Essentials of Human Anatomy & Physiology: Skin and Body Membranes PDF

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint® Lecture Slide Presentation by Patty Bostwick-Taylor, Florence-Darlington Technical College Skin and Body Membranes 4 Copyright © 2009 Pearson Education, Inc., publishing as Be...

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint® Lecture Slide Presentation by Patty Bostwick-Taylor, Florence-Darlington Technical College Skin and Body Membranes 4 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Learning Objectives Classification of Body Membranes  List the general functions of each membrane type-cutaneous, mucous, serous, and synovial-and give its location in the body.  Compare the structure (tissue makeup) of the major membrane types. Integumentary System (Skin)  List several important functions of the integumentary system and explain how these functions are accomplished.  When provided with a model or diagram of the skin, recognize and name the following skin structures: epidermis, dermis (papillary and reticular layers), hair and hair follicle, sebaceous gland, and sweat gland.  Name the layers of the epidermis and describe the characteristics of each.  Describe the distribution and function of the epidermal derivatives-sebaceous glands, sweat glands, and hair.  Name the factors that determine skin color and describe the function of melanin.  Differentiate between first-, second-, and third-degree burns.  Explain the importance of the "rule of nines."  Summarize the characteristics of basal cell carcinoma, squamous cell carcinoma, and malignant melanoma. Developmental Aspects of Skin and Body Membranes  List several examples of integumentary system aging. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Body Membranes  Function of body membranes  Cover body surfaces  Line body cavities  Form protective sheets around organs Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Classification of Body Membranes  Epithelial membranes  Cutaneous membranes  Mucous membranes  Serous membranes  Connective tissue membranes  Synovial membranes Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Cutaneous Membrane  Cutaneous membrane = skin  Dry membrane  Thick and waterproof  Outermost protective boundary  Consists of:  Superficial epidermis is composed of keratinized stratified squamous epithelium  Underlying dermis is mostly dense connective tissue Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Cutaneous Membranes Epidermis Dermis Hypodermis Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Mucous Membranes  Lines all body cavities that open to the exterior body surface  Often adapted for absorption or secretion  Moist: To reduce friction and facilitate transfer  Surface epithelium type depends on site  Stratified squamous epithelium (mouth, esophagus)  Simple columnar epithelium (rest of digestive tract)  Underlying loose connective tissue (lamina propria) Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Simple columnar epithelium Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Serous Membranes  Lines open body cavities that are closed to the exterior of the body  Surface is a layer of simple squamous epithelium  Covered by a thin layer of serous fluid that is secreted by the epithelium  Underlying layer is a thin layer of areolar connective tissue Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Serous Membranes  Serous membranes occur in pairs separated by serous fluid  Visceral layer covers the outside of the organ  Parietal layer lines a portion of the wall of ventral body cavity Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Serous Membranes Figure 4.1d Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Serous Membranes  Specific serous membranes have special names given according to their location  Peritoneum  Abdominal cavity  Pleura  Around the lungs  Pericardium  Around the heart Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Connective Tissue Membrane  Synovial membrane  line structures that do not open to the exterior  lack an epithelium and are therefore not epithelial membranes  Connective tissue only  Lines fibrous capsules surrounding joints  Secretes a lubricating fluid = Synovial fluid Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Connective Tissue Membrane Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Questions?  How do the body locations of serous and mucous membranes differ?  Answer:  Serous membranes line ventral body cavities closed to the exterior. Mucous membranes line body cavities open to the exterior (respiratory, digestive, urinary, and reproductive organ cavities). Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Questions?  A scalpel penetrates the left lung and enters the heart. Name the six serous membrane layers the blade passes through as it moves from the body surface into the heart.  Answer:  Parietal pleura, visceral pleura, (lung), visceral pleura, parietal pleura, parietal pericardium, visceral pericardium, (heart). Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Questions?  Where would you find a synovial membrane?  Answer:  Lining a fibrous capsule surrounding a joint. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Advertisement  Would you be enticed by an advertisement for a coat that is waterproof, stretchable, and washable, that invisibly repairs small cuts, rips, and burns, and that is guaranteed to last a lifetime with reasonable care?  Sounds too good to be true, but you already have such a coat—your cutaneous membrane, or skin. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Integumentary System – Cutaneous Membrane Largest organ of the body in both surface area (2 m2) and weight (4.5–5 kg)  Skin (cutaneous membrane)  Skin derivatives  Sweat glands  Oil glands  Hair  Nails  Blood vessels, nerve terminals, sensory organs (in-teg-u¯-MEN-tar-e¯; in- inward; -tegere to cover) Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Question?  if you cut the epidermis there is no bleeding, but if you cut the dermis there is bleeding. What can you deduce from this statement?  Answer:  While the epidermis is avascular, the dermis is vascular. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Clinical Connection:  What do we call the medical specialty for the diagnosis and treatment of disorders of the integumentary system?  Answer:  Dermatology Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Skin Functions Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Skin Functions Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Question?  Explain the relationships between the words skin, cutaneous membrane, integument, and integumentary system.  Answer:  The skin is the epithelial membrane that covers the body surface. Cutaneous membrane is a synonym for skin, as is integument, which means covering. The integumentary system is the skin and its derivatives (nails, hair, glands). Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Question?  What are three important functions of the integumentary system?  Answer:  Protection  Thermoregulation  Sensory Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Skin Structure  Epidermis—outer layer  Avascular stratified squamous epithelium  Often keratinized (hardened by keratin)  Dermis  Dense connective tissue Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Question?  For subcutaneous injections of insulin, which layer is targeted?  Answer:  Hypodermis is deeper than the dermis  Not part of the skin  Anchors skin to underlying organs  Composed mostly of adipose tissue  Contains lamellated (pacinian) corpuscles which detect external pressure applied to the skin. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Layers of the Epidermis  Summary of layers from deepest to most superficial  Stratum basale  Stratum spinosum  Stratum granulosum  Stratum lucidum (thick, hairless skin only)  Stratum corneum Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Layers of the Epidermis Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings   Old Process of Keratinization  (4-6 weeks)  Young  Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Cells in the epidermis 90% - Produce the protein keratin (protects 8% - Produce underlying tissues) the pigment and lamellar melanin granules (contain a waterproof sealant) Participate in Function in immune the sensation responses of touch (epidermal dendritic cells) Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Layers of the Epidermis  Stratum basale (stratum germinativum)  Deepest layer of epidermis  Lies next to dermis  Cells undergoing mitosis  Daughter cells are pushed upward to become the more superficial layers  Include melanocyte  produce pigment of melanin  Attached to basal lamina by hemidesmosomes  Forms a strong bond between epidermis and dermis Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Clinical Connection: Skin Graft  Would the skin be able to regenerate if an injury destroys a large area of the stratum basale and its stem cells?  Answer:  Skin wounds of this magnitude require skin grafts in order to heal. A skin graft is the transfer of a patch of healthy skin taken from a donor site to cover a wound. If skin damage is so extensive that an autograft would cause harm, a self-donation procedure called autologous skin transplantation may be used. In this procedure, small amounts of an individual’s epidermis are removed, and the keratinocytes are cultured in the laboratory to produce thin sheets of skin. The new skin is transplanted back to the patient so that it covers the burn wound and generates a permanent skin. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Layers of the Epidermis  Stratum spinosum  Consists of numerous keratinocytes arranged in 8–10 layers, some retain their ability to divide  Produce coarser bundles of keratin, which tightly join the cells to one another through desmosomes  Langerhans cells active in immune response  Projections of melanocytes Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Layers of the Epidermis  Stratum granulosum  3 to 5 layers of flattened keratinocytes that are undergoing apoptosis  Produces:  Darkly staining granules of a protein called keratohyalin, which assembles keratin intermediate filaments into keratin  lipid-rich secretion = waterrepellent sealant, retarding loss and entry of water and entry of foreign materials. