Gerontological & Community Based Nursing: Physiologic Changes of Aging
Physiologic Changes of Aging • Biological Theories • Normal Aging changes • Common Pathologic conditions
Aging • Aging starts at birth • Continues throughoutlife span • It is: universal, progressive, intrinsic, and unavoidable
Biologic Theories of Aging • Genetic Theory • Stochastic theories • Nonstochastic theories
Genetic Theory • Aging is an involuntarily process • Occurs over time • Alters cellular or tissue structures (belief that life-span, longevity changes are predetermined) Includes DNA theory, Error and Fidelity theory, Somatic Mutation and Glycogen theories. Eg. ↑cancers & autoimmune d/o’s in aging suggest errors in mutation at molecular & cellular levels.
Error (Stochastic) Theories • Error (Stochastic): Aging occurs randomly and progresses over time. • Error- DNA/RNA transcription causes failure of cellular activity –lead to aging and cell mutation or death.
Three types of Error theories Wear & Tear – • Accumulation of metabolic waste → • products/nutrient deprivation damage to DNA synthesis→ • cells, tissues, organs or body systems deteriorate & malfunction with repeated use of body in specialized functions.
Cross-Link Theory Cross –Link Theory- • Cellular division threatened by radiation or chemical reactions • A cross-link agent attaches self-to DNA stands • With accumulation over time → dense aggregates form • Intracellular transport impaired – • Results in systems & organ failure
Free Radical Theory Free Radical – • Reactive molecules with an extra electrical charge from Oxygen molecules • Oxidation of fats, proteins and carbohydrates creates free radicals • These attach to other molecules -proteins, enzymes & DNA and damage them –creating genetic disorders • Random damage accumulates, aging results, and eventually death of the “damaged” person. • Antioxidants (vitamins B carotene, A,C,E,) can counteract effects
Nonstochastic TheoriesProgrammed Aging Cell aging in is genetically programmed for life. Includes the following: • Programmed- “Inner Biological clock” in each cell determines number of replications and eventual death of cell and organism. • Immune theory-Alteration in cell is recognized as a foreign body and antibody are produced to fight them just as in autoimmune diseases. • Neuroendocrine- Over time, the ability of a cell to auto regulate itself becomes altered or lost resulting in aging and death.
Normal Changes of Aging: Integument • largest most visible organ of the body; protects, identifies us, temp. regulation & security • Integumentary- Skin Changes due to intrinsic and extrinsic factors such as: • _____________ • _____________ • _____________ • _____________
Normal changes of Aging: Hair and Nails • Hair (head) • Thinner • Coarser • Dryer • Facial hair • Nails • Harder, thicker, more brittle, dull and opaque
Flattening of the dermoepidermal junction ↓collagen & elastin ↓ epidermal cell turnover rate ↓vascular responsiveness ↓subcutaneous fat ↓epidermal cells Atrophy of eccrine & sebaceous cells ↓resistence to shearing forces, thinning of skin Wrinkling Prolonged healing time ↓vasodilation (cooling effect) & ↓ transdermal absorption ↓protection-bony prominences & thermporegulation Delayed hypersensitivity response ↓sweating & oil→ ↓thermoregulation Age related skin changesChange---------------Effect
Normal changes of Aging: Musculoskeletal • Influencing Factors • Age • Gender • Race • Environment • Average loss: • 2 inches between ages 40-80
Progressive ↓ height Stiffening of thoracic cage ↓production of cortical & trabecular bone ↓lean body mass w/loss subcutaneous fat Prolonged time for muscular contraction & relaxation Stiffening of joints & ligaments Stooped posture Barrel-chest ↑risk –hip fracture Sharp body contours & ↓muscular strength ↓ reaction time ↑risk for injury Normal Musculosketal Aging ChangesChange-----------------Clinical Implication
Normal changes of Aging: Musculoskeletal • Bone strength/Bone mineral density This graph shows how the bone density of the total hip decreases with age. The units are standardized bone density in (mg/cm2). The lines show the average values, and for each age, race and gender a range of values occurs in the ordinary population.
