Flashcards in Hemodynamics Deck (28):

1

## Mechanism of blood flow through vessels

###
-pressure differences drive blood flow through vessels

-difference between arterial and venous pressure drives blood flow through organ

2

## Location of highest pressure and highest resistence

###
-high pressure @ aorta

-largest drop in pressure/highest resistance @ arterioles

3

## Total blood volume

### ~ 5L

4

## Location of greatest blood volume

### -venous system = "capacitance vessels"

5

## Flow definition w/in context of CV system

###
-(Q)=volume per unit time (ml/min)

-constant throughout closed system

6

## Cardiac output definition

### -total flow in CV system

7

## Velocity definition w/in context of CV system

###
-(v)=distance per unit time (cm/sec)

-inversely related to cross-section area (A)

-velocity high w/small A (i.e. aorta) & velocity low w/high A (i.e. capillaries)

8

## Flow equation

###
-Q=P/R

-Q=flow

-P=pressure difference

-R=resistance

-aka CO=(mean arterial pressure - mean venous pressure)/total peripheral resistance (TPR)

9

## Poiseuille's Equation

###
-Q=P x (pi*r^4)/(8nl)

-Q=flow

-P=pressure difference

-r=radius

-l=length

-n=viscosity of blood

10

## Resistance of vessels in series vs. parallel

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-total resistance of vessels in series is higher than any individual vessel

-total resistance of vessels in parallel is less than the vessel with the smallest resistance

11

## Laminar flow definition

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-smooth, streamlined, most efficient

-velocity slowest at edge, fastest at center

12

## Turbulent flow definition

###
-irregular

-requires more pressure for same average velocity (vs. laminar)

13

## Factors that increase turbulent flow

###
-large diameter

-high velocity

-low viscosity

-abrupt diameter change

-irregularities on tube walls

14

## Pulsatile flow

### -heart pumps intermittently--pulsing flow through aorta; pressure is not constant

15

## Systolic vs. Diastolic pressure

### -peak aortic (~arterial) pressure vs. minimum aortic pressure

16

## Pulse pressure definition

### -pulse pressure=systole - diastole= 120 - 80 = 40mmHg

17

## mean arterial pressure (MAP) definition

### MAP ~ diastolic + 1/3(systolic - diastolic)

18

## Compliance definition/equation

###
-C=(change in V)/(change in pressure)

-represents the elastic properties of a vessel

-determined by proportion of elastin to collagen

19

## Arteriosclerosis

###
-loss of compliance cause by thickening/hardening of arteries

-some normal comes w/aging

20

## LaPlace Law equation

###
-T=(P*r)/u

-T=tension

-P=transmural pressure

-r=radius

-u=wall thickness

21

## Pressure/radius impact on Tension (i.e. in LaPlace Law)

### -Tension increases w/increasing pressure and radius --> hypertension increases stress on vessel/chamber walls

22

## Transformation of pulsatile flow --> continuous flow

### -degree of compliance in main arteries contributes to transformation of pulsatile flow deriving from heart to continuous flow @ capillaries

23

## Major types of transport of CV system

###
-bulk transport=cargo brought from point A to B

-transcapillary transport=movement of cargo between capillaries and tissues

24

## Fick's principle definition and equation

###
-considers how much of a substance is used by a tissue

-x(used)=x(in)-x(out)=Q([x]in - [x]out)

25

## Hydrostatic pressure definition

###
- ~blood pressure

-net hydrostatic @ capillaries: difference between pressure and interstitial pressure

-promotes filtration

26

## Oncotic pressure definition

###
-osmotic force created by proteins in blood and interstitial fluid

-alpha globulin and albumin = major determinants of oncotic pressure

-solutes move from high to low concentration vs. solvents move towards high concentration

-promotes reabsorption of fluid

27

## Starling equation

###
-Flux=k[(Pcap - Pint) - (Ocap - Oint)]

-k=constant

-Pcap=cap hydrostatic pressure

-Pint=interstitial hydrostatic pressure

-Ocap=cap oncotic pressure

-Oint=interstitial oncotic pressure

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