c hapter 5 integumentary system thursday, sept 19 th

CHAPTER 5

Integumentary System

Thursday, Sept 19th

OVERVIEW OF THE INTEGUMENT

Composed of 2 layers: Epidermis Dermis

Hypodermis - lies beneath skin

Thickness varies, normally 1-2 mm

Forms Skin, nails, hair Glands

FUNCTIONS OF THE SKINProtection

Sensory

Maintenance of body temp

Synthesis of Vitamin D

Excretion

FUNCTIONS OF THE SKINProtection

Against traumaFluid lossChemical attackUltraviolet lightInfection

Sensory receptorDetects touchPressurePainTemperature

FUNCTIONS OF THE SKINMaintenance of normal body

temperatureThrough insulation or evaporative cooling

Synthesis of vitamin D Converted to a hormone important to

maintaining Ca++ balance

Excretion SaltsWaterOrganic wastes

THE LAYERS OF SKIN1. Epidermis

Epithelial tissue

2. DermisConnective tissue

HypodermisLoose connective tissue

SKIN STRUCTURE

THE EPIDERMIS

THE EPIDERMIS Keratinized stratified squamous epithelium

Avascular Nourished by diffusion of nutrients from dermis

Cells found in the epidermis include Stem cells Keratinocytes Melanocytes Tactile (Merkel) cells Dendritic (Langerhans) cells

THE EPIDERMIS Cells produced by mitosis in deepest layer

of epidermis

New cells push older cells to surface = desquamate or slough off

Keratinization

LAYERS OF THE EPIDERMIS Stratum basale (or germinativum) – deepest

layer Stratum spinosum Stratum granulosum Stratum lucidum (only in thick skin) Stratum corneum – superficial layer

Cell movement goes from DEEP to superificial

STRATUM BASALE

StructureDeepest layerSingle layer cells attached to basement

membrane

FunctionProtection – Melanocytes (melanin)

Cell types in this layer:Stem cellsKeratinocytesMelanocytes Merkel cells

STRATUM SPINOSUMStructure

Several layers of keratinocytes (8-10 layers)Appear ‘spiny’Called DESMOSOMES (spiny like projections)

FunctionProduces lamellar bodies (lipid filled

organelles)Begin to synthesize protein keratin which

cause cells to flatten

STRATUM GRANULOSUM Structure

3 to 5 layers of flat keratinocytesCells stop dividing here

FunctionContain keratinohyalin granulesForms keratin

Major component of hair and nailsGlycolipids waterproof the skinNucleus degenerate and cell dies

STRATUM LUCIDUM Structure

3 – 5 layers of dead cellsAppears transparentThin translucent zone seen ONLY in thick

skin

LocationFound where skin is hairless and extra

thick

STRATUM CORNEUM

StructureVery thickUp to 15-30 layers of dead, scaly, keratinized

cellsKeratinization (cornification) occurs here

FunctionsOccurs on all exposed skin surfaces except

anterior surface of eyesPrevents water lossResists abrasions

EPIDERMAL LAYERS AND KERATINIZATION

THICK AND THIN SKIN Thick skin

Has all 5 epithelial strata

Stratum corneum has many layers

Found in areas subject to pressure or friction Palms of hands, fingertips, soles of feet

Fingerprints and footprintsPapillae of underlying dermis in parallel rows

THICK AND THIN SKIN Thin skin

More flexible than thick skin

Covers rest of body

Each stratum contains fewer layers

Hair is found only in thin skin

THIN AND THICK SKIN Callus

Found in skin subject to friction or pressure Produces a thickened area Over a bony prominence, a corn forms

Calluses and corns develop in both thin & thick skin

SKIN COLOR: PIGMENTS

Determined by 3 factors: 1. Pigments (melanin, Hb, carotene)

2. Blood circulating through the skin

3. Thickness of stratum corneum

SKIN COLOR: PIGMENTS Pigments

Melanin: provides for protection against UV light

Accounts for color in skin, hair & eyes

Lips, palms and soles contain less melanin

Differences in pigmentation among individuals reflects levels of synthetic activity and NOT numbers of melanocytes

SKIN COLOR: PIGMENTS

PigmentsCarotene: yellow pigment

Acquired from egg yolks and yellow and orange vegetables (corn and carrots)

Source of Vitamin A Results in yellowish tint

Location of pigments affect color produced in skin

ABNORMAL SKIN COLORS

Albinism = a genetic lack of melanin

Erythema = increased redness due to increased blood flow through the skin.

