actual amount of substance supplied (removed)

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