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Chapter 5

CHAPTER 5.docx

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Health Studies
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Michelle Silver

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CHAPTER 5: AGING OF THE SKIN AND MUSCUILOSKELETAL SYSTEM -skin provides covering for body and is 1 line of defense against bacteria, viruses, and other types of environmental damage -bones, ligaments, tendons, and muscles that make up musculoskeletal system provide shape and support for body -make movements and adjustments in position possible and protect internal vital organs from external trauma -skin and musculoskeletal system provide most obvious external signs of aging with both normal changes and disease processes SKIN (Integumentary system) Basic Anatomy and Physiology -important part of our immunologic and endocrine systems -critical in temperature maintenance and aids in homeostasis -sensory nerves in skin allow us to monitor enviro but also warn us of danger through pain -key component of our appearance and is critical source of cues that affect social interaction -aging of skin is one of most obvious clues to an individual’s age -largest and most visible organ of body -outermost layer: epidermis -second layer: dermis -beneath these two layers is layer of subcutaneous fat (consists mainly of adipocytes-fat cells) -gives shape and form to body and provides protection and insulation -hair follicles, nail beds and nails, and sweat and sebaceous glands are embedded in various layers -epidermis consists mostly of keratinocytes (>90% of all epidermal cells), cells that protect skin from outside harm and help it heal if it’s injured -as young cells, keratinocytes are found deep in epidermis and slowly move to surface as they age (process takes ~30days) -if skin’s injured, keratinocytes will reproduce and turn over at more rapid rate, allowing damage to be repaired -keratinocytes also necessary for synthesis of Vitamin D3 (used in absorption of Ca) -melanocytes (2% of cells in epidermis) produce melanin for keratinocytes and give colour to skin -exposure to sun results in increase in melanin production by these cells (which helps to protect skin from damage) -Langerhans cells (1% of cells in epidermis) are important part of immune system -along with mast cells found in dermal layer, they respond to toxic allergic stimuli -dermis consists largely of collagen and elastin tissue (strength and elasticity to skin) -blood vessels, lymphatic tissue, and nerves are imbedded in connective tissue, as are sweat glands and hair follicles -cells in dermis layer include mast cells that are responsible for skin’s ability to respond to allergens Age-Related Changes -large individual diffs in rate at which integument ages -changes in hair follicles result in graying and loss of hair -wrinkles partially due to decrease in subcutaneous fat layer and in collagen and elastin found in dermal layer -some areas more likely to wrinkle than other (nose always stays smooth) -decrease in size & number of keratinocytes limits skin’s ability to help body produce vitamin D -turnover rate of keratinocytes is reduced as much as 50%, limiting skin’s ability to protect itself from sun -decrease in melanocytes affects skin’s ability to protect itself from sun -some of remaining melanocytes clump together, leaving blotchy unpigmented areas of skin -Langerhans cells decrease by as much as 40%, reducing ability of skin to respond to allergic stimuli -dermis is almost 20% thinner in an older person and fewer fibroblasts in this layer make skin less elastic and not as strong as that of younger people -these changes and increasingly thin-walled blood vessels, give skin of an older person a fragile, almost translucent appearance -there’s flattening of junction b/w epidermis & dermis, which decreases adhesion b/w 2 layers -b/c of this, skin much more likely to bruise and tear if an injury occurs and less likely to Heal -decrease in blood vessel availability predisposes older person to hypothermia & hyperthermia -decrease in number of sensory nerves also results in decreased sensitivity to touch, injury and to heat and cold -also lessened ability of integumentary system to inform sensory system of potential danger which contributes to injury -decrease in mast cells lowers antigen sensitivity -thinning of subcutaneous fat layer also affects ability of body to maintain homeostasis with age -thinning makes skin more fragile and loss of insulation increases risk of older person developing hypothermia -loss of sweat (eccrine) glands in skin affects thermal regulation, decreasing ability to sweat -why elders more vulnerable to high temps (hyperthermia) -loss of subcutaneous fat=protruding angles of jaw and elbows become more obvious Disease-Related Processes Xerosis (dry skin) -characterized by red, scaly and itchy skin on legs, back and arms -cause unknown but may be associated with slowing of keratinocyte turnover rate -lack of vitamin A -troublesome during winter when ppl tend to spend lot of time indoors in warm and dry enviro -treatment: skin creams (topical emollients) after bathing-prevents loss of H2O from epidermis -helpful emollients: lanolin, glycerin, lactic acid and urea (sometimes mild corticosteroid) Seborrheic Keratoses (old age spots) -benign (nonmalignant) lesions -usually