Transcript The Integumentary System

Warm-up: 25 January 2012
Exercise helps maintain healthy
• ____________
bones by making bones grow stronger
and denser.
• 140) heredity – the passing of traits from
parents to offspring
• 141) hibernation – to pass the winter in a
sleeping or resting state
• 142) inherit – to receive by genetic
transmission; to have handed on to one by
someone else
Daily Objective
• Describe and identify the structure and
function of the integumentary system.
The Integumentary
System
Chapter 5
The Integumentary System
• The skin is the largest organ in the human
body.
• If an adult’s skin were stretched out flat,
it would cover an area larger than 1.5
square meters—about the size of a
mattress on a twin bed.
The Integumentary System
• Composed of the skin, sweat and oil
glands, hair, and nails.
• Accounts for 7% of the body’s weight.
• Major role is protection from pathogens
and dehydration.
• Varies in thickness from 1.5 to 4.0 mm.
• Composed of 3 distinct layers.
• Epidermis, Dermis, and Hypodermis or
superficial fascia
The Integumentary System
• Role of the Integumentary System
• covers the body
• prevents the loss of water
• protects the body from injury and
infection
• helps to regulate body temperature
• eliminate wastes
• gather information about the
environment
• produce vitamin D
The Integumentary System
• Covers the Body & Prevents Water Loss
• Like plastic wrap that keeps food from
drying out, the skin prevents the loss of
important fluids such as water.
The Integumentary System
• Protects the Body from Injury and
Infection
• Skin protects the body by forming a
barrier that keeps disease-causing
microorganisms and harmful substances
outside the body.
The Integumentary System
• Helps to Regulate Body Temperature
• The skin helps the body maintain
homeostasis, or stable internal
conditions, by keeping body temperature
steady in spite of changing external
conditions.
• When you become too warm, blood
vessels enlarge to increase the amount
of blood that flows through them
allowing heat to move from your body
into the outside environment.
The Integumentary System
• Eliminates Waste
• Sweat glands respond to excess heat by
producing perspiration.
• Perspiration evaporates from your skin,
heat moves into the air.
• Perspiration contains some dissolved
waste materials.
The Integumentary System
• Gathers Information About Environment
• The nerves in skin provide information
about such things as pressure, pain, and
temperature.
• Pain messages are important because they
warn you that something in your
surroundings may have injured you.
The Integumentary System
• Produces Vitamin D
• Produces vitamin D in the presence of
sunlight.
• Vitamin D is important for healthy bones
because Vitamin D helps the cells in your
digestive system to absorb the calcium in
your food.
• Your skin cells need only a few minutes of
sunlight to produce all the vitamin D you
need in a day.
Epidermal Cell Life Cycle
• Each epidermal cell begins life deep in the
epidermis, where cells divide to form new cells.
• The new cells gradually mature and move
upward in the epidermis as new cells form
beneath them.
• After about two weeks, the cells die and become
part of the surface layer of the epidermis.
• Cells remain in this layer for about two weeks.
• Then they are shed and replaced by the dead
cells below
.
Epidermis
• Outermost layer.
• Protects the dermis
• Contains 4 distinct cell types and 4 to 5
distinct layers.
• When cells fall away, they carry with them
bacteria and other substances that settle on
the skin.
• Every time you rub your hands together, you
lose hundreds, even thousands, of dead skin
cells.
Epidermis
• melanin - a pigment, or colored substance,
that gives skin its color
• Located at the deepest layer of the
epidermis.
• If you have melanin that builds up in one
place, it will result in freckles.
• Moles occur when cells in the skin grow in
a cluster instead of being spread
throughout the skin.
The Dermis
• Lower layer of the skin
• Made mostly of connective tissue.
• The hide of the human body.
• Contains the hair follicles, sweat glands, oil
glands, lymphatic vessels, and many
sensory receptors.
The Dermis – Sweat Glands
• Sweat glands produce perspiration, which
reaches the surface through openings called
pores.
• Sweat Glands—more than 2.5 million per
person.
• Sweat contains chemicals, odorants, and a
small amount urea.
• Sweat itself is not the cause of body odor, but
rather the bacteria on the skin which feed on
the sweat.
• Empty into hair follicles. Begin to function at
puberty.
The Dermis - Hair
• Strands of hair grow within the dermis in
structures called follicles.
• The hair that you see above the skin’s
surface is made up of dead cells.
• Oil produced in glands around the hair
follicles waterproofs the hair. In addition,
oil that reaches the surface helps to keep
the skin moist.
• Covers the entire body except for the
palms, soles, and lips
• Mostly dead keratinized cells.
The Dermis - Hair
Nails
Nails
Caring for Your Skin
• Eating Properly
• Your skin is always active. Activities
require energy—and a well-balanced
diet provides the energy
• Drinking Water
• When you participate in strenuous
activities you can perspire up to 10 liters
of liquid a day.
Caring for Your Skin
• Limiting Sun Exposure
• You can take actions to protect your skin
from cancer and early aging.
• Cancer is a disease in which some cells
divide uncontrollably. (Basal cell
carcinoma & Squamous Cell, &
Melanoma)
• Aging effects - thinning of the skin and
slowing of epidermal cell replacement.
Caring for Your Skin
• Keeping Skin Clean
• mild soap helps you get rid of dirt and harmful
bacteria
• oil glands are more active in teenage years
• acne - when oil glands become clogged with
oil and bacterial infection occurs
• fungi can also live on and infect the skin,
growing best in warm, moist surroundings (i.e.
- athlete’s foot)
Burns
• Denaturation of cell proteins.
• Dehydration, protein loss, and infection.
• First degree burns—only the epidermis.
• Second degree burns—epidermis and upper
dermis. May include blisters.
• Third degree burns—full thickness. Not painful.
Skin grafting is almost always necessary.
• Grafting techniques
• Autograft
• Dangers of facial burns and burns near joints.