THE THE INTEGUMENTARINTEGUMENTAR

Y SYSTEMY SYSTEM

I. IntroductionA.Basics

1.Consists of skin, hair, nails, and cutaneous glands.

2.Largest organ of body• 15-20 sq. ft• 9 lbs• 0.5-4.00 mm thick

B. Layers1.Epidermis

• Epithelial t.2.Dermis

• Connective t.3.Hypodermis (subcutaneous t.)

• Loose connective t. (fat)• Not part of the skin• Anchors the skin to bone and muscle

tissue

C. Functions1. protection

2. Vitamin D production

3. Sensation

4. Thermoregulation

5. Excretion (small amount)

II. EpidermisA.A.GeneralGeneral

1.Keratinized, stratified, squamous epithelium

2.New epidermis every 35-45 days

II. Epidermis

A.A.GeneralGeneral3.Callus – gross

thickening due to friction

4. Blister – acute trauma leads to separation of dermis and epidermis

II.EpidermisB. Cell types

II. EpidermisB. Cell typesB. Cell types

1. Keratinocytesa.Produce fibrous protein keratin

• tough, water repellant protein

• protects the skin and the underlying tissues from heat, microbes, abrasion and chemicals

b.Produced in deepest layer

II.EpidermisB. Cell types

B. Cell types

•Pigment is phagocytized by keratinocytes

•Pigment granules protect keratinocytes from UV radiation

2. Melanocytes

•Produce pigment melanin

Normal skin color determinants Melanin

Yellow, brown or black pigments Carotene

Orange-yellow pigment from some vegetables

Hemoglobin

Red coloring from blood cells in dermis capillaries

Oxygen content determines the extent of red coloring

B. Cell typesB. Cell types3. Merkel’s cells

•Associated w/nerve cell endings – touch reception in fingertips

4. Langerhans’ cells• Macrophage-like• Defend against

microorganisms• Found in Stratum Spinosum

II.Epidermis

C. Layers

Hint to remember the layers:

•Can Corneum•Little Lucidum•GiRls GRanulosum•SPeak SPinosum•GERMan/ GERMinativum•British or Basale

Can Little Girls Speak German or British

II. EpidermisC. Layers

1.Stratum Basalis • AKA:Stratum

Germinativum

• Single layer of cuboidal cells• Mitotic•10-25% melanocytes deposited here.

C. Layers1.Stratum

Basalis • Receive nutrients by diffusion from dermis• Composed of columnar keratinocytes melanocytes & Merkel’s cells or disks (light touch receptors)

C. Layers 2. Stratum

Spinosum • Called the “Spiny Layer” (8-10 layers thick)• Less mitotic ~ less nutrition received.• Cells are many sided keratinocytes often called “Prickle Cells”

•Scattered among keratinocytes are Langerhans’ cells (immunity cells)

C. Layers 2. Stratum

Spinosum

Note: The Stratum Basalis and Stratum Spinosum•contain the only epidermal cells that receive adequate nourishment by way of diffusion.

•As the daughter cells are pushed upward, away from the source of nutrition, they gradually die and their soft protoplasm becomes keratinized (hard).

C. Layers

3.Stratum Granulosum

• Granular layer• Keratinization

begins • Cells begin to

die• Thin layer 3-5

cell layers

C. Layers

• Clear layer • Found in thick

skin only as palms and soles of feet

• Contain Keratin fibrils

• Cells begin to degenerate

4. Stratum Lucidum

C. Layers5. Stratum

Corneum• Horny Layer • 20-30 cell = ¾of

thickness. • Prevents water

loss due to lipids in surrounding cells, adds strength due to keratinization & exfoliaiton prevents abrasion of cells.

C. Layers

5.StratumCorneum• Consists of dead

flat (stratified squamous) keratinized cells being sloughed off

• Forms from the embryological ectoderm germ layer.

II. Epidermis

III. Dermis

III. Dermis aka: hide

A.General1.Strong,

flexible, connective tissue

2.Thickness: 0.6 – 3 mm

III. DermisA. Has collagen,

elastic & reticular fibers

B. Develops fromthe mesoderm ofthe embryological

germ layer.