Cyanosis = blueness from deficiency of oxygen in the circulating blood (cold weather)

EPIDERMIS FORMATIVE

Monday, Sept 23rd

FORMATIVE QUIZ – LET’S SEE WHAT YOU KNOW…

1. Name the 2 layers of the skin. What type of tissue is each layer made out of? (Try to be specific)

2. What are 3 of the 5 major functions of the integument?

3. What does keratin do in cells?

4. What is the term for when dead skin cells slough off?


5. Name the 5 layers of epidermis in order from deep to superficial

6. Where do cells START to die off (meaning – no more cell division takes place – cell division has stopped in this layer)


1. Epidermis & DermisEpidermis = Epithelial; Dermis = Connective

2. Protection, Sensory Receptors, Excretion, Synthesis of Vit D and Maintenance of Body Temp

3. Makes the cells hard in order to provide strength

4. Desquamate


5. Stratum basale – deepest layer, Stratum spinosum, Stratum granulosum, Stratum lucidum (only in thick skin), Stratum corneum – superficial layer

6. Stratum granulosum

DERMIS & HYPODERMIS

Quiz on FRIDAY•Functions of integument & hypodermis•Layers of epidermis (list & label)•Melanin•Thick vs thin skin•Nails

DERMIS2nd major layer of the skin

Strong, flexible CONNECTIVE tissueAdipose cells & macrophages

Richly supplied with blood vessels and nerves

CompositionCollagen, elastic and reticular fibers, fibroblasts

Nerve endings, hair follicles, smooth muscles, glands and lymphatic vessels

DERMIS – 2 Layers1. Reticular: Deeper layer; 80% of dermis

Hair follicles, nerves, sweat and oil glands found here

Composed of dense irregular C.T.

Contains collagen and elastic fibers

Stretching of skin (obesity, pregnancy) can tear collagen fibers and produce striae (stretch marks)

DERMIS – 2 LAYERS 2. Papillary - Superficial layer; 20% of dermis

Blood vessels that supply epidermis with nutrients

Removes waste products

Aids in regulating body temperature

Fingertips have a papillary patternAll fingerprints are different (even in twins)

HYPODERMIS AKA subcutaneous tissue or superficial fascia

Mostly adipose tissue (some areolar)½ of the body’s fat deposits is found here

Functions:Binds skin to underlying tissueEnergy reservoir (fat)Thermal insulationPadding/cushioning

Skin rests on the hypodermis which attaches to bone and muscle

ACCESSORY SKIN STRUCTURESHairHair folliclesSmooth muscles (arrector pilli)Sweat and sebaceous (oil) glandsNails

CHARACTERISTICS OF HUMAN HAIR Hair (composed of hard keratin)

Hair is found almost everywhere

75% of the 2.5 million are on body surface, not head

Hair is made by HAIR FOLLICLES

Hair pigment is made by melanocytes

CHARACTERISTICS OF HUMAN HAIR

3 different body hair typesLanugo - fine, unpigmented fetal hair

Vellus - fine, unpigmented hair of children and women

Terminal hair - coarser, longer, pigmented hair Chest, legs and arm hair : 90% males vs. 35%

females

STRUCTURE OF HAIR AND FOLLICLEHair has 3 zones:

