1. The Integumentary System: The Protective Covering8
The Integumentary System: The Protective Covering

2. Multimedia Asset Directory
Slide 26 Wound Repair Animation
Slide 38 Degrees of Burn Animation
Slide 39 Chemical Burns Animation
Slide 69 Pressure Sores Animation
Slide 70 Eczema Video
Slide 71 Skin Cancer Video
Slide 72 Decubitus Ulcers Video
Slide 73 Emergency Medical Technicians Video
Slide 74 Nursing Video

3. Introduction
The integumentary system protects the body from environmental damage.
The skin forms a protective barrier shielding the body from the elements and pathogens, as well as performing several other vital functions.
Skin is essential to well-being, helps to regulate body temperature, and contains many accessory organs such as nails, hair, and glands.

4. Learning Objectives Discuss the functions of the integumentary system.
List and describe the layers of the skin.
Explain the healing process of skin.
Describe the structure and growth of hair and nails.
Explain how the body regulates temperature through the integumentary system.

5. Pronunciation Guide apocrine (APP oh krine) carotene (CARE oh teen)
Click on the megaphone icon before each item to hear the pronunciation.
apocrine (APP oh krine)
carotene (CARE oh teen)
corium (CORE ee um)
eccrine (EKK rin)
epidermis (ep ih DER miss)
epithelial cells (ep ih THEE lee al)
keratin (KAIR eh tin)
keratinization (KAIR eh tin eye ZAY shun)
lesion (LEE zhun)

6. Pronunciation Guide lunula (LOO nyoo lah) melanin (MELL an in)
Click on the megaphone icon before each item to hear the pronunciation.
lunula (LOO nyoo lah)
melanin (MELL an in)
melanocytes (MELL an oh sights)
pustule (PUS tyool)
sebaceous gland (see BAY shus)
sebum (SEE bum)
squamous cells (SKWAY mus)
stratum corneum (STRAY tum core NEE um)
subcutaneous fascia (sub cue TAY nee us FASH ee uh)

7. System Overview
The integumentary system is comprised of the skin and its accessory components including hair, nails, and associated glands.

8. System Overview
The integumentary system performs several vital functions.
Protection from pathogens
Balances fluid levels
Stores fatty tissue for energy supply
Produces vitamin D (with help from the sun)
Provides sensory input
Helps to regulate body temperature

9. The Skin
The skin is the largest organ, weighing approximately 20 pounds and covering an area about square feet on an adult.
A cross section of skin reveals three layers.
Epidermis
Dermis
Subcutaneous fascia

10. Figure 8-1 The three layers of the skin.

11. Epidermis
The epidermis is the layer of skin that we see on the outside. It is made up of five even smaller layers of tissue.
There are no blood vessels in this layer.
The cells on the surface of the epidermis are constantly shedding, being replaced with new cells that grow and arise from the deeper region called the stratum basale every 2–4 weeks.

12. Epidermis
The outermost layer is a layer of dead cells, called the stratum corneum, which are flat, scaly, keratinized epithelial cells.
You slough off 500 million cells every day, or about 1½ pounds of dead skin a year, allowing for rapid repair in case of injuries.

13. Skin Color
Specialized cells called melanocytes are located deep in the epidermis and are responsible for skin color.
Melanocytes produce melanin, a substance that causes skin color.
Variation in skin color is the result of the amount of melanin produced and how it is distributed, not the number of melanocytes.
Carotene, another form of pigment, gives a yellowish hue to skin while a pinkish hue is derived from the hemoglobin in the blood.

14. Effects of Disease on Skin Color
Color of skin can indicate disease.
When liver disease occurs, the body can’t break down bilirubin. The buildup of bilirubin gives the skin a deeper, yellow color.
A malfunctioning adrenal gland can cause the skin to turn bronze due to excessive melanin.

15. Effects of Disease on Skin Color
Excessive bruising could indicate skin, blood, or circulatory problems.
Cyanosis, or a blue coloring, results from a drop in oxygenation.

16. From the Streets: Skin Color
Normal skin color in light-skinned people is pink.
In dark-skinned people, inspect the mucous membranes (such as lips) to detect skin color changes.
Paleness indicates decreased blood flow through skin and can result from anemia, hypothermia or hypovolemia.

