1. Unit 2 ppt#1 Integumentary System
This body system connects to the other systems in many ways!! See handout pg 45.
This system consists of the skin and its accessory organs, hair, nails, and cutaneous glands.

2. Functions of the Integumentary System
1. Resistance to trauma and infection
(epidermal cells have lots of KERATIN (protein) strong!
2. Barrier to liquids
3. Vitamin D synthesis
4. Sensation
Thermoregulation
6. Social functions 

3. Layers of the skin
Epidermis: is the top five layers of skin, and contains five different types of cells
1A. Dead cells (keratinocytes) Cell Layer: Stratum Corneum (top layer)…very durable layer (35 layers ) and stratum Lucidum.
1B. Living Keratinocytes :most of the epidermal cells, they
produce keratin and use UV light to convert a steroid to pre-vitamin D
Stratum Granulosum
2. Dendritic cells (Langerhans cells): microphages that fight
toxins, microbes, and other pathogens that penetrate the
skin, (Immune alarm) Cell Layer: Stratum Spinosum (mid layer)

4. All this just in the Epidermis!!!
3. Tactile cells (Merkel cells) are receptors for touch associated with dermal nerve fiber
Cell Layer: Stratum Basale (bottom layer of Epidermis)
4. Stem Cells: undifferentiated cells, heavily mitotic to produce lots of keratinocytes (migrate to top) Cell Layer: Stratum Basale
5. Melanocytes : produce melanin that reacts to sun light to increase
sun burn protection Cell Layer : Stratum Basale
See table 6.1 on page 194
All this just in the Epidermis!!!

5. Cell Types and Layers of the of the Epidermis
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Sweat pore
Stratum corneum
Exfoliating
keratinocytes
Stratum lucidum
Stratum granulosum
Dead keratinocytes
Sweat duct
Living keratinocytes
Dendritic cell
Stratum spinosum
Tactile cell
Melanocyte
Stem cell
Stratum basale
Dermal papilla
Tactile nerve fiber
Dermis
Dermal blood vessels
Figure 6.3

7. Structure of the Skin Figure 6.1 Hairs Sweat pores Dermal papilla
Epidermis
Tactile corpuscle
(touch receptor)
Blood capillaries
Hair follicle
Dermis
Sebaceous gland
Hair receptor
Apocrine sweat gland
Hair bulb
Hypodermis
(subcutaneous fat)
Sensory
Merocrine sweat
nerve fibers
gland
Piloerector muscle
Cutaneous blood
vessels
Lamellar (pacinian)
corpuscle (pressure receptor)
Motor nerve fibers
Figure 6.1

9. 2nd layer of skin: Dermis
Dermis: lies below epidermis, has large amounts of fibrous connective tissue.
Composed mainly of collagen, elastic, and reticular fibers.
The connective tissue in this layer contains: blood vessels, sweat glands, hair follicles, nail roots, sebaceous glands, smooth muscles,(Piloerector), pressure receptors and nerve endings

10. Structure of the Dermis
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
(b) Papillary layer of dermis
(a)
(c) Reticular layer of dermis
Figure 6.5
a: © The McGraw-Hill Companies, Inc./Dennis Strete, photographer; b-c: Copyright by R.G. Kessel and R.H. Kardon, Tissues and Organs: A Text-Atlas of Scanning Electron Microscopy, 1979, W.H. Freeman, All rights reserved

11. 3rd Layer of the Skin: Hypodermis
The hypodermis is often called the superficial fascia
The fascia contains large amounts of adipose
( subcutaneous fat), connective tissue, blood vessels
Adipose tissue pads the body, is a thermal insulation and energy store and is the preferred injection site due to it vascular rate
Connective tissue binds the skin to the underlying tissues

12. Skin Color There are basically 2 colors:
Skin color is determined by amount of melanin produced by melanocytes.
The keratinocytes phagocytize the melanin pigments and the melanin granules accumulate on the “sunny side” of the nucleus. Basically making an umbrella to protect the DNA.
People have about = numbers of melanocytes.
Dif skin color is due to dif. Rate of melanin synthesis.
UV radiation stimulates the production of Melanin
There are basically 2 colors:
Eumelanin= Brown Black
Pheomelanin= Red/Yellow (sulfur containing)
Other factors are hemoglobin (red/pink hues) and
carotene (yellow/orange…in veggies)

13. Skin Color : can indicate disease or disorders
1. Cyanosis—blueness due to O2 deficiency
2. Erythem—abnormal redness, blush, sunburn
3. Pallor---- ash, pale, too little blood flow, dermal collagen shows through
4. Albanism—lack of melanin..genetic recessive
5. Jaundice– yellowing of skin due to high levels of billirubin, hemoglobin break down product
6. Bronzing—golden brown, Addison Disease, lack of glucocorticoid hormone.
7. Hematoma—bruising, purplish, clotted blood showing through.