Bulb - swelling at base in dermis

Root - remainder of hair with follicle; below the surface of skin

Shaft - exposed portion above skin surface

STRUCTURE OF HAIR FOLLICLE

STRUCTURE OF HAIR FOLLICLE

Follicle - a diagonal tube within the skin

Nerve fibers (hair receptors) encircle follicle; detect motion

Arrector pili muscles stimulate piloerection (goose bumps)

Bulb is where hair originates

HAIR GROWTH AND LOSS Hair growth

Due to mitosis of S. basale cells in epithelial root sheath

Scalp hair - grows 1 mm every 3 days on avg (10-18 cm/yr or about 6 inches)

Pushes out by new hair growing beneath it

Loss of 100 scalp hairs a day is normal

Eumelanin Pheomelanin and little eumelanin

Pheomelanin and little eumelanin

Red HairBlonde HairBrown/Black hair

White hair = air in medulla and lack of pigment in cortex. Gray hair is a mixture of white and pigmented hairs.

GRAY AND WHITE HAIR

HAIR GROWTH AND LOSS Thinning or baldness = alopecia

Pattern baldness - the loss of hair from only some regions of the scalp rather than thinning uniformally

Hirsutism = excessive hair growth in areas not normally hairy in women Hormone imbalance (Ovary or adrenal

cortex problem)

FUNCTIONS OF HAIR Body hair

Alert us to parasites crawling on skin

Scalp hair Heat retention and sunburn cover

Beard, pubic and axillary hair indicate sexual maturity (in some guys, that is) and help distribute sexual scents

Guard hairs and eyelashes Prevent foreign objects from getting into nostrils, ear

canals or eyes

Expression of emotions with eyebrows

DERMIS FORMATIVE

LET’S SEE IF YOU ARE STUDYING!

1. Name the layer of connective tissue that connects the skin to the underlying muscle or bone.

2. Identify the 2 layers of dermis.

3. Which of the 2 layers accounts for 80% of the dermis?

4. What is hair composed of?

LET’S SEE IF YOU ARE STUDYING

5. What gives hair it’s color (pigment)?

6. What are the 3 zones of a piece (or strand) of hair?

LET’S SEE IF YOU ARE STUDYING!

1. Name the layer of connective tissue that connects the skin to the underlying muscle or bone. - HYPODERMIS

2. Identify the 2 layers of dermis. – RETICULAR and PAPILLARY

3. Which of the 2 layers accounts for 80% of the dermis? - RETICULAR

4. What is hair composed of? - KERATIN

LET’S SEE IF YOU ARE STUDYING

5. What gives hair it’s color (pigment)? - MELANIN

6. What are the 3 zones of a piece (or strand) of hair? – BULB, ROOT, SHAFT

DERMIS PART 2

FACT OR FICTION?

Cutting hair causes it to grow back faster? Plucking or waxing causes hair to grow back

thicker or more coarse?

NAILS Derivative of stratum corneum

Densely packed cells filled with hard keratin

Keratin is what makes cells hard

Flat nails allow for fleshy, sensitive fingertips

Growth rate is 1 mm per week

Fingernails vs Toenails

FINGERNAIL STRUCTURE

GLANDS – 2 MAJOR TYPESALL EXOCRINE

2 typesSebaceous (oil)Sweat

SEBACEOUS (OIL) GLANDS Location

Dermis Occur over entire body,

except palms and soles

Function Produces oily secretion

(sebum) Sebum is rich in lipids Collects dirt Soften and lubricate hair Protection

SUDORIFEROUS (SWEAT) GLANDS

Widely distributed on body

Sweat is a filtrate of plasma and some waste products500 ml of insensible

perspiration/daysweating with visible

wetness is diaphoresis

SUDORIFEROUS (SWEAT) GLANDS2 TypesMerocrine (or Eccrine)

Most common Open directly onto surface of skin Have own pores Secretes products with no loss of cellular material