17. Dermis
The layer below, or inferior, to the epidermis is the thicker dermis layer.
This layer contains the following:
Capillaries
Collagenous/elastic fibers
Involuntary muscles
Nerve endings
Lymph vessels
Hair follicles
Sudoriferous glands (sweat)
Sebaceous glands (oil)

18. Dermis
Small “fingers” of tissue project from the surface of the dermis and anchor this layer to the epidermal layer.
Nerve fibers allow you to sense what is happening in your environment.
Vasodilation of capillaries in this layer causes blushing.

19. Dermis
Collagen and elastic fibers allow for the elasticity of skin, preventing the tearing of skin with movement. They allow skin to return to normal shape during periods of rest. Older people lose some of this elasticity, leading to wrinkles.

20. Sudiferous Glands Two main types of sudiferous, or sweat, glands
Apocrine sweat glands secrete at the hair follicles in the groin and anal region as well as the armpits and become active around puberty and are believed to act as sexual attractants.
Eccrine glands are found in greater numbers on your palms, feet, forehead, and upper lip and are important in the regulation of temperature.

21. Sudiferous Glands The body has three million sweat glands.
Sweat has no odor, but bacteria degrades the substances in the sweat over time into chemicals that give off strong smells commonly known as body odors.

22. Sebaceous Glands
Sebaceous glands play an important role by secreting oil, or sebum.
Sebum keeps the skin from drying out and (due to its acidic nature) helps destroy some pathogens on the skin’s surface.

23. Figure 8-2 Sweat and sebaceous glands.

24. Subcutaneous Fascia
The innermost layer of the skin is the subcutaneous fascia, or hypodermis.
The subcutaneous fascia is composed of elastic and fibrous connective tissue and fatty tissue.
Lipocytes, or fat cells, produce the fat needed to provide padding to protect the deeper tissues of the body and act as insulation for temperature regulation.
Fascia attaches to the muscles of the body.

25. How Skin Heals
If skin is punctured and the wound damages blood vessels, the wound fills with blood. Blood contains substances that cause clotting. The top part of the clot exposed to air hardens to form a scab, nature’s bandage, forming a barrier and preventing pathogens from entering.
In minor wounds, the dermis will eventually regenerate. In severe wounds, the dermis will be replaced by a scar.

26. Click here to view an animation on the topic of Wound Repair.
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27. Burns to the Skin
Burns can be caused by heat, chemicals, electricity, or radiation.
Two factors affect assessments of damage:
Depth
Amount of area damaged

28. First Degree Burns
The depth of a burn relates to the layer or layers of skin affected by the burn.
First degree burns damage only the outer layer, or epidermis.
Symptoms include redness and pain, but no blister.
Pain subsides in 2-3 days and there is no scarring.
Complete healing takes about one week.

29. Second Degree Burns
Second degree burns involve the entire depth of the epidermis and a portion of the dermis.
Symptoms include redness, pain, and blistering.
The extent of blistering is dependent on the depth of the burn.

30. Second Degree Burns Blistering extends after the initial burn.
Blisters heal within days if there are no complications, with deeper second degree burns taking 1-3½ months.
Scarring in second degree burns is common.

31. Third Degree Burns
Third degree burns affect all three layers of the skin.
The surface of the burn has a leathery feel and will range in color from black, brown, tan, red, or white.
The victim feels no pain because the pain receptors are destroyed.
Also destroyed are sweat and sebaceous glands, hair follicles, and blood vessels.

32. Fourth Degree Burns Fourth degree burns are the worst burns.
These burns penetrate the bone and cause bone damage.

33. Amount of Area Damaged
The rule of nines is used to estimate the extent of area damaged by burns.
The body is divided into the following regions, each given a percentage of body surface area value:
Head and neck – 9%
Each upper limb – 9% (2 × 9 = 18%)
Front of trunk – 18%
Back of trunk and buttocks – 18%

34. Amount of Area Damaged
The body is divided into the following regions, each given a percentage of body surface area value:
Front of legs – 18%
Back of legs – 18%
Perineum (including anus and urogenital region) – 1%

35. Figure 8-3 Assessing the degree of the burn.

36. Figure 8-3 (continued) Assessing the degree of the burn.

37. Figure 8-3 (continued) Assessing the degree of the burn
Figure 8-3 (continued) Assessing the degree of the burn. Bottom photos showing first degree burn (sun burn) and third degree burn.

38. Click here to view an animation on the topic of Degrees of Burn.
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39. Click here to view an animation on the topic of Chemical Burns.
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40. Burns – Clinical Concerns
The clinical concerns for burn victims relate to the functions of the skin already discussed, including:
Bacterial infections
Fluid loss
Heat loss

41. Burn Treatment
Severe burns require healing steps at an intensity level the body can’t manage on its own.
Damaged skin must be removed as soon as possible and skin grafting must be started.
Autografting is using the patient’s own skin, while heterografting (from a donor) is required if the patient suffered a large area of burn and has little healthy skin to graft.

