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University of Guelph
Family Relations and Human Development
FRHD 2060
Gillian Joseph

1 FRHD*2060 - MIDTERM 1 NOTES Ch.2: Biological Theories of Aging: - to date no existing theory does a complete job of explaining all the normative changes we go through Rate-of-Living Theories - people only have so much energy to expend in a lifetime - some evidence with rodents & rhesus monkeys suggests that reducing caloric intake lowers the risk of premature death, slows down a wide range of normative age-related changes, and in some cases results in longer life spans than do normal diets - another variation of rate-of-living theories involve the hormonal regulatory system’s adaptation to stress - body’s ability to deal with stress significantly declines with age - relationship between this & diseases common in later life has been suggested Cellular Theories - one notion focuses on # of times a cell can divide - cells grown in lab undergo only a fixed # of divisions before dying (Hayflick limit) - what causes cells to limit their # of divisions? - evidence suggests that the tips of the chromosomes called telomeres play a major role - enzyme called telomerase is needed in DNA replication to fully replicate the telomeres - telomerase normally is not present in cells, so with each replication the telomeres become shorter - 2nd cellular theory: cross-linking in which certain proteins (collagen) in human cells interact randomly & produce molecules that are linked in such a way as to make the body stiffer - even though cross-linking by itself is not an adequate explanation of aging, but it can have a significant effect on health & functioning in later life - 3rd cellular theory: proposes that aging is caused by unstable molecules called free radicals, which are highly reactive chemicals produced randomly in normal metabolism - antioxidants prevent oxygen from combining with susceptible molecules to form free radicals Theories of Programmed Cell Death - programmed cell death appears to be a function of physiological processes, the innate ability of cells to self-destruct & the ability of dying cells to trigger key processes in other cells Appearance and Mobility - see outward signs of aging: grey hair, wrinkled skin, expanding waistline or hips, etc. Changes in the Skin: - wrinkling complex 4 step process: - 1st outer layer of skin becomes thinner through cell loss, causing the skin to become more fragile - 2nd: collagen fibres that make up the connective tissue lose much of their flexibility - 3rd: elastin fibres in middle layer of skin lose ability to keep skin stretched out, resulting in sagging 2 - 4th: underlying layer of fat which helps provide padding to smooth out the contours and diminishes - major cause of underlying changes that result in the wrinkles is exposure to UV rays - skin becomes thinner & drier, has a leathery texture & this makes it less effective at regulating heat & cold & more susceptible to cuts, bruises, & blisters - the colouring of ppl with light skin undergoes additional changes with age: the # of pigment- containing cells in the outer layer decreases & those remaining have less pigment, resulting in lighter skin - additionally, age spots, moles & varicose veins appear more often Changes in the Hair - gradual thinning & greying of the hair - hair loss is caused by destruction of germ centres that produce hair follicles, whereas greying results from cessation of pigment production Changes in the Voice - lowering of pitch, increased breathlessness & trembling, slower & less precise pronunciation & decreased - recent research points to changes in the larynx & respiratory system as the cause Changes in Body Build - two changes are especially noticeable: decrease in height & fluctuations in weight - height loss usually caused by compression of the spine from loss of bone strength, changes in the discs between the vertebrae in the spine & changes in posture - weight gain is caused by changes in body metabolism, which tends to slow down & reduced levels of exercise - for men, this weight gain tends to be around abdomen, for women this gain tends to be around the hips - by late life the body loses both muscle and bone, which weigh more than fat, in addition to some fat, resulting in weight loss Changes in Mobility Muscles - although amount of muscle tissue in our bodies declines with age, this loss is hardly noticeable in terms of strength and endurance; at the age of 70 the loss is no more than 20% - after that, the rate of change increases, by age 80 the loss in strength is up to 40% Bones - women lose bone mass approx. 