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31 Cards in this Set
- Front
- Back
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period of slow ventricular filling, when pressure begins to climb in both ventricle and atria |
diastasis |
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pulmonary capillary wedge pressure |
closely follows left atrial pressure |
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pathology determined by pulmonary capillary wedge pressure? |
heart failure; left atrial pressure is high - blood maybe forced into lung interstitium |
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splitting of the second sound of the heart |
due to the pulmonic valve snapping shut before the aortic |
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flow from the heart to the heart (right sided) |
right coronary sinus branches into the right coronary artery and then goes to the right atrium and right ventricle |
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flow from the heart to the heart (left sided) |
left coronary sinus branches into left coronary artery which branches into anterior descending coronary artery and circumflex arteries. provides blood flow to the anterior and lateral side of the left ventricle |
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where is coronary blood collected? |
right ventricular venous blood drains into the right atrium (anterior cardiac veins), left ventricular venous blood drains into the coronary sinus, then right atrium. Thethesbian veins drain ~5% blood into left ventricle |
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the problem with collateral circuits in the human heart |
they can provide near normal blood flow at rest, around an occluded artery, but they cannot compensate as well during exercise |
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what is the driving force for left ventricular coronary flow? why? |
aorta diastolic pressure because during systole, blood flow is shut off due to contraction force and intramyocardial pressure |
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possible agents for vasodilation in coronary arteries due to increase oxygen demand |
adenosine hypoxia pH NO |
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simp/parasymp effect on coronary blood flow |
sympathetic NoE constricts blood vessels, but is overridden by local control agents (adenosine) parasympathetic Ach does dilate blood vessels (stimulation of the vagus nerve) |
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what fuel does cardiac muscle use mainly at rest? |
fatty acids |
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heart rate is controlled by what three mechanisms? |
plasma epinephrine Activity of parasympathetic nerves - Ach (Ach K channels open)(cAMP down)(muscarinic receptors)(HCN funny decrease slope) Activity of sympathetic nerves to heart - NoE (beta 1 adrenergic receptors)(cAMP up)(HCN funny increase slope) |
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Which mechanism is faster? plasma epi, parasympathetic, sympathetic |
parasympathetic, acts as a brake, when brake is removed heart rate increases |
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stroke volume is controlled by what three mechanisms? |
EDV (ventricular volume) Plasma epinephrine Sympathetic nervous system (increase in cAMP)(beta1) ----> PLN (SERCA), RyR, L-Ca2+ |
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how does calcium effect force on the frank starling curve? How does it effect the overall relationship between EDV and stroke volume? |
increases in calcium sensitivity increase the force able to be generated at a specific calcium concentration frank starling curve shifts due to an increase in calcium concentration |
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How do B1 receptors work in cardiac muscle? |
Gs subunit, increase activity of adenylate cyclase, increase ATP --> cAMP, increase in PKA (active), increase in L type Ca2+ channel, increase in RyR receptor, increase in phosphorylation of PLN, and release of SERCA pump, myosin Ca2+ sensitivity increase |
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how do you measure contractility? |
dP/dt SV/EDV= ejection fraction |
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when is stroke volume highest? |
at about 1/2 total CO |
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what is stroke work? |
Pressure x stroke volume Area of pressure volume loop |
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what is minute work? |
HR x SW (P x SV) HR x SV x P HR x (EDV-ESV) x P CO x P |
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Cardiac index |
3 Litres/min/m^2 |
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cardiac output by thermodilution |
bolus of cold saline solution, measure downstream. |
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bulk exchange |
movement of substance X = Q x [X] amount delivered - amount returned = amount used |
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measurement of cardiac output using Fick's principle |
TCx = Q{[Xa]-[Xv]) CO = V02/([02]a-[02]v) ~PRACTICE THIS~ |
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how do you measure left atrial pressure? |
pulmonary capillary wedge pressure |
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what does flow limited mean? |
since 02 absorption cannot increase but 02 consumption must, flow must increase |
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what drives coronary blood flow? |
diastole |
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coronary blood flow is about what percentage of cardiac output? |
5% |
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resting condition metabolic state of the heart muscle |
fatty acids 60-70% of fuel glucose 30% lactate 10% (all aerobic) |
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exercise metabolism of the heart |
FA 20% glucose 15% lactate (from muscles) 60% (all aerobic) |