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Layers of the Epidermis  Stratum lucidum  Formed from dead cells of the deeper strata  Occurs only in thick, hairless skin of the palms of hands and soles of feet  Consists of four to six layers of flattened clear, dead keratinocytes that contain large amounts of keratin and thickened plasma membranes Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Layers of the Epidermis  Stratum corneum  Outermost layer of epidermis  25 to 30 layers of flattened dead keratinocytes  Extremely thin flat, shingle-like dead cells are filled with keratin (familiar as dandruff and dander)  Protective protein prevents water loss  Shed and replaced every 2 weeks  Accounts for three-quarters of the epidermal thickness Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Clinical Connection:  Which disease is characterized by rapid regeneration and shedding of keratinocytes?  Answer:  Psoriasis is a common and chronic skin disorder in which keratinocytes divide and move more quickly than normal from the stratum basale to the stratum corneum. The immature keratinocytes make an abnormal keratin, which forms flaky, silvery scales at the skin surface, most often on the knees, elbows, and scalp. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Clinical Connection  Dermatoglyphics = study of the pattern of epidermal ridges. Can you guess for what purpose this science is used?  Answer:  Fingerprints Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION?  Which layers are made of:  Dead cells  Cells that are alive  Answer:  Dead cells – Corneum and lucidum  Alive cells – basale, spinosum, granulosum Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Question?  Arrange in order the different layers of the epidermis (from deep to superficial)? 1- Stratum spinosum 2- Stratum lucidum 3- Stratum granulosum 4- Stratum basale 5- Stratum corneum  Answer: 4, 1, 3, 2, 1 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Skin Structure: Dermis Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Dermis  Overall dermis structure  Collagen and elastic fibers located throughout the dermis  Collagen fibers give skin its toughness  Elastic fibers give skin elasticity  Blood vessels play a role in body temperature regulation  On the palms of the hands and soles of the feet, the papillae are arranged in definite patterns that form looped and whorled ridges on the epidermal surface that increase friction and enhance the gripping ability of the fingers and feet Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Dermis  Two layers  Papillary layer (upper dermal region)  Projections called dermal papillae  Some contain capillary loops  Other house pain receptors and touch receptors (Meissner corpuscles)  Reticular layer (deepest skin layer)  Blood vessels, sweat and oil glands, hair follicles  Deep pressure receptors Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Question?  When purchasing leather goods, which part of the animal skin are you buying?  Answer:  The treated dermis of animals Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Clinical Connection  Dermatitis is a disease characterized by an inflammation of the papillary layer. What would be one of the characteristic symptoms?  Answer:  Itch or pain Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Clinical Connection  Internal damage to the dermis layer that occurs when the skin is stretched too much are called?  Answer:  Stretch marks  Caused by excessive stretching of the dermis, particularly during pregnancy, weight gain Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Clinical Connection  What Is the consequence of applying constant pressure on the skin?? (hint: decrease blood flow)  Answer:  Pressure ulcers, are caused by a constant deficiency of blood to tissues overlying a bony projection that has been subjected to prolonged pressure against an object such as a bed, cast, or splint; the deficiency results in tissue ulceration. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Normal Skin Color Determinants  Melanin  The only pigment made by the skin (yellow, brown, or black)  Melanocytes produce melanin and protect from UV radiation  Melanocytes are mostly in the stratum basale  Amount produced depends upon genetics and exposure to sunlight  Carotene  Orange-yellow pigment from some vegetables (increase orange tan with large amount of carotene- rich food)  Hemoglobin  Red coloring from blood cells in dermal capillaries  Interrupted blood supply leads to cyanosis (blueish color) Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Question?  IF the number of melanocytes is about the same in all people. How do you explain the differences in skin color?  