PERIPHERALRESISTANCE
The CV system lacks the capacity to perfuse all vascular
beds so we must direct flow where its needed when its
needed
It must reach's
Brain
spmacnic in
Kidneys Mainly flows
to muscle
Liver in
exercise
Muscles
Laminar vs turbulent flow
A Laminar Smooth flow in
layers with quickest at centre of
L lumen
T I n most blood vessels until a
critical velocity
B Turbulent Disordered with extensive mixing
Beyond critical flow past an obstruction
velocity or
clotting more
likely
, Audible bruits murmurs and Korat Koff sounds
Vascular resistance
A In series Different
categories of vessels Arteries
arterioles capillaries venules
veins
More resistance in series the
greater total resistance
B In parallel Within a vascular bed similar categories
of vessels are arranged in parallel
More resistance in parallel LESS TOTAL resistance
Blood flow meast
Doppler flow me try using the doppler shift of Sound
pulses bounced off blood cells to estimate their speed
Fick principle to estimate flow
Venous occlusion piethysmography
Extremity sealed in a watertight
container and its venous drainage
occluded Rate of flow into the
extre ity
is then proportional to the volume
change observed
The CV system lacks the capacity to perfuse all vascular
beds so we must direct flow where its needed when its
needed
It must reach's
Brain
spmacnic in
Kidneys Mainly flows
to muscle
Liver in
exercise
Muscles
Laminar vs turbulent flow
A Laminar Smooth flow in
layers with quickest at centre of
L lumen
T I n most blood vessels until a
critical velocity
B Turbulent Disordered with extensive mixing
Beyond critical flow past an obstruction
velocity or
clotting more
likely
, Audible bruits murmurs and Korat Koff sounds
Vascular resistance
A In series Different
categories of vessels Arteries
arterioles capillaries venules
veins
More resistance in series the
greater total resistance
B In parallel Within a vascular bed similar categories
of vessels are arranged in parallel
More resistance in parallel LESS TOTAL resistance
Blood flow meast
Doppler flow me try using the doppler shift of Sound
pulses bounced off blood cells to estimate their speed
Fick principle to estimate flow
Venous occlusion piethysmography
Extremity sealed in a watertight
container and its venous drainage
occluded Rate of flow into the
extre ity
is then proportional to the volume
change observed
