Integumentary System

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Integumentary System
Notes

• Chapter 36
• Section 3

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Lecture Outline Integumentary System
PowerPoint Notes
textbook questions
Keys
3
Functions

• Covers and protects the body
• What does the skin protect us from?
• Pathogens
• Injury
• Ultra-violet radiation

4
Functions

• 2. Regulate body temperature
• How does it regulate temperature?
• Sweating
• Dilate/constrict of blood vessels
• Goose bumps

5
Functions

• 3. Excretes Waste
• What
• wastes are
• excreted?
• Urea
• as sweat

6
Functions

• 4. Reduces water loss
• Keeps the body from drying out!

7
Functions

• 5. Houses sensory receptors

Chemo
Mechano
Chemo
Photo
Mechano
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There are 2 main layers of skin
I. Epidermis
II. Dermis
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Epidermis

• Outer (surface) layers of skin
• 10-30 cells thick
• Two Parts
• Inner part composed of
  living cells
• Outer part is of dead cells

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Epidermis Inner layers

• Lowest layer of cells reproduce and push older
  cells toward the surface.
• As cells near the surface, they flatten and their
  organelle disintegrate

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Epidermis Inner layers

• These cells also begin producing Keratin a tough,
  fibrous protein.
• This replaces cytoplasm.

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Epidermis Outer layers

• The Keratin producing cells die as they move
  toward the surface.
• Outer dead layer waterproofs and protects inner
  layers
• It is shed continually and is completely replaced
  in 2 - 4 weeks

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Epidermis

• What do we find in the epidermis?
• Melanocytes
• What are melanocytes?
• Cells that produce melanin.
• What is melanin?
• A dark brown pigment
• What does melanin do?
• Gives skin its color
• Protects sensitive dermis from U-V radiation

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Epidermis

• Melanocytes

Do some people have more melanocytes than other
people?
NO!
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Epidermis

• Skin pigmentation is due to the type and amount
  of melanin produced
• Eumelanin produces darker pigments
• Phaeomelanin produces lighter pigments and
  freckles
• These often occur together in varying amounts

Melanocyte
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Dermis

• Deeper layers of skin
• 10-20 times thicker
• than epidermis.
• Top layer arranged
• In ridges.
• Why are there
• ridges?

Dermis
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Dermis

• Ridges help the
• epidermis bind to the
• dermis.
• The uneven ridges
• create fingerprints

Dermis
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Accessory Organs of the Dermis

• 1. Hair follicles tube-like depression where
  the hair develops

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Accessory Organs of the Dermis

• 2. Sebaceous glands secret oily sebum to soften
  and waterproof skin

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Accessory Organs of the Dermis

• 3. Nails protective covers of ends of fingers
  and toes.

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Accessory Organs of the Dermis

• 4. Sweat glands
• secrete waste
• regulate heat
• produces ear wax
• produces milk during lactation

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Accessory Organs of the Dermis

• 5. Blood vessels to nourish skin cells

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Accessory Organs of the Dermis

• 6. Nerves to send and receive messages

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Accessory Organs of the Dermis

• 7. Erector pilli muscle
• -smooth muscle
• -causes
• goosebumps
• -causes
• hair to
• stand erect

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Subcutaneous layer connective tissue

• Anchors dermis to the body
• Contains fat
• cells to
• protect
• and cushion

Subcutaneous layer
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Self Quiz
L.
M.
I.

• Blood vessels
• Connective tissue
• Dermis
• Epidermis
• Fat cells
• Hair
• Hair follicle
• Muscle
• Neuron
• Sebaceous gland
• Subcutaneous layer
• Sweat gland
• Sweat pore

H.
A.
B.
A.
G.
K.
L.
B.
J.
J.
F.
D.
C.
I.
K.
C.
D.
H.
E.
E.
M.
F.
G.
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Disorders of the Skin

• Acne infection of sebaceous gland

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Disorders of the Skin

• Benign tumor fleshy growths on neck, armpits
  and body.
• Harmless!

Tumor
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Disorders of the Skin

• Vascular Birthmarks Blood vessel abnormality
  affecting .5 of population darkens skin

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Disorders of the Skin

• Dermatitis dry, sensitive skin

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Disorders of the Skin

• Nail Fungus

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Disorders of the Skin

• Fungal infections

Ring Worm
Athletes Foot
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Disorders of the Skin

• Impetigo bacterial infection

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Disorders of the Skin

• Psoriasis chronic inflammation

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Disorders of the Skin
Melanoma

• Cancer

Carcinoma
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Disorders of the Skin
Common wart

• Warts- viral infection

Plane warts
Plantar wart
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Disorders of the Skin
BurnsFirst degree Second degree Third
degree
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Interesting Tidbits

• Your body is composed of approximately 100
  Trillion cells
• About 16 of your body weight is skin
• The skin is completely renewed every 27 days
• You will make almost 1000 new skins in a lifetime
• If all the layers of your skin were laid out on
  the ground, it would cover about 20 m2 or 2
  parking spaces

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Interesting Tidbits

• A fingernail or toenail takes about 6 months to
  grow from base to tip
• Fingernails grow faster than toenails
• An average human scalp has 100,000 hairs
• We lose between 40 and 100 hairs per day
• Blondes have more hair than brunettes

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Interesting Tidbits

• Fingerprints provide traction for grasping
  objects
• Even identical twins have different fingerprints
• Every square inch of dermis contains twenty feet
  of blood vessels
• Skin on our hands and feet is thicker. When we
  bathe, skin takes on water and swells slightly.
• In the thicker areas, increased surface area
  creates crowding. The skin must wrinkle to
  accommodate the changes

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Interesting Tidbits

• Friction of the epidermis causes cell division to
  increase.
• This outward thickening is called a callous.
• Sometimes growth is inward, creating a corn.
• Humans shed about 600,000 particles of skin per
  hour about 1.5 pounds per year.
• At age 70, you will have lost about 105 lbs of
  skin.