A. GeneralContains• Blood vessels• Nerves• Hair follicles• Sebaceous Oil glands• Sudiferous Sweat

glands• Nail roots• Skin Appendages

A. GeneralEpidermis projects

intodermis to form

dermalPapillae.Touch ReceptorsHair follicles

B. 2 Layers: Papillary & Reticular

III. Dermis

B. Layers1.Papillary

Layer a.Closest to

epidermsb. Made of areolar, loose

con. t.c. Has Dermal Papillae

• Finger-like projects that indent into the epidermis

• Contain Capillaries

pain receptors Meisner corpuscles:

sensitive to light touch, discriminative touch, & low vibrations. Allows you to gather information about objects shape, texture, & density, so your brain can identify the object

Finger prints

c. Has Dermal Papillae

a.Deepest layerb.Comprises 4/5 of

dermisc.Made of dense

irregular connective tissue

B. Layers 2. Reticular

layer

III. Dermis

d.Rich in blood vessels and nerve

e.Pacinian corpuscles – (egg shaped) sensitive to deep tactile pressure & high frequency vibration. Adapt rapidly. act as intestinal & joint proprioceptors & enable you to detect the object due to its weight

B. Layers

2. Reticular layer

III. Dermis

d.Ruffini’s corpuscle senses heat found skin & mouth

e.Krause’s End Bulb senses cold found in mucus membrane of mouth

B. Layers

2. Reticular layer

III. Dermis

f. Tension lines or cleavage – separation of collagen bundles

g. Flexure line – folding of dermis at joints of wrists, palms, fingers toes

B. Layers

2. Reticular layer

III. Dermis

IV. Hypodermis aka superficial fascia

1.Areolar and adipose tissue

2.Anchors skin to organs

3.Insulates, absorbs shock, stores fat, ½ of body’s stored fat is here.

True or False?

1. The dermis is the superficial layer of the skin.

2. The skin helps regulate body temperature.

3. The epidermis has three layers.

4. The hypodermis is above the dermis.

5. The skin protects against UV radiation.

Functions of Skin?• The four main functions of the integumentary

system are: (Waste Excretion, Movement, Thermoregulation, Protection, Sensation, Immunity)

1. Which function acts as a barrier against chemical, mechanical, and microbial damage?

2. Which function acts to maintain constant internal temperature?

3. Which function acts to receive stimuli from the environment?

4. Which function acts to release sweat contains organic chemicals, salts, and urea?

V. Skin AppendagesA.General(4 embryonic categories: hair,

nails, nerves, & glands)

1.Organs that develop from the embryonic epidermis

2. Also called epidermal derivatives

V. Skin Appendages3.Includesa.Hairb.Sweat ,

sudoriferous, glands

c.Sebaceous, oil, glands

d.Finger nailse.Tooth enamel

V. Skin AppendagesB. Hair

1.Is fused keratinized cells

2.Protects against • Scalp

injury• Sun• Heat loss

3. Hair• Hair is a slender filament of mostly dead keratinized epithelial cells that grow from a follicle

• Is a derative of the modified stratum corneum

• The hair consists of the medulla, a core of loose cells and air spaces, surrounded by a cortex, which is densely packed keratinized cells.

• The cortex is covered by the cuticle.

3. Hair•The bulb is a swelling at the base where the hair originates; the root is the remainder of the hair within the follicle; and the shaft is the portion of the hair above the skin surface.

•Erector pili muscles are smooth muscle

V. Skin AppendagesB. Hair

1.Is fused keratinized cells

2.Protects against • Scalp

injury• Sun• Heat loss

B. Hair3. Structure

a.Shaft• Above

surface• Shape

determines curliness – Round =

straight– Oval =

wavy– Flat = kinky

Note: The

root and shaft are made of 3 tubes

Note: 3 tubesNote: 3 tubes• cuticle: outer tube

1 layer of heavily keratinized cells.

• cortex: middle tube several layers of cells w/

pigments in dark hair and air bubbles in white hair.

• medulla: inner tube made of 2 -3 rows of cells with

pigments and air spaces.

B. Hair Follicle• Hair Bulb Matrix

produces hair • Inner epidermal

sheath made of epithelial tissue

• Outer dermal sheath made of dermal connective tissue.

• Arrector pili muscle – goose bumps

V. Skin AppendagesB.Hair4. Split ends – cuticle wears away5. Color results from melanin

(black, brown, yellow)6. Hair growth/loss – depends on

genes, stress, illness, malnutrition, hormone levels, some hair styles (ie tight braids), excessive combing, & styling (w/use of hair chemicals) & Excessive exercise

V. Skin AppendagesB.Hair: Kinds of hairLanugo – fine downy hair present in fetus and

replaced at birth.

Vellus hair: fine pale body hair of women and children. Approx 2/3 of hair in ♀ and 1/10 in ♂ and all hair in children, except eyebrows, eyelashes and scalp hair.

Terminal hair: coarse, pigmented male body hair. Forms eyebrows, eyelashes, scalp and pubic, axillary, and facial hair after puberty.

Cycle of Hair Growth

• Newly formed hair cells move up the follicle as newer cells form beneath.

• As the cells dry out & fill w/keratin the hair cells begin to harden & die.

V. Skin AppendagesC.Nails

1.Scale-like epidermal derivatives

2.Pink due to capillaries in dermis

C. Nails3. Nail plate isheavily karantinized4. Nail body ormatrix is the nail

itself where mitosis occurs.

