Arterial System Lecture Block 10

Arterial System Lecture Block 10

Arterial System

Bioengineering 6000 CV Physiology

Vascular Structure/Function

Arterial System

Bioengineering 6000 CV Physiology

Functional Overview

Arterial System

Vessel Structure

Bioengineering 6000 CV Physiology

Aorta Diameter 25 mm

Wall

2 mm

thickness

Artery 4 mm

1 mm

Vein 5 mm

0.5 mm

Vena Cava 30 mm

Arteriole Capillary Venule 30 ?m 8 ?m 20 ?m

1.5 mm

6 ?m

0.5 ?m 1 ?m

Endothelium Elastic tissue Smooth Muscle Fibrous Tissue

Arterial System

Bioengineering 6000 CV Physiology

Aortic Compliance

? Factors:

? age

? athersclerosis

300

? Effects

? more pulsatile flow ? more cardiac work

200

dV

C =

dP

? not hypertension

20--24 yrs 30--40 yrs 50-60 yrs

Blood Volume [%]

Laplace's Law

100

(thin-walled cylinder): T = wall tension

T = Pr

P = pressure

r = radius

70--75 yrs

For thick wall cylinder P = pressure = wall stress r = radius w = wall thickness

= Pr w

100

150

200

Pressure [mm Hg]

Aorta Capillary

Tension [dyne/cm] 2 x 105

15-70

Wall Stress [dyne/cm2] 10 x 105

1.5 x 105

Arterial System

Bioengineering 6000 CV Physiology

Arterial Hydraulic Filter

Arterial System

Bioengineering 6000 CV Physiology

Arterial System as Hydraulic Filter

? Pulsatile --> smooth flow

? Cardiac energy conversion

? Reduces total cardiac work

Cardiac Output

Arterial Pressure

t

Physiological

t

Ideal

Cardiac Output

Arterial Pressure

t

Pulsatile

t Challenge

Cardiac Output

Arterial

Pressure

t

Filtered

t Reality

Arterial System

Bioengineering 6000 CV Physiology

Elastic Recoil in Arteries

Arterial System

Bioengineering 6000 CV Physiology

Effects of Vascular Resistance and Compliance

Arterial System

Bioengineering 6000 CV Physiology

Cardiac Output vs. Runoff

Arterial Pressure/Flow

Arterial System

Bioengineering 6000 CV Physiology

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