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26 Cards in this Set
- Front
- Back
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Name all the heart valves.
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A/V valves include:
LEFT: bicuspid valve (mitral valve) RIGHT: tricuspid valve (n/a) Semilunar valves include: LEFT: aortic valve RIGHT: pulmonary valve |
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List the order and location of the heart sounds lub and dub.
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Lub: first heart sound, at the end of diastole when the mitral valve closes.
Dub: second heart sound, at the end of systole when the aortic valve closes. |
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Whats the cause and result of a myocardial infarction?
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Cause: lack of O2 in the heart tissue due to a clot in the coronary artery.
Result: tissue becomes ischemic and can become necrotic/dead. |
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Whats a typical heart rate?
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72 bpm
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Whats the typical systole and diastole pressures for left, and right ventricles.
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LEFT: 120/80 mmHg
RIGHT: 32/8 mmHg |
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What is a dichrotic notch?
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A small dip (v notch) in aortic pressure at the end of systole, due to the backflow of blood against the aortic valve, causing it to bulge back, relieving some of the aortic pressure
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Compare cardiac muscle cells to skeletal muscle cells in terms of:
-Length of action potential -Length of refractory period -Automaticity -Rhythmicity |
-Length of action potential
Longer in cardiac. -Length of refractory period Longer in cardiac (100-200ms), versus 1-2ms in skeletal. -Automaticity (ability to generate an action potential) Only in cardiac -Rhythmicity (of action pots) Only in cardiac |
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Whats the intrinsic rate of the heart, and what modifies it?
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The intrinsic rate is 100 bpm (by the SA node).
The parasympathetic nervous system (PSNS) decreases this down to 72 bpm via the vagal nerve. |
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What is positive chronotropic effect?
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When the SNS increases the heartrate.
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What is negative chronotropic effect?
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When the PSNS decreases the heartrate.
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On the electrocardiogram, what does the QRS wave signify?
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The impulse that causes the ventricles to contract.
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On the electrocardiogram, what does the T wave signify?
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The impulse that causes the ventricle to start relaxing during the middle of systole.
The end of the T wave occurs at the start of diastole. when the a/v valves open. |
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On the electrocardiogram, what does the P wave signify?
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That the atria will soon contract (its at the last 1/3 of diastole).
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How long is the QT interval?
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~4 seconds (encompasses the full systole)
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What is the cause, result, and ecg of sinus tachycardia?
Intervals affected and how? |
Cause:
-fear, anxiety, exercise -high sympathetic stimulation -low parasym stimulation -high temperature/fever All of the above cause an overactive sinus node Result: > 100 bpm Ecg: normal but with shorter intervals. PR and QT are shorter |
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What is the cause, result, and ecg of sinus bradycardia?
Intervals affected and how? |
Cause: ↓sns or ↑pns, or in athletes
Result: < 60 bpm Ecg: normal but with longer intervals. PR and QT are longer |
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What is the cause, result, and ecg of sinus arrhythmia?
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Cause: When breathing alters your heartrate as follows:
inspiration: ↓vagal tone : ↑heartrate expiration: ↑vagal tone : ↓heartrate Ecg: normal, but intervals are irregular (normal means normal shape and amplitudes) |
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Describe first degree block.
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-First degree AV block is delayed/slow transmission through the AV node.
-No dropped beats. -Long PR interval. -Fairly normal occurance. |
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Describe second degree block.
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-Second degree AV block is intermittent transmission through the AV node.
-Some beats are dropped, 2, 3 or 4 atrial contractions per ventricular. -Missing some QRS waves on ecg. -Cause: scarring or ischemia of AV node. -Treatment: artificial pacemaker |
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Describe third degree block.
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-Complete AV block, no transmission to ventricles, only atria beat (at 100 bpm).
-Then ventricular escape kicks in, and ectopic foci takes over near ventricles. -Nonsense ecg -Treatment is artificial pacemaker. |
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Describe PVC.
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-Premature Ventricular Contraction.
-Action pot is generated in an ectopic foci in the ventricle. -Vent contracts prematurely -Followed by a missed beat (compensatory pause). |
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Describe ventricular fibrillation.
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Impulse doesn't stop, inefficient partial contractions (bag of worms).
Cause: electric shock, or re-entry phenomenon. Result: unconscious in 4-5 seconds, death in 1-3 mins. |
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What are the causes of the re-entry phenomenon?
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1. Increased pw around heart (eg due to dilated heart).
2. Decreased velocity of conduction around heart (eg due to ischemia, ↑K+, or electrical stimulation). 3. Shortened refractory period of the heart muscles (eg due to epinephrine, or electrical stimulation). 4. Electric shock: -decreases velocity of impulse. -shortens refractory period -re-entrant signal occurs, with division of impulses. |
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How does defibrillation work?
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Electric shock depolarizes all the cardiac cells, putting all of them into a refractory period, allows the pacemaker to take over, restoring the heart rhythm.
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What is the cause and result of atria fibrillation?
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Cause: Dilation of atria.
Result: Atria fail as primer pumps, but vents still work. Decreased efficiency. |
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What is the cause and result of atrial flutter?
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Cause: Impulse travels in one direction/wave around the atria (in a circle).
Result: -Rapid contraction of atria (200-350 bpm). -Dropped ventricular beats.. -F waves (instead of P waves). -Irregular ecg |