5. Nail root is responsible for growth

C. Nails

C. NailsStratum basale extends beneath the nail bed

The nail contains a free edge, a body, & nail root.

Eponchium (cuticle) is the proximal nail fold that projects onto the nail body.

Lunula is the half moon shaped portion of the nail that lacks pigmentation.

Subungal Hematoma: blood clot beneath the nail.

V. Skin AppendagesD. Sudoriferous Glands

1. Sweat glands2. Two types: Eccrine or Merocrine &

Apocrine3. Both sectete sweat, which

evaporates & cools the body.4. Merocrine/Eccrine – most common

type; most numerous in the palms of the hands & soles of the feet. Not found in lips, nipples and parts of external genitalia. Open by way of a duct to pore in the skin.

V. Skin AppendagesD.Sudoriferous Glands : Sweat

glands Apocrine – are most numerous in the axillary & the genital regions & around the anus. The duct empties into a nearby hair follicle. They become active @ puberty as a result of sex hormones. 6. Mammary Glands are

considered modified apocrine sweat glands.

V. Composition & Function of Sweat Glands Made mostly of water, some metabolic

wastes & fatty acids & proteins (apocrine)

Function

Helps dissipate excess heat

Excretes waste products

Acidic nature inhibits bacteria growth

Odor is from associated bacteria

D. Sudoriferous Glands

4.Function• Assists in

maintaining normal body temp.

D. Sudoriferous Glands5. specialized

sudoriferous glands• Mammary

glands• Ceruminous

glands

Cerum = earwax

D. Sebaceous Glands Sebaceous glands

Produce oil

Lubricant for skin

Kills bacteria

Most with ducts that empty into hair follicles

Glands are activated at puberty

V. Skin AppendagesE.Ceruminous

Glands1. Produce Sebum

• Oil• Prevents skin

from drying out• Protects against

bacteria2. Exocrine

Fill in the blanks with: hypodermis, keratinocytes, sweat, or papillary.

1. Eccrine is a type of _______________ gland.

2. _______________ produce keratin.

3. Adipose tissue is found in the _______________.

4. The _______________ of the dermis forms fingerprints.

V. Skin Appendages

E.Tooth Enamel1. the hard outer

layer of the tooth.

VI. Skin Color

A.Melanin1.Made by

• melanocytes• transferred to

keratinocytes2.Yellow to orange to brown3.Racial differences result of

kind and amount of melanin

A. Melanin4.Builds up with sun

exposure protects •Over exposure

alters DNA cancer and/or leathery skin

Not enough UV to break down of folic acid (vit. B) anemia or neural tube defects

A. Melanin4.Builds up with sun

exposure protects •Under exposure

MS Rickets Osteoporosis

B. Carotene

1.Yellow to orange

2.Found mainly in Corneum Layer, soles, palms

C. Hemoglobin1.In red blood

cells in capillaries

2.Gives pinkish hue to Caucasian skinNote: Caucasian’s have less melanin

VII. OtherA. Regulation of Body Temp.

1.Negative feedback system2.Excessive Heat

• Vessels dilate• Sweat evaporates from skin

3.Prevent heat loss• Vessels constrict• Arrector pili muscles cause

hair to stand on end

VII. Other Infections

Athletes foot

Caused by fungal infection

Boils and carbuncles

Caused by bacterial infection

Cold sores

Caused by virus

VII. Other Infections and allergies

Contact dermatitis

Exposures cause allergic reaction

Impetigo

Caused by bacterial infection

Psoriasis

Cause is unknown

Triggered by trauma, infection, stress

VII. Other Psoriasis

VII. OtherB. Aging

1.Blood flow to skin reduced• Thins skin/ more

easily damaged• Repair is slower

2.Sagging results from• Elastic fibers reduce

in number & diameter

• Loss of subcutaneous tissue

VII. OtherB.Aging

3.Age Spots• Localized areas

of increased # of melanocytes

4.Gray hair• Decrease or lack

of melanin production

VII. OtherVII. OtherC.C. Skin CancerSkin Cancer

1.The most common type of cancer

2. It occurs more often in people with light colored skin who have had a high exposure to sunlight.

Skin CancerSkin Cancer Cancer – abnormal cell mass

Suffix “-oma” means tumor

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

Skin Cancer Moles

VII. OtherC. Skin Cancer

3. Signs of skin cancer a. growth or a sore that

won't healb. a small lump.

• smooth, shiny and waxy

• or it can be red or reddish brown.

c. a flat red spot that is rough or scaly.

