Anatomy and Physiology, Chapter 6 Integumentary System PDF

Anatomy and Physiology, 1e Chapter 6: The Integumentary System Elizabeth Co, Anatomy and Physiology, 1st Ed...

Anatomy and Physiology, 1e Chapter 6: The Integumentary System Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 1  Layers of the Skin Section 6.1 Learning Objectives 6.1.1 – 6.1.13 Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 2  Components of the Integumentary System The integumentary system is composed of: 1. The skin 2. Hair 3. Nails 4. Associated exocrine glands Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 3  Integumentary System Functions The integumentary system is responsible for protection of internal organs It also aids in: Sensory function (to detect the diff sensations of heat, cold, pressure, contact and pain). Thermoregulation (maintenance of body temp within a range when temp surrounding is extremely different). Vitamin D synthesis (the sun’s UVB rays hit cholesterol in the skin cells, providing the energy for vit D synthesis to occur). Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 4  Skin Layers (Figure 6.1) The layers of the skin are the: 1. Epidermis 2. Dermis 3. Hypodermis (Subcutaneous layer) Fascia connects skin to underlying muscle. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 5  Think, Pair, Share Activity 1 List in order the layers of the skin that are cut by a surgeon’s scalpel during an abdominal surgery. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 6  Think, Pair, Share Activity 1 Answer List in order the layers of the skin and underlying tissue that are cut by a surgeon’s scalpel during an abdominal surgery. The layers would be: Epidermis Dermis Hypodermis Fascia Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 7  Epidermis Most superficial layer of the skin Made of keratinized stratified squamous epithelium Avascular (having no or few blood vessels) Contains four to five layers depending on location Thick skin (five layers)—found on palms of hands and soles of feet Thin skin (four layers)—found in all other location Cells are produced in the deepest layer and migrate from deepest layer to the superficial layer. Mature cells are called keratinocytes. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 8  Keratin (Figure 6.3) Produced by keratinocytes Keratin is an intracellular fibrous protein made of long alpha helices Gives hair, nails, and skin hardness and water-resistance Makes up the main component of hair shafts Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 9  Layers of the Epidermis (2 of 2) (Figure 6.2) From superficial to deep: 1. Stratum corneum 2. Stratum granulosum 3. Stratum spinosum 4. Stratum basale Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 10  Knowledge Check Activity 1 Which of the following layers is not found in thin skin? A. Stratum corneum B. Stratum lucidum C. Stratum basale D. Stratum granulosum E. Stratum spinosum Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 11  Knowledge Check Activity 1 Answer Which of the following layers is not found in thin skin? B. Stratum lucidum Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 12  Stratum Basale Deepest of the epidermal layers Single layer of cells Actively divide to replace cells in superficial layers Additional cells found in stratum basale: Merkel cells—sensory receptors used for discriminatory touch Melanocytes—produce melanin to protect cells from UV radiation Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 13  Melanocytes Produce melanin that protects cells from UV radiation Two forms of melanin: Eumelanin – black and brown pigment Pheomelanin – reddish pigment All humans have similar concentration of melanocytes Activity of melanocytes leads to different skin tones Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 14  Stratum Spinosum Eight to ten cell layers thick Keratinocytes are shaped like footballs Pointed ends that look like spines give rise to the name “spinosum” Langerhans (dendritic) cells provide immune protection Cells are continually pushed toward the stratum granulosum Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 15  Stratum Granulosum Named for its granular appearance Cells begin to flatten and accumulate more keratin Melanin can travel to cells within this layer Contained in melanosomes (synthesize and store melanin pigments) Cells begin to die at the most superficial layers of the stratum granulosum Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 16  Melanosomes (Figure 6.5) Melanin produced by melanocytes in stratum basale Long extensions transfer melanin to cells in stratum granulosum Melanin stored in granules called melanosomes Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 17  Stratum Lucidum Only found in thick skin Located in palms and soles of feet Composed of tightly packed, dead keratinocytes Cells contain eleidin Protein that functions as a water barrier Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 18  Stratum Corneum Most superficial layer of the epidermis About 15 to 30 layers of dead keratinocytes Cells are shed and lost due to mechanical forces Cells are replaced by cells in deeper layers migrating into the stratum corneum Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 19  Thin Versus Thick Skin (Figure 6.4) Thin skin covers most of