1. Skin and body membranes
Anatomy and Physiology

2. Bellringer
Think about the skin on your body, is all the skin identical? If no, how is it different?

3. Intro to skin

4. What is integumentary system
What is integumentary system? Integument means “covering” It is the cover of our body and includes 1-the skin that has several important functions. 2- The nails that protects the sensors in our fingers 3- The hair that protects us from UV light and keeps us warm

6. The skin
Fun Facts:
Avg. makes up about 9-11 lbs. or 7% of your weight
Regenerates every days
Every minute you lose 30,000-40,000 dead skin cells

8. Skin Structure (EDH)
Epidermis (epithelial) : Top or outermost layer made of squamous epithelium that continuous regenerates itself from the inside out. Made from the embryonic ectoderm layer. Site where pigments or melanin is made.
Dermis (fibrous): Middle layer made of connective tissue.
Hypodermis (subcutaneous layer – fat): The innermost layer

9. Skin Structure: Epidermis
Epidermis—outer layer
Stratified squamous epithelium

10. 5 Layers “stratum” of the Epidermis (CLGSB)
Stratum corneum: top, dead cells shed by desquamation
Stratum lucidum: present in 4 layers skin: palms of the hand and soles of feet.
Stratum granulosum: Sulfur rich protein “keratin” found in keratinocytes
Stratum spinosum: “Prickly layer” (desmosomes for binding) and Landerhans cells for immunity and healing
Stratum basale (innermost): create new cells through mitosis
* TO REMEMBER USE:
“Come, Lets Get Sun Burn”
Stratum basale: The cells start out cuboidal or columnar, but they become flattened as they migrate to the skin surface. Migration takes days.
Keratin: tough protein for strength

11. Thick skin- covers palms, fingertips, soles of feet
NOTE:
Thick skin- covers palms, fingertips, soles of feet
Thin skin – covers rest of body
Very thin skin is missing stratum lucidum and sometimes stratum granulosum

12. GENETICS is the key factor
Quantity of melanin
(yellow to reddish- brown to black)
protects skin from UV radiation
Melanocytes use enzyme tyrosinase to convert tyrosine into dark brown melanin pigment.
albinos lack DNA code to make tyrosinase
Pigment produced by melanocytes and deposited into the epidermis cells
Amount of melanin produced depends upon genetics and exposure to sunlight

13. Bellringer
A child asks you why his lips “turn blue” when it is cold outside. What would you explain to this child?
The color change is the result of diminished blood flow to the periphery of the body. The skin in more exposed areas is especially susceptible to blood vessel constriction in the body's attempt to retain body heat.
The color change is the result of diminished blood flow to the periphery of the body. The skin in more exposed areas is especially susceptible to blood vessel constriction in the body's attempt to retain body heat.

14. Albinism in Humans

15. Melanin – Skin Color
Sunlight increases melanin production by the release of hormones
freckles or moles are accumulations of melanin
other pigments such as carotene or hemoglobin contribute to skin color
Prolonged exposure causes substantial melanin buildup which helps protect the DNA of viable skin cells from UV radiation by absorbing the light and dissipating the energy as heat

17. Skin Structure Dermis Dense connective tissue “true skin” layer
Anchors skin to underlying organs
Contains areolar connective tissue: binds blood vessels, membranes, muscles, nerves, and skin to other structures.
Attached to the stratum germinativum by hemisdesmosomes along the dermal papilla

19. Dermis Papillary layer (upper dermal region) Dermal papillae:
Fingerlike extensions of the underlying dermis bind tightly to the epidermal cells above by a thin layer of fibrous connective tissue known as the basement membrane
Reticular layer (deepest skin layer)

21. Dermis Overview Collagen fibers give skin its toughness
Elastic fibers give skin elasticity
Blood vessels play a role in body temperature regulation

22. Subcutaneous “hypodermis” Layer
Third and innermost layer of the skin
Thickness of this layer varies throughout the body and from person to person
Absent in thin skin
Anchors to fascia: fibrous tissue that covers muscles, skull bones, and some organs
Contains:
adipose tissue “fat cells”
blood vessels that branch out in capillaries into the dermis
Lymphatic system
Immune system
nerves
Fasciitis caused by microbes or injuries