Numerous in palms and soles

SUDORIFEROUS (SWEAT) GLANDS2 TypesApocrine glands

Produce sweat containing fatty acids

Found in underarms and genitalia

Active at puberty, causes body odor

Mammals use this for scent as means of communication

OTHER INTEGUMENTARY GLANDS

Ceruminous glandsModified merocrine sweat glandsEarwax (cerumen)Function: In combination with hairs,

to protect eardrum, prevent dirt and insects from entry

OTHER INTEGUMENTARY GLANDS

Mammary glands

Modified apocrine sweat gland

Breasts and mammary glands not the sameBoth sexes have breastsIn females, breasts are a secondary sexual

characteristic

Mammary gland is a milk-producing gland within the breast Only during lactation and pregnancy

WHAT TO EXPECT ON THE QUIZ FRIDAY

1. List the 5 layers in order 2. List the functions of the

integumentary system 3. Identify the layer of dead squamous

cells 4. List the layers of the dermis 5. Identify what the layers of dermis

are made of 6. List the function of the hypodermis

WHAT TO EXPECT ON THE QUIZ FRIDAY

7. Define keratin 8. List areas where keratin is found on

the body 9. Identify the cells that produce

melanin 10. List factors that stimulate melanin

production 11. List the function of nails 12. Compare & contrast thick vs thin

skin

CANCER

WHAT IS CANCER?

Cancer - Malignant, spreading tumor

Tumor – any swelling

Oncology – study of tumors and their problems

Neoplasm – abnormal tissue growth resulting in rapid cellular proliferation which continues after growth of normal tissue has stopped or slowed

WHAT ARE NEOPLASMS?

Benign – not inclined to spread or get worse

Less dangerous than malignant tumors

Can compress surrounding tissues Impair tissue functions as a result of

enlargement

WHAT ARE NEOPLASMS?

Malignant – able to spread and become worseMore embryonic, less mature, than normal tissue

Invasive, ability to squeeze into spaces and enter surrounding tissues

Secrete enzymes that cut paths through healthy tissue

WHAT ARE NEOPLASMS?

MalignantGrow irregularly, sending processes in

every direction

Ability to dislodge, enter blood vessels, lymphatic vessels or body cavities

Travel to distant sites, attach and invade tissues

THE GENETICS OF CANCER

Mutations of genes within somatic cells

Occurs during DNA replication

Radiation, chemicals, toxins & viruses cause mutations by damaging or altering DNA

Usually develop in tissues that undergo frequent cell division


Neoplasm can become cancerous when cell’s structure and functions are changedIncrease ability of cancer cells to

invade and destroy surrounding tissue

Metastasize

Resistant to drug treatments


Prevention of development in cancer cells:DNA repair enzymes detect and

correct errors during replication

Self-destruction mechanism destroys cells with abnormal DNA (Apoptosis)


Proto-oncogenes – promote cell division

Oncogenes – abnormal regulatory genes, increases rate of cell division

Tumor suppressor genes – normal genes that slow down or stop cell division

HOW ARE CANCER CELLS DIFFERENT?

TYPES OF CANCER

Metastasis – process by which cancer cells spread to distant sites

Secrete substances that cause blood vessels to grow into the tumor and supply oxygen and nutrients.

TYPES OF CANCER

Carcinoma – cancer of epithelial tissueBasal cell & Squamous cell

carcinomas

Adenocarcinoma – glandular epitheliumBreast cancer

TYPES OF CANCER

Sarcoma – connective tissue

Osteosarcoma – bones

Chondrosarcoma - cartilage

CANCER THERAPY

Concentrates on confining and killing malignant cells

X-rays, lasers, surgical removal, drugs

Problem: Some cancers can’t be removed completely by surgery or killed Affects normal tissues

