Peripheral Circulation & Hemodynamics

Front 1

Blood Vessel Distribution

Back 1

Front 2

Arrangement Vascular Circuits

Back 2

They are in parallel outside of the LV until the returning vena cava. The portion from RA to LV is in series.

Front 3

Distribution Blood vessels (summary)

Back 3

Distribution blood vessels (1000 fold increase X-Sectional area capillaries compared to arteries).

Front 4

Distribution blood volume

Back 4

Majority in venules & veins (lower resistance)

Front 5

Distribution blood pressures

Back 5

1. Very different in pulmonary circuit (gradient = 15-2mmHg) where systemic (gradient =100-0mmHg)
2. Resistance vessels = arterioles where BP ↓ the most (see graph)

Front 6

Equation BP, TPR, CO

Back 6

CO = (p(a.) – p(v.) /TPR

P1 = BP at input of vessel P2 = BP at outflow of vessel R = resistance Q = Volumetric blood flow
Volumetric Flow (m3/min) = (Velocity) (m/min) x (X-Sectional area) (m2)
Note: volumetric flow is constant (closed system)
Note: resistance = (conductance)-1

Front 7

Most important determinant Vascular Resistance

Back 7

Radius of vessel


Where:
R= 8ɳl/(πr^4 )
l =vessel length n = fluid viscosity r = radius

So although there are several factors to resistance the most dominant factor is the radius of the vessel.

Front 8

Vascular Compliance

Back 8

C= ∆V⁄∆P.
Where C = compliance V = volume P = pressure

Compliance is the equivalence of elasticity. The less compliant the less efficient the heart is.

Front 9

2 ways decrease vessel compliance causes poor cardiovascular fx

Back 9

Compliance is fx volume change allowed per unit pressure change. It effects efficiently greatly.
1. Vessels distend to buffer the systole pulse of pressure
2. Lose recoil & ability to “store “ the systole pressure for diastole portion

Front 10

Volumetric Flow Equation

Back 10

Volumetric Flow (m3/min) = (Velocity) (m/min) x (X-Sectional area) (m2)
Note: volumetric flow is constant (closed system)
Note: resistance = (conductance)-1