23. Quiz
Study skin structure notes, vocabulary from textbook for skin structure, and concept check questions.
Labeling: epidermis, dermis, papillary layer of dermis, reticular layer of dermis, hypodermis, hair shaft, pore, layers of the epidermis

24. Quiz
Please clear your desk of all except for a pen or pencil.

25. Word bank Pore Hemidesmosome Dermal papilla Stratum lucidum Fasciitis
Stratum granulosum
Stratum corneum
Stratum basale
Stratum spinosum
Epidermis
Desquamation
Melanin
Areolar connective tissue
Integumentary system
Reticular layer
Pore
Hemidesmosome
Dermal papilla
Stratum lucidum
Fasciitis
Papillary layer
Hypodermis
Dermis
Hair shaft

26. Skin Appendages Glands Hair Hair follicles Nails
Assist the skin with its functions

27. Three most common in skin:
glands
Three most common in skin:
Ceruminous glands: Waxy (cerumen), ear canal
sebaceous glands: Produce oil
Glands are activated at puberty
sweat glands:

28. Sebaceous glands

29. Sweat glands Produce sweat Widely distributed in skin Two types
Eccrine: secrete mostly water and salts, organic compounds, and wastes
on the skin of armpits, forehead, palms, and soles
chemicals in food odors
Microbes feed off nutrients
Apocrine: secrete sweat(odorous material) into hair follicles of armpits, navel, groin region, and areolae
Also broken down by bacteria (odor)
pheromones: “Play a role in courtship and social behavior”

30. Bellringer
What is responsible for the thinness or thickness of your skin? Explain.
Missing layers: stratum lucidum and sometimes stratum granulosum and varying subcutaneous layer.

31. Sweat glands

32. Bellringer
A sales representative for a shampoo company tells you their product “feeds” your hair cells protein. What arguments could you use to debate the validity of their claim?
Students should be able to “tell” the sales representative that the shampoo is useless because it cannot feed the dead hair shaft cells. Any protein in the shampoo would merely stick to the hair surface.

33. Modified stratum corneum> inward protrusion of epidermis
Hair
Modified stratum corneum> inward protrusion of epidermis
Produced by hair follicle
Hair papilla: structure associated with small blood vessels at the base of the follicle
Hair shaft: dead hardened cells that protrude the skin
Hair cortex: dead, densely packed, keratinized cells similar to stratum corneum
Consists of hard keratinized epithelial cells
Melanocytes provide pigment for hair color

34. Hair Hair follicle- shaft, follicle (root)
Growth- 4 in./year or 2 mm/week

35. Associated hair structures
Hair follicle
Arrector pili muscle
Sebaceous gland
Sweat gland

39. Scale-like modifications of the epidermis Made from keratin secretion
Nails
Scale-like modifications of the epidermis
Made from keratin secretion
Grows forward from nail root beneath the skin-nail fold. Keratocytes at the base move up.

40. Nails Consists of: Growth- 0.5 mm/week free edge Body Root Cuticle
Lunula
Growth- 0.5 mm/week

41. Nails

42. Nails
Did you know that your fingernails grow much faster than your toe nails?
3-4 times faster!

43. Please draw and label the figure 4. 7 (a) pg. 145 and Figure 4. 8 pg
Please draw and label the figure 4.7 (a) pg. 145 and Figure 4.8 pg. 146 on blank side(no lines) of index card

44. Skin Infections and Allergies
Contact dermatitis
Exposures cause allergic reaction
Cold sores
Caused by virus
Impetigo
Caused by bacterial infection
Psoriasis
Cause is unknown
Triggered by trauma, infection, stress

45. Skin Infections and Allergies

46. Burns
Burns
Tissue damage and cell death caused by heat, electricity, UV radiation, or chemicals

47. Burns
Associated dangers

48. Rule of Nines Way to determine the extent of burns
Body is divided into 11 areas for quick estimation
Each area represents about 9% of total body surface area

49. Critical Burns Burns are considered critical if
Over 25% of body has second-degree burns
Over 10% of the body has third-degree burns
There are third-degree burns of the face, hands, or feet

50. Rule of Nines

51. First-degree burns Third-degree burns Severity of Burns
Second-degree burns
Third-degree burns