Answer:  The differences in skin color are due mainly to the amount of pigment the melanocytes produce and transfer to keratinocytes. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Clinical Connection:  Freckles and pigmented nevi (moles)  Local accumulations of melanin in patches  Albinism  Inherited inability of an individual to produce melanin  tendency of the skin to burn easily on overexposure to sunlight  Vitiligo  Loss of melanocytes  loss of color  Jaundice  Buildup of bile produced by liver  yellow color  Erythema:  Redness of the skin, is caused by engorgement of capillaries in the dermis with blood due to skin injury Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Clinical Connection: B Albinism A Freckles Erythema D Jaundice C Vitiligo E Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Accessory Structures of the Skin Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Skin Appendages  Cutaneous glands are all exocrine glands  Sebaceous glands  Sweat glands (sudoriferous glands)  Ceruminous Glands  Hair  Hair follicles  Nails Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Appendages of the Skin  Sebaceous glands  Found all over the skin, except on the palms of the hands and the soles of the feet.  Produce sebum  Lubricant for skin  Prevents brittle hair  Kills bacteria  Most have ducts that empty into hair follicles; others open directly onto skin surface  Glands are more activated after puberty Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Appendages of the Skin: Sebaceous glands Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Clinical Connection: Acne  Acne is an inflammation of sebaceous glands caused by colonization by bacteria, some of which thrive in the lipid-rich sebum. The infection may cause a cyst or sac of connective tissue cells to form, which can destroy and displace epidermal cells. This condition, called cystic acne, can permanently scar the epidermis. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Appendages of the Skin  Sweat glands (sudoriferous glands)  Produce sweat (sudor)  Two types  Eccrine  Open via duct to pore on skin surface  Perspiration  thermoregulatory and emotional sweating  Widely distributed on body surface  Especially on palms and soles  Apocrine  Ducts empty into hair follicles  Produce odorous secretion  Become active at puberty  Found in armpits, around nipples, and groin Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Appendages of the Skin Eccrine sweat glands are simple, coiled tubular glands that are much more common than apocrine sweat glands Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Sweat and Its Function  Composition  Mostly water  Salts and vitamin C  Some metabolic waste  Fatty acids and proteins (apocrine only) – yellowish appearance  Function  Helps dissipate excess heat  Excretes waste products  Acidic nature inhibits bacteria growth  Odor is from associated bacteria Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Ceruminous Glands  Modified sweat glands located in the ear canal  Along with nearby sebaceous glands, they are involved in producing a waxy secretion called cerumen (earwax) which provides a sticky barrier that prevents entry of foreign bodies into the ear canal. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Appendages of the Skin  Hair  Produced by hair follicle  Consists of hard keratinized epithelial cells  Melanocytes provide pigment for hair color  The main regions of a hair are the shaft and the root Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Appendages of the Skin Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Appendages of the Skin  Hair anatomy  Central medulla (soft)  Cortex surrounds medulla (hard)  Cuticle on outside of cortex  Most heavily keratinized Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Appendages of the Skin  Associated hair structures  Papilla surrounded by hair bulb and root hair plexus (nerve endings sensitive to touch)  Arrector pili muscle  Smooth muscle  Pulls hairs upright when cold or frightened  Sebaceous gland and Sweat gland Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Clinical Connection  What is the relationship between hair loss and chemotherapy?  Answer:  Chemotherapeutic agents interrupt the life cycle of rapidly dividing cancer cells. Unfortunately, the drugs also affect other rapidly dividing cells in the body, such as the hair matrix cells of a hair. It is for this reason that individuals undergoing chemotherapy experience hair loss. Since about 15% of the hair matrix cells of scalp hairs are in the resting stage, these cells are not affected by chemotherapy. Once chemotherapy is stopped, the hair matrix cells replace lost hair follicles and hair growth resumes. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Clinical Connection: Hair removal  A substance that removes hair is called a depilatory. It dissolves the protein in the hair shaft, turning it into a gelatinous mass that can be wiped away. Because the hair root is not affected, regrowth of the hair occurs.  