the body Has four layers of epidermis Thick skin is found on the soles of the feet and palms of the hands Has five layers of epidermis Contains additional stratum lucidum not found in thin skin Thick skin also has higher number of sensory receptors Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 20  Dermal Papillae (Figure 6.6) Fingerlike projections of the dermis into the epidermis Helps to anchor the epidermis to the dermis Prevents the two layers from separating Noticeable as fingerprints Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 21  Dermis Lies deep to the epidermis Forms projections that extend into the epidermis Composed mainly of connective tissue Also contains: 1. Blood vessels 2. Hair follicles 3. Glands Supports the epidermis with nutrients, strength, and elasticity Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 22  Layers of the Dermis (Figure 6.7) Collagen fibers provide strength and structure Elastic fibers provide elasticity The dermis has two layers: Papillary layer More superficial layer Reticular layer Deeper layer Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 23  Papillary Layer Superficial layer of the dermis Composed of loose areolar connective tissue Contains dermal papillae that project up into the stratum basale of the epidermis Dermal papillae contain: Blood vessels Nerve fibers Tactile (Meissner’s) corpuscles Used to detect light pressure Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 24  Reticular Layer Deeper layer of the dermis Much thicker than papillary layer Made of dense irregular connective tissue Contains hair follicles, blood vessels, and nerves Pacinian corpuscles—cells that sense deep pressure Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 25  Hypodermis Also known as the subcutaneous layer Lies deep to the dermis Composed of adipose and loose areolar connective tissue Provides insulation and cushioning Highly vascularized Contains brown fat in infants Aids in thermoregulation in infants Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 26  Think, Pair, Share Activity 2 If a patient suffers a cut that bleeds, what layer or layers of the skin have been cut? Justify your answer using your knowledge of the anatomy of the skin. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 27  Think, Pair, Share Activity 2 Answer If a patient suffers a cut that bleeds, what layer or layers of the skin have been cut? Justify you’re answer using your knowledge of the anatomy of the skin. The dermis have definitely been cut. The hypodermis may have been cut as well. This is because the blood vessels associated with the skin are located in the dermis. If the cut were limited to the epidermis only, there would be no bleeding. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 28 Accessory Structures of the Skin Section 6.2 Learning Objectives 6.2.1–6.2.5 Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 29  Structures Associated with Skin Accessory structures of the skin include: 1. Hair 2. Nails 3. Sweat glands 4. Sebaceous glands Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 30  Hair Found on most body surfaces Exceptions include palms of hands and soles of feet (thick skin) Composed of dead, keratinized cells from epidermis Structures associated with hair: Sebaceous (oil) glands—secrete sebum Arrector pili muscles—contract to make hair “stand up” Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 31  Functions of Hair Functions of hair include: Physical protection Sensory input Thermoregulation UV protection Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 32  Anatomy of Hair Components of hair from deep to superficial: Hair papilla—blood supply to hair follicle Hair bulb—deepest portion of follicle Hair root—between bulb and shaft Hair shaft—visible portion above skin Medulla—center of hair shaft Cortex—surrounds medulla Cuticle—surrounds cortex Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 33  Matching Activity 1 Match the component 1. Hair bulb A. Visible portion of hair of hair to its 2. Hair root B. Blood supply of hair description. 3. Hair follicle C. Center of hair shaft 4. Hair papilla D. Deepest portion of follicle 5. Hair matrix E. Between bulb and shalf 6. Hair shaft F. Responsible for the growth of hair Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 34  Matching Activity 1 Answer Match the component of hair to its description. 1. Hair bulb—D 2. Hair root—E 3. Hair follicle—F 4. Hair papilla—B 5. Hair matrix—C 6. Hair shaft—A Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 35  Hair Growth (Figure 6.8) Hair growth is not continuous. Follicles alternate between growth and rest cycles. New growth pushes old hair out of follicle. