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Integumentary System
Integumentary System
• The skin covers the entire surface of the
human body.
• An adult’s skin covers about ___ square
meters of surface area.
• The skin has several _____ organs, which
is why it is referred to as the
integumentary system.
Integumentary System
The Skin has Three regions:
the epidermis and the
______. The ______________
lies below the skin.
Structure of the Skin--Epidermis
• The epidermis, the outer region of the skin, is made up
of ________ squamous epithelium.
• New cells continually produced in the stratum ________
of the epidermis are pushed outward and become the
keratinized cells of the stratum ________.
Structure of the Skin--Epidermis
•
•
•
•
Stratum Basale
Basal cells, which lie _______ to the dermis, are
constantly dividing and producing new cells.
As they move farther from the dermis, they
receive less and less _______ and nutrients and
eventually die and sloughed off.
Langerhan cells are _________ found deep in
the epidermis. They feed on microbes and then
travel to lymphatic organs, where they stimulate
the immune system to react.
__________ are found deeper in the epidermis.
They produce melanin, the pigment responsible
for skin color.
Structure of the Skin--Epidermis
• When skin is exposed to sun, melanocytes
produce more _____ to protect the skin
from damaging UV radiation.
• A pigment called carotene is present in
epidermal cells and gives the skin of
Asians a yellowish hue.
• The pinkish color of fair-skinned people is
due to the pigment ________ in the red
blood cells in the capillaries of the dermis.
Why do some
people freckle
when exposed
to the sun?
What is the name
of the hereditary
disease where an
individual lacks
the ability to
produce
melanin?
Structure of the Skin--Epidermis
Stratum Corneum
• As cells are pushed toward the surface of the
skin, they become flat, forming the tough,
uppermost layer of eh epidermis, the stratum
corneum.
• Cells are hardened by a process called
___________, which waterproofs the cells with a
protein called keratin.
• Keratinization protects the body from water ____
and water ____, allowing individuals to live in
the desert or a tropical rain forest without
damaging our inner cells.
Over much of the
body, keratinization
is minimal, but a
couple of parts in
particular are
extremely
waterproofed. What
are they?
Structure of the Skin--Dermis
• The dermis, which is composed of dense
_________ connective tissue, lies beneath
the epidermis.
• It contains collagenous and elastic
______, blood vessels, and nerve fibers.
Why does a
person
blush?
Structure of the Skin—Hypodermis
Subcutaneous Layer
• The hypodermis is made up of loose connective
tissue and ________ tissue, which insulates the
body from heat and cold.
• Excessive adipose tissue results in obesity.
At what stage
in life would
you have the
most adipose
tissue?
Accessory Structures of the Skin
Hair, Nails, and Glands
• Both hair and nails are produced by the division
of epidermal cells and consist of keratinized
cells. Hair color is a result of ______.
• Sweat glands are numerous and present in all
regions of the skin. Sweating helps ______ body
temperature.
• __________ glands are associated with a hair
follicle and secrete sebum, which lubricates the
hair and skin
• Mammary glands located in the breasts produce
milk after childbirth.
Marie Antoinette’s hair
supposedly turned
white overnight after
she heard she would
be sent to the
guillotine. Explain why
you believe or
disbelieve this story.
Hair
• Hair is found on all
parts of the body
______ the palms,
soles, lips, nipples,
and portions of the
external reproductive
organs.
• The portion of a hair
that within the follicle
is called the ___. The
portion that extends
beyond the skin is
called the shaft.
Hair
• When women produce more male sex
hormone than usual, they can develop
hirsutism, a condition characterized by
excessive body and facial hair.
• In males, baldness (Alopecia) occurs
when the hair on the head fails to regrow.
• The lifespan of a head hair is
approximately three to _____ years.
A poor diet, or
excessive dieting,
can cause a
persons hair to fall
out. How long
could it take to
regain a beautiful
head of hair?
Nails
• Nails grow from
special epithelial cells
at the base of the nail
region called the nail
_____.
• The visible portion of
the nail is called the
nail body or ______.
• The cuticle is a fold of
skin that hides the
nail root.
• Nails grow about
1mm per week.
Glands
• There is normally
between 90 (leg) and
400 (palm/soles)
sweat glands per
square cm.
• Every hair is attached
to at least ____
sebaceous gland.
• Acne vulgaris is the
result of _________
of the sebaceous
gland.
Disorders of the Skin:
Skin Cancer
• Skin cancer, which is associated with ultraviolet radiation
occurs in three forms. Basal cell carcinoma and
squamous cells carcinoma can usually be removed
surgically. _______ is the most dangerous form of skin
cancer.
UV rays are
associated with
cancer of the
skin. Should a
person prevent
all exposure to
UV light?
Danger Signals for Cancer
C hange in bowel or bladder habits
A sore that does not heal
U nusual bleeding or discharge.
T hickening or lump in breast or elsewhere
I ndigestion or difficulty in swallowing
O bvious change in wart or mole
N agging cough or hoarseness
Disorders of the Skin:
Staphylococcal Infections
Disorders of the Skin
• Athlete’s Foot: caused by a ______ infection that
usually involves the skin of the toes and soles.
• ________: a highly contagious disease
occurring most often in young children. Bacterial
• Psoriasis: a chronic condition in which the skin
develops pink or reddish patches covered by
silvery scales due to overactive cell division.
• __________: a skin disorder not caused by a
dry scalp, but by an accelerated rate of
keratinization in certain areas of the scalp.
Functions of the Integumentary
System
1. _______. The skin provides protection against
abrasion and UV light. It also prevents the
entry of microorganisms and dehydration by
reducing water loss from the body.
2. ________. The integumentary system has
sensory receptors that can detect heat, cold,
touch, pressure, and pain.
3. ________ _ production. When exposed to UV
light, the skin produces a molecule that can be
transformed into vitamin D.
Functions of the Integumentary
System
4. ________ regulation. Body temperature
is regulated by controlling blood flow
through the skin and the activity of sweat
glands.
5. _________. Small amounts of waste
products are lost through the skin and in
gland secretions.
Touch
• Different
receptors
– ______, pressure,
hot, ____…
• # of sensors vary
– 3 heat/1cold
• More touch in fingers toes &
lips
Why do people’s
nose and ears turn
red on cold winter
days?
When melanin is evenly
distributed, _____ occurs. When
melanin collects in specific
areas, then ________ occur.
_______
_______________
_______
A blush is a result of a
rush of _______ to
vessels in the ______
layer.
______(baby
fat)
The story is impossible. Hair
color results form melanin
that is added to the hair in
the hair bulb as the hair
grows. The hair itself is dead.
To turn white, the hair must
grow out without the addition
of melanin. This, of course,
takes considerably more time
than one night.
_______
No. UV light stimulates
the production of a
precursor molecule in
the skin that is modified
by the liver and kidneys
into vitamin D. Without
enough vit. D, one would
suffer from _______
On cold days, skin blood vessels of
he ears and nose can ______,
bringing warm blood to the ears and
nose, thus preventing tissue _____
from the cold. The increased blood
flow makes the ears and nose
appear _____.