THE INTEGUMENTARY

SYSTEM

General Description

The integumentary system, consisting of the

skin, hair and nails, act as a barrier to

protect the body from the outside world. It

also functions to retain body fluids, protect

against disease, eliminate waste products,

and regulate body temperature.

1. SKIN AND ITS ACCESSORY ORGANS-THE

HAIR, NAILS, AND A VARIETY OF GLANDS,

MAKE UP THE INTEGUMENTARY SYSTEM.

2. The Skin is the human body's Largest Organs.

3. The word INTEGUMENT comes from a LATIN

word that means to COVER.

4. THE MOST IMPORTANT FUNCTION OF THE

INTEGUMENTARY SYSTEM IS

PROTECTION.

5. IT PERFORMS THIS FUNCTION BY: (The FIVE Main Functions of the Integumentary System)

A. SERVING AS A BARRIER AGAINST INFECTION AND INJURY.

B. HELPING TO REGULATE BODY TEMPERATURE.

C. REMOVING WASTE PRODUCTS FROM THE BODY.

D. PROVIDING PROTECTION AGAINST ULTRAVIOLET RADIATION FROM THE SUN.

E. PRODUCING VITAMIN D.

6. Because the skin contains several types of

Sensory Receptors, it serves as the gateway

through which Sensations such as

PRESSURE, HEAT, COLD, AND PAIN

ARE TRANSMITTED TO THE

NERVOUS SYSTEM.

7. The Skin is composed of Two Main Layers

- The EPIDERMIS and DERMIS.

EPIDERMIS 1. The OUTER most layer of Skin is known as the

EPIDERMIS. It is composed of many sheets of

Flattened, Scaly Epithelial Cells. This is a thin

outer layer of skin.

2. Its layers are made of Mostly DEAD CELLS.

3. Most of the cells of the Epidermis undergo rapid

cell division (MITOSIS).

4. As new cells are produced, they push Older cells

to the surface of the skin. The older cells become

Flattened, Lose their Cellular Contents and

begin making KERATIN.

5. KERATIN IS A TOUGH FIBROUS PROTEIN AND FORMS THE BASIC STRUCTURE OF HAIR, NAILS, AND CALLUSES.

6. In animals keratin forms cow horns, reptile scales, bird feathers, and porcupine quills.

7. Eventually, the Keratin-producing Cells (KERATINCYTES) DIE AND FORM A TOUGH, FLEXIBLE WATERPROOF COVERING ON THE SURFACE OF THE SKIN. Our thickest Epidermis in on the palms and soles.

8. THIS OUTER LAYER OF DEAD CELLS IS SHED OR WASHED AWAY ONCE EVERY 14 TO 28 DAYS.

9. The Epidermis contains MELANOCYTES, CELLS THAT PRODUCE MELANIN, A DARK BROWN PIGMENT.

10. BOTH LIGHT SKINNED AND DARK SKINNED PEOPLE HAVE ROUGHLY THE SAME NUMBER OF MELANOCYTES, THE DIFFERENCE IN OUR SKIN COLOR IS CAUSED BY THE AMOUNT OF MELANIN THE MELANOCYTES PRODUCE AND DISTRIBUTE.

11. The Amount of Melanin produced in Skin depends on TWO Factors - Heredity and the Length of Time the Skin is Exposed to Ultraviolet Radiation (Tanning).

12. Melanin is important for protection, by

absorption of Ultraviolet Radiation from the

sun. All people, but especially people with Light

Skin, need to minimize exposure to the sun and

protect themselves from its Ultraviolet Radiation,

which can Damage DNA in Skin Cells and lead to

deadly forms of Skin Cancer such as

MELANOMA CANCER.

13. THERE ARE NO BLOOD VESSELS IN THE

EPIDERMIS, WHICH IS WHY A SMALL

SCRATCH WILL NOT CAUSE BLEEDING.

DERMIS 1. THE DERMIS IS THE INNERMOST THICK LAYER

OF THE SKIN COMPOSED OF LIVING CELLS.

2. The Dermis lies beneath the Epidermis and contains

BLOOD VESSELS, NERVE ENDINGS, GLANDS,

SENSE ORGANS, SMOOTH MUSCLES, AND HAIR

FOLLICLES.

