1. The Integumentary System
Anatomy and Physiology

2. SOME FACTS ABOUT THE SKIN THAT YOU ARE IN…
Its Waterproof, Stretchable,Washable, yet Tough!
Its automatically repairs small cuts, rips & burns & is guaranteed to last a lifetime
It weighs 7% of your body weight!

3. What Is The Structure of Skin?
3 Layers:
Epidermis
Composed of epithelial tissue (stratified squamous)
avascular
Dermis – underlies the epidermis
Tough leathery layer composed of fibrous connective tissue
Good supply of blood
Hypodermis (a.k.a subcutaneous layer -not considered skin)
Made of adipose and loose connective tissue
Stores fat, anchors skin, protects against blows

4. Epidermis
Dermis
Basement membrane

6. What are the different types of cells in the epidermis?
1. Keratinocytes
Make the protein keratin =
tough & water resistant
Are formed in lowest levels & push up by production of new cells below
Become dead and scale-like, millions rub off everyday
FYI: Everything you see on a person is dead! Outer cells thick. Average person sheds 40 pounds of these in a lifetime!

7. What are the different types of cells in the epidermis?
2. Melanocytes
Make pigment melanin (melan = black) it can transfer the pigment to keratinocytes
Absorbs ultraviolet light so skin is not
damaged
melanocyte
Melanin in
keratinocytes

8. What are the different types of cells in the epidermis?
3. Langerhans’ cells
Formed in bone marrow &
Move to the skin
Langerhans’
cell
They are a type of
Macrophage
(White blood cell),which
patrol & eat
bacteria/viruses

9. What are the different types of cells in the epidermis?
4. Merkel Cells
Connected to nerve cells
from dermis
Function as sensory receptors
for touch.

11. What causes the color of skin?
3 pigments contribute to skin color
1. Melanin
Range in color from yellow to reddish-brown to black
Everyone has the same # of melanocytes but make
varying amounts & colors
Sunlight increases production!
2. Carotene-yellow to orange pigment found in foods.
Most in the palms or soles.
3. Hemoglobin- Red blood (from dermal layer)gives a
pinkish hue to fair skin

12. Characteristics of the Dermis
Connective tissue has lots of collagen & elastic fibers - gives skin strength
Thickest =
Palms/soles
Thinnest =
Eyelids
Extensibility = able to stretch (elbow skin)
Elasticity = able to return to its original shape after extension/contraction (pregnancy & swelling)

13. More Characteristics…
Sense Receptors:
touch receptors (Meissner’s Corpuscles) &
pressure receptors (Pacinian Corpuscles)
Ridges formed from papillary layer form
finger prints.

15. What are the major structures in Dermis?
Sweat glands
Sebaceous glands
Hairs
Nails

16. Sweat Glands 1. Merocrine (common sweat glands) 2. Apocrine (“funky”)
Watery sweat
Heat & waste loss (all over skin - lots on palms/soles)
2. Apocrine (“funky”)
Milky/yellow thick sweat - thought to be scent glands
Starts at puberty
Armpits & groin
3. Ceruminous - make ear wax!
4. Mammary - make milk!

17. Sweat glands

18. Sebaceous Glands Blackheads - built up sebum
Oil glands (sebum) - around hair follicles, none on palms/soles
Softens and lubricates hair and skin
Slows water loss and kills bacteria
Blackheads - built up sebum
Pimples - Built up sebum is a nutrient for bacteria (puss!)

19. Hair Made of dead keratinized skin cells 2 parts = shaft & root
Function = Protection!
FYI on Hair:
You have about 100,000 hairs on your head
You lose about 100/day
It grows ~0.5 in/month - goes through cycles
Hirsutism = excessive hair growth (often in women due to disease)

20. Hair Follicles

21. Hair Follicles

22. NAILS 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.
FYI: Nails & Hair DON’T grow after death - skin just shrinks!

24. Hypodermis (Subcutaneous)
Loose connective
Stabilizes skin position - loosely connected to dermis above & muscle below
Lots of fat cells for padding & insulation

25. Functions of the Integumentary System
1. Protection: provides 3 types of barriers
Chemical barriers: low pH of secretions slows bacterial
growth (ring tarnish!)
B. Biological: Macrophages
C. Physical barriers: few things able to enter:
Some Fat-soluble substances
Poisons (poison ivy)
Solvents- paint thinner
Heavy metals- lead & mercury
FYI: Transdermal patches are soaked in oils/solvents to carry drug
Across - nicotine, birth control & motion sickness!

26. Functions 2. Temperature Regulation
3. Vitamin D Synthesis - sunlight converts cholesterol in dermis to Vit. D3 which is needed for calcium uptake
4. Sensation - touch, pressure, pain & temp
5. Storage - fats
6. Excretion (wastes) & Secretions (milk)

27. Aging Skin (A billion dollar industry!)
Major Age-Related Changes
Injury and infection increase
Immune cells decrease
Sun protection diminishes
Skin becomes dry, scaly
Hair thins, grays
Sagging, wrinkles occur
Heat loss decreases
Repair slows
= loses melanin & fills with air!

28. Skin Injury & Repair

29. Skin Injury & Repair

30. Skin Cancer Benign lesions 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

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

32. Basal Cell Carcinoma

33. Squamous cell carcinoma

34. Lesion removed from patient
Basal Cell Carcinoma

35. 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

36. Melanoma

37. What is the ABCD rule?
Used for recognizing melanoma

38. 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.

39. Burns

40. Second-degree burns
Third-degree burn