Transcript The Integumentary System

The Integumentary System
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The Integumentary System
The skin is the body’s largest
organ
Each square inch of
human skin consists of
twenty feet of blood
vessels.
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The Integumentary System
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INTEGUMENTARY SYSTEM

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.
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Functions of the Skin
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•
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Protection
Barrier Function
Resistance to wear and tear
Vitamin D Production
Protection from UV light
Sensations
Temperature regulation
Red with embarrassment!
White from fright!
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Skin Facts:
1.
2.
3.
4.
5.
SKIN AND ITS ACCESSORY ORGANS-THE HAIR, NAILS, AND
A VARIETY OF GLANDS, MAKE UP THE INTEGUMENTARY
SYSTEM.
The Skin is the human body's Largest Organ.
The word INTEGUMENT comes from a LATIN word that
means to COVER.
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.
THE MOST IMPORTANT FUNCTION OF THE
INTEGUMENTARY SYSTEM IS PROTECTION.
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Skin Facts:
•
You have approximately 19,000,000 skin cells on
every square inch of your body.
•
Humans shed about 600,000 particles of skin every
hour – about 1.5 pounds a year.
•
House dust is mainly skin flakes!
•
Skin weighs about 2.5 kilograms - the largest organ in
the body.
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Skin Facts:
•
What hurts if you pull it, but doesn't hurt if you cut
it? Your hair, of course!
•
Skin is elastic - it springs back into shape when
stretched. Some medicines (estrogen, nicotine)
can pass through the skin, but others cannot
(insulin). This is because only fat-soluble
substances can enter the skin, not water-soluble
ones.
•
Skin grows faster than any other organ and
continues to grow throughout our lives.
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
The Skin is composed of Two Main
Layers - The EPIDERMIS and DERMIS.
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It’s the Skin We’re In!

(The epidermis is the topmost layer. It helps to
prevent evaporation of water from the body and
to protect the internal layers from harm.
 The dermis is the middle layer. It contains the
blood vessels, nerves, hair roots, and sweat
glands.
 The subcutaneous tissue is the deepest layer.
It contains fats and connective tissue along
with large blood vessels and nerves.
Why do fingers and toes wrinkle
in the bathtub?
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EPIDERMIS
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.
 Its layers are made of mostly DEAD CELLS.
 Most of the cells of the Epidermis undergo rapid cell
division (MITOSIS).
 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.


THERE ARE NO BLOOD VESSELS IN THE EPIDERMIS, WHICH IS
WHY A SMALL SCRATCH WILL NOT CAUSE BLEEDING.
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Keratin

KERATIN IS A TOUGH FIBROUS PROTEIN AND
FORMS THE BASIC STRUCTURE OF HAIR, NAILS,
AND CALLUSES.
 In animals keratin forms cow horns, reptile scales, bird
feathers, and porcupine quills.
 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.
 THIS OUTER LAYER OF DEAD CELLS IS SHED OR
WASHED AWAY ONCE EVERY 14 TO 28 DAYS.
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Melanocytes



The Epidermis contains MELANOCYTES, CELLS
THAT PRODUCE MELANIN, A DARK BROWN
PIGMENT.
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.
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).
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Skin Color
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
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.
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Skin Cancers

Basal Cell Carcinoma
least malignant and most common
 affects cells of the
stratum basale
 full cure in 99% of
cases when
removed surgically

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Skin Cancers

Squamous Cell Carcinoma
Arises from the cells of the stratum
spinosum
 grows rapidly and
metastisizes to adjacent
lymph nodes if not
removed.
 chance of complete cure
good with early detection

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Skin Cancers

Malignant Melanoma
accounts for only 5% of skin cancers
 often deadly
 chance for survival
about 50%
 therapy includes wide
surgical excision with
immunotherapy.

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ABCD Rule

(A) Assymmetry: the two sides of the
pigmented spot or mole do not match.

(B) Border irregularity: the borders of
the lesion are not smooth but exhibit
indetations.

(C) Color: the pigmented spot contains
areas of different colors (blacks, browns,
tans, and sometimes blues and reds).

(D) Diameter: the spot is larger than 6
mm in diamter (the size of a pencil
eraser).
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Dermis


THE DERMIS IS THE INNERMOST THICK LAYER OF THE
SKIN COMPOSED OF LIVING CELLS.
The Dermis lies beneath the Epidermis and contains BLOOD
VESSELS, NERVE ENDINGS, GLANDS, SENSE ORGANS,
SMOOTH MUSCLES, AND HAIR FOLLICLES.

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.

