Aging of the Organ Systems

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Aging of the Organ Systems

• Nancy V. Karp, Ed.D., P.T.
• nvkarp_at_gmail.com

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Change

• Life is a process of continual change.
• Age-related changes occur at many levels.
• Biological level
• Physiological level
• Psychological level
• Functional level
• During adulthood, there is a slow decline in
  function. As you age, homeostasis is maintained
  at a level of decreased function.

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Change

• This presentation will focus on some of the
  changes that occur in different organ systems as
  they age.
• Physical therapists must recognize these changes
  to
• determine how to objectively measure the extent
  of the changes i.e., changes in muscle function.
• modify physical therapy interventions to
  accommodate these changes.
• prevent unnecessary therapy complications
  resulting from functional and structural changes
  to organs or systems.

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Remember

• Average or Normal does not imply Optimal
  or Healthy.
• Average does not apply to an individual.
  Elders are a heterogeneous population.

On the average, they are a normal height.
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Age-related Changes In The Cardiovascular System
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Normal Cardiovascular Changes Related to Aging

• The changes I am about to present are considered
  a NORMAL part of the aging process.
• These changes occur with age. They are not
  associated with pathological conditions.
• There is some controversy over the contribution
  of aging vs. disease to some of the changes that
  are presented.

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Cellular Changes

• Alterations of DNA, RNA, mitochondria and other
  sub-cellular changes are seen with aging.
• This changes result in decreased cellular
  activities resulting in
• altered homeostasis
• altered protein synthesis
• altered degradation rates

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Cellular Changes

• The myoctye cells of the heart increase in size.
• This may account for the myocardial wall
  thickening that is seen with aging.
• Some myocytes are replaced by fibrous tissue.
• Amyloid deposits in the myocardium increase with
  age.
• 50 in persons 70
• They are not present in ALL older persons.
• Often seen in other organs (Alzheimers dx)

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Cellular Changes

• There is a decrease in pacemaker cells at the
  sinoatrial node.
• Occurs around the age of 60
• 10 decrease by age 75
• A smaller decrease of cells is seen in the
  atrioventricular node and the Bundle of His

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Cellular Changes

• Thickening and calcification of heart and
  vessels occur.
• Cells become irregular in size and shape.
• By age 50, the aorta has thickened 40.
• There is a thickening of aortic, pulmonary and
  heart valves.
• 98 of aortas have some calcification by age 40

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Heart Changes

• Modest increase in left ventricular wall
  thickness (myocytes). This is exaggerated with
  hypertension.
• Slight enlargement of the left ventricular cavity
• Myocardial stiffness during contractions. The
  walls of the heart are less compliant

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Ventricular Hypertrophy

• The enlarged left ventricular wall has a
  decreased ability to expand during diastole.
• Results in reduced and delayed filling
• The left ventricle contracts less and ejects less
  blood.
• There is an increase in left atrium size,
  secondary to the decline in left ventricle
  compliance.
• This increases the work load on the atria.

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Vessel ChangesArterial

• Age causes the walls of the arteries to thicken
  and to become less flexible.
• Thickening results from cellular accumulation and
  matrix deposition.
• Increase in arterial diameter size accompanies
  thickening and loss of elasticity.
• Dilated vessels have a limited ability to dilate
  in response to increase blood volume.

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Vessel ChangesArterial

• The decrease in the elasticity of vessels results
  in
• Increased arterial pressure
• Increased peripheral resistance
• Residual increase in vessel diameter
• Vessel wall rigidity
• Fragmentation of the internal elastic membrane
• Increases in collagen and changes in
  cross-linking collagen which cause the vessel to
  be less elastic

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Vessel ChangesVenous

• The ability of the vessel to contract is
  decreased.
• Dilation and tortuosity of veins results in
  decreased venous return.
• The Frank-Starling relationship of the heart
  changes stroke volume which is dependent on
  venous return.
• Little research has been done on the aging veins
• The electrical excitability and responsiveness to
  the autonomic nervous system is less rapid and
  pronounced.

