1. External Features of the Skin
Epidermis Activity
Do you remember what type of tissue this is?
General:
Epithelial
Specific:
Stratified Squamous Keritinized

2. Dissecting Scope or Stereoscope
When properly put away, the fastener is around the cord.
If you no longer have a fastener, wrap the cord around the arm and lock the male head around the cord.

3. Lights Turn on the main light.
To observe the skin on your hand, do you think it would be better to use the
top light or
bottom light?

4. Magnification and Focusing
You can magnify the image 2x or 4x.
2. You can raise the nose piece to assist with focusing.

5. Send me cool pictures Include a description

6. Structure determines function
Characteristic
Skin covering the back of the hand
Skin covering the palm of the hand
Why?
Thickness
Thinner
Thicker
More layers on the palm, provide more protection
Calluses
None
Usually yes
Friction promotes increased cell division
Oily feel
Oily
Not oily
Oils would result in reduced friction when gripping objects

7. Elasticity of skin
Elastic- able to return to original form after a force is applied
Why do you think the skin of the palm is more elastic than the back of the hand?
What other objects can you
think of that are elastic?

8. What factors reduce elasticity?
Genetics
Smoking
UV radiation
Stress- production of the stress hormone cortisol destroys collagen fibers (this hormone also causes breakouts.)
Sleep- Repair of skin occurs when you sleep
A diet high in sugar causes glycation- sugar binds to collagen and elastin and disrupts normal production
It’s all about the fibers when it comes to elasticity.
Watch Amazing Medical Stories

9. Fingerprints
Loop (60-65%)
Whorl (35%)
Arch (5%)

10. The skin as a barrier Is the epidermis waterproof?
Is the skin a barrier to all
organic molecules?
Is lotion water based or lipid based?

11. Application to pharmacology
Nicoderm- cessation of smoking
Scopolamine- motion sickness
Opiads- pain relief
Hormones- including birth control
MIT develops new technology that allows larger molecules to pass through the skin. Click on pic to watch movie

12. Protective barrier
Relate the function of apple skin to human skin.

13. hair shaft
sweat gland pore
epidermis
Basement
membrane

14. Integumentary System Structures Function Skin (cutaneous membrane)
Epidermis
-stratified squamous epithelial (keratinized)
  -stem cells
-melanocytes
Retards water loss (osmoregulation) Protection from microorganisms Protection from injury Readily divide to replace injured or worm out cells Contain the light absorbing pigment, melanin, which protects deeper cells

15. The “horny” layer
Site of shedding cells
An optional layer of dead cells
Occurs in areas of heavy wear
Layer of dead cells
May be absent in areas of thin skin
Pre-keratin granules present
Cells are alive
As few as 2 layers thick in thin skin
Cells have spines and are tightly packed
One layer thick
Site of mitosis

16. Cellular extension of melanocyte
Word Bank
Basement membrane
Cellular extension of melanocyte
Epidermis
Golgi apparatus
Nucleus
Pigment granules 6 1 5 4 3 2