Skin cancers

VII. OtherC.Skin CancerMost common type

yet least malignant:

a.a.Basal CellBasal Cell CarcinomasCarcinomas

b.Caused by exposure to the sun

Basal Cell Carcinoma

VII. OtherC.Skin Cancer

3.Frequent type:

b.b.Squamous Cell Squamous Cell CarcinomaCarcinoma

Metastasizes to lymph Metastasizes to lymph nodesnodesSun exposureLips of smokersEarly removal allows

forgood chance of survival

Squamous Cell Carcinoma

VII. OtherC.Skin Cancer

3.Most deadly type:

c.c.MelanomaMelanoma• Most malignant• Caused by sun

exposure• Metastasizes

rapidly to lymph and blood vessels

Melanoma

IV. OtherIV. OtherC.C.Skin CancerSkin Cancer

4.4. ABCD Rule ABCD Rule to distinguish a to distinguish a normal mole from a melanomanormal mole from a melanoma• AA ... Asymmetrical halves the

different halves of the mole don't look like each other

• BB ... Border irregularity the edges of the mole are indented or notched.

• CC ... Color variation different colors in pigmented area

• DD ... Diameter greater than the size of a pencil eraser tip or 6mm

VII. Other Burns

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

Associated dangers

Dehydration

Electrolyte imbalance

Circulatory shock

Severity of a BurnSeverity of a Burn

• Severity of a thermal wound correlates directly with:– Temperature– Concentration– Amount of heat energy

possessed by the object or substance

– Duration of exposure

Burn severity depends on:

1. Depth of burn

2. Extent of burn

3. Critical areas involved• Face, upper airway,

hands, feet, genitalia

4. Preexisting medical conditions

5. Patient younger than 5 or older than 55

VII. OtherVII. OtherD.D. BurnsBurns

1.1. 11stst Degree, Mild, Degree, Mild, SuperficialSuperficial• Minor epithelial damage • Red, tender• DryDry • No blisters • Mild Edema

Mild Burn

VII. BurnsVII. Burns22ndnd Degree, Moderate, Degree, Moderate,

Partial ThicknessPartial Thickness• Damage to epidermis and

superficial (papillary) dermis• Pink, exquisitely tender• MoistMoist• Blisters • Heals in 2-3 wks w/oscarring.

Partial Thickness Burns

Partial Thickness Burns

VII. BurnsVII. BurnsD.D.33rdrd Degree, Severe, Full- Degree, Severe, Full-

thicknessthickness• Involves all 3 skin layers• Color variable: white, waxy,

red, brown, red (scalds)• Destroys elasticity• Dry• Painless• Does not heal

Third Degree Burn

Rule of 9’s

– Used to estimate surface area affected by the burn.

• Divide body into 9% sections

D. BurnsD. Burns 3. Rule of 9’s3. Rule of 9’s

• Torso: 18% • Leg: 18% • Head: 9% • Arm: 9% • Genitalia:

1% • Palm: 1%

Critical BurnsCritical Burns

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

VII. VII. HOMEOSTASIS & HOMEOSTASIS & TISSUESTISSUESA. Inflammatory Response A. Inflammatory Response

1.Inflammation produces swelling, redness, heat, tenderness, and a loss of function at the inflamed site.

VII. VII. HOMEOSTASIS & HOMEOSTASIS & TISSUESTISSUESA. Inflammatory Response A. Inflammatory Response

An infection infection is an inflammation produced by an invading organism, such as a bacterium.

BB. Inflammatory Response . Inflammatory Response 2.2. Sequence of EventsSequence of Events

homeostasis disturbed mast cells release chemicals blood flow and permeability increases clot formation isolates area phagocytes remove debris and microorganisms homeostasis returns

Injury and Repair• The skin can regenerate after injury.

• After injury there are four stages of healing:1. After injury bleeding usually occurs into the site.

2. Clot or scab forms at the surface of the epidermis.

3. Granulation occurs and the clot dissolves.

4. Scar tissue forms and the extent of scarring depends on the degree of the injury.

2 types of Tissue Repair2 types of Tissue Repair

Slide 3.69Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

1. Regeneration Replacement of destroyed tissue by the

same kind of cells

2. Fibrosis Repair by dense fibrous connective tissue

(scar tissue)

Determination method for repair type: Type of tissue damaged

Severity of the injury

Events in Tissue RepairEvents in Tissue Repair

Slide 3.70Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Capillaries become very permeable Introduce clotting proteins

Wall off injured area

Formation of granulation tissue

Regeneration of surface epithelium

Regeneration of TissuesRegeneration of Tissues

Slide 3.71Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Tissues that regenerate easily Epithelial tissue

Fibrous connective tissue and bone

Tissues that regenerate poorly Skeletal muscle

Tissues that are replaced largely with scar tissue Cardiac muscle

Nervous tissue within the brain and spinal cord

Developmental Aspects of TissueDevelopmental Aspects of Tissue

Slide 3.72Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Epithelial tissue arises from all three primary germ layers

Muscle and connective tissue arise from the mesoderm

Nervous tissue arises from the ectoderm

With old age there is a decrease in mass and viabililty in most tissues

THE ENDTHE END