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aging
aging
114
Anatomy
Graduate
11/07/2013

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Term
what are the 3 general theories of the cellular basis of aging?
Definition
1. wear and tear damage from internal and external sources; 2. damage from accumulation of internal byproducts of normal metabolism; 3. genetic predeterminatin of life=span of cell that exists within the cell nucleus
Term
what are external sources that cause toxic damage of chromosomes or genes?
Definition
irradiation, chemicals, infection
Term
what are internal sources of wear and tear damage
Definition
repeat usage that produces change in mechanical structure
Term
how does the accuulatio nof internal byproducts of normal metabolism induce cellular aging
Definition
as a result of metabolism, you have byproducts that escape degradative processes and accumulate. With accumulation, they produce damage.
Term
what does the genetic predetermination of life-span of cells determine?
Definition
the age that we will reach, and the way aging will manifest: pretty or not so prety?
Term
what are current recommendations for long life
Definition
nutritious and low cal diet, exercise, red wine in moderation, avoid stress, life partner, optimistic attitude, continued lifelong education, no smoking, old parents
Term
what are the general effects of aging
Definition
decrease in blood supply to tissues, decrease in number of reparative cells, less extensible tissues secondary to increased collagen fiber cross-links, decrease in metabolic activity of reparative cells
Term
what is the result of decreased metabolic activity of reparative cells
Definition
decreased capacity for healing, decreased inflammatory response, healing tissue is structurally weaker => need to be patient with these patients!
Term
up to what age does tensile strength and density increase in bone
Definition
30
Term
how to promote tensile strength and densith in bone?
Definition
good diet with dairy products, dark green leafy veggies, normal menses, limit caffeine
Term
describe rates of bone change after age 30
Definition
increased rate of bone loss secondary to increased rate of bone resorption without increased rate of bone deposition
Term
what are the results of bone resorption
Definition
decreased bone densit, decreased number of trabeculae, decreased cortical and trabecular thickness
Term
what is osteoporosis
Definition
decreased mass of bone/volume, increased porosity
Term
how does strength of bone change in aging
Definition
decreases
Term
how does brittleness of bone change with aging
Definition
increases
Term
how do osteocytes change with aging
Definition
decreased cellular metabolic activity, decreased number
Term
what is the result of decreased osteocytes
Definition
decreased production of collagen/ground substance matrix
Term
how does the percentage of mineral content to collagen in bone change with aging, and what are the results
Definition
increase in mineral content percentage because of less collagen. This causes increased porosity with more calicum content, creating bone that is more brittle
Term
how does decreased estrogen in postmenopausal women effect bone?
Definition
decreased estrogen levels in women results in less inhibition of bone resorption
Term
what determines the degree to which women have more bone loss than men?
Definition
anatomic site
Term
what is the bone loss of femoral neck for women compared to men
Definition
women lose bone at a rate that is 150% the rate of loss for men. 2:1 ratio, therefore, for hip fractures.
Term
what is the bone loss in the lumbar spine for women compared to men
Definition
the rate is 4 times greater for older women than for older men. There is an 8:1 ratio for lumbar vertebral body fractures for older women compared to older men.
Term
how to help older women reduce lumbar spine fractures
Definition
stretch tight anterior soft tissues, add a little strength in the back extensors, and do postural training so they can achieve a more extended spine position
Term
what is senile osteoporosis
Definition
decreased bone mineral density that occurs with age in cortical and trabecular bone, primarily in women and to a lesser degree in men
Term
what is postmenopausal osteoporosis
Definition
excessive trabecular bone loss in women associated with decrease in estrogen levels and vertebral body fractures
Term
how to prevent senile osteoporosis
Definition
exercise
Term
bone mineral density of what bones are maintained in older runners
Definition
spine, lower extremities
Term
how does Tai Chi affect BMD in the elderly?
Definition
Tai Chi improves BMD AND decreases fall risk = big!
Term
how does strength training affect bone density in older adults
Definition
increases
Term
what effect do steroids have on bone
Definition
25% of patients receiving long-term steroid treatment will develop an osteoporosis-related fracture
Term
what to say to patients on long-term steroid treatment
Definition
counsel prevention of osteoporosis and fall prevention through exercise, making sure things are asfe in the home, take a multivitamin, strengthen
Term
what are the effects of excessive loading on bone in older adults
Definition
excessive loading from abdominal flexion exercises and posture can cause fractures in the spine
Term
how does articular cartilage change with aging
Definition
increased water, decreased ground substance, decreased collagen density
Term
what is the result of decreased ground substance and collagen density in aging articular cartilage
Definition
increased permeability with loading.