CANCER THERAPY

Newer drugs prevent blood vessel development

Anticancer therapies – cells that can recognize tumor cells and destroy them

CHEMOTHERAPY

Any treatment involving chemical agents to stop cancer cells from growing

Eliminate cancer cells at sites great distances from original cancer

More than half receive chemotherapy

SKIN CANCER

Most common type of cancer

Caused by UV rays, chemicals, x-rays, inflammation, genetics

Amount of protective melanin affects skin cancerFair-skinned = gen. predisposed to develop skin

cancerIndividuals over 50 yrs = increased risk

SKIN CANCER

Three major types of skin cancer are:

Basal cell carcinomaSquamous cell carcinomaMelanoma

NO. 1 BASAL CELL CARCINOMA

Least malignant and most common skin cancer

Stratum basale cells proliferate and invade the dermis and hypodermis

Slow growing and do not often metastasize

Can be cured by surgical excision in 99% of the cases

NO. 2SQUAMOUS CELL CARCINOMA

Arises from keratinocytes of stratum spinosum

Arise most often on scalp, ears, and lower lip; bleeding can occur

Grows rapidly and metastasizes if not removed; if travels to lymph nodes, can be fatal

Can be treated by radiation therapy or removed surgically

NO. 3MELANOMA

Cancer of melanocytes is the most dangerous type of skin cancer because it is:

Highly metastatic

Resistant to chemotherapy

77% of skin cancer deaths in U.S.

40% develop in preexisting moles

MELANOMA (ABCDE RULE) Melanomas have the following characteristics

A: Asymmetry; the two sides of the pigmented area do not match

B: Border is irregular and exhibits indentationsC: Color (pigmented area) is not uniform: black,

brown, tan, and sometimes red or blueD: Diameter is larger than 6 mm (size of a pencil

eraser)E: Evolving (lesions change over time) Change size,

shape, elevation or color, bleed, crust or become tender

UVA VS UVB

The sun has 2 types of UV (ultraviolet), rays:

1. UVA2. UVB

UVA

UVA - long-wave solar rays of 320-400 nm. Goes through windows, light clothing and

even windshields

Responsible for agingPenetrates the skin more deeply, causing

wrinkling and leathering of the skin

May also directly induce some skin cancers, including melanomas.

UVB

Short-wave solar rays of 290-320 nm

More potent than UVA in producing sunburn

Main cause of skin cancers

The"tanning ray", UVB stimulate the melanocyte cell, producing a suntan as a defense against UV radiation

SKIN CANCER PREVENTION

NOT FOOLPROOF BUT IMPORTANT….wear SUNCREEN!

CANCER FORMATIVE ASSESSMENT

LET’S SEE IF YOU CAN ANSWER THESE QUESTIONS….

1. What is the difference between benign and malignant tumors?

2.What does the term “metastasis” mean?

3. What is a neoplasm?


4. How does the body defend itself against cancer?

5. What are 2 ways we can treat cancer?


1. What is the difference between benign and malignant tumors? Benign not inclined to spread or get worse,

less dangerous, can compress surrounding tissue, cannot grow into other tissue

Malignant able to spread, invasive, secretes enzymes that cut paths through healthy tissue, grow irregularly, can dislodge and travel to distant sites


2.What does the term “metastasis” mean? process by which cancer cells spread to distant sites through the bloodstream or lymph vessels

3. What is a neoplasm? Abnormal tissue growth resulting in rapid cellular

division; continues after normal tissue growth has slowed or stopped


4. How does the body defend itself against cancer? Cells detect and correct errors within mutated

DNA; can self destruct if correction cannot occur (Apoptosis)

5. What are 2 ways we can treat cancer? surgical removal, x-rays, lasers, drugs

CANCER FORMATIVE #2

Cancer Quiz is TOMORROW - Friday

LET’S SEE WHAT YOU DO KNOW….

