Normal Physiologic Changes Associated with Aging PDF

Normal Physiologic Changes Associated with Aging in Gastrointestinal, Nervous and Integumentary System By Dr. Mona Abdel Khalek Normal Physiologic Changes Associated with Aging in Gastrointestinal System Introduction • There are significant changes in gastrointestinal function that occur in geri...

Normal Physiologic Changes Associated with Aging in Gastrointestinal, Nervous and Integumentary System By Dr. Mona Abdel Khalek Normal Physiologic Changes Associated with Aging in Gastrointestinal System Introduction • There are significant changes in gastrointestinal function that occur in geriatric patients • Aging increases the risk of several disorders: • GI bleeding, colorectal cancer, constipation, diverticular disease, diarrhea, fecal incontinence, hepatobiliary disorders, and pancreatic cancer • The GI tract (gastrointestinal tract) The muscular alimentary canal • • • • • • • Mouth Pharynx Esophagus Stomach Small intestine Large intestine Anus • The accessory digestive organs Supply secretions contributing to the breakdown of food • • • • • Teeth & tongue Salivary glands Gallbladder Liver Pancreas 4 The Digestive Process • Ingestion • Taking in food through the mouth • Propulsion (movement of food) • Swallowing • Peristalsis – propulsion by alternate contraction &relaxation • Mechanical digestion • Chewing • Churning in stomach • Mixing by segmentation • Chemical digestion • By secreted enzymes: see later • Absorption • Transport of digested end products into blood and lymph in wall of canal • Defecation • Elimination of indigestible substances from body as feces 5 Smooth muscle • Muscles are spindle-shaped cells • One central nucleus • Grouped into sheets: often running perpendicular to each other • Peristalsis • No striations (no sarcomeres) • Contractions are slow, sustained and resistant to fatigue • Does not always require a nervous signal: can be stimulated by stretching or hormones Smooth muscle • 6 major locations: 1. inside the eye 2. walls of vessels 3. respiratory tubes 4. digestive tubes 5. urinary organs 6. reproductive organs Age-related changes in Gastrointestinal System • Decreased salivation, taste, and smell along with inadequate chewing (tooth loss, poorly fitting dentures), • poor swallowing reflex may lead to poor dietary intake, and nutritional deficiencies. • Decreased thirst perception Age-related changes in Gastrointestinal System • Decreased esophageal motility & lower esophageal sphincter pressure • Decreased stomach motility; delayed gastric emptying; and hydrochloric acid. • Decreased small intestine motility, villi, digestive enzyme secretion so constipation is common Age-related changes in Gastrointestinal System • Decreased large intestine blood flow, motility, defecation sensation • Decreased liver size, blood flow, enzymatic metabolism of drugs; increased biliary lipids • Decreased tone in stomach & intestines result in slower peristalsis  constipation Nutrition • Geriatric patients, especially aged > 85 years, are at risk for decreased food intake due to several factors: • Mobility impairment • Ability to obtain food • Loss of taste, may be due to decreased olfaction • Poor dentition • Decreased appetite • Depression Etiology of weight loss • Three distinct mechanisms of weight loss in older people have been identified 1. Wasting 2. Sarcopenia Etiology of weight loss 1. Wasting • Wasting, an involuntary loss of weight, is mainly due to poor dietary food intake which can be caused by disease and psychological factor causing an overall negative energy balance. Etiology of weight loss 2. Sarcopenia • The major age-related physiological change in older people is a decline in skeletal muscle mass, 1. Reduced physical activity has a crucial role since lack of exercise causes muscle disease and, with time, muscle loss. 2. Increased cytokine activity increases levels of acute phase proteins which break down muscle. 3. Levels of sex hormones, glucocorticoids and catecholamines decline in older people which in turn increase pro-inflammatory cytokines. Associated changes in colonic motility • Diarrhea • Fecal Incontinence • Constipation Diarrhea • Defined as abnormally loose stool accompanied by change in frequency or volume Diarrhea • Causes • • • • • Virus Food poisoning Food contamination Medications Lactose intolerance Diarrhea • Symptoms • • • • • • Urgency Cramping Bloating Incontinence Pain on defecation Presence of blood in stool Diarrhea • Assessment • Interview • Physical examination • Management • Antidiarrheal agents • Soluble fiber Fecal Incontinence • Seen in 50% of institutionalized elderly • Causes: • Mobility problems • Severe depression • Cognitive impairment Lifestyle Modification • Lose weight as appropriate • Avoid tight clothing • Remain in upright position after eating • Reduce alcohol, caffeine, and fat intake Lifestyle Modifications • Increase dietary fiber • Drink at least 8 full glasses of water per day (unless contraindicated by other medical condition) • Exercise regularly • Avoid foods that precipitate painful attacks Interventions to Prevent Aspiration • Minimize distractions during eating • Provide a pleasant mealtime environment • Use consistent feeding techniques • Document patient food preferences and consumption patterns • Position patient upright during and 1 hour following mealtime • Allow time for swallowing Interventions to Prevent Aspiration • Monitor respirations • Provide oral hygiene before and after mealtimes • Provide meals when patient is rested • Provide food and fluid of appropriate consistencies • Never force-feed • Monitor weight, function status, and patient satisfaction during meals • Avoid nasogastric tubes Normal Physiologic Changes Associated with Aging in Nervous System Functions of the Nervous System 1. Sensory input – gathering information  To monitor changes occurring inside and outside the body (changes = stimuli) 2. Integration –  to process and interpret sensory input and decide if action is needed. 3. Motor output  A response to integrated stimuli  The response activates muscles or glands Structural Classification of the Nervous System  Central nervous system (CNS)  Brain  Spinal cord  Peripheral nervous system (PNS)  Nerve outside the brain and spinal cord Functional Classification of the Peripheral Nervous System  Sensory (afferent) division  Nerve fibers that carry information to the central nervous system Functional Classification of the Peripheral Nervous System  Motor (efferent) division  Nerve fibers that carry impulses away from the central nervous system Functional Classification of the Peripheral Nervous System  Motor (efferent) division  Two subdivisions  Somatic nervous system = voluntary  Autonomic nervous system = involuntary Organization of the Nervous System Age-related changes • Decreased cerebral blood flow and energy metabolism. • Atrophy of nerve cells in cerebral cortex: loss of cerebral mass/brain weight of 6-11% between ages of 20 and 90; accelerating loss after age 70. Age-related changes • Changes in brain morphology. (1) Gyral atrophy: narrowing and flattening of gyri with widening of sulci. (2) Ventricular dilation. (3) Generalized cell loss in cerebral cortex: especially frontal and temporal lobes. Age-related changes • (4) Presence of lipofuscins, senile or neuritic plaques, and neurofibrillary tangles (NFf): significant accumulations associated with pathology, e.g., Alzheimer's dementia. • (5) More selective cell loss in basal ganglia, and cerebellum Age-related changes • Changes in synaptic transmission: (1) Decreased synthesis and metabolism of major neurotransmitters, e.g., acetylcholine, dopamine. (2) Slowing of many neural processes, especially in polysynaptic pathways. Age-related changes • Changes in spinal cord/peripheral nerves: (1) Neuronal loss and atrophy: 30-50% loss of anterior hom cells, 30% loss of posterior roots (sensory fibers) by age 90. (2) Slowed nerve conduction velocity. Age-related changes (3) Loss of motoneurons results in increase in size of remaining motor units (development of macro motor units). (4) Loss of sympathetic fibers: may account for diminished, autonomic stability, increased incidence of postural hypotension in older adults. Age-related changes • Age-related tremors: (1) Occur as an isolated symptom, particularly in hands, head and voice. (2) Characterized as postural or kinetic, rarely resting. (3) Exaggerated by movement and emotion. Clinical implications • Effects on movement: (1) Overall speed and coordination are decreased; increased difficulties with fine motor control. (2) Slowed recruitment of motoneurons contributes to loss of strength. (3) Both reaction time and movement time are increased. Clinical implications (4)The simpler the movement, the less the change. (5) More complicated movements require more preparation, longer reaction and movement times. (6) Faster movements decrease accuracy, increase errors. Interventions to slow or reverse changes. • Correction of medical problems: improve cerebral blood flow. • Improve health: diet, smoking cessation. • Increase levels of physical activity: may encourage neuronal branching, slow rate of neural decline, improve cerebral circulation. Interventions to slow or reverse changes • Provide effective strategies to improve motor learning and control. • Allow for limitations of memory: avoid long sequences of movement . • Allow for increased cautionary behaviors:provide adequat explanation, demonstration when teaching new movement skills. Age-related changes in sensory system • A.Vision (1)Decreased ability to adapt to dark and light. (2) Increased sensitivity to light . (3) Loss of color discrimination, especially for blues and greens. • Additional vision loss with pathology • 1-Cataracts: opacity, clouding of lens due to changes in lens proteins; results in gradual loss of vision: • 2-Glaucoma: increased intraocular pressure,with degeneration of optic disc, atrophy of optic nerve; results in early loss of peripheral vision (tunnel vision), progressing to total blindness. Age-related changes in