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Heart Rate

• Supine resting heart rate (HR) does not change
  very much with age.
• Sitting position HR decreases with age.
• Respiratory sinus arrhythmia decreases with age.
• 104 beats/minute at age 20
• 92 beats/minute at age 45-50

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Heart Rate

• The maximum exercise heart rate decreases with
  age.
• 200 beats/min at age 20
• 150 beats/min at age 80
• The decline in maximal heart rate with age is
  independent of fitness level.

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What is the maximum exercise heart rate ?

• Not all patients will have a graded exercise test
  (GXT) to determine the maximum heart rate.
• Most elderly patients do not have a GXT.
• Rule of Thumb to calculate estimated maximum
  exercise heart rate
• 220 minus the patients age
• patients with pathological conditions
• 200 minus the patient's age with a standard
  deviation of 10

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Stroke Volume

• No significant changes in resting stroke volume
  is seen with age.
• Age may effects stoke volume during exercise.
• Reduction in the rate of filling ventricles
  secondary to diminished diastolic compliance
  (preload)
• Filling in early diastole is less and is greater
  in later diastole
• Stroke Volume may be decreased during exercise

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Cardiac Output

• Cardiac Output Stroke Volume X Heart Rate
  (ml/min) (ml/cycles)
  (cycles/min)
• Declines slightly with age as a function of
  other age-related changes.

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Cardiac Output
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Blood Pressure

• Changes in blood pressure (BP) caused by aging is
  difficult to separate from changes in blood
  pressure caused by cardiovascular disease.
• There are very few elderly people with no
  cardiovascular disease in which to study normal
  BP changes.
• Blood pressure Cardiac Output X Total
  Peripheral Resistance
• Increases in BP with age is a result of changes
  in total
• peripheral resistance and aortic compliance.

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Blood Pressure

• Systolic BP tends to increase with age throughout
  life
• 5-8 mm Hg per decade after 40-50 years of age
• an index of arterial stiffness
• Diastolic BP tends to increase until the age of
  60, then it stabilizes or slowly declines
• Generally increases 1 mm Hg per decade

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Summary SlideAging Effects on the Heart

• Structural changes at the cellular level
• Decrease in SA cells and autonomic nerve function
• Thickening and calcification of heart and
• vessels
• Myocardial stiffness
• Decreased elasticity of vessels
• Decreased venous return
• Decreased maximum heart rate
• Changes in cardiac output,stroke
• volume and blood pressure

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All the changes that have beendiscussed so far
relate to a person at rest.
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What Happens When You Exercise ?
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• Perhaps the single, most salient and
  age-related difference is the diminishing ability
  of the body to respond to physical and emotion
  stress
• Carole Lewis
• Jennifer Bottomley

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Age-Related Changes During Exercise

• Aging changes (impairments) are seen when the
  system is stressed.
• The cardiovascular system must support the
  exercise by increasing O2 in working muscles.
• The Maximum Oxygen Consumption (VO2 max) is
  considered an indicator of cardiovascular fitness.

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Maximum Oxygen Consumption (VO2 max)
VO2max is the maximum amount of oxygen that your
heart can pump and your muscles can use in a
given period of time. VO2max is the product of
maximum cardiac output and maximum systemic
arteriovenous O2 difference.
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Just for Fun- Check this out!

• http//www.brianmac.demon.co.uk/vo2max.htmscore

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Changes During Exercise

• The response of heart rate to exercise is
  decreased in an elderly heart when compared to a
  younger heart. This is due to
• reduction of vagal tone
• impaired neural activation/release
• Stroke volume during exercise can be10-20 less
  in elderly patients compared to younger adults.

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Changes during Exercise

• Cardiac output increases with increasing loads.
• The reasons for increased cardiac output vary
  when comparing young adults and the elderly.
• In young adults, stroke volume is increased by an
  increased HR and decreased end-systolic volume
  due to beta-adrenergic stimulation
• In the elderly, stoke volume is increased by an
  increase in end-diastolic volume (shift in the
  Frank-Starling relationship).