3. The Dermis helps us to control our body temperature:

A. On a cold day when the body needs to conserve heat,

the Blood Vessels in the Dermis NARROW

(vasoconstriction)

B. On hot days, the Blood Vessels WIDEN (vasodialation),

warming the skin and increasing heat loss.

4. Tiny Muscle fibers attach to Hair Follicles contract and pull hair upright when you are cold or afraid, producing what is commonly called Goose Bumps.

5. Beneath the Dermis is the HYPODERMIS, (SUBCUTANEOUS LAYER), A LAYER OF FAT AND LOOSE CONNECTIVE TISSUE THAT INSULATES THE BODY AND ACTS AS AN ENERGY RESERVE.

6. The Dermis contains TWO major types of

GLANDS: SWEAT GLANDS AND

SEBACEOUS, OR OIL GLANDS.

7. These Glands PASS through the Epidermis and

RELEASE THEIR PRODUCTS AT THE

SURFACE OF THE SKIN.

8. SWEAT GLANDS PRODUCE THE WATERY

SECRETIONS KNOWN AS SWEAT, WHICH

CONTAINS SALT, WATER, AND OTHER

COMPOUNDS.

9. These secretions are stimulated by nerve impulses that

cause the production of sweat when the temperature of the

body is raised. They help to cool the body.

10. SEBACEOUS GLANDS, (OIL GLANDS) PRODUCE

OILY SECRETION KNOWN AS SEBUM THAT

SPREADS OUT ALONG THE SURFACE OF THE SKIN

AND KEEPS THE KERATIN RICH EPIDERMIS

FLEXIBLE AND WATERPROOF.

11. The production of Sebum is controlled by Hormones.

12. Oil Glands are usually connected by Tiny Ducts

(Exocrine Glands) to Hair Follicles. Sebum coats the

surface of the skin and the shafts of hair, preventing excess

water loss and lubricating and softening the Skin and Hair.

13. Sebum is mildly toxic to some Bacteria - protection.

14. If the Ducts of Oil Glands become clogged with excessive

amounts of Sebum, Dead Cells, and Bacteria, the Skin

disorder ACNE can result.

15. When first wearing new shoes, the skin of the foot may be

subject to friction. This will separate layers of Epidermis, or

separate the Epidermis from the Dermis, and tissue fluid may

collect, causing a BLISTER.

16. If the skin is subjected to pressure, the rate of mitosis will

increase and create a thicker Epidermis; we call this a

CALLUS.

BURNS 1. FLAMES, HOT WATER OR

STEAM, SUNLIGHT,

ELECTRICITY, OR CORROSIVE

CHEMICALS MAY CAUSE

BURNS OF THE SKIN.

2. THE SEVERITY OF BURNS

RANGES FROM MINOR TO

FATAL AND THE

CLASSIFICATION OF BURNS IS

BASED ON THE EXTENT OF

DAMAGE.

Classification of Burns FIRST-DEGREE BURN- ONLY THE

SUPERFICIAL EPIDERMIS IS BURNED, AND IS PAINFUL BUT NOT BLISTERED. Causes death of Epidermal Cells.

SECOND-DEGREE BURN DEEPER LAYERS EPIDERMIS ARE EFFECTED,

COULD HAVE INFLAMMATION, BLISTERS, AND THE BURNED SKIN IS OFTEN

PAINFUL.

Third Degree Burns THE ENTIRE EPIDERMIS IS CHARRED OR BURNED

AWAY, AND THE BURN MAY EXTEND INTO THE

DERMIS. OFTEN SUCH A BURN IS NOT PAINFUL

AT FIRST, IF THE RECEPTORS IN THE DERMIS

HAVE BEEN DESTROYED.

Fourth Degree Burns Burns protrude into muscular tissue and possibly

char osseous tissue. Both 3rd and 4th degree burns require grafting and possible amputation.

EXTENSIVE THIRD-DEGREE BURN-

POTENTIAL LIFE-THREATENING

BECAUSE OF LOSS OF SKIN,

WITHOUT THIS NATURAL BARRIER,

LIVING TISSUE IS EXPOSED TO THE

ENVIRONMENT AND IS SUSCEPTIBLE

TO INFECTION AND DEHYDRATION.

HAIR AND NAILS

1. HAIR IS PRODUCED BY CELLS AT THE

BASE OF STRUCTURES CALLED HAIR

FOLLICLES.

2. Hair Follicles are tube like pockets of Epidermal

Cells that extend into the Dermis.