Term
what is the result of increased permeability of articular cartilage
Definition
decreased time of loading, which increases the contact force.
Term
what offsets the problem of increased permeability of aging articular cartilage?
Definition
increased water helps maintain the time of deformation
Term
what causes increased wear of articular cartilage with aging?
Definition
increased stiffness of subchondral bone results in increased compressive stress on the articular cartilage AND proteoglycan loss decreases corss-links between collagen fibers
Term
how to intervene to reduce effects of aging on articular cartilage?
Definition
attenuate contact force and improve contact area to reduce contact pressure, do exercises that involve fluid film lubrication, repair ligamentous insufficiencies, modify/redirect activites that damage articular cartilage, moderate exercise, brace for instabilities with low level loads
Term
how to attenuate contact force on articular cartilage?
Definition
F = mv/t; several ways
Term
how to improve contact area of articular cartilage
Definition
address malalignments to increase contact area and reduce soft tissue forces
Term
what to consider with bracing for articular cartilage effects of aging
Definition
bracing is only effective for activites that involve low level loads transmitted across joints. They can't have forceful activities where the muscle tendon forces cause shearing across joints
Term
how does exercise help articular cartilage?
Definition
increases GAGs
Term
describe the structure of intervertebral discs
Definition
nucleus pulposus is surrounded by an annulus fibrosus and bordered superiorly and inferiorly by the cartilaginous vertebral endplates
Term
what is the structure of the annulus fibrosu
Definition
arranged in 10-12 sheets or lamellae: thick anteriorly and laterally but thin and packed tighter posteriorly, an area of structural weakness
Term
what is the result of the posterolateral weakness in the annulus fibrosus
Definition
at risk for bulging, lesions
Term
what is the structural organization of the annulus fibrosus
Definition
orientation of collagen fibers in each sheet is oblique, with alternating obliqueness in each sheet.
Term
who do the collagen fibers alternate direction in each sheet of the annulus fibrosus?
Definition
if they all went in the same direction, you'd only have strength in that one direction. This way, the entire structure with all he sheets together is much stronger in tensile stress
Term
what part of the intervertebral disc disperses pressure so that you don't get focal areas of high pressure?
Definition
fluid/water in the nucleus pulposus provides pressure dispersion to avoid focal areas of high prsesure
Term
what would happen if you had focal areas of high pressure in the intervertebral disc
Definition
the disc in that region would undego damage, and the vertebral body in line with that secion of the disc would also be damaged
Term
what is the job of the nucleus pulposus of the intervertebral disc
Definition
to even out the pressures that are transmitted so that they go across the entire disc and therefore across the entire vertebral body
Term
when is dispersion of pressure especially important
Definition
for off-center loading, such as on one side
Term
what would happen if pressure was not distributed across all regions
Definition
compression fracture in vertebralbody
Term
what is required for adequate dispersion of pressure in an intervertebral disc?
Definition
a lot of water in the disc
Term
when the intervertebral disc is compresse,w hat happens
Definition
compression raises pressure in the fluid filled nucleus pulposus. Pressure is then directed radially into the annulus, rasing tension in the annulus fibers
Term
what happens when the annulus fibers feel tenson
Definition
they provide a reaction force against the nucleu to resist further radial expansion of the radius and so that nuclera pressure is exerted evenly on the vertebral end plates
Term
what happens once the vertebral end plates feel pressure from the nucleus pulposus?
Definition
contact pressure is then distributed from the vertebral end plates to the next vertebral body
Term
what are the structural changes in the nucleus pulposis with aging?
Definition
decreased proteoglycans, decreased water, decreased chondroitin sulfate, increased collagen, increased collagen-proteoglycan binding
Term
what is the amount of decrease of proteoglycans in the nucleus pulposus by age 60?
Definition
decreased proteoglycans from 65% of dry weight to 30% of dry weight by age 60
Term
what is the result fo decreased proteoglycans
Definition
decreased strength of the tissue
Term
how much water is lost from the nucleus pulposus with aging
Definition
6% decrease in water during adulthood
Term
what are the results of the decrease in water in nucleus pulposus?
