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CardiovascularDynamics

Schematicof

CirculatorySystem

systemiccircuit

pulmonarycircuit

heart

left atriumleft ventricle

aortapulmonaryarterypulmonaryveins

The Heart

inferiorvena cava

The Heartsuperior

vena cava

right ventricleright atrium

pulmonaryartery

pulmonary veins

bicuspidvalve

aorticsemilunarvalve

tricuspidvalve

pulmonarysemilunar

valve

Heart Valves

BloodFlow

Throughthe

Heart

2

ContractionCycle of the

Heart

ContractionCycle of the

Heart

ContractionCycle of the

Heart

BloodVessel

Structure

simplesquamousepithelium

smoothmuscletissue

connectivetissue

Arteries• Carry blood away from the heart.

• Thick-walled to withstandhydrostatic pressure of theblood during ventricular systole.

• Blood pressure pushes bloodthrough arteries.

Veins• Carry blood to the heart.• Thinner-walled than arteries.• Possess one-way valves

that prevent backwardsflow of blood.• Blood flow due to body

movements, not fromblood pressure.

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One-WayValves in

Veins

Schematicof

CirculatorySystem

systemiccircuit

pulmonarycircuit

heart

Schematicof

CirculatorySystem

systemicarteries

pulmonaryarteries

capillarybeds

capillarybeds

systemicveins

pulmonaryveins

Blood Pressure

Mechanics of CirculationSome Definitions

Blood FlowBlood Pressure

Peripheral ResistanceBlood Viscosity

Factor InfluencingPeripheral Resistance

Blood ViscosityVessel RadiusVessel Length

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Poiseuille’s Equation

Blood Flow (∆Q) = πΔPr 4

8ηl

Poiseuille’s Equation

π = pi ( ≈ 3.14)

Blood Flow (∆Q) = πΔPr 4

8ηl

Poiseuille’s Equation

ΔP = pressure difference

Blood Flow (∆Q) = πΔPr 4

8ηl

Poiseuille’s Equation

r = vessel radius

Blood Flow (∆Q) = πΔPr 4

8ηl

Poiseuille’s Equation

η = blood viscosity

Blood Flow (∆Q) = πΔPr 4

8ηl

Poiseuille’s Equation

l = vessel length

Blood Flow (∆Q) = πΔPr 4

8ηl

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VesselResistance

Pump MechanicsSome Definitions

End Diastolic Volume (EDV)End Systolic Volume (ESV)

Cardiac OutputStroke Volume (SV = EDV - ESV)

PumpMechanics