3. Individual hairs are actually large columns

of DEAD Cells that have filled with KERATIN..

4. Rapid cell growth at the base of the Hair Follicle in the HAIR ROOT causes hair to grow longer. Hair gets its color from Melanin.

5. Hair Follicles are in close contact with Sebaceous Glands. The oily secretions of these Glands help maintain the condition of each individual hair.

6. Hair protects and insulates the body.

7. Most individual hairs grow for several years and then fall out.

8. NAILS GROW FROM AND AREA OF RAPIDLY

DIVIDING CELLS KNOWN AS THE NAIL MATRIX

or NAIL ROOT.

9. THE NAIL MATRIX IS LOCATED NEAR THE TIPS

OF THE FINGERS AND TOES.

10. During Cell division, the Cells fill with Keratin

and produce a tough, strong platelike nail that

covers and Protects the tips of the fingers and toes.

11. Nails rest on a Bed of tissue filled with Blood

Vessels, giving the nails a Pinkish Color.

12. Nails grow at a rate of 0.5 to 1.2 mm per day,

with fingernails growing faster than toenails.

Skin Lesions

• Bulla-a large fluid filled

area such as a large blister.

• Macule-A round flat area

distinguishable by color.

Ex: freckle.

• Nodule-Elevated solid

area, deeper and firmer that

a papule such as a wart.

• Papule-elevated solid area

less than 5 mm in diameter.

• Pustule-Discrete pus filled

raised area such as a

pimple.

• Ulcer-Open sore at the skin

surface that may extend

deep into the dermis.

• Tumor-Solid abnormal

mass larger than 1-2 cm.

• Vesicle-fluid filled raised

area. Ex: chicken pox.

• Wheal-Itchy, temporarily

elevated area formed from

local edema. Ex: Hives.

Examples of Integumentary

Disorders

Ulcer-an open sore or wound.

Alopecia

• Sudden hair loss

Athletes foot Fungal infection (Tinea pedis) usually of the

skin of the toes and soles.

Birthmark Congenital blemish or spot on the skin.

Boil

Bacterial infection (furuncle) of the skin.

Blister • Fluid filled area greater than 5mm in

diameter.

Cyst

Liquid-filled sac or capsule

Dermatitis

• Inflammation of the skin

Eczema • Noncontagious skin rash that produces itching,

blistering and scaling. Otherwise known as atopic dermatitis.

Gangrene Necrosis of tissue due to the blockage of

blood supply from disease or direct injury. Amputation is necessary to prevent spread of necrotic tissue.

Herpes Infectious disease of the skin, usually caused by the

herpes simplex virus and characterized by recurring

formations of small clusters of vesicles.

Impetigo contagiosa An acute, inflammatory and contagious skin disease

seen in babies ns young children. Caused by bacterial infections and characterized by pustules that rupture and become covered with loosely held crusts.

Psoriasis • Chronic inflammation of the skin

characterized by reddish patches, covered

with silvery-white scales.

Ringworm • Highly contagious fungal infection marked

by raised, itchy, circular patches with crusts.

Scabies • Contagious skin disorder caused by an infestation

of mites. Marked by intense itching brought on by the female insect burrowing beneath the skin to lay eggs.

Furuncles • Boils that are usually the result of bacterial

infections in the hair follicles.

Carbuncles • Hard, round, deeply embedded and painful

abscesses of the subcutaneous skin tissue. Larger than a boil. Pus oozes from the surface at multiple points.

Shingles (herpes zoster) • A skin irritation due to a viral infection of

nerve endings. Commonly seen on the chest or abdomen.

Skin Cancers

• Skin cancers (carcinomas) usually arise

from nonpigmented epithelial cells within

the deep layer of the epidermis. If the

cancer arises from melanocytes, it is termed

a melanoma.

• Cutaneous carcinomas are the most

common occoring most frequently in fair-

skinned individuals over the age of 40.

This individual has an

extreme case of squamous

cell carcinoma causing a

rupture of the scrotal sac.

Carcinomas are slow

growing and if treated early

have a high rate of cure.

Squamous cell carcinoma in the head of an elderly man.

Melanomas

• Because melanomas arise from

melanocytes, they are pigmented. Color

variation ranges from brown, black, gray or

blue. Usually irregular rather than smooth

outlines and may feel bumpy.