42. Burn Treatment
Grafting requires many trips to the OR because large areas can’t be done all at once and often the grafts don’t “take.”
It is possible to grow sheets of skin tissue in the laboratory from patient cells or utilization of synthetic materials.

43. Nails
Specialized epithelial cells originating from the nail root form your nails.
As these cells grow out and over the nail bed, they become keratinized forming a substance similar to the horns on a bull.
The cuticle is a fold of tissue that covers the nail root.

44. Nails The portion that we see is called the nail body.
Nails normally grow 1 mm every week.
The pink color of the nail comes from the vascularization of the tissue under the nails, while the white half-moon shaped area, or lunula is a result of the thicker layer of cells at the base.

45. Figure 8-5 Clinician performing capillary refill assessment.

46. Figure 8-4 Structures of the fingernail.

47. Hair Body hair is normal and serves important purposes.
Hair helps to regulate body temperature and functions as a sensor to help detect things on your skin such as bugs or cobwebs.
Eyelashes help to protect our eyes from foreign objects while hair in the nose helps filter out particulate matter.

48. Hair Anatomy
Visible hair is composed of fibrous protein called keratin.
The hair you see is called the shaft with the root extending down into the dermis to the follicle.
The follicle is formed by epithelial cells with a rich source of blood provided by the dermal blood vessels.
Cells divide and grow in the base of the follicle, older cells are pushed away and die, so the shaft of the hair is comprised of dead cells.

49. Hair Anatomy
Shaving or cutting hair doesn’t make it grow quicker or thicker.
There is a sebaceous gland associated with each hair follicle, secreting sebum that coats the hair follicle and works its way to the skin’s surface to prevent drying of the hair, acting as an antibacterial, and lubricating the hair shaft.
Sebum production decreases with age, explaining why older people have drier skin and more brittle hair.

50. Hair Color and Texture
Your hair color is dependent on the amount and type of melanin you produce.
The more melanin, the darker your hair.
White hair occurs in the absence of melanin.
Red hair is the result of hair that has melanin with iron in it.

51. Hair Color and Texture
Flat hair shafts produce curly hair, while round hair shafts produce straight hair.
The life span of hair is dependent on location, with eyelashes lasting 3-4 months while the hair on your head lasts 3-4 years.

52. Temperature Regulation
The integumentary system plays a major role in the regulation of the body’s temperature.
Part of the regulation of temperature is accomplished by changes in the size of the blood vessels. Vasodilation exposes heated blood to external cooling air. Vasoconstriction keeps cooling of blood to a minimum when it’s cold outside.

53. Temperature Regulation
Sweat glands excrete water onto the skin’s surface, allowing cooling through evaporation. This requires adequate hydration to continue to produce sweat. By the time you feel thirsty you’re already dehydrated. You can potentially secrete 12 liters of sweat in a 24 hour period.

54. Shivering
Shivering causes muscle activity that produces heat to warm you when you’re cold.
Hairs on your skin stand erect when arrector pili muscles contract; this is known as goose bumps. These hairs create a dead space insulating you from cooler surroundings, like a goose down jacket.

55. Figure 8-6 Diagram of a hair follicle.

56. Diseases of the Skin
There are whole sections of medical libraries dedicated to diseases of the skin.
A lesion is a single affected patch of skin.
There are many common pathological conditions of the integumentary system.

57. Figure 8-7 Integumentary regulation of body temperature.

58. Figure 8-8 Various types of skin lesions.

59. Figure 8-8 (continued) Various types of skin lesions.

60. Table 8-1 Common Pathological Conditions of the Integumentary System.

61. Table 8-1 (continued) Common Pathological Conditions of the Integumentary System.

62. Table 8-1 (continued) Common Pathological Conditions of the Integumentary System.

63. Figure 8-9 Various types of integumentary conditions
Figure Various types of integumentary conditions. (a) Urticaria (hives). (Courtesy of Jason L. Smith, MD.)

64. Figure 8-9 (continued) Various types of integumentary conditions
Figure 8-9 (continued) Various types of integumentary conditions. (B) Erythema infectiosum (fifth disease). (Courtesy of Jason L. Smith, MD.)

65. Figure 8-9 (continued) Various types of integumentary conditions
Figure 8-9 (continued) Various types of integumentary conditions. (C) Acne. (Courtesy of Jason L. Smith, MD.)

