemoglobinHemoglobin

►Oxygen carrying blood pigmentOxygen carrying blood pigment►Gives skin its pinknessGives skin its pinkness

►So skin color is a blend of 3 So skin color is a blend of 3 pigments as influenced by pigments as influenced by genetics and environment genetics and environment

Epidermal DerivativesEpidermal Derivatives

► Hair:Hair: somewhat protective ( nose, eyelashes somewhat protective ( nose, eyelashes or from sun/cold)or from sun/cold)

► A hair (pili) consists ofA hair (pili) consists of::

1.1. Shaft:Shaft: visible portion visible portion ► consisting of 3 layers of dead cells: 1. cuticle consisting of 3 layers of dead cells: 1. cuticle

(outer) 2. medulla (inner) and 3. cortex (outer) 2. medulla (inner) and 3. cortex (middle)(middle)

2.2. Root: portionRoot: portion of hair below surface, of hair below surface, extends into the dermis and possible even extends into the dermis and possible even hypodermis. Has the same 3 layers.hypodermis. Has the same 3 layers.

►The root is surrounded by epidermal The root is surrounded by epidermal extensions which form the extensions which form the hair hair folliclefollicle ( sac around the hair) ( sac around the hair)

►The enlarged base of the root is called The enlarged base of the root is called the the bulbbulb

►The indention into the bulb is called The indention into the bulb is called the the papilla of hair papilla of hair (contains blood vessels)

Epidermal DerivativesEpidermal Derivatives

►Arrector pili muscleArrector pili muscle: : ►smooth muscle attached to the follicle smooth muscle attached to the follicle

and anchored in dermisand anchored in dermis► pulls air up straight out from skin in pulls air up straight out from skin in

response to cold and fright response to cold and fright

Cross section of HiarCross section of Hiar

NailsNails

►Another epidermal modification with Another epidermal modification with little remaining functionlittle remaining function

►Are hard keratinized dead cells Are hard keratinized dead cells produced by stratum basale, but nail produced by stratum basale, but nail itself is stratum corneum itself is stratum corneum

GlandsGlands

►Sebaceous glands: oilSebaceous glands: oil ► Exocrine glands, usually associated with hair Exocrine glands, usually associated with hair

folliclefollicle► An oily mixture of cholesterol, lipids and cell An oily mixture of cholesterol, lipids and cell

fragments is called sebumfragments is called sebum► Sebum:Sebum: protects hair from drying, becoming protects hair from drying, becoming

too brittle and from bacterial growthtoo brittle and from bacterial growth► A blocked sebaceous gland is a whitehead A blocked sebaceous gland is a whitehead

( or a blackhead if the melanin and sebum ( or a blackhead if the melanin and sebum oxidize), if it is infected it is a pimple oxidize), if it is infected it is a pimple

GlandsGlands

►Sudoriferous gland: (sweat)Sudoriferous gland: (sweat)►SweatSweat: mixture of water, salt and : mixture of water, salt and

organic waste ( very similar to urine)organic waste ( very similar to urine)►Functions:Functions: ►eliminate wasteeliminate waste► temp regulatortemp regulator►

Types of sudoriferous glandsTypes of sudoriferous glands

1.1. EccrineEccrine: : small coiled tubular glands release small coiled tubular glands release “sweat”“sweat”

► Found everywhere except lipsFound everywhere except lips, nipples and , nipples and genital genital

► Sweat is about 99% waterSweat is about 99% water

2.2. ApocrineApocrine:: largely still tubular, but ducts largely still tubular, but ducts open into hair folliclesopen into hair follicles

► Found only in axillary and pelvic regions and Found only in axillary and pelvic regions and do not begin to function until stimulated by do not begin to function until stimulated by hormones at pubertyhormones at puberty

► Produce thicker sweat with more organic Produce thicker sweat with more organic wastes ( likely to have an odor due to bacteriawastes ( likely to have an odor due to bacteria living on it)living on it)

3.3. Ceruminous glandCeruminous gland: modified : modified apocrine sudoriferous glandsapocrine sudoriferous glands

► Found in external auditory meatus Found in external auditory meatus ear canal)ear canal)

► Secrete a fluid which reacts with Secrete a fluid which reacts with sebum to produce sebum to produce cerumen cerumen ( a waxy ( a waxy protective substance)protective substance)

Injury and Tissue RepairInjury and Tissue Repair

►Contact inhibitionContact inhibition: : ►Cells will migrate and continue to Cells will migrate and continue to

divide until they come in contact with divide until they come in contact with other cells of the same tissue typeother cells of the same tissue type

►A wound which only penetrates as far A wound which only penetrates as far as stratum basale ( epidermis) as stratum basale ( epidermis)

►Heals with no scar tissueHeals with no scar tissue

Deep wound healing:Deep wound healing:

►Inflammation:Inflammation: first response to first response to damagedamage

►The damage cells release histamine The damage cells release histamine (cause vascular dilation (bigger) and (cause vascular dilation (bigger) and increase cell membrane permeability)increase cell membrane permeability)

►This causes more blood to enter wound This causes more blood to enter wound ( swelling, heat and redness)( swelling, heat and redness)

►The increased blood delivered increase The increased blood delivered increase nutrition, and blood clotting factors and nutrition, and blood clotting factors and macrophages (WBC)macrophages (WBC)

►A blood clot forms scaling wound from A blood clot forms scaling wound from both external world and surrounding both external world and surrounding healthy cellshealthy cells

►The surviving cells next to the wound The surviving cells next to the wound divide beneath the divide beneath the necrotic (dead) necrotic (dead) tissuetissue repairing the wound repairing the wound

►Since this new tissue does not match Since this new tissue does not match the original, it is called the original, it is called granulation granulation tissuetissue (scar tissue) (scar tissue)

