Physiological Changes and Adaptation in the Older Adult Flashcards
Muscle strength
Peaks at 30
Constant loss after 50 (20-40% by age 65 in the nonexercising adult)
Changes in muscle fiber composition
loss of type II fast twitch and increase in proportion of type I fibers
Collagen changes
Denser, irregular due to cross linkages, loss of water content and elasticity - affects tendons, bone, cartilage
CT becomes
denser and stiffer
leads to inc risk of sprains, strains, tendon tears
Loss ROM
inc risk of adhesions and contractures
Gait changes
Dec amp and speed, slower cadence
Shorter steps, wider stride, inc DS, dec trunk rotation and arm swing
Cartilage changes
Dec water content
becomes stiffer, fragments, erodes
by age 60 more than 60% of adults have degenerative changes and cartilage abnormalities
Bone mass
Peak bone mass at 40
Dec between 45 and 70
Loss of Ca, dec bone marrow RBC production
IVD changes
flatten, less resilient due to loss of water content (30% loss by age 65) and loss of collagen elasticity, trunk length and overall height dec
Postural changes
Forward head
Kyphosis of thoracic
Flattening of lumbar
Hip and knee flexion contractures with prolonged sitting
Clinical implications - Skeletal changes
Maintenance of WB is important
Nerve cells
Atrophy of them in cerebral cortex
overall loss of brain weight 6-11% between ages of 20 and 90
Accelerating loss after age 70
Brain morphology
Gyral atrophy
Ventricular dilation
Loss in cortex (esp frontal and temporal)
Presence of lipfuscins, senile, or neuritis plaques and neurofibrillary tangles (NFT)
More selective loss in BG
Changes in SC and peripheral nerves
Neuronal loss and atrophy - 30-50% loss of anterior horn cells
30% loss of posterior roots/sensory fibers by age 90
Vision changes
Rapid decline between ages 60 and 90
visual loss high as 80% by age 90
Presbyopia
visual loss in middle and older ages characterized by inability to focus properly and blurred images due to loss of accommodation, elasticity of lens
Cataracts
Opacity, clouding of lens due to changes in lens proteins
results in gradual loss of vision - central first, then peripheral
Glaucoma
increase intraocular pressure with degeneration of optic disc, atrophy of optic nerve
results in early loss of peripheral vision (tunnel vision) - progressing to total blindness
Senile macular degeneration
Loss of central vision associated with age related degeneration of the macular
dec blood supply or abnormal growth of blood vessels underneath the retina
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
CVA - homonymous hemianopsia
Loss of half of visual field in each eye (nasal half of one and temporal half of the other)
Hearing changes
Occur as early as fourth decade
Conductive hearing loss
mechanical hearing loss from damage to external auditory canal, tympanic membrane, or middle ear ossicles
Results in hearing loss, tinnitus might be present too
Sensorineural hearing loss
central or neural hearing loss from multiple factors (noise damage, trauma, disease, drugs, arteriosclerosis)
Presbycusis
Sensorineural hearing loss associated with middle and older ages
characterized by hearing loss, esp at high frequencies at first then all freq.
poor auditory discrimination and comprehension esp with background noise
tinnitus
Changes in vestibular/balance system
Degenerative chnages in otoconia of utricle and saccule
Loss of vestibular hair cell receptors
dec number of vest neurons
VOR gain dec
begins at age 30 and acc decline between 55 and 60
Menieres disease
Episodic attacks characterized by tinnitus, dizziness, and a sensation of fullness or pressure in the ears
may also experience sensorineural hearing loss
BPPV
Brief episodes of vertigo (less than 1 min) associated with position change
result of degeneration of the utricular otoconia that settle on the cupula of the post semicircular canal
Somatosensory changes
Dec sensitivity of touch associated with decline of peripheral receptors
atrophy of afferent fibers
LE more affected than UE
Propriocetive changes
Loss
Inc threshold to vibratory sensibility - beginning around age 50 - greater in LE and UE and greater in distal vs. proximal extremities
Age related cog changes - what age
Not until mid-60s
significant decline impacting everyday life not until early 80s
Heart mm changes
degeneration with accumulation of lipfuscins
mild cardiac hypertrophy (LV wall)
Cardiac valves thicken and stiffen
Coronary blood flow
dec
Changes in BVs
arteries thicken and are less distensible
slowed exchange through capillary walls
inc peripheral resistance
Resting BP
rises
sys greater than dias
Stroke volume
dec due to dec contractility
Pulmonary - chest wall and lungs
Chest wall stiffness
loss of lung elastic recoil
dec lung compliance
Lung parenchyma
alveoli enlarge, become thinner, fewer capillaries for delivery of blood
Pulmonary BV changes
thicken and are less distensible
Total lung capacity
dec
resdual lung vlume inc
vital capacity dec
FEV
dec