Osteoporosis • Kyphosis
Osteoporosis • Affects women 4x more often than men • ♀ Estrogen loss after menopause • ♂ Long term steroid use
Normal Changes of Aging • Ligaments, Tendons, Joints =>rigid, hardened, stiff • Arthritis is the #1 cause of disability in elderly
Did you know?During the course of your lifetime, your heart will typically beat 2.5 billion times--about once a second, every minute of your life. The heart pumps about five or more quarts of blood a minute, nearly 2,000 gallons of blood throughout your body. A healthy heart is strong enough to drive a single drop of blood throughout your entire body in about 24 seconds
Normal Changes of Aging: Cardiovascular System • Presbycardia=normal changes in the healthy heart • stroke volume • cardiac output • Left ventricle wall thickens • As much as 50% by age 80 • Left atrium enlarges (to compensate) • Possible development of a fourth heart sound (S4)
↑mass & fibrosis ↑thickness –L Ventricle ↑pericardial stiffness Thickened valve leaflets ↓ # of pacemaker cells ↓responsiveness to catecholamines Reduction in ventricular filling→ ↓cardiac output Impaired flow access valves Dysrhythmias common ↓ HR with exercise Age-related changes Cardiovascular SystemCardiac Change -------------------Effect
Peripheral Vascular Changes • Arteries become less elastic and more brittle • Calcium leaving the bones is deposited in the blood vessels • Lumen size of the vessels is d • May lead to increased blood pressure
Upper Airway Changes in nasal structure ↓in # of submucosal glands ↑obstruction of nasal breathing Thickened mucus gets trapped in nasal pharynx Age-related Changes in the Respiratory SystemChange ----------------------------Effect
Lower Airway ↓ in cilia Calicification of ribs/vertabrae Atrophy of respiratory muscle Enlargement of aveolar duct & resp bronchioles ↑residual vol. ↓tidal vol. ↑ventilation & perfusion ↓in the mucocillary escalator ↓compliance –thorasic cage ↓respiratory effort ↓surface area for gas exchange Prolonged expiration time ↓response to hypoxia & hypercapnia ↑alveolar arterial gradient Age-related Changes in the Respiratory SystemChange ----------------------------Effect
↓size & efficiency ↓nephrons ↓blood flow ↓ glomerular filtration rate; renin-angiotensin system ↑arterial pressure ↑NA, H2O retention Kidney changes in aging
Kidney mass ↓ 25-30 % # glomeruli ↓ 30 to 40 % ↓ hormonal response (vasopressin) & impaired ability to conserve salt ↓Bladder capacity & ↑residual urine and frequency. ↓ ability to filter/ concentrate urine & clear drugs ↑risk for dehydration ↑ risk for fluid & electrolyte imbalances, UTI’s, incontinence, and urinary obstruction. Age-related Changes in the Renal SystemChange ----------------------------Effect
↓bladder capacity atrophy of bladder pelvic relaxation &reduced estrogen ↑residual volume ↑prostate size ↑urinary retention frequency in urination; ↑involuntary bladder contractions ↑nighttime urine flow rates ↑risk for UTI’s Changes in lower urinary track-bladderChange-----------------------Effect
Change Insulin resistance ↓ in aldosterone and cortisol Effect may prevent efficient conversion of glucose into energy. may affect immune and cardiovascular function Age-related Changes in the Endocrine System
Decreased peristalsis Increased stomach pH ↓liver function weakened intestinal walls in the colon. ↓ peristalsis of colon reflux and hiatal hernias ↑susceptibility to gastric irritation & ulcers. Drugs metabolized slowly;↓ repair of liver cells. Diverticuli / pain can increase risk for constipation. Major Gastrointestinal Changes with AgingChange---------------------------Effect
Age-related Changes in the Female Reproductive System • Ovulation ceases and estrogen levels drop by 95%. • Vaginal walls become thinner and lose elasticity • Most women experience a decrease in the production of vaginal lubrication.
Age-related Changes in the Male Reproductive System • testosterone levels may drop by up to 35%. • size of testes decreases. • decline in sperm production - the extent varies among individuals. • erectile dysfunction (impotence), in occurs in15% of men by the age of 65 ↑to 50% by age 80
Age-related Changes in the C N S • Brain is resilient • ∆ in cognitive function---NOT normal • Delayed neurological function • NOT the loss of cognitive function • Intellectual performance remains intact • Performing tasks may take longer • ↓levels of neurotransmitters - choline,acetylase, Catecholamines,↑MAO
↓peripheral nerve conduction ↑lipofuscin along neurons ↓thermo-regulation by hypothalamus Differential rate/distribution of dopamine ↓deep tendon reflex w/↑ reaction time ∆ in vasodilation & constriction Heat/cold intolerance Slowing motor movements & fine motor skills Age-related Changes in the Neurological SystemChange-----------------------effects
↓ neurons in autonomic nervous system ↓neurons in cerebral & cerebellar cortex ↓sensorimotor processing Impaired barorecpetor responsiveness,vaso-constrictor & postural response ↓visual/auditory reaction time;↓Short –memory,↓visual/spatial ↓neurotransmitter coordination ↓reaction time /↑ risk for falls Age-related Changes in the Neurological SystemChange-----------------------effects
Normal Age-related Changes in the Peripheral Nervous System • in tactile sensitivity • Loss of nerve endings in skin • risk for injuries and burns • Altered kinesthetic sense (one’s position in space) • risk for falling
Normal Age-related Changes in the Eyes • Drooping eyelids (senile ptosis) • orbicular muscle strength • Arcus senilis • Gray/white/silver ringinside the outer edge of iris • Decrease in number of goblet cells producing eye lubrication
Normal Age-related Changes in the Eyes cont’d • Presbyopia-the crystalline lens accumulates tissue built up that becomes stiff →iris muscles work harder to bring near objects into focus • ↑ accommodation - light • ↑ sensitivity to glare • ↓ in pupil size • require ↑lighting
Common Diseases Affecting Vision • Cataracts—heredity & advanced age ↑risk high exposure to sunlight, diabetes, hypertension, Kidney disease, eye trauma • Glaucoma- 2nd most common eye disease • Macular Degeneration • Detached Retina
Cataracts • A cataract is a clouding of the normally clear lens of the eye. It can be compared to a window that is frosted or "fogged" with steam. • Common symptoms of cataract include: • Painless blurring of vision • Glare, or light sensitivity • Frequent eyeglass prescription ∆ • Double vision in one eye • Needing brighter light to read • Poor night vision • Fading or yellowing of colors
Nursing Interventions Post Cataract Surgery Most common surgical procedure in U.S. • Lens is removed-replaced with plastic intraocular lens Patient teaching: • Avoid heavy lifting, straining, bending at the waist • Can resume activities within a day
Intraocular Changes of Eye • Sclera may become yellowish (imitating jaundice) • Floaters—bits of vitreous that have broken off the retina • Retina becomes dull • Glaucoma is a degenerative abnormal condition resulting when intraocular pressure (IOP) becomes higher than what is healthy for the optic nerve