Definition
decrease in water makes tissue less able to distribute pressure throughout nucleus. You then see focal areas of pressure going through vertebral end plates and into vertebral body below
Term
what does chondroitin sulfate do in the nucleus pulposus
Definition
binds water in the nucleus
Term
what are the effects of loss of chondroitin sulfate in nucleus pulposus
Definition
explains why we're losing water
Term
how does increased collagen-proteoglycan binding change the look of the nucleus pulposus
Definition
type II collagen of the nucleus takes on the appearance of Type I collagen of the annulus = the nucleus becomes more like the annulus
Term
what is the annulus's job
Definition
to be a container for the nucleus
Term
why is it bad when the nucleus pulposus has more collagen-proteoglycan bind that causes it to look more like the annulus?
Definition
we need the water filled-nucleus contents to distribute pressure, not act like a container. Without pressure distribution, we see focal areas of damage in the disc and in the vertebral body below' the stiffer nucleus is less able to recover from creep deformation
Term
is there more or less distinction between annulus and nucleus with aging
Definition
less
Term
what are the effects of aging on the annulus fibrosus
Definition
decrease in diameter of collagen fibrils, loss of proteoglycans, decrease in elastin fibers, fibrillations in age that can form fissures
Term
what is the result of the decrease in diameter of collagen fibrils of the annulus fibrosus
Definition
lost cross-sectional area of the individual fibers
Term
what is the result of the loss of proteoglycans in the annulus fibrosus
Definition
increase in percentage of collagen content, meaning the tissue is weaker
Term
how much loss of elastin fiber occurs in the annulus fibrosus from age 26 to 62
Definition
13% at age 26, 8% at age 62
Term
what is the result in decreased elastin fiber content in the annulus fibrosus with age
Definition
the tissue is stiffer, less extensible = easier to damage
Term
what is the problem with fibrillations with age in the annulus fibrosus
Definition
they may enlarge into fissures that allow protrusion of nucleus material
Term
how does the size/shape of intervertebral discs change with age
Definition
discs enlarge in anterior-posterior diameter as well as height by 10% from age 20 to 70 as the vertebral body endplates fail and become concave
Term
why do we get an overall loss in height despite this growth of the intervertebral discs?
Definition
there is more collapse/failure in vertebral end plates than increase in size of the disc
Term
how does smoking affect your risk for intervertebral disc injury?
Definition
increases your risk for prolapsed disc
Term
how does smoking affect your ability to recover from discectomy
Definition
makes it harder to repair and recover
Term
why is smoking so bad for intervertebral discs?
Definition
nicotine reduces the number of viable cells, reduces GAG and collagen syntehsis: bad for all reparative cells
Term
what to consider for the aging spine to help out the intervertebral discs
Definition
not too much magnitude, duration, and frequency. Avoid smoking. Good posture to avoid focal concetration of loads
Term
why is it good to have good posture when you age
Definition
may help avoid focal concentration of loads in discs that are less able to distribute load throughout the disc and are less capable of withstanding focal loading of weaker annulus material
Term
if you have kyphotic posture and you are an older adult, what problems are happening
Definition
the nucleus has less water, the annulus is weaker. The pressure on the anterior portion of the disc from kyphotic posture is not dispersed well to the posterior portion, so there is increased compression on the anterior portion of vertebral bodies
Term
what are the effects of aging on the meniscus
Definition
fraying, increased proteoglycans, increased CPPD crystals, increased hydroxyapatite crystals, overall increased stiffness
Term
what contributes to increasd fraying of meniscal edges
Definition
loading
Term
what is the rsult of increased CPPD and hydroxyapatite crystalsin the menisus
Definition
make the tissue stiffer, increases stress concetration between areas where the crystals are, increases chance of lesion
Term
what is the effect of these component changes that cause the meniscus to be stiffer
Definition
it is less able to act as a shock absorber and distribute pressures over a larger area of articular cartilage; it is more likely to fail itself, and it is worse at protecting articular cartilage
Term
what are the effects of aging on tendon?
Definition
no great change in ultimate strength of tendon with aging until the 7th decade since thetendon is half dead to begin with
Term
what are the effects of aging on ligament
Definition
increased avulsion fracture risk because bone is getting weaker and ligament is still pretty strong since it doesn't change a lot with aging.
