LC 3.2 - Changes in Structure and Function with Ageing Flashcards
At what age does FEV.1 level peak?
30 years
What four effects does ageing have on lung and chest-wall function?
Decreased lung elastic recoil
Decreased respiratory muscle strength
Increased chest wall stiffness
Decreased intervertabral space
What three effects does ageing have on lung gas exchange?
Decreased pulmonary capillary volume
Decreased pulmonary artery dispensability
Decreased lung surface area
What three effects does ageing have on the lungs ventilatory control?
Decreased responsiveness to hypoxia/hypercapnia
Decreased sensitivity to elastic and resistive loads
Decreased protective airway reflexes (leading to increased disease susceptibility)
What is the only organ to enlarge with age?
The heart (left ventricle)
Why does systolic blood pressure increase with age?
Larger elastic arteries become thicker and stiffer with age
What two effects does ageing have on cardiac function?
Stiffening of main arteries leads to left ventricular hypertrophy
Decreased beta-adrenergic stimulation decreases the hearts efficiency at increasing cardiac output when required (exercise)
What effect does ageing have on cardiac ejection fraction?
Ejection fraction does not change
What is postural hypo-tension?
Change in position (supine - standing) causes a temporary reduction in blood flow and therefore a shortage of O2 to the brain
Why is postural hypo-tension more common in the elderly?
ANS baroreceptors do not function as well with age and therefore the vasoconstriciton reflex which usually counters postural hypo-tension no longer occurs
Why is postural hypo-tension more dangerous in the elderly?
Risk of falls and blackouts increases
Risk of fractures and injuries increases
Where are baroreceptors located?
In the carotid sinuses
What do baroreceptors respond to?
Stretch in blood vessels
Define carotid sinus syndrome?
More blood to the head = more stretch detected by baroreceptors, they trigger vasodilation and decreased HR to compensate. In CSS baroreceptors respond to both internal stretch and EXTERNAL factors including shaving and turning of the head
What five effects does ageing have on the gastrointestinal system?
Decreased teeth Decreased taste-buds Decreased saliva Decreased HCL production Decreased gut motility
What effect does ageing have on the control of blood glucose?
Insulin works less efficiently to ‘pack away glucose’ via insulin resistance and decreased tissue sensitivity to insulin.
Risk of DIABETES increased
What effect does ageing have on osmoregulation?
Decreased sensation of thirst as production of ADH is less effecient, therefore old people have a poorer response to water deprivation.
Risk of DEHYDRATION increased
What effect does ageing have on drug handling bioavailability?
Decreased first pass metabolism via decreased liver size and blood flow, therefore more lipid soluble drugs are able to enter the circulation
What effect does ageing have on drug handling distribution volumes?
Decreased body water
Increased fat - can lead to the ‘hangover effect’ with sedative drugs as they may be retained in the fat the morning after leading to increased risk of falls
What four effects other than bioavailability and distribution does ageing have on drug handling in the body?
Increased passage across blood-brain-barrier
Increased tissue sensitivity
Decreased renal clearance
Decreased hepatic clearance
What four effects does ageing have on the immune system?
Decreased number and function of T-helper lymphocytes
Reduced size of thymus gland at 60
Reduced antibody production via B-cells
Decreased IgE production (less allergies)
Which latent virus has a 5-fold increased chance of re-activation in patients aged 45-85?
Shingles (re-activation of varicella-zoster-virus)
What four effects does ageing have on the renal system?
Decreased renal blood flow
Decreased kidney size
Decreased GFR
Decreased renin and aldosterone levels
What is presbyopia?
Difficulty with near vision onset usually post 50 - reading glasses required
What is presbyacusis?
loss of high frequency hearing due to degeneration of the cochlear cells
What type of memory loss is commonly found through increased age?
Declarative memory loss
Why do women have accelerated bone loss?
Menopause
