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Phys. Exam 2 Hemodynamics
Hemodynamics
37
Physiology
Graduate
10/12/2010

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Term
Blood has 3 forms of energy:
- ____ energy due to position.
- _____ energy due to ____ ___ and ____ ____ commonly called ___ ____.
- ___ energy due to motion.
Definition
- gravitational
- pressure aka blood pressure
- kinetic
Term
One form of energy can/cannot be transferred to another type of energy.
Definition
can
Term
When blood speeds up through a narrowing, it gives up ____ energy to become ____ energy.
Definition
- pressure
- kinetic
Term
At the top of a oolumn filled with fluid, the ____ energy is 0, but the _____ energy, due to position, is greater at the top of the column than at the bottom.
Definition
- pressure
- gravitational
Term
At the bottom of a column filled with fluid the ____ energy increases proportionally to the height of the column, but ____ energy decreases proportionally to the height of the column.
Definition
- pressure
- gravitational
Term
In a column of fluid, the ____ is greater at the bottom, but this balanced by a greater ____ energy at the top. These energies balance each other so that there is no movement in the column. This is an example of how fluid does NOT always flow from high to low pressure.
Definition
- pressure
- gravitational
Term
In a static column of fluid the sum of the ____ energy and ____ energy everywhere is always the ____, thus there is no ____. So even though the pressure throughout is different, and the gravitational energy throughout is different, their sum is always the same.
Definition
- pressure
- gravitational
- same
- no movement
Term
In a supine position, there is no significant ____ ___ factor. Pressure at any point while laying flat is due to energy imparted by the ____ minus the energy ____ by ___ ____.
Definition
- no significant gravitational hydrostatic pressure
- heart
- dissipated by the vascular resistance
Term
In a supine position, the ____/____ blood pressure at the foot is close to that at the heart b/c large arteries/veins have ____ resistance.
Definition
- arterial/venous
- low

arterial pressure at heart= 100 mm Hg, foot and head- 95 mm Hg.

venous pressure at heart 2 mm Hg, at foot and head 5 mm Hg.
Term
In a static column of fluid there is __ flow but there is still a ___ ____.
Definition
- no
- pressure gradient
Term
There is a big ___ between a foot artery and a foot vein, so blood going from a foot artery to a foot vein gives up ____ as ____ in the microcirculation of the foot.
Definition
- gradient
- gives up pressure as heat
Term
When there are differences in height, as there are in a standing person, the blood pressure is the sum of the ___ ___ due to the ___ ___ and the pressure due to ____.
Definition
- driving pressure due to heart contraction
- pressure due to height
Term
deltaP across the foot is the difference between ___ pressure and ____ pressure.
Definition
- arterial pressure
- venous pressure
Term
look at slides 6 and 7 from this lecture and make sure you know how to calculate and understand what it means.
Definition
Term
volume of flow= ___ of flow x ___ area.
Definition
- volume of flow= velocity of flow/cross sectional area
Term
Blood is flowing from a moderate tube, to a smaller tube, and back into a moderate sized tube. The volume of flow is the same in all three tubes, but since the ____ ___ is much smaller in the small tube, ___ of ___ must increase in order to keep the same volume of flow. This also means that ___ energy increases a lot when going through the ___ tube.
Definition
- cross sectional area is smaller
- velocity of flow must increase to keep same volume of flow
- kinetic energy increases
Term
____ always decreases along a tube going from left to right. So flow always goes from high ___ to low ____ but does NOT always go from high pressure to low pressure.
Definition
- Energy
- high energy to low energy
Term
blood going from a moderate tube, to a smaller tube, to another moderate tube, will have the highest kinetic energy where? Highest pressure and total energy?
Definition
- small tube
- first moderate tube
Term
Blood vessels get smaller in some areas, so blood ___ increases, but if the pressure pushing out on these walls gets lower than it should be, you get vessel wall vibration which can break free a plaque and lead to embolism.
Definition
- velocity
Term
pressure in a small tube that has come from a moderate tube is ____ b/c of some of that pressure has transitioned into ___ energy.
Definition
- lower
- kinetic
Term
The fundamental relationship between flow, pressure gradient, and resistance is represented by what equation? This assumes that there are no additional energy gradients due to ___ or ___ energy.
Definition
F= deltaP/R

F= blood flow
delta P= difference in pressure at two points along the vessel

R= hydraulic resistance to flow b/w the two points along the vessel

- no gravitational or kinetic energies accounted for in this equation
Term
Pressure is ___ as blood flows along a ___.
Definition
- dissipated
- vessel
Term
In the equation F= deltaP/R, what value of R would stop flow and what pathological condition would cause this?
Definition
- infinite R
- total obstruction of an artery
Term
Circulation is designed to maintain a nearly constant high ____ blood pressure and a nearly constant low ____ blood pressure. Thus, blood flow through all tissues can be regulated by controlling the ____ of regional vessels, especially _____.
Definition
- arterial
- venous
- resistance
- arterioles
Term
equation for systemic vascular resistance:
Definition
system vascular resistance (SVR)

SVR= (mean arterial pressure-mean right atrial pressure)/ cardiac output
Term
The cardiac output to systemic circulation and pulmonary circulation is the same, ___ is just lower in pulmonary circulation.
Definition
- resistance
Term
How do you calculate resistance of resistances in series?
Definition
- when vessels are in series you just sum the individual resistances

Rt= R1 +R2 + R3
Term
How do you calculate total resistance when resistances are in parallel?
Definition
- inverse of the total resistance is equal to the sum of the individual inverse resistances

1/Rt= 1/R1 + 1/R2 + 1/R3
Term
With a parallel series, the total resistance is more/less than those of the individual arteries.
Definition
total is less
Term
Poiseuille's Law helps determine ___ resistance. Define and explain it and its variables.
Definition
- vascular
R= (8nL)/(pix r^4)

n= eta, viscosity of fluid
L= length
r= radius
Term
Flow is proportional to what?
Definition
deltaP/resistance

r^4/nL
Term
resistance is proportional to the ___ of the fluid and to __ of the tube.
Definition
- viscosity
- length
Term
since r is raised to the fourth power in Pouisell's law, a constant driving force with a small decrease in diameter will do what?
Definition
- greatly increase resistance and decrease flow
Term
Poiseuill's law applies to laminar flow, and blood flow is laminar. Explain what this means.
Definition
- flow in the center of the tube is going faster than flow on the sides of the tubes b/c there is the most reistance along the sides of the tubes
- so blood in center is moving the fastest
Term
The alternative to laminar flow is ___ flow. Explain.
Definition
- turbulent flow
flow not always going down tube, it can go around, uses much more energy, causes vibrations that can damage the vessel, you can hear the vibrations in your stethoscope
Term
so if there is a disease in the carotid artery and is constricted, you will increased velocity of flow, also due to the decreased outward pressure vibrations will occur.
Definition
Term
polycytemia:
Definition
increased red blood cells so blood is more viscous
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