brown/black and have irregular edges -can occur in young adulthood but appear more frequently with age -sun exposure is risk factor but some prob have hereditary predisposition to develop them -important they be evaluated and removed to differentiate them from malignant growths Skin Cancer -2 of most common forms are basal-cell and squamous-cell carcinomas -basal-cell: small, fleshy bump or nodule usually on head or neck -greatest risk factor is exposure to sun -very slow growing and metastases are rare -but lesions generally removed in early stage of growth to minimize further damage to skin nd -common for ppl with this type of lesion to have 2 primary growth -squamous-cell: found on face or back of hand -red, scaly, and hard patch…become ulcerated and crusty with time -exposure to sun is significant risk factor but others include chronic irritations -ex. Chronic dermatitis due to exposure to allergens or scarring from radiation or ulcers can increase risk of this type of carcinoma -always removed and follow-up is important as risk of recurrence is great -these to carcinomas less likely to be found in younger ppl than are malignant melanomas -malignant melanomas are most dangerous of skin cancers -they’re cancers of melanocytes -typically red, white, blue, or black growth with an irregular border -painless but may ulcerate and bleed in later stages -risk factors: very light skin and blond or red hair, fam history, history of severe intermittent sunburns especially when young -may metastasize to lymph nodes and then to other parts of body (liver, brain, etc.) -can develop as primary site in eye, digestive tract, or liver b/c melanocytes found in these parts -men more likely to have on trunk of body or head and neck -women on lower legs or soles of feet -when dark skin ppl develop it, likely under fingernails or toenails or on soles of feet -occurs at all ages but increases with age Pressure Ulcers (pressure over susceptible tissue) -occur in those who spend long periods of time immobile in wheelchairs or beds -begins b/c area of skin has been damage or there’s breakdown of tissue over bony prominence -numerous risk factors in later years -ability to sense cutaneous pain decreases in later years and with disease, making ppl unaware that they’ve injured tissue -more likely to occur in those who are unable to easily move themselves -can be very painful -extremely difficult to heal especially given decrease in keratinocyte turnover rate -not all patients able to complain of pain but it’s been reported that pain medication in significant number of cases is inadequate -treatment: adequate nutrition with protein, skin hydration, cleanliness, special beds, prevention of infection, and surgery to debride the unhealthy tissue of ulcer -can take weeks or even months to heal and some never heal -prevention far easier to accomplish than treatment Promoting Optimal Aging -rate at which skin ages is influenced by genetics, disease, nutrition, smoking, SES and enviro conditions -ppl of some ethnic groups have fewer wrinkles and smoother skin than others -those who smoke are exposed to harsh pollutants and more likely to have damaged skin -skin if one of 1 systems to be affected by poor nutritional intake -healthy skin: adequate food and fluid intake, protein -general illness-prevention strategies also help skin -moisturizers can’t decrease wrinkles, but can mitigate their appearance -Retin-A improves sun-damaged skin and helps increase skin smoothness -estrogen replacement therapy improves appearance of aging skin and increases skin thickness in postmenopausal women -also botox injections, face-lifts, chemical peels and use of laser helps smooth skin MUSCULOSKELETAL SYSTEM -consists of hard tissue (bones that constitute skeleton) and soft tissue (including muscles, ligaments, tendons and cartilage) Basic Anatomy and Physiology Bones -provide both structure and strength for body -regardless of size, all bones made up of trabecular or cortical tissue -cortical (compact) bone makes up outer layer of all bones and constitutes bulk of long bones of body (legs and arms) -tightly packed or compact…extremely heavy and strong (75% of body’s skeletal weight) -trabecular bone (25% of weight) found largely in vertebrae, ribs, cranium, and ends of long bones…extremely strong but more porous than cortical bone and has lacy/honecomblike look -bones contain blood vessels, nerves and bone marrow which produces and stores immature red and white blood cells -storage site for mineral salts (Ca, P, Mg) widely used for bone building and for fcns such as muscle contraction and maintaining fluid and electrolyte balance -not a static system; dynamic..responding to internal and environmental demands -when Ca needed for contraction during pregnancy, Ca is leached from bones -old bone resorbed by osteoclasts and new bone generated by osteoblasts Soft Tissues -ligaments and tendons composed of extremely strong fibrous connective tissue -tendons attach muscles to bones -ligaments bind bones to bones and other structures of body -tissues work to stabilize joints b/w bones while allowing for flexibility and movement -periosteum (fibrous membrane) that covers bone serves as place of attachment for both tendons and ligaments -cartilage (specialized type of connective tissue) found on ends of bones
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