1. List 2 ways that cancer cells can differ from normal cells.

2. Describe one of the disadvantages (or problems) with current cancer treatments.

3. Identify the most common type of skin cancer.

4. List the 3 types of skin cancer

5. Using the ABCDE rule, identify what 3 of the letters stand for.


6. Name 2 ways in which people develop skin cancer.

7. What individuals are most likely to develop skin cancer?

8. What is the best way to prevent skin cancer?

ANSWERS

1. List 2 ways that cancer cells can differ from normal cells. Invasive (can squeeze into spaces and enter

surrounding tissue) Dislodge (can travel to distant sites)

2. Describe one of the disadvantages (or problems) with current cancer treatments. Kills good cells with the bad


3. Identify the most common type of skin cancer. Basal cell carcinoma

4. List the 3 types of skin cancer Basal cell carcinoma Squamous cell carcinoma Melanoma

5. USING THE ABCDE RULE, IDENTIFY WHAT 3 OF THE LETTERS STAND FOR.

Melanomas have the following characteristicsA: Asymmetry; the two sides of the pigmented area

do not match B: Border is irregular and exhibits indentationsC: Color (pigmented area) is not uniform: black,

brown, tan, and sometimes red or blueD: Diameter is larger than 6 mm (size of a pencil

eraser)E: Evolving (lesions change over time) Change size,

shape, elevation or color, bleed, crust or become tender

LET’S SEE WHAT YOU DO KNOW…. 6. Name 2 ways in which people develop skin cancer.

UV rays Chemicals Genetics X rays

7. What individuals are most likely to develop skin cancer? Fair skinned and individuals over 50

8. What is the best way to prevent skin cancer? Sunscreen

OLD AGE, DISORDERS AND BURNS

DEVELOPMENTAL ASPECTS OF THE INTEGUMENT: OLD AGE

Epidermal replacement of cells slows and skin becomes thinner

Skin becomes dry and itchy

Subcutaneous fat layer diminishes, leading to intolerance of cold

DEVELOPMENTAL ASPECTS OF THE INTEGUMENT: OLD AGE Decreased elasticity and loss of

subcutaneous tissue leads to wrinkles

Decreased numbers of melanocytes and Langerhans’ cells increase the risk of skin cancer

Decrease in blood supply causes poor ability to regulate body temperature

Functioning melanocytes decrease or increase; age spots

DISORDERS

AcneDisease of the hair follicles of the face,

chest and back Is NOT caused by bacteria – bacteria plays a

roleCaused by elevated sebum production and

the maturation of skin cells

Psoriasis Inflammatory skin disease – no known causeScaly skin thought to result from abnormal

lymphocytes

PSORIASIS

DISORDERS

SeborrheaCommon form of eczema

DandruffOccurs in areas of high sebum productionNo known cause, but the yeast that lives

on the skin may play a role

MolesBrown or black growthsOccur when melanocytes in the skin grow

in a cluster instead of being spread out

BURNS First-degree – only the epidermis is damaged

Least seriousLocalized rednessSwellingpain

Second-degree – epidermis and upper regions of dermis are damagedSkin becomes intensely redBlisters also appear and swelling

1ST DEGREE

2ND DEGREE

1ST & 2ND DEGREE BURNS TREATMENT Cool the burn

Hold burn under cool water for 10 to 15 minutesCool compress also works

Cover the burn with a gauze bandageWrap it loosely to avoid pressureDon’t use fluffy cotton to avoid getting lint into

the woundOver the counter pain reliever

Usually heal without further treatment

BURNS

Third-degree – entire thickness of the skin is damagedPermanent damageFat, muscle and bone may be affectedBurned area appears gray-white, cherry red,

or blackThere is no initial edema or pain (since nerve

endings are destroyed)

Treatment - IV nutrition and fluid replacement, de-bridement, and infection control

3RD DEGREE

RULE OF NINES

You can estimate the body surface area on an adult that has been burned by using multiples of 9.

RULE OF NINES

Estimates the severity of burns

Burns considered critical if:Over 25% of the body has second-

degree burnsOver 10% of the body has third-

degree burnsThere are third-degree burns on face,

hands, or feet

c hapter 5 integumentary system thursday, sept 19 th

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