Transcript The Integumentary (Skin) System

The Integumentary
System
(Skin)
Department of Biology and
Anatomy and Physiology
Mission Hills High School
The Skin:
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The skin is an organ that forms a
water-proof protective barrier
against germs (and other
organisms)
keeps the inside of your body
inside your body
keeps what's outside of your
body outside.
Skin also helps maintain a
constant body temperature.
Regulates electrolytes
It is also important in the
production of vitamin D
Important sensory organ for pain,
touch and temperature
The Skin:
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The skin is the largest
organ of the body
Human skin is only about
0.07 inches (2 mm) thick.
On average, an adult has
from 18-20 square feet
(about 2 square meters)
of skin, which weighs
about 6 pounds (2.7 kg).
Skin is made up of two
layers that cover a third
fatty layer…
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The outer layer is called the epidermis; it is a
tough protective layer that contains melanin
(which protects against the rays of the sun and
gives the skin its color).
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The second layer (located under the epidermis)
is called the dermis; it contains nerve endings,
sweat glands, oil glands, and hair follicles.
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Under these two skin layers is a fatty layer of
subcutaneous tissue (the word subcutaneous
means "under the skin"). It is also called the
Hypodermis
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The epidermis
The top most layer
(epidermis) of the skin is
translucent and allows light
to be transmitted through to
the dermis.
It is composed of five layers
of cells:
Cornified layer,
Lucidum layer(only in skin
of palms of hands and soles
of feet)
Granular layer,
Spinous layer
and the germinal or basal
layer.
Cornified Layer: - dead cells converted to a
water-repellant protein called keratin that
coninously flakes off (desquamates)
Cornified (horny) layer
Lucidum layer – So named because of the
translucent protein eleidin from which Keratin forms.
It is present only on palms of hands and soles of feet
Lucidum Layer
Thin skin- Most of the epidermis on the human body
has four layers due to the Lucidum layer missing:
Granular layer: - So named because of granules
visible in the cytoplasm of the cells (cells die in
this layer)
Granular layer
Spinous layer: - Several layers of irregularly
shaped cells.
Spinous Layer
Basal (or germinal) Layer – Only cell layer in the
epidermis that undergoes mitosis. New cells are produced in this
deepest layer at the same rate as Keratinized cells are lost in the
cornified layer.
Basal (or Germinal)
Layer
Basal Layer and Skin Color– Melanocytes which
produce the skin pigment melanin, are found in this layer. Amount
of melanin produced is a hereditary factor and determines skin
color.
Melanocytes found
In the basal layer
Melanocytes– Excessive Ultraviolet light exposure (sun) also
stimulates the melanocytes to produce melanin (sun tan). So too
does excessive ACTH (a hormone) and MSH (melanocytestimulating hormone) produced by the pituitary gland.
UV and Hormone
Stimulation
Skin Cancer
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Skin cancer is the most common
form of cancer in the United
States.
More than 500,000 new cases
are reported each year-and the
incidence is rising faster than
any other type of cancer.
While skin cancers can be found
on any part of the body, about
80 percent appear on the face,
head, or neck, where they can
be disfiguring as well as
dangerous.
WHO GETS SKIN CANCER ...AND WHY
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The primary cause of skin
cancer is ultraviolet radiation
–most often from the sun,
but…
also from artificial sources like
sunlamps and tanning
booths…
an increase in outdoor
activities…
perhaps the thinning of the
earth's protective ozone layer
are behind the alarming rise
we're now seeing in skin
cancers.
TYPES OF SKIN CANCER
1. Basal Cell Carcinoma
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By far the most common type of skin
cancer is basal cell carcinoma.
Fortunately, it's also the least
dangerous kind--it tends to grow slowly,
and rarely spreads beyond its original
site.
Though basal cell carcinoma is seldom
life-threatening, if left untreated it can
grow deep beneath the skin and into
the underlying tissue and bone, causing
serious damage (particularly if it's
located near the eye).
2. Squamous Cell Carcinoma
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Squamous cell carcinoma is
the next most common kind
of skin cancer
frequently appearing on the
lips, face, or ears.
It sometimes spreads to
distant sites, including lymph
nodes and internal organs.
Squamous cell carcinoma
can become life threatening
if it's not treated.
3. Malignant Melanoma
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A third form of skin cancer,
malignant melanoma, is the least
common (less than 5% skin
cancer cases)
incidence is increasing rapidly,
especially in the Sunbelt states.
Malignant melanoma is also the
most dangerous type of skin
cancer.
If discovered early enough, it can
be completely cured.
If it's not treated quickly, however,
malignant melanoma may spread
throughout the body and is often
deadly.
Malignant Melanoma
Normal skin vs. Melanoma
Treatment:
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Skin cancer is
diagnosed by removing
all or part of the growth
and examining its cells
under a microscope.
It can be treated by a
number of methods,
depending on the type
of cancer, its stage of
growth, and its location
on your body.
Surgery:
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Most skin cancers are
removed surgically, by a
plastic surgeon or a
dermatologist.
If the cancer is small, the
procedure can be done
quickly and easily, in an
outpatient facility or the
physician's office, using
local anesthesia.
Major surgery, chemotherapy and radiation
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If the cancer is large,
however, or if it has
spread to the lymph
glands or elsewhere in
the body, major surgery
may be required.
Topical chemotharapy
X- ray radiation may be
helpful in some cases.
Prevention:
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Avoid prolonged exposure to
the sun, especially between
10 a.m. And 2 p.m. and
during the summer months.
Remember, ultraviolet rays
pass right through water and
clouds, and reflect off sand
and snow.
When you do go out for an
extended period of time,
wear protective clothing such
as wide brimmed hats and
long sleeves.
SPF
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On any exposed skin, use
a sunscreen with an SPF
(sun protection factor) of at
least 15. Reapply it
frequently, especially after
you've been swimming or
sweating.
Regular self examinations
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Finally, examine your skin regularly.
If you find anything suspicious, consult a plastic
surgeon or a dermatologist as soon as possible.