2 times as fast as men because women have less bone mass than men in young adulthood, meaning they start out with less ability to withstand bone loss before it causes problems, 2nd the depletion of estrogen after menopause speeds up bone loss - loss of bone loss inside the bone which makes the bones more hollow - hollow, porous bones break more easily - women are especially susceptible to osteoporosis in which the loss of bone mass & increased porosity create bones that resemble laced honeycombs - osteoporosis is the leading cause of broken bones in older women - disease appears more often in fair-skinned, thin, small-framed women of European descent Joints 3 - beginning in 20’s, protective cartilage in joints shows signs of deterioration, such as thinning & becoming cracked & frayed - over time the bones underneath the cartilage become damaged which can result in osteoarthritis, a disease marked by gradual onset & progression of pain & disability, with minor signs of inflammation, especially common in ppl subjected to routine overuse and abuse - usually affects the hands, spine, hips & knees - more common form of arthritis is rheumatoid arthritis, a more destructive disease of the joints that also develops slowly & typically affects different joints and causes different types of pain than osteoarthritis Psychological Implications - given the social stereotypes examined in ch. 1, many women (& increasingly some men) use any available means to compensate for these changes - some age-related changes in facial appearance can be disguised with cosmetics - hair dyes can restore colour - surgical procedures such as facelifts - losses in strength & endurance in old age have much the same psychological effects as changes in appearance - changes in joints, especially arthritis have profound psychological effects - these changes can severely limit movement, thereby reducing independence - further, joint pain is very difficult to ignore or disguise Sensory Systems Vision - one of the 1st noticeable signs of aging - 2 change classes: changes in the structures of the eye which begin in the 40s & changes in the retina which begin in the 50s Structural Changes in the Eye - 2 major kinds of change - 1 is a decrease in the amount of light that passes through the eye (can’t see as well in the dark) - become increasingly sensitive to glare - ability to adjust to changes in illumination, called adaptation declines - 2: other key structural changes involves the lens - lens becomes more yellow, causing poorer colour discrimination in the green-blue-violet end of the spectrum - also, lens’s ability to adjust & focus declines as the muscles around it stiffen - this is what causes difficulty seeing close objects clearly (presbyopia) - further, the time our eye needs to change focus from near to far (or vice versa) increases - some people will experience diseases caused by abnormal structural changes - opaque spots called cataracts may develop on the lens - fluid may not drain properly, causing very high pressure (glaucoma) Retinal Changes: - with increasing age, probability of degeneration of the macula increases - macular degeneration involves the progressive & irreversible destruction of receptors from any # of causes - this disease results in loss of ability to see details - diabetic retinopathy can involve fluid retention in the macula, detachment of the retina, hemorrhage and aneurysms 4 - the ability to see detail and discriminate different visual patterns, called acuity declines steadily Psychological Effects of Visual Changes - some vision problems are easily fixable - others are not - the environment can be adapted to help deal with vision impairments Hearing - one of the most well-known normative changes with age - wearing ear buds or head phones can lead to hearing loss later in life - the cumulative effects of noise and normative age-related changes create the most common age-related hearing problem: reduced sensitivity to high pitched tones, called presbycusis which occurs earlier & more severely than loss of sensitivity to low-pitched tones - results from 4 types of changes in the inner ear: sensory, neural, metabolic & mechanical - the different causes have different implications for other aspects of hearing - loss of hearing later in life can cause numerous adverse emotional reactions, such as loss of independence, social isolation, irritation, paranoia & depression - hearing loss may not directly affect older adults’ self concept or emotions, but it may negatively affect how they feel about interpersonal communication - fortunately many ppl with hearing loss can be helped through 2 types of amplification systems & cochlear implants: analog hearing aids (most common, least expensive, but lowest quality sound) & digital hearing aids (microchips that can be programmed for different hearing situations) Somesthesia and Balance Somesthesia - takes more pressure with age to feel touch on smooth (non hairy) skin on the hand such as fingertips, but touch sensitivity in the hair covered parts of the body is maintained into later life - older adults often have more trouble regulating body temp. - no clear picture of age-related differences in sensitivity to pain - pain sensitivity varies across different locations on the body & with different types of stimulation - experiencing pain is more than just a sensory experience; it involves cognitive, motivational, personality & cultural forces as well - knowing how our body is situated at any particular moment means that we have experienced our sense of body position or kinesthesis - kinesthesis involves sensory feedback about two kinds of movement: passive & active movement - passive movements are instigated by someone or something else (i.e. whe
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