Brain flow Flashcards
Functional consequences blood flow to brain
vital for survival
performance
cognitive function
impairement - dementia, stroke, TBI/concussion
Effects of ageing on the brain
decrease size
exercise offset natural age-related decline in brain blood flow
aerobic exercise and brain blood flow positively related
Brain imaging techniques
MRI
ASL - arterial spin labelling
transcranial doppler
near-infrared spectroscopy
combination best
Consequences large changes in blood pressure during exercise
faint
drop in blood pressure
Cerebral blood flow regulators
cerebral autoregulation
cardiac output
blood pressure
metabolism
(para)sympathetic nerve activity
Brain blood flow responsiveness to CO2
increase CO2 = increase brain blood flow
Brain blood flow during exercise
increase to 65% VO2max
continue to rise as exercise intensity increases
max threshold = hyperventilation = BBF decrease
Dominant regulator BBF
PaCO2
Autoregulation due to
locally produced factors such as nitric oxide, prostaglandins and adenosine
Sympatholysis
local inhibition of sympathetic-induced vasoconstriction
Local increase in nitric oxide conc around arterioles =
vasodilation
Where is the greatest resistance to blood flow?
arterioles
What is the distribution of cardiac ouput to the heart in the transition from rest to exercise?
% cardiac output unchanged
volume blood increases
