(03) p1-38

Question 1

(Resistance)

1. total peripheral resistance (TPR) = ?
2. R = change in P/?

Answer 1

1. Net R of systemic circulation = systemic vascular resistance (SVR)
2. Q

(systemic resistance is about 7 times pulmonary)

so if pumonary resistance is lower, why isn’t pulmonary blood flow so much greater? pulmonary vessels are very compliant

Question 2

(Resistance)

1. What would happen if pulmonary resistance were to increase dramatically?

(pulmonary hypertension)

2. what effect would this have on heart and pulmonary vessels?
3. would pulmonary vessels change?

Answer 2

1. pressure will go up - “pulmonary hypertension”
2. right ventricle has to eject higher pressure to eject blood (get hypertrophy)
3. yes, in a number of different ways…

(heartworm disease causes increased resistance and pulmonary hypertension)

(dog with heartworm)

Question 3

(Conductance)

1. conductance = ?
2. define it

Answer 3

1. 1/resistance
2. measure of blood flow thorugh a vessel for a given P difference

Question 4

(Conductance)

1. Why does blood flow increase so much with increased width?
2. bascially the blood further from the walls can flow faster - closer to wall goes slower
3. she says not to memorize equation - but be familiar

Answer 4

Question 5

(Poiseuille’s Law)

1. the rate of blood flow is directly proportional to what?
2. what has the greatest effect on blood flow through it?
3. resistance is directly proportional to what? inversely proportional to what?

Answer 5

1. the 4th power of radius
2. vessel’s width
3. blood viscosity and vessel length; r^4

Question 6

Question 7

another case…

mean arterial pressure is pretty normal - lots of compensatory mechanisms

RAP is high

Answer 7

continued onto next slide

Question 8

Answer 8

why did blood pressure fall? increased vessel radius, decreased vessel resistance

What are the 2 main determinants of MAP?

blood volume and flow, degree of vasoconstriction

Why might have RAP declined?

increased in vascular capacitance (more storage in veins), increased CO

Question 9

(Resistance)

1. what (in total) are the site of greatest increase in R to blood flow?
2. total peripheral R (TPR) = ?
3. Arterioles also provide what kind of R?

Answer 9

1. arterioles
2. systemic vascular R (SVR)
3. adjustable R (control amount of flow to different organs)

Question 10

(Resistance)

(series circulation)

1. total R = ?

(parallel circuations - what is in most of body)

2. total R = ?

Answer 10

1. sum of individual R’s
2. 1/sum of conductances

Question 11

(Properties of Blood flow - Laminar Flow)

1. flow in streamlines - velocity in any layer is constant over time
2. where is velocity highest?
3. “parabolic flow profile”
4. little flow near wall - why?
5. fewer or more cells toward wall?

Answer 11

2. in center (slowest toward wall)
3. increased shear near wall
4. fewer

Question 12

(Properties of Blood Flow - Turbulent Flow)

1. disorganized flow - velocity at X varies
2. eddy currents (whorls), cause increased what? thus turbulence creates what?
3. turbulence occurs with what three things?

Answer 12

2. increased friction of blood flow; increased resistance to flow
3. increased flow velocity, obstruction, vessel turn

Question 13

(Reynold’s number)

1. a measure of what?
2. as viscosity increases what happens?

Answer 13

1. the tendency for turbulence to occur
2. the tendency for turbulence decreases

Question 14

Answer 14

aorta (big vessel), obstruction (plaque), anemia, malformed heart valves, increased CO,

Question 15

(What do you think might be some clinical manifestations of abnormally turbulent flow)

1-2. what are the two?

Answer 15

1. murmurs
2. vascular dilation

Question 16

(Critical Reynold’s Number)

1. When critical number exceeded, what occurs?

Answer 16

1. enough turbulence to cause audible vibrations (murmurs)

(plus check these out…)

Question 17

1. With sudden stenosis or obstruction - what happens?
2. what does this result in across the narrowed area?

(xsa = cross sectional area)

Answer 17

1. RBC accelerate
2. pressure gradient

Question 18

(Simplified Bernoulli Relationship)

1. Quantifies relation between what and what?
2. by measure peak RBC velocity we can predict what?
3. an estimate of what?
4. in example p gradient = ?
5. systolic BP at aortic root = ?

Answer 18

1. P gradient and velocity
2. the P gradient across an obstruction
3. severity

Question 19

(so how do we measure velocity?)

Answer 19

Question 20

she’s not going to test us on this

first question

Answer 20

lower across M and T because its bigger