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Maximum Aerobic Power(Aerobic Capacity)

• Aerobic Capacity declines 1 per year in adults
  when measured by VO2max. The measurement of
  VO2max is dependent on age-related changes in
• Maximum heart rate
• Cardiac output
• Decreased muscle mass
• Decreased skeletal muscle quality
• Older persons in good physical condition can
  match or exceed the aerobic capacity of
  unconditioned younger persons.

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Age-related Changes In Muscles
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Aging Muscles

• Age-related reductions in muscle mass are a cause
  of
• decreased muscle strength
• disability
• gait and balance problems
• Between 30-75 years old, the number and size of
  muscle fiber progressively deceases-sarcopenia

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Sarcopenia

• Healthy Young Adult
• 30 of weight is muscle
• 20 of weight is adipose tissue
• 10 of weight is bone

• Normal 75 Year Old
• 15 of weight is muscle
• 40 of weight is adipose tissue
• 8 of weight is bone

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Aging Muscles

• There is a decrease in total muscle
  cross-sectional area.
• 40 decrease by 80 years
• increase in fat and connective tissue
• decrease in protein synthesis
• The faster-contracting type II fibers decrease at
  a greater rate than type I fibers.
• Loss of maximum isometric contraction force
• replaced with fat and fibrous tissue
• angulated fibers and atrophy are seen in elderly
• Over time, Type I fibers greatly outnumber Type
  II fibers.

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Aging Muscles

• Blood flow to the muscles is decreased.
• Results in decreased endurance capacity.
• Capillary density decreases which makes less O2
  available during muscle work.
• Decreased Enzyme Activity
• Aerobic enzymes decrease resulting in
  mitochondrial decay.
• Increased mitochondrial DNA deletions and
  mitochondrial mutations appear.

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Neuromuscular Changes

• There is a decrease in the number of motor units
• Motor neuron innervates more muscle fibers
• Seen after 60 years
• More come in distal muscle groups
• The number and diameter of motor axons decreases.
• After 60, there is a reduction in spinal cord
  axons
• Surviving segmental neurons branch and display
  collateral growth.

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Changes is Muscle Performance

• Muscle strength decreases
• Beginning at 30, strength decreases 8 per
  decade.
• The rate of decrease is similar for both males
  and females,
• Muscle strength loss is greater in leg muscles
  than in arm muscles.
• There is a significant decease in strength by age
  70.
• 20 -40 decrease in maximal isometric strength
• Strength is related to sustainable walking speed

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Changes is Muscle Performance

• Power and Endurance
• Power rapid force generation
• Decreased power is associated with decreasing
  walking speed and a decreased ability to climb
  stairs.
• Endurance- stresses the cardiovascular system
• Contributes to functional loss
• Reduced blood supply
• Altered muscle contractibility and metabolism

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Changes is Muscle Performance

• Velocity
• The maximal speed of muscle contraction decreases
  with age
• This is seen in slowly moving elders.
• Also seen as the inability to quickly regain
  balance resulting in a fall.

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.
So far, two major aging systems have a
significant impact on an elderly persons ability
to move.

• What happens when you add exercise as your PT
  intervention to these aging systems

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Fact of Fiction ?
Resistive strengthening increases BP.
Increasing LE strength will improve walking.
Muscle bulk will never be normal.
Decreased endurance is a result of the aging
heart.
Active exercises is better than using weights to
protect joints.
Isometric contractions are a good indicator of
strength.
Fatigue is a part of aging.
Exercise improves function.
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How do you Assess the Need for Exercise ?

• How do you measure strength?
• How do you measure fatigue?
• How do you measure endurance?
• How do you measure muscle atrophy?
• How do you measure the success of the exercise
  intervention?
• How do you know the type and intensity for
  exercise?

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Age and Exercise

• Skeletal and cardiac muscle change according to
  the intensity, duration, and frequency of
  physical activity.
• Changes occur at the cellular, tissue, and
  performance level
• Exercise is one of the few interventions that can
  restore or improve physiologic capacity once it
  has been lost.

