BM - Cardiovascular Biomechanics

Laws governing fluids

Laws governing fluids

Law of conservation of mass, navier sokes law

Navier stokes equation is for flow in a…

Cylinder

The sum of forces per unit volume is equal to…

density times acceleration

The Navier Stokes law governs what 4 properties?

velocity, pressure, viscocity, height

This equation describes…

Steady inviscid flow

The Bernouli equation describes what 3 properties?

velocity (constant), pressure, height

If the Reynolds number of a fluid is < 2300, it is considered _____ flow.

Laminar

If the Reynolds number of a fluid is >= 2300, it is considered _____ flow.

Turbulent

Number 1

Right atrium

Number 2

Right ventricle

Number 3

Left Atrium

Number 4

Left ventricle

Number 5 (5L & 5R)

Pulmonary artery

Number 6

Aorta

Number 7

Superior vena cava

Number 8

Inferior vena cava

Number 9

Pulmonary veins

Letter A

Tricuspid valve

Letter B

Pulmonary valve

Letter C

Aortic valve

Letter D

Mitral valve

Letter E

Septum

The aorta pumps blood into the…

Left ventricle

The right ventricle is in a _________ shape.

Semilunar

The left ventricle is a _______ shape.

Globular shape

The right ventricle contracts…

Top to bottom

The left ventricle contracts…

Diameter and logitudinal

The myocardium makes up ____% of cardiac thickness.

95

Myocardium is made up of 90% _______ and 5% ______.

Fiber bundles, collagen

Myocardial cells are connected to each other by specialized gap junctions called ______________.

Intercalated disks

The only node that is electrically connected

AV Node

The SA node has how many action potentials per minute?

60-80 per minute (same as heartbeat)

The QRS complex occurs at the end of…

Atrial systole

In an EKG, the R peak occurs when the…

AV valve closes

In an EKG, the S dip occurs when the…

Semilunar valve opens

Bottom LEFT of a pressure/volume graph

Mitro valve opens

Top LEFT of a pressure/volume graph

Atrioventricular (tricuspid) valve closes

Top RIGHT of a pressure/volume graph

Atrioventricular (tricuspid) valve opens

Bottom RIGHT of a pressure/volume graph

Mitro valve closes

The cardiac cycle moves in a ________ direction on a pressure/volume graph.

• Counterclockwise

• Clockwise

Counterclockwise

The stroke work is the ______ of a pressure/volume graph.

• Area

• Change in volume

• Change in pressure

• Pressure at the top right curve

• Maximum pressure

Area

The stroke volume is the ______ of a pressure/volume graph.

• Area

• Change in volume

• Change in pressure

• Pressure at the top right curve

• Maximum pressure

Change in volume

The diastolic blood pressure is the ______ of a pressure/volume graph.

• Area

• Change in volume

• Change in pressure

• Pressure at the top right curve

• Maximum pressure

Pressure at the top right curve

The systolic blood pressure is the ______ of a pressure/volume graph.

• Area

• Change in volume

• Change in pressure

• Pressure at the top right curve

• Maximum pressure

Maximum pressure

Mean arterial pressure formula

(1/3)(SBP + 2DBP)

Stroke volume

Change in volume

Cardiac output

Stroke volume * Heart Rate

Cardiac index

Cardiac output / body surface area

Stroke work

Stroke Volume * (mean arterial pressure)

Power (of the heart)

Stroke work * Heart rate

Frank-Starling Law: Ventricular contractility (_________) is proportional to ventricular filling volume (_________)

Stroke volume, pre load

In a normal heart, as after-load increases, stroke work __________.

Increases

Stroke volume will only drop if the after load becomes…

Extremely high

In a pipe-circuit mock, the resistance is the…

Resistance

In a pipe-circuit mock, the change in pressure is the…

Voltage

In a pipe-circuit mock, the current is the…

Flow rate

In parallel, the flow rates are…

Summed

In parallel, the pressure drops are…

Equal

In series, the voltage drops are…

Summed

In series the flow rates are…

Equal

Systemic vascular resistance is

1 PRU

Pulmonary vascular resistance is

0.1 PRU

Δp =

Res * Q

The following properties describe what type of flow?

• Newtonian fluid

• Laminar flow

• Rigid walls

• No slip at walls

• Fully developed, steady flow

• Cylindrical vessel

Hagen-Poiseuille

High shear stress causes what on the blood?

Platelet activation, hemolysis

Low shear stress causes what on the blood?

Platelet aggregation/adhesion

RBC destruction occurs at 10³ (dynes,cm2). This leads to…

Poor oxygen supply

Platelet activation/destruction starts occuring at 10², but can cause…

Clotting

The peak Reynolds number in the body is 5100, which occurs when…

The aortic valve closes

Normal blood flow in the arteries is turbulent or laminar?

Laminar

Freely floating entity in the blood

Emboli

Buildup of plaque in arteries

Atherosclerosis

The three types of ___________ are regurgitation, stenosis, and atresia.

Valvular diseases

Expansion and eventual bursting of arteries.

Aneurysms

Which type of cells actually experience wall shear stress in the circulatory system?

Endothelial cells

Doppler limitations

• Many layers of arteries

• Velocity is different throughout the body

  • We have to assume neglibile viscosity

Any sort of narrowing of a tube, can be caused by atherosclerosis

Stenosis

Atherosclerotic lesions occur at…

Curvature, bifurcation, branches

2/3 of the time the blood vessels experience some pressure is in the _____ region.

Diastolic

Pulse Pressure

SBP - DBP

As a rule of thumb, PP should be…

SBP * 1/3