1. Thursday October 3rd, 2016 Announcements Agenda
I won’t be here Friday, you will be completing the skin notes
Agenda
Start Chapter 5 Skin
Grab a notetaker if you haven't yet
“Success is liking yourself, liking what you do and liking how you do it” – Maya Angelou
Happy National Sandwich Day- it’s buy a sub get a free sub at subway
Fun Fact: Every year more people die from taking selfies than from shark attacks

2. Chapter 5: Integumentary
5.1: The Skin

3. Integumentary System
Body covering composed of the skin, hair, nails, glands
Skin also known as the cutaneous membrane
Covers the external surface of the body
Largest organ in the body in surface area and weight
Weighs about lbs. (16% of total body weight)

4. Structures of the Skin Composed of 2 main parts Epidermis Dermis
Superficial, thinner portion
Composed of epithelial tissue
Dermis
Found underneath the epidermis
Thicker than the epidermis
Composed of connective tissue

5. Structures of the Skin Epidermis
Composed of layers of stratified squamous epithelium
Contains 4 main types of cells
Keratinocytes
Melanocytes
Langerhans cells
Merkel cells

6. Structures of the Skin Epidermis Keratinocytes
Make up 90% of the epidermal cells
Produced by stem cells in the stratum basale
Found in all 5 layers of the epidermis
Produce the protein keratin
Tough, fibrous protein that helps protect the skin

7. Structures of the Skin Epidermis Melanocytes
Make up 8% of the epidermal cells
Produce the pigment melanin
Yellow-red or brown- black pigment that contributes to skin color
Absorbs ultraviolet light (UV)

8. Structures of the Skin Epidermis Merkel cells Langerhans cells
Participate in the immune response
Merkel cells
Touch a flattened process of a sensory neuron (Merkel disc/tactile disc)
Merkel cells and Merkel disc detect touch sensations

9. Structures of the Skin Layers of the Epidermis
Composed of layers of stratified squamous epithelium
Thin Skin: composed of 4 stratified squamous epithelium layers
Found in most regions of the body
Thick Skin: composed of 5 stratified squamous epithelium layers
Found in the fingertips, palms and soles, where exposure to friction is the greatest

10. Check For understanding 1
The difference between thin and thick skin
Epidermal cells which produce melanin
Largest organ in the body in terms of surface area and weight
Makes up 90% of epidermal cells, produces keratin
Detect touch sensations
Found in the fingertips, palms and soles where friction is the greatest
Tough, fibrous protein that helps protect the skin
Video (4-7:00)

11. Structures of the Skin Layers of the Epidermis Stratum Basale
Deepest layer of the epidermis
Single layer of cuboidal or columnar keratinocytes (simple cuboidal or simple columnar)
Layer contains stem cells, which undergo cell division to produce new keratinocytes

12. Structures of the Skin Layers of the Epidermis Stratum Spinosum
Layer above the stratum basale
Contains 8-10 layer of keratinocytes packed closely together

13. Structures of the Skin Layers of the Epidermis Stratum Granulosum
Layer above the stratum spinosum
3-5 layers in the middle of the epidermis
Cells are undergoing apoptosis
Programmed cell death

14. Structures of the Skin Layers of the Epidermis Stratum Lucidum
Layer above the stratum granulosum
FOUND ONLY IN THICK SKIN
Consist of dead keratinocytes with large amounts of keratin

15. Structures of the Skin Layers of the Epidermis Stratum Corneum
Most superficial layer of the epidermis
25-30 layers of flattened dead keratinocytes
Dead keratinocytes are constantly shed
Process of the cells forming in the stratum basale to when they reach the stratum corneum to be shed takes about 4 week

16. Structures of the Skin Dermis Deepest layer of the skin
Composed of connective tissue containing collagen and elastic fibers
Composed of 2 layers
Papillary layer: contains dermal papilla
Reticular layer: contains adipose cells, hair follicles, oil and sweat glands, nerves
Gives skin strength, ability to stretch and elasticity

17. Structures of the Skin Dermis (7:00-9:40)
Papillary layer: contains dermal papilla
Dermal papilla: small fingerlike projections which indent into the epidermis (make fingerprints)
Can contain:
Capillary loops (blood capillaries)
Meissner corpuscles: nerve endings sensitive to touch
Free nerve endings: associated with sensations of warmth, coolness, pain, tickling, itching

18. Check For understanding 2
Layer which contains stem cells, undergoing cell division to produce new keratinocytes
Small fingerlike projections which indent into the epidermis which hold cells very close together
Layer of the epidermis which is only found in Thick Skin
Deepest layer of the skin
Most superficial layer of the epidermis
Layer of the epidermis from deep to superficial