Integumentary System

Turn to your neighbor…what is the integumentary system?

Skin Nails Hair

Act as a protective barrier to the outside world.

Body Bucket

Retains: body fluidsprotect against diseaseeliminate waste productsregulate body temperature

Basically, holds all your “stuff” from falling out or getting contaminated.

Fun Facts

Human body’s largest organIntegumentary derives from a Latin word

meaning to coverMost important function…PROTECTIONThe outer layer of dead skin cells is shed

or washed away once every 14 to 28 days

How skin protects…

Serving as a barrier against infection and injury Helping to regulate body temperature: by radiation and

evaporation. When you are sick, your temp goes up, the body delivers

the internal temperature to the surface of your skin where it is taken away by evaporation. When your temp drops, the body signals that heat must be saved and sweating will stop.

Removing waste products from the body Providing protection against ultraviolet radiation from the

sun Producing vitamin D

Two main layers

EpidermisDermis

Sensory receptors

Perceives sensations such as: Pressure Heat Cold Pain

All of which are then transmitted to the nervous system.

EpidermisOuter most layer of skinComposed of many sheets of flattened, scaly

epithelial cellsThin layer of skin made mostly of dead cellsUndergoes rapid cell divisionNew cell are produces pushing older cells to

the surface of the skin. The older skin begin making keratin

There are no blood vessels in the epidermis, which is why a small scratch will not cause bleeding

KeratinIs a tough fibrous protein Forms basic structure for hair, nails and

callusesEventually, the keratin-producing cells die

and form a tough, flexible waterproof covering on the surface of the skin

Melanin (a dark brown pigment)

Skin pigmentBoth light skinned and dark skinned

people have roughly the same number of melanocytes (cells that produce pigment)

The difference in our skin color is caused by the amount of melanin the melanocytes produce and distribute.

Amount of Melanin

Dependent on two factorsHeredityLength of time skin is exposed

to ultraviolet radiation

Role – Absorption of ultraviolet radiation

Dermis

Middle thick layer of the skin composed of living cells

Contains: blood vessels, nerve endings, glands, sense organs, smooth muscles, and hair follicles

Helps control body temperature

Body temperature

Cold days the blood vessels narrowDecreases surface area in order to

conserve body heatHot days the blood vessels widen

warming the skin and increasing heat loss

Goose Bumps

Tiny muscle fibers attach to hair follicles contract and pull hair upright when you are cold or afraid producing what we call Goose Bumps

Dermis contains 2 major glands

Sweat glands Secretions are stimulated by nerve impulses that cause

the production of sweat when the temperature of the body is raised.

2,000,000 pores in your skin are connected to sweat-glands.

They help cool the body off.

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.

Hypodermis

This layer is beneath the dermisA layer of fat and loose connective tissue

that insulates the body and acts as an energy reserve.

What causes blisters?The rubbing of the separate skin

layersThe Epidermis and the Dermis

separateTissue fluid may collect between the

layersCalluses

Skin prone to this pressure will create an area of thicker epidermis causing a callus

Burns

Severity ranges from minor to fatalFirst degree burns

Only the superficial epidermis are effected Painful but no blistering Causes death of epidermal cells

Second degree burns Deeper layers of the epidermis are charred Inflammations, blisters and painful

…burns continued

Third degree burns The entire epidermis is charred or burned away,

and the burn may extend into the dermis Not usually painful at first if the receptors in the

dermis have been destroyedExtensive third degree burns

Loss of skin Potentially life threatening, because the natural

barrier has been destroyed exposing tissue that is extremely susceptible to infection and dehydration.

HairProduced by cells at the base of the

structures called hair folliclesHair follicles – tube like pockets of

epidermal cells that extend into the dermisIndividual cells are actual large columns of

dead cells that have been filled with keratin

Hair gets color from melaninProtects and insulates the body

Nails Grows from rapidly divided cells known as the nail

matrix or nail root Nail matrix is located near the tips of the fingers and

toes 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

The pinkish color comes from the blood vessels in the nail bed

Nails grow at a rate of 0.5 to 1.2 mm per day Finger nails grow faster than toe nails

Diagram of the skin

Cleavage Lines

These “lines” are really crease marks on the skin and the same for most bodies.

Your “birthday suit” It is a suit with many surfaces: wet (mouth),

dry, smooth, rough, pleats and folds, tracks and ridges (toes, fingers, for gripping). Spots will tend to thinken where usage is heaviest (feet, which can be 3/16 inch thick!) and thinnest (eyes 1/500” thick!)

Integumentary System Review

What does Integumentary mean?What are the three layers of the skin?What is the purpose of this system? Why

is it important?

Care of this system

Why is it important to take care of this system?

Talk to a partner.Decide what can be done to take care of

this system.

Abuses/Diseases of this system

What can happen if you do not take care of this system?

Discuss with a partner