Term
what change really does happen with tendon and ligament with aging
Definition
increase in stiffness with aging secondary to an increase in cros-linkage binding between adjacent collagen fibers, therefore slightly weaker material that reaches greater levels of stress with accessory motions secondary to increased stiffness.
Term
after age 20, what is the occurrence of loss of strength of tissues?
Definition
skeletal muscle becomes weaker at 20, cartilage becomes weaker at 30, bone also gets weaker at 30 but doesn't fall as quickly as catilage, tendon gets weaker at 70
Term
what to consider with aging tendon/ligament interventios
Definition
modulate magnitude, duration, and frequency of loads. Progressively increase these variables. Be patient withhealing
Term
why do you have to be patient with healing tendon and ligament
Definition
they have a lack of blood supply and they are metabolically sluggish
Term
why is progressive increase in magnitude, duration, and frequency required for tendon and ligament
Definition
give the bone time to catch up: avoid avulsion fracture
Term
are older people more at risk for chronic or acute musculoskeletal consitions
Definition
chronic
Term
which type of muscle fiber atrophies faster
Definition
Type II.
Term
which type of muscle fiber has a greater decrease in number of fibers
Definition
Type ii
Term
describe type ii muscle fibers
Definition
type II are the large motor units. The individual fibers are larger in cross section than Type I fibers.
Term
when do you use type ii muscle fiber
Definition
when you are in a hurry
Term
why is older muscle less able go generate large muscle force
Definition
less type ii muscle fibers
Term
what is the lost muscle tissue replaced with?
Definition
fibrous connective tissue
Term
what does the loss of type ii fibers + replacement of fibrous connective tissue add up to
Definition
loss of overall ability to produce peak tension, torque, and angular work = hard to cross the street in a hurry!
Term
what is an operational definition of endurance
Definition
how long it takes to get a 50% decrement in torque (for example)
Term
how are operational definitions of endurance effected in older muscle
Definition
relatively unaffected; they produce less peak force, so it takes them just as long to get to the point of 50% peak force
Term
what is a benefit of aging and muscles
Definition
decreased blood supply means less intense inflammatory response after injury, meaning less scar tissue
Term
what are some downfalls of aging and muscle
Definition
fewer and less metabolically active satellite cells to help with healing, lower levels of strength attainable
Term
what are the implications for fewer and lessmetabolically active satellite cells
Definition
requires patience with healing and rehabilitation efforts
Term
what are the effects of aging on proprioception
Definition
loss of proprioceptoin: decreased ability to detect that your joints have moved, and decreased ability to replicate joint position
Term
what are the effects of aging on simple and complex reaction time
Definition
both are increased, meaning a decreased ability to respond to internally or externally imposed perturbations during rehab or functional activities
Term
how do sweat rates change with aging
Definition
sweat rates decrease
Term
what is bad about decreased sweat rates
Definition
you need to dissipate heat when you're exercising. Without sweat, you'll get greater bloodflow to the skin to try to dissipate heat through radiation. Thes means there is less bloodflow available for working muscles. And the working muscles are at a disadvantage already ebcause they're atrophied. so now the atrophied muscles don't have as much oxygen. and you're hot.
Term
what lung changes occur with aging?
Definition
decreased lung functinal surface area for gas exchange: can't get oxygen in and CO2 out; increased airway resistance; decreased vital capacity
Term
how does mean arterial pressure change with aging, and what does that mean
Definition
increases: so you may have trouble controlling your blood pressure
Term
what are reasons why mean arterial pressure increases with aging
Definition
vessles are stiffening, less extensible AND there is stuff in the lumen of the blood vessels = atherosclerosis
Term
how does cardiac stroke volume change with aging and what does this mean
Definition
decreased cardiac stroke volume: with each pumping fo the left ventricle, you aren't sending as much blood out. This adds up to decreased capacity to do work. Heat overload, inability to exchange gases as well, inability to deliver oxygen to the muscles. don't expect as much performance from older individuals
Term
summarized cardiopulmonary reasons for reduced exercise capacity
Definition
less able to dissipate heat, reduced capacity to oxygenate blood, reduced capacity to deliver blood to working muscles, reduced blood supply to cardiac muscle
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