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Age and Exercise
Regular exercise benefits

• Preserve or improve skeletal muscle strength and
  aerobic capacity
• Improve bone density
• Increases insulin sensitivity and glucose
  tolerance
• Reduces resting BP
• Normalizes blood lipid levels
• Reduces fat
• Contributes of mobility and independence
• Decreases falls
• Reverses decline

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Exercise Specificity

• The type of exercise chosen elicits different
  changes in metabolic and physiological systems.
• Resistance training increases strength.
• Aerobic exercise increases endurance.
• Isometric exercise increases blood pressure????
• Strength and endurance training adaptations may
  occur independently or concurrently.

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Exercise Prescription
Many factors must be considered

• Medical conditions
• Medications
• Response to exercise
• Postural or physical limitations
• Cardiopulmony functioning
• Mental functioning
• Functional level
• Type of monitoring or supervision
• Motivation
• Goals

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Strength Training

• Increases muscle fiber size and enzyme activity
• Hypertrophy
• Increase in muscle volume without increase in
  mitochondria
• Elderly persons with disuse atrophy can increase
  muscle size with strength training.
• Increases bone mineral density

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Strength Training

• The intensity of the training, not the overall
  fitness level, determines the amount of gain in
  muscle strength and size.
• Strengthening exercises need to be performed at
  least 2 days/week for large muscle groups.
• Use one-repetition maximum as guide
• 60-89 of max is considered high intensity for
  the elderly
• Under very close supervision high intensity
  exercise yields good result in the frail elderly.

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Aerobic Exercise/Endurance Training

• Regularly performed aerobic exercise, not the
  undying fitness level, determines the amount of
  adaptive response.
• Adaptive responses include
• increased stroke volume and ventricular
  end-diastolic volume
• bradycardia
• improved myocardial contraction
• a slowing or reduction in the rate of bone loss
  (walking, jogging, stair climbing etc.)

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Adaptive Responses

• VO2max
• Rapid adaptation
• Men
• 2/3 augmented cardiac output, 1/3 to peripheral
  adaptations
• women form the peripheral adaptations
• Improved Skeletal muscle
• increase in number and size of mitochondria,
  enzyme activity and muscle size
• Increase in blood flow
• Glucose Tolerance

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Endurance Training

• Endurance exercises stresses the cardiovascular
  system.
• The American College of Sports Medicine (ACSM)
• of maximum heart rate
• rating of perceived exertion

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Endurance Training

• Exercises are continuous, rhythmical, use large
  muscle groups, and increase O2 consumption.
• The oldest old need endurance and strength
  training under close supervision.

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How do you determine how much exercise is too
much exercise?

• VO2Max is the best guide, but not practical for
  most situations.
• Target heart rate
• Medication may alter heart rate response.
• Cardiovascular disease may change heart rate
  guidelines.
• The Borg Perceived Exertion Scale - This is a
  different scale from the Borg Shortness-of-Breath
  Scale

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TestingIndividual Exercise Capacity

• Never exceed the persons approximated, maximum
  target heart rate.
• MD present for maximal stress test
• Submaximal tests to assess fitness
• See Exercise Testing Guidelines Box 15-3 page
  251
• Monitor the person closely for respiration, HR,
  BP, pulses and signs of undue stress.
• Know the patients medical history, functional
  level, mental status, and precautions.

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TestingIndividual Fitness for Exercise

• The test should measure the persons fitness in
  the method of the exercise, itself.
• Endurance tests
• 6-Minute Walk Test (page 253)
• Chair Step Test (page 253)
• Monitor patient
• Strength - One repetition maximum (1RM)
• Example, 60 of 1RM for no. of reps
• Use with Borgs test
• Monitor patient

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ExerciseA Guide from the National institute of
Aging

• http//www.niapublications.org/exercisebook/index.
  asp
• Go over the exercises found on pages 35-53

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Muscle Fatigue and Muscle Endurance

• Fatigue is the reduced ability of the muscle to
  achieve the same level of force output
• Endurance is the ability to sustain a force
  (approx. 50) for a period of time
• Clinically endurance and fatigue are used
  synonymously
• If a patient muscle fatigues, then endurance is
  reduced.
• If a patients endurance is low, the muscle will
  fatigue
• Motivation is an important aspect for both
  fatigue and endurance.

