Post on 11-Jan-2016
description
Actual amount of substance supplied (removed)
A = Q x ( Ca – Cv)
What determines flow (Q)
Q = (Pa – Pv)/R
Q
Low vascular resistance
High vascular resistance(vasoconstriction
Measurement of Q
Electromagnetic flowmeter
Doppler effect
Fick principle
Blood flow velocity
Q=10ml/s
A= 2cm2 10cm2 1cm2
V= 5cm/s 1cm/s 10cm/s
V = Q / A
a b c
flow
Vascular wall
murmur
Laminar high flow turbulent laminar
velo
city
Resistance to blood flow
Rt = R1 + R2 + R3…………. Resistance in series
1/Rt = 1/R1 + 1/R2 + 1/R3…. Resistance in parallel
SERIES PARALLELR1 R2 R3
R1
R3R2
x
xx
Redistribution in exercise
x
Viskoaity ↑ při ↓↓ Q (anomalous blood viscosity)
What determines R ?
Wall tension vasokonstriction
vasodilatation
Pro trubici platí
Laplace
r
Wall tension
Q
pressure pressure
Critical closingpressure
RECRUITMENT
exercise
Blood pressure
Q = (Pa – Pv)/R
systolic
diastolic
Blo
od
pre
ssu
re
(
torr
)M
ean
vel
oci
ty
c
m/s
ec
Velocity of blood flow
Q=10ml/s
A= 2cm2 10cm2 1cm2
V= 5cm/s 1cm/s 10cm/s
V = Q / A
a b c
SYSTOLIC SV
elasticity of aorta
DIASTOLIC R
heart rate
V
P