14. Types of Skin Markings
Friction Ridges: markings on fingertips, form during fetal development (most primates)
Flexion Lines: Lines on digits, palms, wrists, elbows
Freckles: flat melanized patches of skin that vary with heredity and sun exposure
Moles: same as freckle but elevated
Hemangiomas: birth marks caused by begnin tumors of dermal blood capillaries

15. Accessories of the skin: Hair, Nails, and CutaneousGlands

16. Hair and Nails are composed of mostly dead keratinized cells.
Skin (stratum corneum has soft keritin)
Hair and Nails made of more compact, hard keritin, cross linked between keritin moelcules.

17. Cross section of a hair

18. Structure of Hair and Follicle
three layers of the hair in cross-section from inside out
medulla
core of loosely arranged cells and air spaces
cortex
constitutes the bulk of the hair
consists of several layers of elongated keratinized cells
cuticle
composed of multiple layers of very thin, scaly cells that overlap each other
free edges directed upward
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Connective
tissue
root sheath
Epithelial root
sheath
Hair medulla
Hair cortex
Hair matrix
Hair bulb
Dermal
papilla
(b)
0.5 mm
© CBS/Phototake
Figure 6.7b

19. Structures of hair

20. Basis of hair color and texture
See page 199
Hair grows from the hair matrix just above the hair bulb.
The hair bulb is near vascular connective tissue which provides hair with it’s nutrients.

21. Hair Texture and Color
texture – related to differences in cross-sectional shape
straight hair is round
wavy hair is oval
curly hair is relatively flat
color – due to pigment granules in the cells of the cortex
brown and black hair is rich in eumelanin
red hair has a slight amount of eumelanin but a high concentration of pheomelanin
blond hair has an intermediate amount of pheomelanin and very little eumelanin
gray and white hair results from scarcity or absence of melanin in the cortex and the presence of air in the medulla

22. © The McGraw-Hill Companies, Inc./Joe DeGrandis, photographer
Hair Color and Texture
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Eumelanin
Pheomelanin
Cuticle
Cortex
(c) Red, wavy
Air space
Eumelanin
Pheomelanin
Medulla
(b) Black, straight
(a) Blond, straight
(d) Gray, wavy
Figure 6.8
© The McGraw-Hill Companies, Inc./Joe DeGrandis, photographer

23. Nail structure What are the Accessory Structures: Nails? Nail body
Dense mass of keratinized cells
Nail bed
Nail root
Cuticle (eponychium)
Lunula

25. Fingernail Structure Figure 6.10 Free edge Nail body Nail groove
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display
Free edge
Nail body
Nail groove
Nail fold
Lunule
Eponychium
(cuticle)
Nail
root
Nail plate
Nail fold
Free
edge
Nail
body
Eponychium
(cuticle)
Nail bed
Nail matrix
Figure 6.10

26. Glands of the skin The skin has 5 types of Glands
1. Merocrine Sweat Glands
2. Apocrine Sweat Glands
3. Sebaceous Glands
4. Ceruminous glands
5. Mammary Glands

27. Sweat Glands Merocrine (eccrine) Apocrine Most numerous
Produces watery 99% perspiration for cooling
3-4X106 all over
Palms, soles, forehead
pH 4-6
Tubular gland with twisted coil
Narrow lumen, opens at pore on skin
Apocrine
Occur in groin, anal, axilla, beard area.
Produces thicker soln. with fatty acids
Are scent glands
Large lumen, opens to hair follicle

28. Sebaceous Glands Produce an oily secretion called SEBUM
Flask shaped, located higher up in dermis
Short ducts opening to hair follicles
Keeps skin and hair from becoming dry
(brushing hair spreads this)
Lanolin in moisturizers is sheep sebum

29. Ceruminous Glands Found only in external ear canal
Secretion combines with sebum &dead epithelial cells to make ear wax CERUMEN
Waterproofs the ear canal and is anti-bacterial

