1. Integumentary System

2. Epidermis is replaced monthly
Integumentary Facts
Epidermis is replaced monthly
30, 000 dead skin cells are lost each minute
Skin is the largest organ of the body
You shed on average 1 pound of skin each year

3. 3 Part to the Integumentary System
1. Hair
2. Skin (6-9 lbs in most humans)
3. Nails

4. Skin Structure Figure 4.4 Slide 4.13b
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5. Skin Includes all of the following:
Skin (cutaneous membrane)
Skin derivatives
Sweat glands
Oil glands
Hairs
Nails
Slide 4.8
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6. Skin Functions Protects deeper tissues from: Mechanical damage
Chemical damage
Bacterial damage
Thermal damage
Ultraviolet radiation
Aids in heat regulation
Aids in excretion of urea and uric acid
Synthesizes vitamin D
Slide 4.9a

7. Skin Layers 1. Epidermis – outer protective layer
Varies in thickness depending on if area gets a lot of wear and tear. Often keratinized (hardened by keratin)
Keratinized(hardened keratin-a fibrous protein) squamous epithelial
Melanocytes found in the deepest layer of the epidermis
Slide 4.10a
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8. Skin Renewal Cells undergoing mitosis(cell division)
Cells fill with Keratin-waterproofing
Cells flake away with daily wear and tear exposing cells from below
Takes 4 weeks for cells to move from the bottom epidermal layer to top layer

9. 2. Dermis Dense connective tissue
Blood vessels-aids in temperature regulation
Glands-sweat (sudoriferous) and oil (sebaceous)
Nerve receptors
Pain receptors
Pressure receptor- sense of touch
Capillary loops

10. 3. Hypodermis-deep to dermis Not part of the skin
Anchors skin to underlying organs
Composed mostly of adipose tissue-subcutaneous fact
Thermal insulation against hot/cold
Slide 4.10b
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11. Sense of Touch-Receptors are in the dermis
Skin patch the size of your fingernail contains 1, 000 different types of microsensors
Types of Sensors
Meissner’s corpuscles-palms, lifps, eyelids, genitals, and nipples. Respond to light pressure.

12. 2. Pacinian corpuscles-deep in the dermis, in the bladder wall, senses stronger more sustained pressure.
Free nerve ending that sense temperature, light touch, pressure and pain are found all over the body

13. Thermoregulation
Blood vessels constrict and dilate to allow more or less blood to the surface.
More blood to the skin allows heat to be lost and cooling to result.
Blood vessels narrow when cold to prevent heat loss and reduce sweating.
Errector Pilli muscle contracts when cold.

14. Temperature Regulation-Homeostasis
Sweat glands-sudoriferous glands
3 million/person;
Two types
Eccrine-open to sweat pore; maintain temperature
Palms, soles and forehead
Apocrine-ducts empty into hair follicles
Begin functioning at puberty
Axillary(armpits) & genital areas
Slide 4.16
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15. Sweat and Its Function Composition Function
Mostly water
Some metabolic waste
Fatty acids and proteins (apocrine only)
Function
Helps dissipate excess heat
Excretes waste products
Acidic nature inhibits bacteria growth
Odor is from associated bacteria
Slide 4.17
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16. Defense Sebaceous glands Produce oil(sebum) Lubricant for skin
Kills bacteria-water repellent antibiotic
Most with ducts that empty into hair follicles
Glands are activated at puberty
Keratin-protects against chemicals
Slide 4.15
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17. Skin Repair-skin suffers more damage than any other organ
Steps to repair
Injury
Clotting-process of circulatory system
Plugging-skin cells-mitosis
Scabbing

18. Melanin- Skin Pigment Pigment (melanin) produced by melanocytes
Color is yellow to brown to black
Amount of melanin produced depends upon genetics and exposure to sunlight
Darker skin has larger melanocytes producing more melanin
Exposure to UV stimulates the melanocytes to produce more melanin
Slide 4.12
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19. Normal Skin Color Determinants
Melanin
Yellow, brown or black pigments
Carotene
Orange-yellow pigment from some vegetables
Hemoglobin
Red coloring from blood cells in dermis capillaries
Oxygen content determines the extent of red coloring
Slide 4.14
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20. Hair –Protects & Helps regulate body temperature
Dead flattened cells filled with keratin.
The hair root is buried in a pit, the follicle
Different kind of hair grow at different rates
Hair follicles can either be in rest or growth phase
Figure 4.7b
Slide 4.19
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21. Hair Consists of hard keratinized cells
Scalp hair shield head. eyebrows & eyelashes divert dirt & sweat away from eye
Consists of hard keratinized cells
Melanocytes provide pigment for hair color
Shape of hair follicle determine if hair is curly or straight.
Figure 4.7c
Slide 4.18
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22. Associated Hair Structures
Hair follicle
Dermal and epidermal sheath surround hair root
Arrector pilli
Smooth muscle-hair will rise for temperature regulation.
Sebaceous gland-oil
Sweat gland
Figure 4.7a
Slide 4.20
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23. Nail Structures Free edge Body Root of nail Cuticle Figure 4.9
Slide 4.22
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24. Nails Scale-like modifications of the epidermis Heavily keratinized
Lack of pigment makes them colorless
Slide 4.21
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25. Skin Homeostatic Imbalances
Infections
Athletes foot
Caused by fungal infection
Cold sores
Caused by virus
Slide 4.23
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26. Boil-caused by bacterial infection

27. Wart-viral

28. Impetigo-bacterial infection

29. Psoriasis-cause is unknown; trigger by trauma, infection & stress

30. Eczema (dermatitis)-caused by allergies

31. Vitiligo-genetic

32. Skin Homeostatic Imbalances
Burns
Tissue damage and cell death caused by heat, electricity, UV radiation, or chemicals
Associated dangers
Dehydration
Electrolyte imbalance
Circulatory shock
Slide 4.25
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33. Severity of Burns First-degree burns Second degree burns
Only epidermis is damaged
Skin is red and swollen
Second degree burns
Epidermis and upper dermis are damaged
Skin is red with blisters
Third-degree burns
Destroys entire skin layer
Burn is gray-white or black
Slide 4.27
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35. Rules of Nines Way to determine the extent of burns
Body is divided into 11 areas for quick estimation
Each area represents about 9%
Slide 4.26
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37. Critical Burns Burns are considered critical if:
Over 25% of body has second degree burns
Over 10% of the body has third degree burns
There are third degree burns of the face, hands, or feet
Slide 4.28
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38. Skin Cancer Cancer – abnormal cell mass Two types Benign
Does not spread (encapsulated)
Malignant
Metastasized (moves) to other parts of the body
Skin cancer is the most common type of cancer
Slide 4.29
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39. Skin Cancer Types Basal cell carcinoma Squamous cell carcinoma
Least malignant
Most common type
Arises from statum basale
Squamous cell carcinoma
Arises from stratum spinosum
Metastasizes to lymph nodes
Early removal allows a good chance of cure
Slide 4.30
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40. Skin Cancer Types Malignant melanoma Most deadly of skin cancers
Cancer of melanocytes
Metastasizes rapidly to lymph and blood vessels
Detection uses ABCD rule
Slide 4.31
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41. ABCD Rule A = Asymmetry B = Border irregularity C = Color D = Diameter
Two sides of pigmented mole do not match
B = Border irregularity
Borders of mole are not smooth
C = Color
Different colors in pigmented area
D = Diameter
Spot is larger then 6 mm in diameter
Slide 4.32
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