physiology of aging Flashcards
parts of the pulmonary system affected by aging
elastic recoil
bony thorax
ventilatory muscles
respiration
change in REEP with age
increases with age because residual volume increases
less air is under volitional control
change in elastic recoil
lungs increase compliance, elastic recoil decreases
changes in bony thorax with aging
compliance decreases
bones become stiffer, more pressure to inhale same amount of air
respiratory muscles and aging
decreased number of muscle fibers
change in length tension relationship
breathing becomes more energy expensive
overall change in compliance of the respiratory system
decreased, bony thorax has a greater effect
changes in pulmonary function with age
ventilatory reserve goes up
only 70% of air is useable
even worse with smoking
alveolar changes during aging
decreased elastic recoil
less surface area for gas exchange
capillary changes during aging
decreased capillary bed
decreased perfusion for gas exchange
changes in diffusion with aging
for every year beyond 60, there is a reduction of 1mmHg in PaO2 from a baseline of 90mmHg
PaO2=90-(age-60)
change in cardiac output with aging
max decreases, because HRmax decreases, SVmax decreases
rest values DONT change
what causes circulatory changes with aging
automaticity
conductivity
contractility
excitability
load changes
pre load: blood in ventricle before systole; decreases
after-load: amount of resistance in the aorta to keep the heart from pushing out more; increases
heart becomes “actively insufficient”
diffusion changes
capillary size and number are decreased decrease muscle mass PaO2 is lower decreased gradient for gas exchange O2 has a long enough pathway to get into the capillary bed as it is, but the gradient decreases makes diffusion harder
compliance
change in volume/change in pressure
