Section 2 Lecture 3 Flashcards
Benefit of our circulation being configured in parallel system:
each organ can have different metabolic levels/ permutations of blood flow
Pulmonary circulation is AKA:
central circulation
What is the stressed volume tanslocator ?
the heart
Produces the standing gradients:
stressed volume translocator
Which has higher pressure, L aorta or R aorta?
L (5 mm Hg vs. 2mm Hg)
Pressure in pulmonary artery:
20 mm Hg
pressure in aorta:
95 mm Hg (avg P in human aorta)
R =
(Change in P)/ Q
Change in P =
Q X R
Continuity of flow principle:
conservation of mass, what enters one end must exit the other
T or F. Pressure drop is uniform across each element of the circulatory system.
F. not uniform
Pressure across each part of the circulatory system is a function of:
the R of each element
Q =
(Change in P)/ R
What percentage of the total BV is in the capillaries and venous system?
65%
What percentage of the BV is in the arteries and arterioles?
2-%
High Pressure Reservoir:
arteries (not arterioles, right?)
Volume reservoir:
the capillaries and venous system
Pressure of blood entering capillaries:
20-25 mm Hg
What percentage of the total BV is in the high pressure reservoir?
20%
What % of BV is in the arterioles?
15%
Is there a larger BV in the higher pressure reservoir or the arterioles?
HPR
The greatest pressure drop in the cardiovascular system occurs here:
arterioles
Why is the change in pressure NOT proportional to flow in the circulation?
bc the flow is constant throughout
Pre-capillary resistance vessels:
arterioles
These vessels have a high variable resistance:
arterioles
Slope of the line graph of change in pressure vs. flow?
1/R = conductance
What does the slope of the line graph of change in pressure vs. flow?
Conductance (1/R)
T or F? The change in pressure, the resistance and the flow all stay constant throughout the circulatory system.
T
This is the ease with which fluid can pass thru tube:
condunctance
What happens if you decrease slope of the line graph of change in pressure vs. flow?
increase resistance
If you decrease resistance in a vessel how will the conductance be effected?
it will increase
If you decrease resistance in a vessel how will the flow be effected?
it will increase
How does our circulation regulate flow given that the driving force is the same throughout the system?
alteration of the resistance of the vessels
What is the head pressure and what is the tail pressure in our circulatory system?
head- pressure in aorta
tail - pressure in right atrium
T or F L and R heart always give the same output.
F. In the health individual they should
CO of avg heart:
5L/min
Resistance in the systemic portion of our circulation for healthy adult:
28 mmHg/L/min
Resistance in the pulmonary portion of our circulation for healthy adult:
3 mmHg/L/min
The pressure on the pulmonary side of our circulation is what fraction of that of the systemic?
1/6
Why is the systemic circulations pressure so much higher?
longer (6 times greater resistance) increase length, increase SA bw lamina, decrease velocity, decrease flow
How much harder must the LV work to drive the same flow as the R ventricle?
6 times harder
T or F? Resistance is proportional to tube length.
T
T or F? Resistance is proportional to fluid viscocity.
T
T or F? Resistance is proportional to tube radius^4.
F.
T or F? Flow is proportional to presure gradient.
T
T or F? Flow is proportional to tube radius^4.
T
T or F? Flow is proportional totube length.
F inversely
T or F? Flow is proportional to viscocity.
F. inversely
Flow =
(Pressure gradient X tube radius^4)/ (tube length X viscosity)
Double the radius you will increase the flow rate how many times?
16 times (2^4 = 16)
What is the relationsihp bw resistncne and flow?
4th power relationship bw resistance and flow
If you increase the surface area bw the lamina you increase:
pathway length
If you decrease the # of lamina you decrease:
pathway resistance
What confers viscositiy on blood?
% of RBC
too many RBCs in blood:
polycythemia
How will anemia change resistance?
lowers resistance (lower hematocrit) throughout the whole body
Viscosity goes down, flow will go:
up
What is the typical hematocrit % range?
35-50% hematocrit
Viscocity of water:
1cP
viscosity of plasma:
2cP
Normal range of viscocity of blood:
2.8 - 4cP
If viscosity changes it’s effects on the circulation will be:
Universal
T or F? BV’s change length in a fully grown adult.
F
T or F? Viscosity is a highly regulated term
T
If (Pa-Pv) is decreased, how will the flow though each organ system be effected, if at all?
flow will decrease in all organ systems
If the viscosity (n) increases how, if at all, will the flow though each organ system be effected?
flow will decrease in all organ systems
If the radius of the vessels in one organ system increase, how will it affect the flow through the other organ systems?
it won’t effect the other organ systems (why wouldn’t it decrease in the other systems? If overall flow is the same, when one organ system gets a higher flow rate, the others must get a lower flow rate, right? I guess this is an isolated system and not what would happen in our body?)
How is the flow in one organ system kept the same while the flow through another is increased due to an increase in vessels radius?
the heart adjusts the CO
velocity =
flow/X-area
T or F? Smaller tubes have a smaller cross sectional area.
F. larger
What does continuity of flow mean in our CS?
larger x sectional area = slower fluid flow
cross sectional area of aorta vs. capillaries:
4 cm^2 vs. 3,000cm^2
Flow through aorta vs. flow through capillaries:
20 cm/s in aorta - 0.03 cm/s (very slow)
Capilllaries provide both:
larger surface area and slower rate of flow
Which have a larger X-sectional area, arteries or veins?
veins 4 vs 6cm^2
is the X-sectional area of the capillaries of the lungs greater or those of the extremities?
lungs (really?!)
Laminar flow
Running along its own streamline pathway through the vessel
Streamline flow
silent flow
The sounds that stethoscopes can hear are a result of _____ flow
turbulent
When does turbulent flow occur in the healthy individual?
Only when rapidly ejected out of the heart in normal conditions
the greatest velocity with which a fluid can flow through a given conduit without becoming turbulent:
critical velocity
Q/P for laminar flow increases ____ while turbulent flow increases in this fashion.
linearly, non-linearly (greater change in P with each change in Q)
Flow is proportional to what in turbulent flow?
to square root of delta P (less efficient)