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 36  Nails (Figure 6.9) Composed of keratinized epidermal cells Nail bed – living component of nail Produces nail body Nail body – visible hard portion of nail Nail root – proximal side of nail body Nail cuticle (eponychium) – thin layer of skin at base of nail Lunula – crescent-shaped region of nail bed Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 37  Sweat Glands (1 of 2) Also known as sudoriferous glands Produce sweat (perspiration) to aid in temperature regulation Two types of sweat glands: 1. Eccrine sweat glands 2. Apocrine sweat glands Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 38  Comparison of Sweat Glands Eccrine sweat glands Found all over body Less viscous sweat Involved in thermoregulation Apocrine sweat glands Found in groin and axilla (armpit) More viscous secretion May be involved in pheromone release Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 39  Sweat Glands (2 of 2) Apocrine sweat glands secrete a viscous sweat within hair follicles Associated with pubic hair Not active till puberty Eccrine sweat glands secrete a less viscous sweat onto surface of skin Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 40  Knowledge Check Activity 2 Which of the following locations has eccrine sweat glands? A. Skin on the forearm B. Skin on the back of the leg C. Skin on the neck D. A and B are correct E. All of the above are correct Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 41  Knowledge Check Activity 2 Answer Which of the following locations has eccrine sweat glands? E. All of the above are correct Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 42  Sebaceous Glands (Figure 6.10) Usually associated with hair follicles Secrete an oily mixture called sebum Lubricate and waterproof skin Secretion stimulated by hormones released during puberty Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 43  Acne (Figure 6.11) Accumulation of sebum, keratin and dead cells can block hair follicle Bacteria feed on sebum and sweat to grow This leads to inflammation of the skin called acne Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 44  Think, Pair, Share Activity 3 Bacteria can use nutrients in sebum to grow rapidly. Explain how overly active sebaceous glands can contribute to acne. Why would decreasing sebaceous gland activity decrease acne? Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 45  Think, Pair, Share Activity 3 Answer Bacteria can use nutrients in sebum to grow rapidly. Explain how overly active sebaceous glands can contribute to acne. Why would decreasing sebaceous gland activity decrease acne? Overly active sebaceous glands would increase the available nutrients for bacteria. Additionally, the increased sebum may block the exit of sebum from sebaceous glands. By decreasing the secretion of sebum, the nutrients available to the bacteria would decrease and that should slow their growth. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 46  Functions of the Integumentary System Section 6.3 Learning Objectives 6.3.1–6.3.2 Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 47  Protection Keratin, sebum, and glycolipids protect against water loss Dermcidin in sweat and macrophages (immune cells) protect against microbes Melanin protects against UV radiation Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 48  Sensory function The skin contains different types of sensory receptors found in various layers Meissner’s corpuscles and Pacinian corpuscles—tactile sensations Touch, pressure, vibration, tickle Thermoreceptors—warm, cool Nociceptors—pain Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 49 Sensory Receptors of the Skin (Figure 6.12) Thermoreceptors detect heat or cold Nociceptors detect pain Tactile corpuscles detect touch Lamellated corpuscles detect pressure and vibration Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 50  Think, Pair, Share Activity 4 List reasons that the location of different sensory receptors in the skin may influence their function. Would you expect the same receptors that allow you to feel the surface features of a dime to detect deep pressure or vibrations? Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 51  Think, Pair, Share Activity 4 Answer List reasons that the location of different sensory receptors in the skin may influence their function. Would you expect the same receptors that allow you to feel the surface features of a dime to detect deep pressure or vibrations? The locations of the sensory receptors may influence their function due to the intensity of the stimulus needed to activate them. No, the receptors that allow you to feel the surface features of a dime would not be the same as those used to detect deep pressure. This is because the surface features of a dime do not require the same intensity of sensation as deep pressure. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 52  Thermoregulation (Figure 6.13) Sweat helps keep the body cool Increased blood flow to the skin cools body Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 53  Think, Pair, Share Activity 5 Describe the changes in the integumentary system that help keep the body warm on a cold day. Contrast those changes with the changes that help cool the body on a hot day. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 54  Think, Pair, Share Activity 5 Answer Describe the changes in the integumentary system that help keep the body warm on a cold day. Contrast those changes with the changes that help cool the body on a hot day. The integumentary system adjusts blood flow to help regulate body temperature. On a cold day, blood flow is diverted away from the skin and toward the internal organs to maintain a warmer temperature for those critical organs. Sweat glands remain inactive. On a hot day, blood flow through the skin is increased to allow for heat to dissipate from the body. Sweat glands are activated to dissipate heat through the skin. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 55  Vitamin D Synthesis Ultraviolet (UV) rays activate the precursor molecule to initiate vitamin D synthesis Vitamin D aids in the absorption of calcium from foods in the gastrointestinal tract Necessary for bone growth and immune function Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 56  Application: Rickets (Figure 6.14) Misshaped bones due to calcium deficiency in children Bones are weak due to lack of calcium May develop into osteomalacia in adults Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 57  Discussion Activity 1 Discuss why a person who isn’t exposed to sunlight for a long period of time would have weak bone structure. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 58  Discussion Activity 1 Answer Discuss why a person who isn’t exposed to sunlight for a long period of time would have weak bone structure. Vitamin D is required for the absorption of calcium from the intestine. Without exposure to UV radiation from the sun, the body would produce less active vitamin D. This would lead to decreased calcium absorption from the intestine. Loss of calcium would eventually affect bones by decreasing their density. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 59 Healing the Integument Section 6.4 Learning Objectives 6.4.1–6.4.2 Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 60  Injuries Skin is highly vulnerable to injury Examples include abrasions, cuts, burns Skin is highly regenerative Wound healing may lead to scars Loss of accessory structures (hair, glands) Repaired tissue may have a different texture or consistency Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 61  Burns Occur when damage is caused by heat, radiation, electricity, or chemicals Skin cells die and can be replaced Different categories of burns: First-degree burns—only affect epidermis Second-degree burns—affect epidermis and dermis Third-degree burns—affect epidermis, dermis, and hypodermis Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 62  The Severity of Burns (Figure 6.17) First-degree burns—only affect epidermis Second-degree burns— affect epidermis and dermis Third-degree burns—affect epidermis, dermis, and hypodermis Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 63  Estimating the Size of a Burn (Figure 6.16) Size of burn is important in determining treatment “Rule of nines” is used for estimation Head and neck – 9% Upper limbs – 9% each Trunk – 36% Genitalia – 1% Lower limbs – 18% each Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 64  Breakout Group Activity 1 In a small group, briefly sketch the structure of the epidermis and dermis. Be sure to include the location of sensory receptors. Next, sketch the layers after damage is done by a third-degree burn. Which layers are affected? Why would a patient experience very little pain at the site of a third- degree burn? Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 65  Breakout Group Activity 1 Answer In a small group, briefly sketch the structure of the epidermis and dermis. Be sure to include the location of sensory receptors. Next, sketch the layers after damage is done by a third-degree burn. Which layers are affected? The epidermis, dermis, and hypodermis would be affected. Why would a patient experience very little pain at the site of a third- degree burn? The loss/destruction of nerve endings in the dermis would lead to a loss of the sensation of pain. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 66  Wound Healing (Figure 6.15) Multi-step process: 1. Blood clotting 2. Fibroblasts produce new collagen (granulation tissue) 3. Regeneration of epidermis Scar may form after healing Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 67  Application: Skin Cancer Associated with overexposure to UV radiation UV radiation causes mutations in DNA, leading to increased cancer risk Skin cancers vary depending on cell where the cancer originated Three forms of skin cancer: Basal cell carcinoma – cause by cells of stratum basale Squamous cell carcinoma – caused by keratinocytes of stratum spinosum Melanoma – caused by melanocytes Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 68  Discussion Activity 2 Discuss why severe cuts would require sutures (i.e., stitches). Would the direction and type of suture influence the formation of a scar at the area? Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 69  Discussion Activity 2 Answer Discuss why severe cuts would require sutures (i.e., stitches). Would the direction and type of suture influence the formation of a scar at the area? Severe cuts would require stitches due to the tissue separating too far for the healthy margins to approximate or come close to each other. While the quality of the sutures may influence healing, the direction usually does not have as much influence. More influential would be the orientation of the cut. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 70  Summary At the end of this chapter, you should be able to: List the components of the integumentary system. Discuss the functions of the integumentary system. Discuss the layers of the skin. List the layers of the epidermis. List the layers of the dermis. Discuss the steps in wound healing. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 71