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Muscle Fatigue

• Muscle fatigue is a common complaint.
• As seen by the inability to maintain ROM
• As seen by quivering and shaking
• The causes of fatigue vary. Lack of muscle
  strength is a major contributor.
• The stronger the muscle, the less fatigue
• increasing strength increases muscle
  mass, function reduces fatigue
• increasing strength, decreases muscle anoxia

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Muscle Endurance

• Muscle endurance is related to the aerobic
  capacity of the muscle, which, in turn, is
  related to the number of mitochondria and the
  number of type I fibers.
• Muscle strength and aerobic condition are major
  determinants of muscle endurance.

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Tests and Measures of Fatigue and Endurance

• There is no agreement among therapists on one,
  valid test.
• Each therapist develops his/her own measure.
• Examples
• Fatigue Test
• How long a weighted upper extremity can climb
  a finger ladder.
• Endurance Test
• How long a patient can hold a muscle contraction.

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Age-related Changes In The Lung
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Pulmonary Changes

• Aging lungs are physiologically and anatomically
  similar to the lungs of patients with mild
  emphysema.
• In aging, there is a decrease in lung compliance
  and chest wall thickness.
• There are postural changes and calcification of
  intercostal cartilage.
• There is a weakened muscular force.

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Pulmonary Changes

• Airway size decreases
• The proportion of collapsible airways increases.
• There is a loss of elastic recoil.
• There is decreased air flow.
• Deceased diffusion of gases
• After 20 years, gas diffusion declines at a rate
  of 1.47 to 2.03 ml/minute/mmHg/decade
• estrogen?

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Other Age-related Changes
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Aging ChangesSkin

• Skin
• The skin wrinkles, looses
• elasticity and a decline in cell
• replacement occurs.
• The skin tears and blisters easily.
• There is a loss of dermal thickness (20),
  especially in sun-damaged skin.
• Skin neoplasms (benign and malignant) increase.
• Vitamin D production declines.

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Aging ChangesSkin
A gradual decline is seen in

• Touch (Meissners corpuscles)
• Pressure (Pacinians corpuscles)
• Temperature (Krauses corpuscles)

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Aging ChangesEye

• Ptosis, wrinkling and loss of orbital fat
• Lens- grows during life span, increasing in
  density and weight
• There is a progressive decrease in lens
  elasticity, so that by 40-50 years, you con no
  longer focus (presbyopia) and have to use reading
  glasses.
• Corrective lenses
• Aqueous humor- Increased introcular pressure as
  you age may lead to glaucoma.

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Aging ChangesEars

• Hearing loss accompanies aging
• 10 of U.S. population has hearing loss
• 33 of persons 65-75 years have hearing loss
• 50 of persons over 75 have hearing loss
• Presbycusis- aging of middle ear
• Ear drum loses elasticity
• Decreased 8th nerve sensitivity due to noise
  exposure
• Decline in hair cells of the cochlea
• Joints of the bones of the ear become stiff
• Mechanical blockage- earwax, effusion

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One note about oral health

• You do not loose teeth as a result of aging. With
  proper oral hygiene and regular dental visits,
  your teeth will last your entire lifetime.
• Gum disease (periodontal disease) does not occur
  as a result of aging. If an older person has
  trouble, manually, when brushing and flossing to
  prevent periodontal disease, there are many oral
  hygiene assistive devices available for use by
  older persons.
• If a patient has dentures, the dentures need to
  be evaluated on a yearly basis by a dentist and
  replaced frequently. As gum tissue changes with
  aging, dentures will not fit correctly, making
  chewing difficult.
• Altered salivary flow may necessitate the need
  for drinking more frequently when eating. There
  are also artificial salivas
  available for use.

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• The following slides are a quick review of
  normal aging and some pathological conditions
  associated with aging.
• Source The University or California, Academic
  Geriatric Resource Center

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Aging of the Organ SystemsThe End

• Next time we will look at the skeletal system and
  osteoporosis.