1. Do Now
You heard about this new sanitizer that is supposed to not only kill off the germs, but also provides moisture. However, when you tried it out you experience an allergic reaction and develop a rash.
What system is the rash affecting? What is purpose of this system? What components make up this system and which component is the rash on?

2. Integumentary System
Chapter 6

3. Objectives To explain the function of the integumentary system
Identify the components of the epidermis
Identify and list the strata of the epidermis

4. Video!

5. Integumentary System:
Functions
Protect underlying tissues from:
infection
Exposure
dehydration
Maintain normal body temperature
Sensory detection
Restricts water loss from deep tissues
Excretes small amounts of waste
Creates various biochemicals
Integumentary System:
Functions

6. Components Cutaneous membrane Accessory Structures Subcutaneous Layer
Epidermis: superficial epithelium, contains stratified squamous ET
Dermis: inner layer, contains CT, glands, smooth muscle, and blood
Accessory Structures
Hair
Nails
Exocrine Glands
Subcutaneous Layer
Beneath the skin
Loose CT
Adipose

7. The Epidermis

8. Epidermis: Characteristics
Stratified squamous ET
Composed of layers of keratinocytes (produce keratin) to help reduce water loss
Avascular (no blood vessels)
Deepest layer is nourished by blood vessels from dermis.
Further away cells are from this layer, the less nutrient supply = cell death (Keratinization)

9. Layers of the Epidermis
Stratum corneum
Stratum lucidum
Stratum granulosum
Stratum spinosum
Stratum basale/germinativum
Superficial
Deep

10. Layers of the Epidermis Continued
Corneum
15-30 layers of dead keratinocytes
Exposed to the surface, shed every 2 weeks
Lucidum
Thick skin only
Appears clear
Granulosum
Grainy layer
Stops dividing and starts producing keratin (Cells begin to die)
Spinosum
Spiny layer
Cells flatten as pushed to surface
Basale/ Germinativum
Single layer
Basal cells (stem) constantly reproducing/dividing

12. Thick vs. Thin Skin Epidermis consists of layers (strata):
Thin Skin: 4 Layers
Usually Hairy( Has hair follicles)
No Stratum Lucidum
Thick Skin: 5 Layers
No Hair
Located in areas subject to pressure or friction
Ex: Palms of hands and soles of feet

14. Skin Color
Melanocytes: specialized cells found in stratum basale that produce melanin
Dark pigment that provides skin colo
Absorbs UV radiation
Depends on:
Blood supply: blood pigment (hemoglobin) is red
Cyanosis: low oxygen concentration, skin appears bluish
Physiological Factors:
Ex: diets high in yellow vegetables= orange/yellow skin (carotene)
Melanin production
UV exposure

15. Epidermal Cells Respond to epidermal growth factor (protein)
Division
Repair
Secretion
Synthesize vitamin D3 when exposed to UV
Too much exposure= damage (DNA mutation)
Can lead too:
Wrinkles (altered fibroblasts)
Cancers (altered epidermal cells and melanocytes)

16. Skin Cancer
Cutaneous Carcinomas: Skin cancer originating from epithelial cells
Squamous cell or basal cell carcinoma
Most common
Regular Exposure to sunlight
Slow growing, usually cured by surgery or radiation
Cutaneous Melanomas: Skin cancer originating from melanocytes
Pigmented with melanin
Caused by short, intermittent exposure to high intensity sunlight
May be cured with surgery if caught early

18. Videos! https://www.youtube.com/watch?v=_4jgUcxMezM

19. The Dermis

20. Dermis: Characteristics
Located between epidermis and subcutaneous layer
Dense CT
Vascular (blood vessels present)
“feeds” itself and epidermis above
Anchors accessory structures
Hair follicles, sweat glands, blood vessels, nerves, sensory receptors
Two layers:
Papillary Layer (Superficial Layer)
Reticular Layer (Deep Layer)

21. Dermis: Layers Papillary Layer Reticular Layer Thin Areolar CT
Dermal Papillae help form fingerprints
Feeds Epidermis (Contains blood vessels, lymphatics, and sensory nerves)
Reticular Layer
Thick
Dense Irregular CT
Provides Strength and Flexibility

22. Dermal Components

23. Stretch Marks Excessive stretching of the dermis
Collagen and Elastin Fibers form lines of cleavage

24. Subcutaneous Layer (Hypodermis)
Areolar CT and Adipose (not part of skin)
Stabilizes skin’s position against underlying organs and tissues
Shock absorber and insulator
Few capillaries and no vital organs
Vascular for quick absorption
Safe for subcutaneous injections
Useful for administering drugs

25. Cellulite Persistent/herniation of subcutaneous fat
Causes dimpling of the skin (orange peel syndrome)
May affect up to 90% of women at some point
Causes:
Hormones
Genes
Diet
Lifestyle Factors
Clothing

26. Accessory Structures
Hair
Sebaceous (oil) glands
Sweat Glands
Nails

27. Hair Human body has roughly 2.5 million hairs (75% on body)
Everywhere except palms, soles, and lips
Composed of keratinized dead cells produced in hair follicle
Project deep into dermis, and often into the hypodermis

28. Hair Structure Hair papilla CT that contains capillaries and nerves
Root
Anchors hair into skin
Shaft
Pokes through epidermis (what you see)
Has three layers:
Cuticle- outermost layer, shiny surface
Cortex- middle layer, contains pigments
Contains a lot of sulfur=bad smell when hair burns
Medulla- core of hair

29. Hair Follicle

30. Locations and Functions of Hair
Head
Protection from UV light
Cushion a light blow to head
Insulation
Nostrils, ears, and eyes
Prevent entry of particles
Sensory
Sensory nerve fiber at the base of every hair

31. Hair Color Produced by melanocytes at the hair papilla
Range from yellow (little melanin) to black (mostly melanin)
Red hair is a red type of melanin called pheomelanin
When you age, melanin production declines
Gray or white hair = no melanin

32. White streak
“Poliosis”: the melanocytes, structures that make melanin and color the hair, shut down and the hair grows without pigment

33. Going Bald?
Causes of hair loss: Not precisely known but is a mixture of the following:
Genetics
Presence of DHT (dihydrotestosterone)
Medical conditions
Certain medications

34. Other Structures Sebaceous glands Arrector Pili Muscle
Secrete Sebum (oil) into hair follicle
Helps keep hair and skin soft, pliable, and waterproof
Inhibit bacterial growth
Acne: inflammation of glands
Arrector Pili Muscle
Smooth muscle cells attached to hair follicle
Muscle contracts → hair stands on end
Very cold or emotional states: goose bumps!