1. Integumentary System Skin and accessory structures (hair, nails)
Integument means “covering”

2. Functions of the Integumentary System
Protection
Against UV light, entry of pathogens, abrasions, water loss
Sensation
Sensory receptors detect heat, cold, touch, pressure, pain
Temperature regulation
By controlling blood flow and sweat glands
Vitamin D production
In UV light, skin produces a molecule that can be transformed into Vitamin D

3. Vitamin D Necessary for normal absorption of calcium from intestine
Rickets in children is a disease from reduced mineralization of bone matrix

4. Skin in composed of two layers

5. The Skin Consists of TWO layers 1. Epidermis
The Epidermis and the Dermis
1. Epidermis
Outer layer
Stratified squamous
Contains no blood vessels
Has four types of cells
Most cells are Keratinocytes
Produce keratin
Malanocytes
Skin color, produced from melanin
Langerhans’ cells
Part of the immune system
Merkel’s cells
Detect light and pressure

6. Epidermis Cells are produced by mitosis in the deepest layer
New cells push older, dead cells to surface to slough off or desquamate
Keratinization is the process of moving older cells to surface because they fill with keratin.
These cells will resist abrasion and form a permeability barrier

7. 5 layers of epidermal cells
Strata are regions of the epidermis
Stratum Corneum
Stratum Lucidum
Stratum Granulosum
Stratum Spinosum
Stratum Basale

8. An easy trick to remember these 5 epidermal layers in order from the most superficial to the deepest: "Can Little Girls Speak British"
Can Corneum
Little Lucidum
GiRl GRanulosum
Speak SPinosum
British Basale

10. Stratum Corneum 25 + layers of dead skin
Cornified cells (dead cells with a hard protein envelope)
Hard keratin (nails, hair)
Soft keratin (skin)

11. Stratum Lucidum Thin, clear region 3-5 layers Dead cells
Only found in thick skin (palms, soles of feet, fingertips)

12. Strata Granulosum 2-5 layers of diamond shaped cells
Most cells are dead
Keratohyalin granules
Protein envelope that forms below plasma membrane

13. Strata Spinosum 8-10 layers of flatten cells Some mitosis occurs
Lamellar bodies form
These structures move to the cell membrane and release their lipid (adipose) content into the intercellular space
The lipids are responsible for the permeability of the epidermis.
Abundant Langerhans (used for immunity) cells

14. Strata Basale Deepest layer Single layer of cuboidal/columnar cells
Mitosis occurs every 19 days
One daughter cell pushes to surface to become keratinized (40-56 days)

15. Thick and Thin Skin Thick Thin
All 5 strata
Areas subject to pressure and friction (soles of feet, palms of hands, fingertips)
Thin
4 layers
Hair present
Callus is increased layer of strata corneum
Corn is a cone-shaped structure that develops in thin or thick skin over a bony prominence.

16. Dermis Deeper layer Exchanges gases, nutrients, wastes from epidermis
Comprised of 2 layers (papillary and reticular)
Responsible for strength and flexibility

17. Structures of the dermis
Sebaceous glands
Sweat glands
Sensory receptors
Blood vessels
Collagen and Elastin
Hair follicle

18. 2 Layers of the Dermis 1. Papillary region 2. Reticular region
Loose connective
Dermal Papillae projections are the
bumps that are visible
These make your fingerprints
2. Reticular region
Dense, irregular connective
Collagen and elastin fibers
Cleavage/tension lines seen on the surface of your skin
Stretch marks (overstretched, ruptured dermis)

19. Background Information about Acne
Sebum is produced by the sebaceous glands in the skin.
The Latin meaning of sebum is fat.
It comes out of the glands in the skin and coats the hair follicles.
It reaches the skin’s surface through the follicle.
There it mixes with other
lipids and sweat and forms a
coating on the skin.
This coating is called acid
mantle. Acid mantle protects
the skin against bacteria and
keeps the skin hydrated
So…….what is acne?

20. Acne Sebum is one of the main causes of acne.
When sebum gets blocked in the hair follicle pores, it forms acne.
Acne tends to run in families and can be triggered by:
Hormonal changes related to menstrual periods, pregnancy, birth control pills, or stress
Greasy or oily cosmetic and hair products
Certain drugs (such as steroids, testosterone, estrogen, and phenytoin)
High levels of humidity and sweating

21. Melanosomes (vesicle for carrying melanin) are produced by Golgi apparatus of the melanocytes
Melanin is a term used to describe a group of pigments responsible for color of hair, skin, eyes. (UV protection)
Melanosomes move into cell processes of the melanocyte
Epithelial cells engulf
melanosomes
Production due to genes, hormones, sun exposure
Skin Color

22. Skin Color Freckles = large amounts of melanin
Albinism = inability to produce melanin
Tanning= UV light darkens melanin and stimulates production
Carotene = yellow pigment in carrot/ corn that accumulates in stratum corneum and tints skin yellow
Cyanosis = bluish color from shock due to decrease in blood oxygen

23. Freckles
Albinism
Tanning
Carotene
Cyanosis

24. Hypodermis Subcutaneous tissue Not a part of skin Functions as the
Foundation for the dermis
Supplies blood vessels and nerves
Adipose abundant
Accounts for half of the body’s fat!