1. The Integumentary System
Integument means COVERING.

2. The integumentary system
Many functions, most but not all are
PROTECTIVE
Insulates & cushions the deeper body organs & protects entire body from mechanical damage (bumps & bruises), chemical damage (such as acids & bases), thermal damage (heat & cold) ultraviolet damage (sunlight) and bacteria. The uppermost layer is keratin & cornified, or hardened, to help prevent water loss from body surface.

3. The skin’s rich capillary network & sweat glands (both controlled by nervous system) play an important role in regulating heat loss from the body surface. It acts as a mini excretory system: urea, salts & water are lost when we sweat. It manufactures protein important to immunity and synthesizes Vitamin D (modified cholesterol molecules located in skin are converted to Vitamin D). Finally, cutaneous sensory receptors (touch, pressure, temperature & pain) provide us with information from external environment.

4. What are the major characteristics of the skin?
Waterproof, stretchable,washable, and permanent-press, that automatically repairs small cuts, rips and burns and is guaranteed to last a lifetime.
Surface area of up to 2.2 square meters
11 pounds
7% of total body weight
Pliable yet tough

5. What are the major layers of the skin?
Epidermis (epi-upon)
Composed of epithelial tissue (stratified squamous)
Non-vascularized
Dermis – underlies the epidermis
Tough leathery layer composed of fibrous
connective tissue, blood & lymph vessels, sensory
Tissue and glands (sweat & sebaceous)
Hypodermis (not considered skin)
Made of adipose and areolar tissue
Stores fat, anchors skin, protects against blows

7. Epidermis
Dermis
Basement membrane

8. The epidermis and dermis are firmly connected
The epidermis and dermis are firmly connected. However a burn or friction may cause them to separate allowing interstitial fluid to accummulate in the cavity between the layers which results in a
blister.

9. Epidermis
Dermis
Hypodermis

10. The epidermis Composed of 5 layers or strata Avascular
* This explains why a man can shave daily
and not bleed even though he cuts off many
cell layers each time he shaves.

11. Thin or thick skinned? We all have thin & thick skin !!!
Areas of presssure
or friction.
Palms of hands
Soles of feet
Tips of fingers
Has all 5 strata
Thin skin
Covers rest of body
More flexible
Each stratum contains
fewer layers of cell

12. Thick & thin only refers to epidermis
In areas of excessive friction or pressure the outer most strata of the epidermis increases in layers causing a
callus.
The skin over bony prominences may develop a cone shaped structure called a
corn.

14. What are the different types of cells in the epidermis
What are the different types of cells in the epidermis? 1) Keratinocytes (covering) 2) Melanocytes (color) 3) Langerhans’ cell (immunity) 4) Merkel cells (receptors)

15. 1) Keratinocytes- most # cells
Produce a fibrous protein called KERATIN
Formed in the lowest levels of the epidermis.
Pushed upward by the production of new cells beneath them.
Become dead and scale-like making a tough protective layer
Millions rub off everyday

17. 2) Melanocytes Melan-black Can transfer melanin to keratinocytes
Synthesizes the pigment melanin
Melan-black
Can transfer melanin to keratinocytes
Protects skin from ultraviolet light. Sun stimulates production of melanin- tanning
Freckles & moles are accummulated melanin
melanocyte
Melanin in
keratinocytes

18. What causes the color of skin?
3 pigments contribute to skin color
1) Melanin
2) Carotene
3) Hemoglobin

19. Carotene-yellow to orange pigment found in carrots.
Melanin- protein pigment (natural sunscreen)
Everyone has the same number of melanocytes but make varying amounts and colors (differences in skin color)
Carotene-yellow to orange pigment found in carrots.
Most commonly found in the palms or soles. Most intense when large amounts of carotene-rich foods are eaten.
Hemoglobin- Red blood gives a pinkish hue to fair skin

20. When hemoglobin is poorly oxygenated both the blood and skin of Caucasians appears blue. This is called
CYANOSIS.
In darker skinned people it is not as apparent
due to the masking effects of melanin. It is
apparent in the mucous membranes and nail
beds.

21. Other color variations
Redness or erythema- inflammation, allergy, fever, embarrassment
Pallor- emotional stress some people become pale. Also could be due to anemia, impaired blood flow to area.
Jaundice- abnormal yellow skin tone due to liver disorder.

22. Bruises or black & blue marks- blood has escaped from the circulatory system and clotted in tissue. aka HEMATOMA

23. Homeostatic imbalance & the SUN
Despite melanin’s protective effects excessive sun exposure eventually damages the skin. It causes the elastic fibers to clump, leading to leathery skin.
It also depresses immune system. Those infected with the herpes simplex, or cold sore, virus are more likely to have an eruption after sunbathing.
DNA can also be altered leading to skin cancer.

25. 3) Langerhans’ cells Participating in the immune response
by stimulating
defense against:
1) microorganisms
2) superficial skin
cancers
Langerhans’
cell

26. 4) Merkel cells Has a spiked appearance
Connected to nerve cells from dermis
Function as sensory receptors for touch.

27. The layers of the epidermis
deepest layer of the epidermis, undergoes rapid cell division.
intermediate layer, contain spiny shaped keratinocytes.
outermost layer cells thick of dead keratinized cells.
Dandruff- excessive shedding of scalp cells
Average person shed 40 pounds of these cells in their lifetime.
Everything you see on a human is dead!

