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86 Cards in this Set
- Front
- Back
What happens when Atrial Systole begins (A)?? |
Atrial contraction forces a small amount of additional blood into relaxed ventricles |
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What happens when atrial systole ends (B)? |
Atrial Diastole begins |
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What happens during Ventricular Systole (C, 1st phase)? |
- 1ST PHASE - Ventricular contraction pushes AV valves closed but does not create enough pressure to open the semilunar valves |
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What happens during Ventricular Systole (D, 2nd phase) ? |
As ventricular pressure rises and exceeds the pressure in the arteries , the semilunar valves open and blood is ejected |
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What happens during Ventricular Diastole (early ,E) ? |
As the ventricles relax : - the pressure in the ventricles drops - blood flows back against the cusps of semilunar valves and forces them closed. - Blood flows into the relaxed atria |
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What happens during Ventricular Diastole (late, F)? |
All chambers are relaxed , ventricles fill passively |
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One cardiac cycle lasts roughly how long? |
roughly 800 seconds for entire cycle |
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Timing is everything , because we need to have what? |
need to have pressure differences, for blood to flow from high pressure to low pressure |
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What is a cardiac cycle? |
beginning of one heart beat to the next. Includes a cycle of contraction and relaxation |
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When will blood only move? |
Blood will only move from one chamber to the next - if the pressure in the 1st chamber exceeds the pressure in the second |
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What is boyle's law? |
Inverse relationship between pressure and volume |
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Change in pressure gradient creates a change in? |
Creates a change in volume and drives blood flow |
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What are the opposing pressures , in the heart? |
- Atria - Ventricles - Large arteries |
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As volume increases , what happens to pressure? |
Pressure decreases |
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As volume decreases what happens to pressure? |
Pressure Increases |
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How is cardiac output determined? |
HR x stroke volume = cardiac output |
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If someone had a resting heart rate of 70 BPM and the average stroke volume is 70 mL per beat. What is the cardiac output? |
70 X 70 = 4,900 mL / min |
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If we say this is the demand for the cells for the tissues of the body. You have a stroke volume of 100 , but still need 5,000 ml/ min distributed. What can happen to the HR? |
- we know stroke volume is 100 divide cardiac output 5,000 by 100 = 50 for HR |
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What happens during Diastasis? |
- All four chambers are relaxed - AV (mitral and tricuspid) valves open and blood flows into ventricles - Heart sound 3 occurs from blood "pouring" into ventricles - 80 percent of ventricular filling occurs passively ( occurs in TP segment) |
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The cardiac cycle is 800 msec total , has how many msec during diastasis? |
430 sec of diastasis |
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During Diastasis all chambers are relaxed and blood is coming back to? |
Blood is coming back to the Atria through the veins. Blood accumulates in the Atria and eventually that volume gets so large that it opens b/c of pressure. And blood continues to fill. |
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When heart is healthy it could eject a good? |
Stroke volume , because they could afford more time in between beats and perfuse |
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80 % of ventricular filling occurs passively. During what segment does this occur? |
TP segment |
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During diastasis , as blood comes back from the Atria to the veins: - Blood accumulates where? |
- Blood accumulates in the Atria , eventually volume gets so large that it opens av valves b/c of pressure |
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During Diastasis, when AV valves are pushed open , it continues to pour into the? - What occurs during this time? |
- Continues to pour into the ventricles - 80 percent of ventricular filling occurs during this time "passive filling" |
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What is the most important segment to watch on an EKG for your patient's heart health? |
T-P segment |
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If we have a long T-P segment , what does this mean? |
- more time for filling and more time for perfusion |
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When cardiocytes "remodel" , what does this mean? |
When cardiocytes "remodel" (hypertrophy) equally bigger in width as they do in height = more contractile proteins |
