1. Integumentary System
Notes

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

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

4. Functions 3. Excretes Waste What wastes are excreted? Urea as sweat
subcutaneous

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

6. Functions 5. Houses sensory receptors Chemo Mechano Chemo Photo

7. There are 2 main layers of skin
I. Epidermis
II. Dermis

8. Epidermis Outer (surface) layers of skin Two Parts:
Dead
keratinocytes
Lamellar granules
Keratinocyte
Langerhans cell
Melanocyte
Merkel cell
Tactile disc
Sensory neuron
Stratum
corneum
lucidum
granulosum
spinosum
basale
Dermis
Outer (surface) layers of skin
10-30 cells thick
Two Parts:
Inner part composed of living cells
Outer part is of dead cells

9. 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

10. Epidermis – Inner layers
These cells also begin producing Keratin a tough, fibrous protein.
This replaces cytoplasm.

11. 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 weeks

12. 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 it’s color
Protects sensitive dermis from U-V radiation

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

14. 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

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

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

17. Accessory Organs of the Dermis
1. Hair follicles – tube-like depression where the hair develops

18. Accessory Organs of the Dermis
2. Sebaceous glands – secret oily sebum to soften and waterproof skin

19. Accessory Organs of the Dermis
3. Nails – protective covers of ends of fingers and toes.

20. Accessory Organs of the Dermis
4. Sweat glands:
secrete waste
regulate heat
produces ear wax
produces milk during lactation

21. Accessory Organs of the Dermis
5. Blood vessels – to nourish skin cells

22. Accessory Organs of the Dermis
6. Nerves – to send and receive messages
Subcutaneous

23. Accessory Organs of the Dermis
7. Erector pilli muscle
-smooth muscle
-causes
“goosebumps”
hair to
stand erect
subcutaneous

24. Subcutaneous layer – connective tissue
Anchors dermis to the body
Contains fat
cells to
protect
and cushion
Subcutaneous layer

25. Self Quiz I. Blood vessels Connective tissue H. Dermis Epidermis B.
Fat cells
Hair
Hair follicle
Muscle
Neuron
Sebaceous gland
Subcutaneous layer
Sweat gland
Sweat pore H. A. B. A. G. K. B. L. J. J. F. D. I. C. K. C. D. H. E. E. M. G. F.

26. Disorders of the Skin
Acne – infection of sebaceous gland

27. Disorders of the Skin
Benign tumor – fleshy growths on neck, armpits and body.
Harmless!
Tumor

28. Disorders of the Skin
Vascular Birthmarks – Blood vessel abnormality affecting .5% of population – darkens skin

29. Disorders of the Skin
Dermatitis – dry, sensitive skin

30. Disorders of the Skin
Nail Fungus

31. Disorders of the Skin
Fungal infections
Ring Worm
Athlete’s Foot

32. Disorders of the Skin
Impetigo – bacterial infection

33. Disorders of the Skin
Psoriasis – chronic inflammation

34. Disorders of the Skin
Melanoma
Cancer
Carcinoma

35. Disorders of the Skin Warts- viral infection Common wart Plane warts
Plantar wart

36. Disorders of the Skin
Burns First degree
Second degree
Third degree

37. 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

38. 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

39. 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

40. 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.