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37 Cards in this Set
- Front
- Back
Every cardiac cycle is ____ for every species |
Different |
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Conduction system of heart |
SA Node, Internodal pathways (specific), AV node ("Node of delay"), Bundle branches, Bundle of His, Purkinje fibers (myocardial cells without fibrous skeletons, contraction starts at apex) |
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One leave point |
Above SA node --> L. Side |
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SA Node |
(sinoatrial node) located in R. Atrium (near where vena cava enter), "Pacemaker of heart"- under control of the autonomic nervous system, Specialized area of cardiac muscle cells that have the quality of automatically generating electrical impulses triggering repeated beating of heart |
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AV Node |
(Atrioventricular Node), top of atrioventricular septum, specialized group of cardiac muscle cells, serve as auxiliary pacemakers, protect ventricles from beating too fast, only route of conduction from atria to ventricles |
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Bundle of His |
(AV Bundle), travels down interventricular septum, 1st part- slow conduction of action potentials, creates a delay btwn atrial and ventricular contractions, R and L bundle branches (only route of conduction from atria to ventricles) |
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Purkinje fibers |
AV bundle branches break into dispersed network of fibers, carry action potentials to into ventricular myocardium (apex upwards) |
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Wave of depolarization |
SA node depolarizes --> Electrical activity goes rapidly to AV node via intermodal pathways --> depolarization spreads more slowly across atria, conduciton slows through AV node--> Depolarization moves rapidly through ventricular conducting system to the apex of the heart --> depolarization wave spreads upwards from apex |
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Cardiac Cycle |
each complete cycle of contraction and relaxation of the heart Two parts- systole and diastole |
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Syn |
coming together (contraction) |
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Dia |
Coming apart (relaxation) |
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First step of Cardiac Cycle |
(passive ventricular filling, both sets of chambers relaxed) 70% filling of ventricles- AV valves open --> atria-systole fills up the last 30% --> AV valve shuts |
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Ejection Fraction |
portion of total blood in ventricles that is pushed out in systole Typically 60-70% of total volume |
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Second Step of Cardiac Cycle |
(Ventricular Diastole) pressure decrease and blood starts to fall but semilunar valves catch it Semi-lunar valves only open up during ventricle systole |
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Lub |
first sound of heartbeat, closure of AV valves, S1, separated from Dub by a short interval and then followed by a longer pause |
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Dub/Dupp |
second sound, semi-lunar valves closing, S2 |
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Measuring ventricuar systole and diastole |
120/80, atria systole and diastole is too short (1/3 of ventricular) Ventricular and atrial diastole overlap |
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(EDV) End-Diastolic Volume |
the max. amount of blood in ventricles occurs at end of ventricle relaxation 135 mL |
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Isovolumic Ventricular contraction |
first phase of ventricular contraction pushes AV valves closed, but not enough pressure to open semilunar valves |
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Ventricular Ejection |
Ventricular pressure increases, greater pressure in arteries, semilunar valves open and blood ejected |
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(ESV) End-Systolic Volume |
Min amount of blood in ventricles 65 mL |
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Isovolumic Ventricular Relaxation |
Ventricular pressure decreases, blood --> cups of semilunar valves and they close |
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Cardiac murmurs |
turbulent flow of blood due to any defect in valves, indicate the presence of cardiac abnormalities, can either by systolic or diastolic, mitral valve is normally the problem |
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Murmur Insufficiency |
creates gurgling sound, allows regurgitation, valve fails to close completely |
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Murmur stenosis |
creates whoosing sound, fails to open completely, creates restriction |
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Murmur grading |
1 (not bad) --> 5 (very bad) can live up to three Four or five req. surgeries |
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Electrocardiogram |
(ECG) a recording of the electrical changes that occur in the myocardium during a cardiac cycle, noting electrical activity in walls of the heart P + T wave w/QRS complex in middle |
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QRS |
masks atrial repolarization, corresponds to ventricular depolarization |
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P wave |
corresponds to depolarization of SA node |
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T wave |
corresponds to ventricular repolarization |
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Arrythmia |
abnormal cardiac electrical activity (rate, rhythms, and propagation of action potential) SA node fails to function normally (sinus bradycardia or tachycardia) |
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AV Block |
impulses aren't conducted from the atria to the ventricles through the AV node, arrythmia |
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Arrythmia involving accessory pathways |
abnormal conduction pathways are followed, ie accessory pathways between atria and ventricles |
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Arrythmia involving ectopic pacemakers |
other pacemaker sites within the artia or ventricles (ectopic pacemakers) trigger depolarization |
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Artierial blood pressure |
arterial pressure= CO (cardiac output) times TPR (total peripheral resistance) Pressure in vessels depends on amount of blood in vessel (CO) and rate that it can leave (TPR) |
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What regulates Blood Pressure |
neural reflexes- arterial baroreceptor reflexes Humoral Agents- Angiotensin and aldosterone Paracrine Agents- Nitric oxide and endothelin |
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Auscultation |
to listen or hear |