Term
| causes of The first heart sound |
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Definition
| "LUB" is produced by the closing of the AV valves at the onset of systole...occurs as soon as ventricular pressure exceeds atrial pressure |
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Term
| Things that make S1 heart sound more intense |
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Definition
| shortened PR interval, mild mitral stenosis, high cardiac output |
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Term
| Things that make S1 heart sound less intense |
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Definition
| longer PR interval, mitral regurgitation |
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Term
| causes of the second heart sound |
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Definition
| "DUB" is produced by closure of the semilunar (aortic and pulmonic) valves...this occurs when P in the ventricle falls below the pressure in the corresponding great a. |
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Term
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Definition
| S2 can be heard split because in normal adults the aortic valve closes before the pulmonic |
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Term
| causes of clicks heard early in systole |
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Definition
| aka ejection clicks...indicate the presence of aortic or pulmonic stenosis |
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Term
| causes of clicks heard in mid or late systole |
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Definition
| usually due to the bulging of prolapsed mitral or tricuspid valves into the corresponding atrium |
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Term
| cause of an opening snap during diastole |
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Definition
| opening snap of a mitral or tricuspid valve can be heard after S2 when either of the valves is stenosed |
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Term
| Cause of a 3rd heart sound and when does it occur? |
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Definition
| occurs during diastole, during the rapid filling phase of the ventricles. Is thought to be due to excessive oscillation of blood back and forth between the ventricular walls as blood rushes in from the atria...may be due to vibration of the tissue that anchors the av valve leaflets |
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Term
| fourth heart sound causes and timing |
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Definition
| occurs in late diastole. Results from atrial contraction into a stiffened, (low compliance) ventricle. |
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Term
| 3 Causes of systolic murmurs |
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Definition
1.) Aortic or pulmonic valve stenosis (crescendo/decrescendo)
2.) mitral or tricuspid valve insufficiency
3.) Interventricular septal defects |
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Term
| 2 causes of diastolic murmurs |
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Definition
1.) mitral stenosis
2.) aortic insufficiency
(rarely diastolic murmurs are caused by tricuspid stenosis or pulmonary artery insufficiency because there is less pressure on the right side |
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Term
| continuous murmur and the most common of these |
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Definition
| a continuous murmur occurs throughout all of systole and diastole. probably the most common of these is caused by a patent ductus arteriosus |
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Term
| To and fro murmurs and what causes them |
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Definition
| to and fro murmurs occur during parts of systole AND diastole...to and fro murmurs occur when an outflow valve is both stenosed and insufficient |
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Term
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Definition
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Term
| Hydrostatic pressure equation |
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Definition
| Pressure=density of fluidxgravity constantx height of fluid above point |
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Term
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Definition
| the pressure generated by blood movement |
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Term
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Definition
| sum of hydrostatic and dynamic pressures |
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Term
| Total resistance of resistors arranged in series |
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Definition
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Term
| total resistance of resistors arranged in parallel |
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Definition
| 1/R(total)=1/R1 + 1/R2 + 1/R3.... |
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Term
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Definition
1/R
*flow is directly proportional to conductance |
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Term
| Poiseuille's Law equation |
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Definition
| 1/R={(pi)(radius^4)}/{8)(viscosity)(length of tube) |
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Term
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Definition
viscosity= (Force/area)/ (velocity)/(distance)
or shear stress/shear rate, when shear stress=the force that must be applied to a second sheet to make it move faster and shear rate=the velocity gradient between two sheets |
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Term
| Reynold's number equation |
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Definition
indicates the propensity for turbulent blood flow
Reynold's number= density x tube diameter x velocity/viscosity |
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Term
| equation for total energy |
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Definition
| E= potential E + {fluid density(velocity)^2}/2 |
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Term
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Definition
| Wall tension=transmural pressure x radius/wall thickness |
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Term
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Definition
SV=EDV-ESV
(Is the volume ejected per beat) |
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Term
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Definition
blood flow per unit time
CO=SV x HR |
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Term
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Definition
Cardiac Output/surface area
Compensates for the fact that larger individuals have greater cardiac outputs |
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Term
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Definition
The amount of work the heart does during a single contraction..specifically
SW=VPPxSV
where VPP is ventricular pulse pressure (the peak pressure minus end-diastolic pressure) and SV is the stroke volume |
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Term
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Definition
Tension=Pressure x radius
Describes PRELOAD tension (the resting tension prior to a contraction) |
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Term
| Equation for ventricular compliance |
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Definition
| compliance= change in volume / change in P |
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Term
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Definition
SV/EDV
Is the % of blood ejected in a single beat |
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Term
| Treppe/Staircase Phenomenon/Bowditch effect |
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Definition
| states that an increase in heart rate will directly produce an increase in contractility, which will cause an increase in the stroke volume |
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Term
| Equation for left ventricular stroke work |
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Definition
LVSW=LVPP x SV OR [h x (a+b)]/2
where
LVSW= left ventricular stroke work
LVPP= left ventricular pulse pressure (peak pressure-end diastolic pressure)
h=width of pressure-volume loop
a=pulse pressure generated during isovolumetric contraction phase
b=the pressure at the point of aortic valve closure |
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Term
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Definition
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Term
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Definition
| The work done to generate pressure and eject blood...is the area of the pressure=volume loop |
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Term
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Definition
| the work done by the heart prior to the development of pressure....the work done against the non-contractile elements of the heart |
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Term
| comparison between volume work and pressure work |
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Definition
| for equal amounts of external work performed by volume loading (increased preload) or pressure loading (increased after load)...the volume-loaded heart will have LES oxygen consumption and generally be more efficient |
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Term
| Cardiac efficiency equation |
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Definition
| cardiac efficiency=work performed/oxygen uptake |
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Term
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Definition
Flow=Quantity Consumed/ arterial content-Venous Content
OR
Cardiac output=whole body oxygen consumption/ (arterial blood oxygen content-pulmonary artery blood) |
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Term
| Resistance vessel examples |
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Definition
| arterioles and precapillary sphincters |
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Term
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Definition
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Term
| capacitance vessel example |
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Definition
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Term
| relationship between velocity of blood flow and cross sectional area of vessels |
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Definition
| as increase cross sectional area of vessel, decrease velocity of blood |
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Term
| equation for blood flow using velocity and cross sectional area |
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Definition
| Blood Flow=velocity x cross sectional area |
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Term
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Definition
| systolic pressure-diastolic pressure |
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Term
| physical factors which influence arterial blood pressure |
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Definition
| arterial blood volume and arterial compliance |
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Term
| physiological factors which influence arterial blood pressure |
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Definition
| cardiac output (HR x SV) and peripheral resistance |
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Term
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Definition
| the transfer of blood from the arterial circulation into the capillaries and vv during diastole |
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Term
| mean arterial pressure and how to calculate it |
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Definition
the average pressure of the blood perfusing the capillaries during a cardiac cycle
MAP can be determined from the area under the pulse curve divided by a period of time
OR
MAP can be approximated by adding diastolic pressure to 1/3 of the pulse pressure
OR
MAP=Cardiac output x total peripheral resistance |
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Term
| equation for change in arterial pressure over time |
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Definition
| change in arterial pressure/time= CO- Peripheral runoff if cardiac output>>peripheral runoff, then you increase the arterial pressure if cardiac output<<peripheral runoff, then you decrease the arterial pressure ***Under steady state conditions, cardiac output always equals peripheral runoff |
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Term
| equation for pulse pressure which involves stroke volume |
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Definition
| pulse pressure= stroke volume/ aortic compliance |
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Term
| effect of a decrease of compliance on pulse pressure for a given TPR |
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Definition
| For a given TPR, as compliance decreases the arterial pulse pressure widens |
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Term
| effect of increase in TPR on systolic and diastolic pressures for a given compliance |
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Definition
| For a given compliance, as TPR increases, both systolic and diastolic pressures increase (although diastolic is affected more) |
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Term
| effect of decrease/increase in SV on systolic pressure and pulse pressure |
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Definition
| If SV is reduced, systolic pressure is reduced as well as pulse pressure...if SV is increased, systolic pressure and pulse pressure increase |
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Term
| Effect of a decrease in arterial compliance on pulse pressure |
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Definition
| A decrease in arterial compliance causes and increase in pulse pressure |
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Term
| The 2 main determinants of diastolic pressure |
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Definition
Diastolic pressure is mainly influenced by heart rate and total peripheral resistance
HR determines the interval for peripheral runoff and peripheral resistance determines the rate of peripheral runoff...both HR and TPR affect the volume of blood remaining in the arterial system at the end of diastole |
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Term
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Definition
| Venous Blood Flow from the peripheral vv to the right atrium...@ steady state this must equal the cardiac output |
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Term
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Definition
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Term
| peripheral venous pressure |
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Definition
| pressure generated by flow of blood from the capillaries into the peripheral vv |
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Term
| 0 reference point for hydrostatic pressure in the body |
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Definition
| the base of the tricuspid valve |
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Term
| What happens to venous/arterial pressure when a muscle in the calf contracts? |
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Definition
| venous pressure falls while arterial pressure remains constant...this improves perfusion of muscle capillary beds |
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Term
| What happens in veins during inspiration |
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Definition
| During forced inspiration, intrathoracic pressure becomes more negative...this causes an increase in venous transmural pressure, causing the central veins to dilate, and the central venous pressure to decrease...simultaneously the pressure in intraabdominal vv increases, these all combine to increase venous return and ultimately SV |
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Term
| Effect of an increase in CO on central venous pressure at a constant TPR |
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Definition
| At a constant TPR, an increase in cardiac output will decrease central venous pressure...this occurs because of the transfer of blood from the venous circulation to the arterial circulation...at the highest theoretical CO, CVP would fall below ambient pressure, collapsing the vv...this phenomenon limits the maximal values that CO can have |
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Term
| The effect of a sudden increase of TPR on arterial blood volume, venous blood volume, venous blood pressure and MCP |
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Definition
| A sudden increase in TPR will cause a greater volume of blood to be retained in the arterial system, accompanied by an equivalent decrease in venous blood volume...thus at any cardiac output, an increase in TPR will cause a decrease in venous pressure, but with no change in MCP |
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Term
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Definition
| Cardiac output on y axis, central venous pressure on x axis |
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Term
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Definition
| cardiac output on y axis, central venous pressure on x axis |
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