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What happens during Atrial Systole? |
- SA node fires , atria depolarizes - P wave = atria will contract - Atrial contraction forces final 20 % percent of blood into ventricles - EDV (end diastolic volume, avg 120 mL) - heart sound 4 occurs (turbulence caused by inrush of blood into ventricles) |
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A p-wave on the EKG means? |
Atria will contract |
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20 % of ventricular filling is also going to cause what two things? |
1. Turbulent flow 2. Causes heart sound 4 |
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All four valves can never be? |
opened!! |
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What happens during isovolemic contraction of the ventricles? |
- Atria repolarize and relaxes, ventricles depolarize= QRS complex - Ventricles initiate contraction - Rising pressure closes AV valves - No ejection of blood yet (no change in volume) - Heart sound 1 (S1) occurs (turbulence against AV valves) |
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AV valves stands for? |
atrioventricular valves - mitral = left valve , bicuspid - tricuspid = right valve |
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Where do you hear heart sound 1(S1)? |
- During isovolemic contraction of the ventricles - turbulence against AV valves |
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Where is QRS coming from? |
From two bundle branches spiking AP down the IV septum |
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Where does the Q wave come from? |
Comes from Right bundle branch, that has a weird turn to it (anatomical bend) , explains downward electrode of Q |
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What does the R wave represent? |
Overall current going down to the left, towards the Apex of the heart |
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When Purkinje fibers are carrying AP to the Right myocardial wall in the ventricle and the Left myocardial wall. What are the differences? |
Right side of heart ,myocardial wall =
- 1/7 of resistance compared to the left and has the same volume out (70 mL), just doesn't have to work as hard! Left side of heart = - Thicker than the right - Has to generate greater force to push blood to the entire body. A lot of resistance , heart has to work harder |
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What happens during Ventricular Ejection? |
- Semilunar (aortic and pulmonary artery) valves open b/c of rising pressure - Stroke volume (SV , amount ejected) = 70 mL - Rapid and Reduced ejection phases - SV / EDV = Ejection Fraction - End-systolic Volume (ESV) = amount left in heart = 50 mL |
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Stroke Volume divided by End Diastolic Volume = |
SV / EDV = ejection fraction |
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What is End- Systolic Volume (ESV) ? |
- Amount left in the heart - 50 mL |
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What happens during Isovolemic Relaxation of ventricles? |
- T wave appears on EKG= Ventricles repolarize - Semilunar valves close - AV valves remained closed - Ventricles expand but do not fill - heart sound 2 (S2) = turbulence against semilunar valves |
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In isovolemic relaxation , what do you see on the EKG? What heart sound do you hear , during this phase? |
T wave and Heart sound 2 (S2) |
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During Heart sound 2 (S2) , what happens during this time? |
Turbulence against semilunar valves |
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What happens during Ventricular Filling? |
- AV valves open - 3 phases of filling : 1. Rapid Ventricular Filling 2. Diastasis 3. Filling completed by atrial systole - Heart sound 3 (S3) may occur (in rushing blood against ventricular walls) |
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Where does heart sound 3 occur? |
During ventricular filling |
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What is cardiac output? |
The amount of blood ejected by ventricles per minute |
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Normal resting value of Cardiac output is? |
4 to 6 L/min |
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Vigorous exercise increases Cardiac output to? |
21 L /min *for a fit person |
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If someone was a world class athlete, their
Cardiac output would be? |
35 L/ min |
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A couch potato gets 50 mL out instead of 70 mL. Whats their HR to reach 5,000? |
100 BPM for HR |
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The heart has to compensate to? |
To meet the demands of the body |
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When a heart has less time to fill , What happens? |
The heart works harder and it has less time to be perfused |
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After you workout , your heart has what two things? |
- muscle mass that can generate a great force of contraction - eject a greater stroke volume |
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If you don't workout , what happens to your heart? |
- The heart has to compensate , it has less time to fill , heart is working harder - has less time to perfuse ( T-P segment shortened) |
