Integumentary system

integumentary system bio102lec

1. INTEGUMENTARY SYSTEM

2. 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.

3. 1. SKIN AND ITS ACCESSORY ORGANS-
THE HAIR, NAILS, AND A VARIETY OF
GLANDS, MAKE UP THE
INTEGUMENTARY SYSTEM.
2. The Skin is the human body's Largest
Organs.
3. The word INTEGUMENT comes from a
LATIN word that means to COVER.
4. THE MOST IMPORTANT FUNCTION
OF THE INTEGUMENTARY SYSTEM IS
PROTECTION.

4. 5. IT PERFORMS THIS FUNCTION BY: (The
FIVE Main Functions of the Integumentary
System)
A. SERVING AS A BARRIER AGAINST
INFECTION AND INJURY.
B. HELPING TO REGULATE BODY
TEMPERATURE.
C. REMOVING WASTE PRODUCTS FROM
THE BODY.
D. PROVIDING PROTECTION AGAINST
ULTRAVIOLET RADIATION FROM THE SUN.
E. PRODUCING VITAMIN D.

5. 6. 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.

6. –7. The Skin is composed of Two Main
Layers - The EPIDERMIS and DERMIS.

7. EPIDERMIS
1. 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.
2. Its layers are made of Mostly DEAD
CELLS.
3. Most of the cells of the Epidermis
undergo rapid cell division (MITOSIS).

8. 4. 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.
5. KERATIN IS A TOUGH FIBROUS
PROTEIN AND FORMS THE BASIC
STRUCTURE OF HAIR, NAILS, AND
CALLUSES.
6. In animals keratin forms cow horns,
reptile scales, bird feathers, and porcupine
quills.

9. 7. 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.
8. THIS OUTER LAYER OF DEAD CELLS
IS SHED OR WASHED AWAY ONCE
EVERY 14 TO 28 DAYS.
9. The Epidermis contains
MELANOCYTES , CELLS THAT
PRODUCE MELANIN, A DARK BROWN
PIGMENT.

10. 10. 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.
11. 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).

11. 12. 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.
13. THERE ARE NO BLOOD VESSELS
IN THE EPIDERMIS, WHICH IS WHY A
SMALL SCRATCH WILL NOT CAUSE
BLEEDING.

12. DERMIS

13. 1. THE DERMIS IS THE INNERMOST
THICK LAYER OF THE SKIN COMPOSED
OF LIVING CELLS.
2. The Dermis lies beneath the Epidermis
and contains BLOOD VESSELS, NERVE
ENDINGS, GLANDS, SENSE ORGANS,
SMOOTH MUSCLES, AND HAIR
FOLLICLES.

14. 3. 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.

15. 4. 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. 5.
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.

16. 6. The Dermis contains TWO major types
of GLANDS: SWEAT GLANDS AND
SEBACEOUS, OR OIL GLANDS .
7. These Glands PASS through the
Epidermis and RELEASE THEIR
PRODUCTS AT THE SURFACE OF THE
SKIN.
8. SWEAT GLANDS PRODUCE THE
WATERY SECRETIONS KNOWN AS
SWEAT, WHICH CONTAINS SALT,
WATER, AND OTHER COMPOUNDS.

17. 9. 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.
10. 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.

18. 11. The production of Sebum is controlled
by Hormones.
12. 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.
13. Sebum is mildly toxic to some Bacteria
- protection.

19. 14. If the Ducts of Oil Glands become clogged
with excessive amounts of Sebum, Dead Cells,
and Bacteria, the Skin disorder ACNE can
result.
15. 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.
16. If the skin is subjected to pressure, the rate
of mitosis will increase and create a thicker
Epidermis; we call this a CALLUS.

20. BURNS
1. FLAMES, HOT WATER OR STEAM,
SUNLIGHT, ELECTRICITY, OR
CORROSIVE CHEMICALS MAY CAUSE
BURNS OF THE SKIN.
2. THE SEVERITY OF BURNS RANGES
FROM MINOR TO FATAL AND THE
CLASSIFICATION OF BURNS IS BASED
ON THE EXTENT OF DAMAGE.

21. 3. FIRST-DEGREE BURN- ONLY THE
SUPERFICIAL EPIDERMIS IS BURNED,
AND IS PAINFUL BUT NOT BLISTERED.
Causes death of Epidermal Cells.
4. SECOND-DEGREE BURN - DEEPER
LAYERS EPIDERMIS ARE EFFECTED,
COULD HAVE INFLAMMATION,
BLISTERS, AND THE BURNED SKIN IS
OFTEN PAINFUL.

22. 5. THIRD DEGREE BURN- THE ENTIRE
EPIDERMIS IS CHARRED OR BURNED
AWAY, AND THE BURN MAY EXTEND INTO
THE DERMIS. OFTEN SUCH A BURN IS NOT
PAINFUL AT FIRST, IF THE RECEPTORS IN
THE DERMIS HAVE BEEN DESTROYED.
6. EXTENSIVE THIRD-DEGREE BURN-
POTENTIAL 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.

23. HAIR

24. 1. HAIR IS PRODUCED BY CELLS AT
THE BASE OF STRUCTURES CALLED
HAIR FOLLICLES. (Figure 46-15)
2. Hair Follicles are tubelike pockets of
Epidermal Cells that extend into the
Dermis.
3. Individual hairs are actually large
columns of DEAD Cells that have filled
with KERATIN..

25. 4. 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.
5. Hair Follicles are in close contact with
Sebaceous Glands. The oily secretions of
these Glands help maintain the condition of
each individual hair.
6. Hair protects and insulates the body.
7. Most individual hairs grow for several
years and then fall out.

26. NAILS

27. 1. NAILS GROW FROM AND AREA OF
RAPIDLY DIVIDING CELLS KNOWN AS
THE NAIL MATRIX or NAIL ROOT.
(Figure 46-16)
2. THE NAIL MATRIX IS LOCATED NEAR
THE TIPS OF THE FINGERS AND TOES.
3. 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.

28. 4. Nails rest on a Bed of tissue filled
with Blood Vessels, giving the nails a
Pinkish Color.
5. Nails grow at a rate of 0.5 to 1.2 mm
per day, with fingernails growing faster
than toenails.