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.
B. On hot days, the Blood Vessels WIDEN, warming the skin
and increasing heat loss.
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Layers of the Dermis: Papillary Layer

Papillary layer
Areolar connective tissue with collagen and
elastic fibers
 Its superior surface contains peglike
projections called dermal papillae
 Dermal papillae contain capillary loops,
Meissner’s corpuscles, and free nerve
endings

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Layers of the Dermis: Reticular Layer

Reticular layer
Accounts for approximately 80% of the
thickness of the skin
 Collagen fibers in this layer add strength
and resiliency to the skin
 Elastin fibers provide stretch-recoil
properties

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Blisters & Calluses

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.
 If the skin is subjected to pressure, the rate of
mitosis will increase and create a thicker
Epidermis; we call this a CALLUS.
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Hypodermis

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.
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
The Skin is composed of Two Main
Layers - The EPIDERMIS and DERMIS.
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Epidermal Ridges (Fingerprints)

These
epidermal
serve
to amplify
fingerprint
narrow
sense
is an
A friction
ridgeinisits
aridges
raised
portion
of
the
vibrations
example,
when
epidermis
on
and toes
impressiontriggered,
leftthe
byfingers
thefor
friction
ridges
of a
fingertips
brush
across
an
uneven
(digits),
the
palm
of
the
hand
or
the
sole
human
finger.
In
a wider use
of signals
the term,
surface,
better
transmitting
the
of the foot, consisting of one or more to
fingerprints
are the
traces
an texture
sensory
nerves
involved
inoffine
connected
ridge
units
of friction
ridge
perception.
These
ridges
also
assist
impression
the
friction
ridges
of
any
skin.
Thesefrom
are sometimes
known
asin
gripping
surfaces,
as
as theby
"epidermal
ridges"
which
arewell
caused
part of a rough
human
hand.
A print
from
smooth
wet surfaces.
the
underlying
interface
between the
foot can also leave
an impression
of
dermal papillae of the dermis and the
friction
ridges.pegs of the epidermis.
interpapillary
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Fingerprints

Impressions of fingerprints may be left
behind on a surface by the natural
secretions of sweat from the eccrine
glands that are present in friction ridge
skin, or they may be made by ink or
other substances transferred from the
peaks of friction ridges on the skin to a
relatively smooth surface such as a
fingerprint card.
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3 Basic Types of Fingerprints
Loop
Whorl
Arch
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Red, Yellow, Black or White
The red and yellow hues of skin are due
to hemoglobin in the red blood vessels,
which pass through the capillaries
beneath the epidermis, and carotene
(yellowish pigment), which accumulates
in fat cells found in the dermis and
hypodermis.
 Brown skin color is due to melanin.

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Skin Color

Three pigments contribute to skin color:
1. the amount and kind of melanin in the
epidermis
 2. the amount of carotene deposited in the
stratum corneum and subcutaneous tissue.
 3. the amount of oxygen bound to
hemoglobin in the dermal blood vessels.

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Malfunctioning Melanocytes
Albinism – melanocytes completely fail
to secrete melanin. Hair, skin and/or iris
are white.
 Vitiligo – loss of pigment in certain areas
of the skin producing white patches.
 Freckles and Moles are formed when
melanin becomes concentrated in local
areas.
What can cause a baby to
turn orange?

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Skin Color

Skin color is also influenced by emotional
stimuli and can signal disease.

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Erythema (redness) – embrassment, fever,
hypertension, inflammation or allergy.
Pallor (pale) – fear, anger, low blood pressure,
impaired blood flow.
Jaundice (yellow cast) – liver disorder
Bruises (black & blue) – blood has escaped from
circulation and clotted.
Cyanosis (blue) – poorly oxygenated blood
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Tattoos
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Tattoos

Tattoos are made by
inserting pigment into the
skin with an electrically
powered solid needle
that punctures the skin
between 50 and 3,000
times per minute. The
needle penetrates the
skin by about a
millimeter and deposits a
drop of insoluble ink into
the skin with each
puncture.
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Tattoos

When you look at a
person's tattoo, you're
seeing the ink through
the epidermis. The ink
resides in the dermis.
Dermis cells are far
more stable than the
cells of the epidermis, so
the tattoo's ink will stay
in place, with only minor
fading and dispersion,
for a person's entire life!
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Tattoo Removal

Laser removal
surgery is the most
common form of
tattoo removal.
Lasers penetrate the
skin and break up
ink trapped in the
dermis, fading or
erasing the tattoo.
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Tattoo Removal
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Tattoo Removal

Other methods of tattoo removal include:
Intense Pulsed Light Therapy
 Excision
 Dermabrasion

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Appendages of the Skin
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Appendages of the Skin
The Dermis contains TWO major types
of CUTANEOUS GLANDS: SWEAT
GLANDS AND SEBACEOUS, OR OIL
GLANDS.
 These Exocrine Glands PASS through
the Epidermis and RELEASE THEIR
PRODUCTS AT THE SURFACE OF
THE SKIN.