29. What are the characteristics of the dermis?
Divided into 2 layers
Papillary (upper) & reticular (lower) layer
Made up of connective tissue
Richly supplied with blood vessels and lymph vessels
Has hair follicles, sensory receptors, sebaceous (oil) and sweat glands.
Ridges formed from the papillary layer can form finger prints.

31. What are the major appendages of the skin?
Sweat glands
What is sweat: water, salts, vitamin C,
urea & even lactic acid
It is acidic with a pH from 4-6
Sebaceous glands
Hairs
Nails

32. What are the types of glands found in the skin?
Sweat glands- sudoriferous glands
Eccrine- common sweat glands
thermoregulation
Apocrine- produce sweat plus a milky or yellowish substance composed of fat and protein.
Found in the arm pits and genitalia
Thought to be scent glands.

33. Sebaceous glands- oil glands (sebum)
Softens and lubricates hair and skin
Slows water loss and kills bacteria
Ceruminous glands- produce cerumen (ear wax)
Mammary glands-
produce milk

34. Whiteheads & blackheads

39. Why is hair useful? Senses insects that land on the skin.
Hair on the head protects the head from a blow, sunlight and heat loss.
Eyelashes shield the eye
Nose hairs filter the air

41. What are hairs? Made from hair follicles
Made of dead keratinized skin cells
Two parts shaft and root
Shaft has 3 layers of cells
Medulla(central core)
Cortex (bulky layer)
Cuticle (heavily keratinized; protects hair)

43. ALOPECIA- LOSS OF HAIR
DUE TO ANXIETY, PROTEIN DEFICIENT DIETS, THERAPIES LIKE CHEMOTHERAPY, RADIATION, EXCESSIVE VITAMIN A, CERTAIN FUNGAL DISEASES (RINGWORM), IMMUNITY,
MAY ALSO BE DUE TO GENETICS AS IN MALE PATTERN BALDNESS (ANDROGENETIC ALOPECIA)
RECENT STUDIES HAVE INDICATED THE CHROMOSOME # 20 AND THE X AS CONTRIBUTERS TO GENETIC ALOPECIA

46. What are the parts of nails?
A nail is a scale like modification of the epidermis
Made of tightly compressed keratinized cells
Useful tools to pick up small objects or scratch an itch.
Nail matrix is the region responsible for nail growth.

48. What are the primary functions of the Integumentary System?
Protection: provides 3 types of barriers
Chemical barriers: low pH of skin secretions slows bacterial growth. Human defensin is an antibiotic that destroys bacteria (produced by human skin)

49. Physical barriers
Physical barriers: very few substance are able to enter the skin. Substances able to pass.
Lipid-soluble substances: oxygen, carbon dioxide, some vitamins
Oleoresins- poisons (poison ivy)
Organic solvents- dry-cleaning fluid, paint thinner
Salts of heavy metals- lead, mercury, nickel
Penetration enhancers- drug agents that help substances into the body.

50. Biological barriers
Langerhans’ cells- act as macrophages police the epidermis for viruses and bacteria.

51. Functions cont.
Thermoregulation- skin contains sweat glands that secrete watery fluid, that when evaporated, cools the body.
Sensation- Skin contains sensory receptors that detect cold, touch, and pain.
Vitamin D synthesis- cholesterol in the skin is bombarded by sunlight and converted to vitamin D (calcium cannot be absorbed from digestive tract)

52. Functions cont.
Blood reservoir- blood will be moved from skin to muscles during strenuous activity.
Excretion- Sweating is an important outlet for wastes such as salt and nitrogen containing compounds. (urine)

53. Skin Cancer Benign tumors such as warts and moles are not serious.
Malignant tumors can start on the skin and invade other body areas.
Crucial risk factor- overexposure to UV radiation

54. Types of Skin Cancer
Basal cell carcinoma- most common, 30% of all white skin people get it.
Arises from the stratum basale layer of the skin
99% curable if caught early
Dome shaped nodules that form an ulcer in the center.
Squamous Cell carcinoma-
Arise from stratum spinosum
Grows rapidly and metastasizes if not removed
Small red rounded elevation on the skin

55. Skin Cancer Types cont. Melanoma
Cancer of melanocytes (very dangerous)
5% of skin cancers but rising fast
Can arise from preexisting moles
Appears as a spreading brown or black patch
Chance of survival is poor if the lesion is greater than 4 mm thick

56. Basal Cell Carcinoma

57. Lesion removed from patient
Basal Cell Carcinoma

58. Squamous cell carcinoma

59. Melanoma

60. What is the ABCD rule? Used for recognizing melanoma
A-Asymmetry: two sides of the pigmented mole do not match
B-Border irregularity: borders are not smooth
C- Color: lesion has a multiple of colors
D- Diameter the spot is larger than 6 mm in diameter (size of a pencil eraser)

63. What are the 3 types of burns?
First-degree burns: only the epidermis is damaged. Redness, swelling and pain are common. (sunburn) 2-3 days to heal
Second-degree burns: epidermis and upper layers of dermis. Blistering can occur. 3-4 weeks to heal.
Third-degree burns: involves the entire thickness of the skin. (pg )

65. Second-degree burns
Third-degree burn

70. Decubitus ulcer

73. IMPETEGO

77. psoriasis

78. ECZEMA

80. Lipoma