Laser treatments may also be used to remove hair. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Clinical Connection: Thin Hair  Thinner hair may be lacking what structural component of a typical hair?  a) medulla  b) cortex  c) cuticle  d) root  e) follicle Answer: a Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Appendages of the Skin  Nails  Scale-like modifications of the epidermis  Heavily keratinized  Stratum basale extends beneath the nail bed  Responsible for growth  Lack of pigment makes them colorless Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Appendages of the Skin  Nail structures  Free edge  Body is the visible attached portion  Root of nail embedded in skin  Cuticle is the proximal nail fold that projects onto the nail body Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Appendages of the Skin Figure 4.9 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Question? Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Skin Homeostatic Imbalances  Burns  Tissue damage and cell death caused by heat, electricity, UV radiation, or chemicals  Associated dangers  Dehydration  Electrolyte imbalance  Circulatory shock ( shutdown of the kidneys)  Infection of burn sites Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  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 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Rule of Nines  Anterior and posterior head and neck = 9%  Anterior and posterior shoulders, arms, forearms, and hands = 18%  Anterior and posterior trunk = 36%  Perineum = 1%  Anterior and posterior thighs, legs, and feet = 36% 100% Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Question?  If both legs and the face were burned, this would involve ____ of the body.  36% + 4.5% = 40.5%  If the entire left arm and the face were burned, this would involve ____ of the body.  9 + 4.5% = 13.5% Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Severity of Burns  First-degree burns  Only epidermis is damaged  Skin is red and swollen  Second-degree burns  Epidermis and upper dermis are damaged  Skin is red with blisters  Third-degree burns  Destroys entire skin layer  Burn is gray-white or black Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings 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 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Skin Cancer  Cancer—abnormal cell mass  Classified two ways  Benign  Does not spread (encapsulated)  Relatively slow growth  Rarely fatal if removed before compressing vital organs  Malignant  Metastasized (moves) to other parts of the body  Fast-growing neoplasms  Skin cancer is the most common type of cancer Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Skin Cancer Types  Basal cell carcinoma  Least malignant  Most common type  Arises from stratum basale Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Skin Cancer Types  Squamous cell carcinoma  Metastasizes to lymph nodes if not removed  Early removal allows a good chance of cure  Believed to be sun- induced  Arises from stratum spinosum Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Skin Cancer Types  Malignant melanoma  Most deadly of skin cancers  Cancer of melanocytes  Metastasizes rapidly to lymph and blood vessels  Detection uses ABCD rule Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings ABCD Rule  A = Asymmetry  Two sides of pigmented mole do not match  B = Border irregularity  Borders of mole are not smooth  C = Color  Different colors in pigmented area  D = Diameter  Spot is larger then 6 mm in diameter Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Question?  Applying the ABCD rule on the below, which one would suspect of being a cancerous skin development? Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Questions?  What are the two life-threatening consequences of a severe burn?  Loss of body fluids containing needed proteins and electrolytes, resulting in circulatory shock, and overwhelming infection.  What are the criteria for classifying burns as first-, second-, or third-degree?  First-degree burns are red and swollen but usually heal in 2–3 days; only epidermal damage.  Second-degree burns damage the epidermis and some of the dermis; blisters appear but epithelial regeneration can occur.  Third-degree burns destroy the entire skin thickness. The burn is gray and painless; must graft. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Questions?  What name is given to the rule for recognizing the signs of melanoma?  ABCD rule  What is the single most common risk factor for skin cancer?  Sun exposure  Why do no skin cancers develop from stratum corneum cells?  Because stratum corneum cells are dead Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Developmental Aspects of Skin  With age  Integument thins  Blood flow decreases  Cellular activity decreases  A decrease in:  Amount of collagen in the dermis  Number of elastic fibers in the dermis Sag and  fat from the hypodermis wrinkled skin  Activity of sweat glands Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings