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32 Cards in this Set
- Front
- Back
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How many ml of blood in each heart beat |
70 ml |
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Explain the steps in a cardiac contraction |
Pressure rises in LV, exceeding that of the Aorta. Aortic valve opens, blood ejected, BP rises |
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An increase in heart rate also increases.... |
Blood volume |
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What factor determines the amount of blood entering the arterial system |
Cardiac output |
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What factors determine the amount of blood that LEAVES the arterial system |
Arterial pressure and total peripheral resistance |
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What serves as a type of reservoir for blood volume storage and energy supplied to the system |
The arteries |
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Movement of any fluid medium between 2 points requires these 2 things |
1. A pathway along which fluid can flow 2. Pressure differential (higher pressure E to lower pressure E) |
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The AMOUNT of blood flow depends on these 2 things |
1. Energy difference (includes losses resulting from fluid movement) 2. Any resistance which tends to oppose such movement |
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In regards to flow rate....lower resistance=_____, higher resistance=______ |
Lower resistance=higher flow rate Higher resistance=lower flow rate |
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The total energy contained in moving fluid is the sum of_____, _______, and________ energies |
Pressure, kinetic, and gravitational energies |
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Stored (potential) energy that is released when walls recoil. Major form of Energy for circulation of blood, and is expressed in mmHg. |
Pressure energy |
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Velocity. Expressed in terms of fluid density and its velocity measurements (cm/s) Small for circulating blood. |
Kinetic energy |
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Hydrostatic pressure (HP) is equivalent to the weight of the column of blood extending from the heart to level where pressure is measured. |
Gravitational energy |
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When a patient is standing as opposed to supine, HP increases by ________mmHg against ankle vessels |
100 mmHg |
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Relates to the tendency of a fluid to resist changes in its velocity. |
Inertia |
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As blood moves farther out to periphery, energy is dissipated largely in the form of_________ |
Heat |
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Energy is continually restored by_____ |
Pumping action of the heart |
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Movement of a fluid (blood) is dependent upon....._______, and________. |
Physical properties of the fluid, and what its moving through |
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R= 8nL / ñr^4 |
R- resistance n- viscocity L- vessel length r-radius ñ- pie |
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What has the biggest effect on resistance |
Vessel diameter |
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Internal friction within a fluid is measured by its........ |
Viscocity |
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What type of energy is lost as RBC's rub against each other |
Heat |
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Elevated hematocrit increases what |
Blood viscocity |
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What does severe anemia do to blood viscocity |
Decreases it |
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Is hematocrit level directly or inversely proportional to resistance |
Directly proportional |
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Is blood viscocity directly or inversely proportional to velocity |
Inversely proportional |
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2 characteristics of Laminar (stable) flow |
1. Evenly distributed frequencies during systole. 2. Higher frequency flow in center of vessel. Stationary layer remains at the wall. |
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Where are you likely to see plug flow (blunted flow) |
At the vessel origin as well as during initial cardiac upstroke. |
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This type of energy loss is due to increased friction between molecules and layers. |
Viscous |
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This most significant type of energy loss occurs with deviation from laminar flow due to direction and/or velocity changes (bends in vessel, bifurcations) and also occurs at the EXIT of a stenosis. |
Inertial |
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What does poiseuilles equation define |
The relationship between pressure, volume flow, and resistance. Also helps definehow mich fluid volume moves through vessel. |
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Poiseuilles equation |
Q= P/R Q- volume flow P- pressure R- resistance |