66. Figure 8-9 (continued) Various types of integumentary conditions
Figure 8-9 (continued) Various types of integumentary conditions. (D) Poison ivy (dermatitis). (Courtesy of Jason L. Smith, MD.)

67. Figure 8-9 (continued) Various types of integumentary conditions
Figure 8-9 (continued) Various types of integumentary conditions. (E) Herpes simplex. (Courtesy of Jason L. Smith, MD.)

68. Figure 8-9 (continued) Various types of integumentary conditions
Figure 8-9 (continued) Various types of integumentary conditions. (F) Burn, second degree. (Courtesy of Jason L. Smith, MD.)

69. Click here to view an animation on the topic of Pressure Sores.
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70. Click here to view a video on the topic of Eczema.
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71. Click here to view a video on the topic of Skin Cancer.
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72. Click here to view a video on the topic of Decubitis Ulcers.
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73. Click here to view a video on the topic of Emergency Medical Technicians.
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74. Click here to view a video on the topic of Nursing.
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75. Snapshots from the Journey
Your skin is your largest organ; it acts as a barrier to infection and injury; helps to keep you from drying out; stores fat; synthesizes and produces vitamin D; regulates body temperature; provides a minor excretory function in the elimination of water, salts, and urea; and provides sensory input.

76. Snapshots from the Journey
The skin is composed of three layers: epidermis, dermis, and subcutaneous fascia. Glands secrete oil to moisturize, waterproof, and control body temperature.
The skin has several accessory structures including various glands, hair, and nails.

77. Snapshots from the Journey
Burns are assessed by depth of burn and area covered. The severity of burns to the skin is evaluated the depth of the burn and the area that the burn covers.
Nails are protective devices composed of dead material.
Hair (also dead material) aids in controlling body temperature.

78. Case Study
A 27-year-old female presents to her doctor’s office with complaints of red, itching, and oozing skin for the past two days.

79. Case Study
Physical exam and history reveal a well-nourished, white female who is otherwise in good health, has no known allergies, normal vital signs, pupils are normal and reactive, has good reflexes, normal breath sounds, liquid filled vesicles, and scabbing on both legs from the top of her sock lines to the bottom of her shorts, and new vesicles have formed around her eyes.

80. Case Study Questions
The patient states that she returned from a primitive camping and hiking vacation in Virginia two days ago.
Based on the case study information, what do you think the diagnosis is?
What caused the vesicles to begin to form around her eyes?

81. From the Streets
You are called to the scene of a 20-year-old male involved in a fire in his garage. He has sustained second-degree burns to his entire chest and abdomen and the anterior of both arms and legs.

82. From the Streets Questions
Calculate the percent body area burned.

83. From the Streets Questions
Calculate the percent body area burned.
Each upper limb (4.5 X 2)= 9%
Front of trunk= 18%
Front of legs= 18%
Total = 45%

84. End of Chapter Review Questions
The substance that is mainly responsible for skin color is:
Melanin
Pigmentin
Carrots
Luna

85. End of Chapter Review Questions
Whether you have naturally curly or straight hair is dependent on the shape of your:
Hair follicles
Hair shafts
Sebum
Melanin

86. End of Chapter Review Questions
The fibrous protein that makes up your hair and nails and fills your epidermal cells is called:
Carotene
Myelin
Keratin
Dermasene

87. End of Chapter Review Questions
In a cold environment, in order to maintain a core body temperature, peripheral blood vessels will:
Vasodilate
Venospasm
Shiver
Vasoconstrict

88. End of Chapter Review Questions
Excess blood loss may cause this sign in the integumentary system:
Decreased hair growth
Decreased capillary refill
Increased wound healing
Brittle nails

89. End of Chapter Review Questions
The three main layers of skin are the _______, ________, and ________.
This type of sweat gland is involved mainly in temperature regulation _____ and the ___ glands are involved mainly in nervous sweating.
Sebaceous glands secrete an oily substance called____.

90. End of Chapter Review Questions
For some individuals, melanin locates in small patches called _________.
Jaundice, a condition associated with liver disease, occurs as a result of the buildup of _________.

91. End of Chapter Review Questions
Discuss three functions of the integumentary system.
Explain the organization of the epidermis. What happens to epidermal cells as they rise to the surface of the skin?
Why is there an increased production of melanin when there is an increased sun exposure?

92. End of Chapter Review Questions
Explain the classifications of burn severity.
List and briefly describe the major accessory structures of skin.