30. Mammary Glands Milk producing glands in female breasts
Are modified apocrine glands which produce richer secretions
For summary see chart 6.2 on page 203

31. Skin Disorders see chart 6.3
What are the Effects of UV Radiation?
Beneficial effect
Activates synthesis of vitamin D3
Harmful effects
Sun burn
Wrinkles, premature aging
Malignant melanoma
Basal cell carcinoma

32. Skin Cancer 1. Basal cell carcinoma:
Cancer: rapid mitotic division of cells caused by a environmental or genetic trigger
Skin cancer: is caused by exposure to UV rays. There are three types named for tissue affected
1. Basal cell carcinoma:
most common,
easiest to remove.
Appears as a red shiny bump that enlarges with depressed center

33. © NMSB/Custom Medical Stock Photo, Inc.
Basal Cell Carcinoma
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
(a) Basal cell carcinoma
© NMSB/Custom Medical Stock Photo, Inc.
- most common type
- least dangerous because it seldom metastasizes
- forms from cells in stratum basale
- lesion is small shiny bump with central depression and beaded edges

34. 2. Squamous Cell Carcinoma
found usually on scalp, ears, lip, back of hands.
Arise from keratinocytes from stratum spinosum
Has red scaly appearance with concave center.
High survival rate with early detection,
will metastasize to lymph nodes highly lethal

35. Squamous Cell Carcinoma
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(b) Squamous cell carcinoma
© Biophoto Associates/Photo Researchers, Inc.
- arise from keratinocytes from stratum spinosum
- lesions usually appear on scalp, ears, lower lip, or back of the hand
- have raised, reddened, scaly appearance later forming a concave ulcer
- chance of recovery good with early detection and surgical removal
- tends to metastasize to lymph nodes and may become lethal

36. 3. Malignant melanoma
most deadly
arises in melanocytes in moles.
Fast to metastasize, does not respond to chemotherapy
lethal without immediate treatment 6 months

37. © James Stevenson/SPL/Photo Researchers, Inc.
Malignant Melanoma
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
(c) Malignant melanoma
© James Stevenson/SPL/Photo Researchers, Inc.
skin cancer that arises from melanocytes
often in a preexisting mole
less than 5% of skin cancers, but most deadly form
treated surgically if caught early
metastasizes rapidly - unresponsive to chemotherapy - usually fatal
person with metastatic melanoma lives only 6 months from diagnosis
5% - 14% survive 5 years
greatest risk factor – familial history of malignant melanoma
high incidence in men, redheads, people who experience severe sunburn
in childhood

38. Recognizing Malignant Melanoma
A= Asymmetry
B= Border irregularity
C= Color (brown, black, tan, red, purple)
D= Diameter (6mm)

39. Burns and Healing
Burns: Leading cause in accidental death, death results from fluid loss and the toxic effect of eschar
First degree: found in only epidermis, epidermis turns red, edema and pain, heals in a few days

40. Second degree: or partial-thickness burns due to damage only in top of dermis layers, has blisters can scar and takes about 2 weeks to heal
Third degree: or total thickness burns, turns black, skin can only grow from sides of damaged area so grafts are needed, debridement must occur in 24 hours, then toxic. Need fluid replacement!

41. Degrees of Burn Injuries
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Partial-thickness burns
Full-thickness burns
(a) First degree
(b) Second degree
(c) Third degree
a: © SPL/Custom Medical Stock Photo, Inc.; b-c: © John Radcliffe/Photo Researchers, Inc.
Figure 6.13

42. Healing and Repair on injury to skin
What are the Four Stages in Skin Healing?
1. Inflammation
Blood flow increases
Phagocytes attracted
2. Scab formation
3. Cell division and migration
4. Scar formation

43. Bleeding occurs at the site of injury immediately after the injury, and mast cells in the region trigger an inflammatory response.

44. After several hours, a scab has formed and cells of the stratum germinativum are migrating along the edges of the wound. Phagocytic cells are removing debris, and more of these cells are arriving with the enhanced circulation in the area. Clotting around the edges of the affected area partially isolates the region.

45. After several weeks, the scab has been shed, and the epidermis is complete. A shallow depression marks the injury site, but fibroblasts in the dermis continue to create scar tissue that will gradually elevate the overlying epidermis
One week after the injury, the scab has been undermined by epidermal cells migrating over the meshwork produced by fibroblast activity. Phagocytic activity around the site has almost ended, and the fibrin clot is disintegrating.