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Appendages of the Skin
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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.
The production of Sebum is controlled by Hormones.
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.
Sebum is mildly toxic to some Bacteria - protection.
If the Ducts of Oil Glands become clogged with excessive
amounts of Sebum, Dead Cells, and Bacteria, the Skin
disorder ACNE can result.
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SWEAT GLANDS PRODUCE THE
WATERY SECRETIONS KNOWN AS
SWEAT, WHICH CONTAINS SALT,
WATER, AND OTHER COMPOUNDS.
 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.

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Don’t Sweat It!

Eccrine glands are the most common
sweat gland . They produce sweat, a
watery mixture of salts, antibodies
and metabolic wastes.
How much do we sweat
in a day?
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Hair
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Appendages of the Skin
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Hair





HAIR IS PRODUCED BY CELLS AT
THE BASE OF STRUCTURES CALLED
HAIR FOLLICLES. (Figure 46-15)
Hair Follicles are tubelike pockets of
Epidermal Cells that extend into the
Dermis.
Individual hairs are actually large
columns of DEAD Cells that have filled
with KERATIN..
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.
Hair Follicles are in close contact with
Sebaceous Glands. The oily secretions
of these Glands help maintain the
condition of each individual hair.
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Hair protects and insulates the body.
 Hairs are found all over the body surface
except the palms of the hands, soles of
the feet, nipples, and lips.
 Humans are born with as many hair
follicles as they will ever have, and hairs
are among the fastest growing tissues in
the body.
 Most individual hairs grow for several
years and then fall out.

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Hair Color

Hair pigment is made by melanocytes in
the hair bulb, and varying amounts of
different types of melanin (yellow, rust,
brown, black) combine to produce all
varieties of hair color from pale blond to
pitch black.
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It’s a Hairy Situation!
• Melanocytes become less active with
age. Gray hair is a mixture of pigmented
and non-pigmented hairs.

Red hair results from a modified type of
melanin that contains iron.
Why do men have to
shave everyday?
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Hair Texture

When the hair shaft is . . .

oval, hair is smooth and silky and
the person has wavy hair.

flat and ribbon-like, the hair is
curly or kinky.

perfectly round, the hair is straight
and tends to be course.
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NAILS!
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Nails
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Nails

NAILS GROW FROM AN AREA OF RAPIDLY
DIVIDING CELLS KNOWN AS THE NAIL
MATRIX or NAIL ROOT. (Figure 46-16)
 THE NAIL MATRIX IS LOCATED NEAR THE
TIPS OF THE FINGERS AND TOES.
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Nails

During cell division, the cells fill with keratin
and produce a tough, strong plate-like nail that
covers and protects the tips of the fingers and
toes.
 Nails rest on a bed of tissue filled with blood
vessels, giving the nails a pinkish color.
 Nails grow at a rate of 0.5 to 1.2 mm per day,
with fingernails growing faster than toenails.
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Infections & Allergies
Athlete’s foot
 Boils and carbuncles
 Cold sores
 Contact dermatitis
 Impetigo
 Psoriasis

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BURNS
FLAMES, HOT WATER OR STEAM,
SUNLIGHT, ELECTRICITY, OR
CORROSIVE CHEMICALS MAY CAUSE
BURNS OF THE SKIN.
 THE SEVERITY OF BURNS RANGES
FROM MINOR TO FATAL AND THE
CLASSIFICATION OF BURNS IS BASED
ON THE EXTENT OF DAMAGE.

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First-Degree Burns
(partial-thickness burns)
ONLY THE
SUPERFICIAL
EPIDERMIS IS
BURNED, AND IS
PAINFUL BUT
NOT BLISTERED.
Causes death of
Epidermal Cells.
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Second-Degree Burns
(partial-thickness burns)
DEEPER LAYERS EPIDERMIS ARE
AFFECTED, COULD HAVE
INFLAMMATION, BLISTERS, AND
THE BURNED SKIN IS OFTEN
PAINFUL.
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Third-Degree Burns
(full-thickness burns)
The entire epidermis is charred or burned
away and may extend into the dermis.
May not be painful at first if the receptors in
the dermis have been destroyed.
• Extensive third-degree burn is potentially 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.
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Rule of Nines
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Skin Gun
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Developmental Aspects

Rickets


The primary cause of rickets is a vitamin D
deficiency. Vitamin D is required for proper calcium
absorption from the gut.
Cases have been reported in Britain in recent years
of rickets in children of many social backgrounds
caused by inability to make vitamin D because the
sun's ultraviolet light was not reaching the skin
because of persistent use of strong sunblock, or too
much "covering up" in sunlight, or spending too
much time indoors.
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Life Span Changes
• Skin becomes scaly
• Age spots appear
• Epidermis thins
• Dermis becomes reduced
• Loss of fat
• Wrinkling
• Sagging
• Sebaceous glands secrete
less oil
• Melanin production slows
• Hair thins
• Number of hair follicles
decrease
• Nail growth becomes impaired
• Sensory receptors decline
• Body temperature unable to be
controlled
• Diminished ability to activate
Vitamin D
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