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Cardiac Physiology > Quiz 4, Part 1- Hemodynamics > Flashcards

Quiz 4, Part 1- Hemodynamics Flashcards

1
Q

As cross sectional area increases, velocity _____

Equation?

A

decreases

Flow= Velocity x Area
Velocity= Flow/Area
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2
Q

Ohm’s Law - What two factors determine blood flow thru vessel?

Equation?

A

voltage diff and resistance.

Q= (PressureArterial - PVenous) or ∆P= QxR
_____________________
Resistance

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3
Q

According to Ohm, increasing resistance ___ flow

A

decreases

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4
Q

According to Ohm, increases resistance ___ pressure

A

increases

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5
Q

Define BP

A

the force exerted by the blood against any unit area of the vessel wall

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6
Q

Conversion factor from mmHG to cmH20

A

1mmHg = 1.36cm h20 pressure

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7
Q

Cerebral perfusion pressure

A

MAP - CVP or ICP (whichever is higher)

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8
Q

What dose Poiseuille’s Law talk about?

A

Determinants of FLOW

1) Radius*
2) Viscosity
3) Length
4) Pressure Gradient (a.k.a gravity)

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9
Q

According to Poiseuille, flow is ___ proportional to the pressure gradient

A

directly

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10
Q

According to Poiseuille, flow is ____ proportional to the radius

A

directly

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11
Q

According to Poiseuille, flow is INDIRECTLY proportional to ____ and ____

A

viscosity and length

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12
Q

***According to Poiseuille’s law what factor has the greatest impact on the rate of blood flow thru a vessel

A

Radius to 4th power

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13
Q

If radius is doubled, flow increases by how much? Tripled?

A

16 fold

64 fold

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14
Q

What is resistance and can resistance be measured directly?

A

The impediment to blood flow in a vessel.

NO

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15
Q

SVR Formula?

Normal?

A

SVR= (MAP-CVP) x 80
_________
CO

700-1600

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16
Q

PVR Formula?

Normal?

A

PVR= (MPAP-PCWP) x 80
_________
CO

100-300

17
Q

Blood vessels in series =

A

R total= R1+R2+R3..

The sum of resistances of each vessel

18
Q

Blood vessels in parallel =

A

1/R1 + 1/R2 + 1/R3…

19
Q

Flow thru each of the parallel vessels is determined by

A

the pressure gradient and its own resistance

20
Q

If you add another blood vessel what happens to total vascular resistance

A

decreases

..d/t increase/widening of pressure gradient?

21
Q

Laminar flow is most related to

A

Viscosity

22
Q

Turbulent flow is most related to

A

Density

23
Q

Laminar flow - blood near vessel wall is ___, blood in middle is ___

A

slow, fast

= parabolic nature

24
Q

What formula predicts laminar vs turbulent?

Values?

A

Reynolds #
When > 2000, turbulence usually occurs*

<2000- laminar
2000-3000- variable
>3000- turbulent

25
Q

Reynolds number formula

A

(density x tube diameter x mean velocity)
________________________________
viscosity

26
Q

Increasing hematocrit ____ viscosity

A

increases

HCT= % of blood that is RBCs

27
Q

Reduced hematocrit causes ___ viscosity, which causes ____ (high or low) turbulence

A

decreased/ high

because viscosity is inversely related to Reynolds number

28
Q

Higher viscosity , ___ Reynolds #

A

decreases #

= more laminar flow/ less tendency for turbulent flow

29
Q

As blood pressure increases within a vessel.. why does FLOW increase much greater than one would expect?

A 
because of DILATION (arterial resistance decreased) and
Sympathetic stimulation (increasing pa-pv gradient)
30
Q

Flow takes the path of

A

Least resistance

31
Q

Whats a predictor of when laminar flow becomes turbulent?

A

Reynolds #

32
Q

What are the 3 factors that affect resistance?

Proportional or inversely proportional to resistance?

A

1) Radius- inversely proportional to 4th power
2) Viscosity- proportional
3) Length- proportional

33
Q

Vessel RESISTANCE is ____ proportional to radius to the 4th power

A

inversely

34
Q

FLOW is ___ proportional to radius to 4th

A

directly

35
Q

(Bernoulli) stenosis - Velocity ___ as diameter decreases

A

increases

36
Q

SVR is primarily determined by

A

vessel diameters

37
Q

When the volume of flow starts to decrease, arterial resistance ___. because the organ is saying I need ____!

A

decreases , dilates. volume… (doesn’t constrict thinking its a BP problem)

38
Q

Bernoulli Principle:

______ energy and _______ energy can be interconverted to that total energy remains unchanged

A

Kinetic energy

pressure energy

Cardiac Physiology (12 decks)

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