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A person has a stroke volume of 100 mL and still needs 5,000 mL/min distributed. What can happen to their HR? |
HR would decrease - 100 times ____ = 5,000 mL - 100 (SV) x HR = CO 100 x 50 = 5,000 HR is 50 BPM |
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End diastolic volume (EDV) mL? |
120 mL |
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End Systolic Volume (ESV) mL? |
50 mL |
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Ejection Volume also known as? how many mL? |
also known as stroke volume 70 mL |
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How can you find ejection volume? |
120 - 50 = SV or ejection volume (EDV) (ESV) |
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What is ejection fraction? |
Ejection volume (SV) / EDV 70 mL / 120 mL = 58 % normally 60 % |
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If HR is 70 BPM , What is the cardiac output? |
70 beats/min * 70mL/min = 4900 mL/min (HR) (SV) |
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Stroke volume is affected by? |
EDV and ESV |
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What does End Diastolic Volume depend on? |
- VENOUS RETURN - Filling time (diastole) - Skeletal pumping (muscular pressure exerted on veins) - Respiratory pumping ( lower intrathoracic pressure during inspiration takes blood into atria) |
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What is Venous return? |
the rate of blood flow into the heart from veins |
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What is part of the intrinsic regulation ( aka regulation of heart pumping)? |
1. EDV 2. ESV 3. Frank sterling mechanism |
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End Systolic Volume (ESV) depends on? |
- Preload (frank-sterling principe) - Contractility of the Ventricle - Afterload |
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What is Preload? |
- degree of muscle tension , when it begins to contract - frank-sterling mechanism (more in , more out) |
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What is Contractility of the Ventricle? |
- Availability of calcium - positive or negative inotropy(rare) |
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What is Afterload? |
- Contractile force needed for ejection - affected by peripheral vasculature |
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A high stroke volume results in? |
LOW ESV (end systolic volume) |
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What is the Frank-sterling mechanism? |
- More in , more out - Within physiological limits, the heart pumps all the blood that comes to it without excessive damning in the veins |
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In frank-sterling mechanism, length-tension relationship of cardiocytes is? |
- Extra stretch on cardiac myocytes makes actin and myosin filaments interdigitate to a more optimal degree for force of generation |
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What happens to cardiac cycle when HR increases? |
- all phases are shortened - Diastole is shortened the most ( TP segment on EKG) - reduced by almost 75 % at 200 BPM - Reduced Diastole = less time to fill |
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What drugs affect the Cardiac Output , HR and Stroke volume? |
1. Atropine 2. Pilocarpine 3. Propanalol 4. Digoxin |
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Atropine |
- Parasympathetic blocking -blocks muscarinic AchR agent (+,+) |
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Pilocarpine |
- drug that causes cholinergic neurons to release Ach - since Ach decreases HR , it causes (-,) effect on heart |
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Propranalol |
- Reversible competitive blocker of Beta 1 receptor - Blocks sympathetic effect of heart (-,-) - decrease HR and force of contraction and lowers BP |
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Where does Digoxin (shorter half life) come from? Where is it derived from? |
- come from a group of drugs derived from digitalis - derived in turn from foxglove plants |
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What effect does Digoxin have on the heart? |
Has a (-,+) effect - Negative chronotropy - Positive Inotropy - slows heart rate but increases force of contraction (the only drugs with this effect) |
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What is another name for Digoxin? |
Cardiotonic Glycosides or Cardiac Glycosides |
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How do Cardiac Glycosides (Digoxin) increase cardiac contractility? |
- Glycosides inhibit the Na / K (sodium potassium) ATPase - increases intracellular NA+ - decreases NA+ gradient - decrease NA+ / CA+ counter transport - increase intracellular CA+ |
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Digoxin is used to treat? |
Heart failure * has been used for decades and is the only oral inotropic support agent in clinical practice |
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Digitalis is extremely toxic and optimal dose is close to? |
optimal dose is close to a lethal dose (stops the heart) |
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What are the side effects of Digoxin (Digitalis toxicity) ? |
- disturbance in yellow-blue vision , similar to viewing the world through yellow filter (xanthopsia) - Glare and colored Haloes , (may be experienced as visual side effects) |