sensory system • 3-Diabetic retinopathy: damage to retinal capillaries,growth of abnormal blood vessels and hemorrhage leads to retinal scarring and finally retinal detachment; central vision impairment; complete blindness is rare. Age-related changes in sensory system • B . Hearing. • (1) Outer ear: buildup of cerumen (ear wax) may result in conductive hearing loss; common • (2) Middle ear: minimal degenerative changes of bony joints. • (3) Inner ear: significant changes in sound sensitivity, understanding of speech, and maintenance of equilibrium Age-related changes in sensory system • C. Vestibularlbalance control. • Reduced function of vestibular ocular reflex (VOR); affects retinal image stability with head movements, produces blurred vision. • Postural response patterns for balance are disorganized: characterized by increased postural sway. Age-related changes in sensory system • D. Somatosensory. • (1) Decreased sensitivity of touch associated with decline of peripheral receptors, atrophy of afferent fIbers. • (2) Proprioceptive losses. • (3) Loss of joint receptor sensitivity; losses in lower extremities, cervical joints may contribute to loss of balance. • (4) Cutaneous pain thresholds increased. Age-related changes in sensory system • E. Cognition • No uniform decline in intellectual abilities throughout adulthood. • Numeric ability (tests of adding, subtracting, multiplying): abilities peak in mid-40s, well maintained until 60s. • Verbal ability: abilities peak at age 30, well maintained until 60s. • memory impairments are typically noted in short term memory; long-term memory retained. Normal Physiologic Changes Associated with Aging Integumentary System What are the 3 major layers of the skin? • Epidermis (epi-upon) • Composed of epithelial tissue (stratified squamous) • Non-vascularized • Dermis – underlies the epidermis • Tough leathery layer composed of fibrous connective tissue • Good supply of blood • Subcutaneous tissues: underneath dermis; consists of loose connective and fat tissues; provides insulation, support, and cushion for skin; stores energy for skin. Epidermis Dermis Basement membrane Circulation • 1. Blood flows through arteries to capillaries of the skin. • a. Increased blood flow with an increase in oxyhemoglobin to skin capillaries causes reddening of the skin. • b. Peripheral cyanosis is due to reduced blood flow to skin and loss of oxygen to tissues (changes to deoxyhemoglobin) and results in a darker and somewhat blue color. What are the primary functions of the Integumentary System? • Chemical barriers: low pH of skin secretions slows bacterial growth. Human defens in is an antibiotic that destroys bacteria (produced by human skin) Functions cont. • Thermoregulation- skin contains sweat glands that secrete watery fluid, that when evaporated, cools the body. • Sensation- Skin contains sensory receptors that detect cold, touch, and pain. • Vitamin D synthesis- cholesterol in the skin is bombarded by sunlight and converted to vitamin D (calcium cannot be absorbed from digestive tract) Functions cont. • Blood reservoir- blood will be moved from skin to muscles during strenuous activity. • Excretion- Sweating is an important outlet for wastes. Normal Physiologic Changes Associated with Aging Integumentary System • Dermis thins with loss of elastin. • Decreased vascularity; vascular fragility results in easy bruising (senile purpura). • Decreased sebaceous activity and decline in hydration • Nails grow more slowly, become brittle and thick. Normal Physiologic Changes Associated with Aging Integumentary System • Appearance: skin appears dry, wrinkled, yellowed, and inelastic; aging spots appear (clusters of melanocyte pigmentation); increased with exposure to sun. • Normal Physiologic Changes Associated with Aging Integumentary System • Skin grows and heals more slowly, less able to resist injury and infection. • Decreased sensitivity to touch, perception of pain and temperature; increased risk for injury from concentrated pressures or excess temperatures. • Normal Physiologic Changes Associated with Aging Integumentary System • Decreased sweat production with loss of sweat glands results in decreased temperature regulation and homeostasis. • Inflammatory response is attenuated. Normal Physiologic Changes Associated with Aging Integumentary System • General thinning and graying of hair due to vascular insufficiency and decreased melanin production. Integumentary Disorders and Diseases • Pressure ulcers (decubitus ulcers). • a. Characteristics. • (1) Affects 10 to 25 % of hospitalized, ill elderly patients. • (2) Risk factors: immobility and inactivity, sensory impairment, cognitive deficits, decreased circulation, poor nutritional status, incontinence and moisture. Integumentary Disorders and Diseases • (3) Common over bony prominences: ischial tuberosities, sacrum, greater trochanter, heels, ankles, elbows and scapulae. • (4) If not treated promptly, can progress to damage of deep structures. • (5) Potentially fatal in frail elderly and chronically ill.