►Regeneration:Regeneration: replacement of replacement of destroyed tissue by same kind of destroyed tissue by same kind of cellscells

►Fibrosis:Fibrosis: process of fibrous process of fibrous connective tissue repair ( scar)connective tissue repair ( scar)

►Scab:Scab: blood clot and dead tissue blood clot and dead tissue which are sealed from healthy cells which are sealed from healthy cells

So tissue repair depends on So tissue repair depends on type of tissue damagedtype of tissue damaged

►Epithelial tissueEpithelial tissue: heals rapidly and : heals rapidly and nearly perfectnearly perfect

►Connective tissueConnective tissue: repairs fairly : repairs fairly rapid, but is imperfect (scars)rapid, but is imperfect (scars)

►Muscles and nervous tissueMuscles and nervous tissue: hardly : hardly replace the destroyed cell at all, just replace the destroyed cell at all, just work around themwork around them

BurnsBurns

► Tissue damage by heat, electricity, Tissue damage by heat, electricity, radioactivity or chemical causesradioactivity or chemical causes

► Burns destroy protective epidermis Burns destroy protective epidermis allowing: allowing:

1.1. Microbial infectionMicrobial infection

2.2. Extensive fluid, electrolyte, protein Extensive fluid, electrolyte, protein lossloss

3.3. Loss of temperatureLoss of temperature

BurnsBurns

► Immediate danger of burns is the loss Immediate danger of burns is the loss of fluid and electrolytes ( reduces of fluid and electrolytes ( reduces volume of blood, renal shutdown and volume of blood, renal shutdown and shock)shock)

►After fluid replacement the first 24 hrs, After fluid replacement the first 24 hrs, the major damage is infectionthe major damage is infection

►Burns are classified by depth and Burns are classified by depth and percentage of surface area affected: percentage of surface area affected:

Burn ClassificationBurn Classification

►11stst degree degree: surface epidermis only : surface epidermis only ( no scarring) ex sunburn( no scarring) ex sunburn

►22ndnd degree degree: epidermis and some : epidermis and some dermis, blistering and pain, mild dermis, blistering and pain, mild scarringscarring

►33rdrd degree degree: integumentary system or : integumentary system or more is destroyed, no pain, charred dry more is destroyed, no pain, charred dry appearance extensive scarring slow appearance extensive scarring slow healing, skin graft or deathhealing, skin graft or death

CancerCancer

► Tumor or neoplasmTumor or neoplasm: excessive growth of : excessive growth of tissue uncontrolled cell divisiontissue uncontrolled cell division

►Benign tumorBenign tumor: harmless, cells don’t spread : harmless, cells don’t spread (stay in one clump)(stay in one clump)

►Malignant:Malignant: cells keep dividing, spreading cells keep dividing, spreading and invading other body areasand invading other body areas

►Metastasis:Metastasis: migration of cancer cells and migration of cancer cells and other body parts. They produce 2ndary other body parts. They produce 2ndary tumors and usually the cause of death in tumors and usually the cause of death in cancer cancer

Check your risk for skin cancerCheck your risk for skin cancer

►Sarcoma:Sarcoma: general term for cancer of general term for cancer of connective tissueconnective tissue

►AdeosarcomaAdeosarcoma: cancer in a gland: cancer in a gland►Myeloma:Myeloma: cancer in bone marrow cancer in bone marrow►Osteogenic sarcomaOsteogenic sarcoma: bone cancer: bone cancer

Melanoma Melanoma

►Melanoma can grow very quickly. Melanoma can grow very quickly. ► It can become life-threatening in as little as It can become life-threatening in as little as

six weeks and if untreated, it can spread to six weeks and if untreated, it can spread to other parts of the body. other parts of the body.

► It can appear on skin not normally exposed to It can appear on skin not normally exposed to the sun.  the sun.  

► It is usually flat with an uneven smudgy It is usually flat with an uneven smudgy outline.outline.

► It may be blotchy and more than one color – It may be blotchy and more than one color – brown, black, blue, red or grey.brown, black, blue, red or grey.

Melanoma Melanoma

►      

Basal cell carcinoma Basal cell carcinoma

►This is the most common but least This is the most common but least dangerous form of skin cancer.dangerous form of skin cancer.

► It grows slowly, usually on the head, neck It grows slowly, usually on the head, neck and upper torso.and upper torso.

► It may appear as a lump or dry, scaly area.It may appear as a lump or dry, scaly area.► It maybe red, pale or pearly in color. It maybe red, pale or pearly in color. ►As it grows, it may ulcerate or appear like a As it grows, it may ulcerate or appear like a

sore that fails to completely heal or one sore that fails to completely heal or one that does heal but then breaks down again.that does heal but then breaks down again.

Basal cell carcinoma Basal cell carcinoma

Squamous cell carcinomaSquamous cell carcinoma

►This type of skin cancer is not as This type of skin cancer is not as dangerous as melanoma but may spread dangerous as melanoma but may spread to other parts of the body if not treated. to other parts of the body if not treated.

► It grows over some months and appears It grows over some months and appears on skin most often exposed to the sun.on skin most often exposed to the sun.

► It can be a thickened, red, scaly spot that It can be a thickened, red, scaly spot that may bleed easily, curst or ulcerate.may bleed easily, curst or ulcerate.

Squamous cell carcinoma Squamous cell carcinoma

Warning signs of sun damaged Warning signs of sun damaged skin and skin cancer risk skin and skin cancer risk

►Spots, blemishes, freckles and moles, Spots, blemishes, freckles and moles, similar to those pictured , are signs of similar to those pictured , are signs of sun-damaged skin. They are usually sun-damaged skin. They are usually harmless, but harmless, but if you notice them if you notice them changing, see a doctor. changing, see a doctor.