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Flashcards in Hemodynamics Ballam Deck (72)
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1

the rate at which blood is pumped from the ventricles is called the

cardiac output

2

cardiac output =

SV X HR

3

CO%: Cerebral

15%

4

CO%: Coronary

5%

5

CO%: Renal

25%

6

CO%: Gastrointestinal

25%

7

CO%: Skeletal muscle

25%

8

CO%: skin

5%

9

Three main mechanisms of distributing blood to the major organ systems: 1

CO is constant, but blood flow is redistributed among the organ systems by the selective alteration of arteriolar resistance

10

Three main mechanisms of distributing blood to the major organ systems: 2

CO increases or decreases, but %'s remain the same

11

Three main mechanisms of distributing blood to the major organ systems: 3

CO is altered AND %s are altered

12

Stressed Volume

the volume of blood in the arteries (under high pressure)

13

where is the site of highest resistance to blood flow

arterioles

14

arterioles have what kinds of receptors that do what

alpha 1 adrenergic receptors that cause vasoconstriction. vasoconstriction increases resistance

beta adrenergic receptors

15

at any given moment the greatest amount of blood is contained in the

veins

16

unstressed volume

% of blood in the veins (!00%)

17

veins have ____ receptors

adrenergic receptors, causing contraction and reducing their capacitance, therefore, reducing unstressed volume

18

velocity of blood flow =

v = Q/ A

Q = flow ml/s
A = cross sectional area (cm squared)

A = pi(r^squared), r= radius

19

the units of velocity are

cm/s

20

as vessel diameter increases, velocity

decreases, because radius in the calculation for Area is squared, so it continually gets bigger

21

the relationship between pressure, resistance, and flow: formula

Flow (Q) / Delta Pressure/ R

Q = P/R

22

the magnitude of blood flow is directly proportional to

size of pressure difference

Q = P/R

23

Blood flow is _____ proportional to resistance

inversely proportional

Q = P/R

24

TPR

total peripheral resistance

can be measured by substitution Q (flow) with CO, and the pressure difference between vena cava and aorta

25

SVR

systemic vascular resistance (SVR) = TPR

26

Poiseuille equation tells us what

the relationship between resistance, blood vessel diameter and blood viscosity

the Poiseuille equation allows us to determine the resistance of the a blood vessel to blood flow.

27

Poiseuille equation: formula

R = (8 * viscosity of blood * length of blood vessel)/ (radius of blood vessel raised to fourth power * pi)

28

What big picture relationshops of the Poiseuille equation can we talk about without seeing numbers?

direct and indirect relations, and that with each increase in the radius of the blood vessel, the numerator is reduced by fourth power of the radius

when radius increases, resistance decreases

29

Total resistance of the system arranged in series is

equal to the sum of the individual resistances

R+R+R

30

Which factor in total vascular resistance is the most determinant?

arteriolar resistance