Term
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Definition
| -the innermost layer of the heart |
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Term
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Definition
-the thick middle layer of the heart
-cells contain specialized structures to help rapidly conduct electrical impulses from one cell to another to enable contraction |
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Term
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Definition
-protective sac around the heart contains two layers:
*visceral - inner layer, in contact with the heart
*parietal - outer layer
-between is the pericardial cavity which has about 25mL of lubricating pericardium fluid |
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Term
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Definition
-the two superior chambers of the heart
-receive incoming blood |
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Definition
-two larger inferior chambers of the heart
-pump blood out of the heart |
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Definition
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Definition
| -separates the ventricles |
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Definition
| -control blood flow between the atria and the ventricles |
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Term
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Definition
-right atrioventricular valve
-3 leaflets, or cusps |
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Definition
-left atrioventricular valve
-2 leaflets |
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Definition
-Toilet Paper My Ass
*Tricuspid
*Pulmonary
*Mitral
*Aortic |
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Term
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Definition
-connections for the valves of the heart
-allow for opening and closing of valves |
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Definition
-connect valves leaflets to papillary muscles
-prevent valves from prolapsing into the atria and allowing backflow during ventricular contraction |
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Definition
| -regulate blood flow between the ventricles and the arteries |
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Definition
-left semilunar valve
-connects the left ventricle to the aorta |
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Definition
-right semilunar valve
-connects the right ventricle to the pulmonary artery |
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Definition
| -receives deoxygenated blood from the head and upper extremities |
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Definition
| -receives deoxygenated blood from the areas below the heart |
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Definition
-carries deoxygenated blood to the lungs
-only artery that carries deoxygenated blood |
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Term
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Definition
-comes directly off the heart
-carrying oxygenated blood from the left ventricle |
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Term
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Definition
-the vessels through which the heart receives its blood supply
-originate in the aorta, just above the leaflets of the aortic valve
-receive blood during diastole, the aortic valve leaflets cover the artery openings during systole |
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Term
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Definition
-supplies the left ventricle, the interventricular septum, part of the right ventricle and the hearts conduction system
*the SA node, the AV node, the Purkinje fibers and the bundle branches
-two major branches:
*anterior descending artery and circumflex artery
-blood drains from the system via the anterior great cardiac vein and the lateral marginal veins into the coronary sinus |
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Term
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Definition
-supplies a portion of the right atrium and right ventricle and part of the conduction
-two major branches:
*posterior descending artery and marginal artery
-blood returns directly into the right atrium via smaller cardiac veins |
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Term
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Definition
| -communication between two or more vessels |
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Term
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Definition
| -protective mechanism that provides an alternative path for blood flow in case of a blockage somewhere in the system |
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Term
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Definition
| -the period of time from the end of one cardiac contraction to the end of the next |
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Term
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Definition
| -the period of time when the myocardium is relaxed and cardiac filling and coronary perfusion occur |
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Term
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Definition
| -the period of the cardiac cycle when the myocardium is contracting |
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Definition
| -ratio of blood pumped from the ventricle to the amount remaining at the end of diastole |
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Definition
| -the amount of blood ejected by the heart in one cardiac contraction |
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Definition
-the pressure within the ventricles at the end of diastole
-commonly called the "end-diastolic volume" |
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Term
| Starling's law of the heart |
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Definition
| -law of physiology stating that the more the myocardium is stretched, up to a certain amount, the more forceful the subsequent contraction will be |
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Definition
| -the resistance against which the heart must pump against |
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Definition
-the amount of blood pumped by the heart in one minute
-stroke volume(mL) x heart rate (bpm) |
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Definition
| -a network of nerves at the base of the heart |
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Definition
-the chemical nuerotransmitter for the sympathetic nervous system and the cardiac plexus
-it's release increases heart rate and cardiac contractile force
-primarily acts upon beta receptors |
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Term
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Definition
-located in the peripheral blood vessels
-responsible for vasoconstriction |
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Definition
-primarily located in the heart
-increase heart rate and cardiac contractile force |
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Definition
-where parasympathetic control of the heart occurs
-descends from the brain to innervate the heart and other organs |
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Definition
-the nuerotransmitter for the parasympathetic nervous system and the vagus nerve
-release slows both the heart rate and atrioventricular conduction |
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Definition
| -plays a major role in depolarizing the myocardium |
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Term
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Definition
| -takes part in myocardial depolarization and myocardial contraction |
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Term
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Definition
| -influences repolarization |
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Term
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Definition
| -specialized bands of tissue inserted between myocardial cells that increase the rate in which the action potential is spread from cell to cell |
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Term
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Definition
-group of cardiac muscle cells that physiologically function as a unit
-the only way an impulse can be conducted from the atria to the ventricles is through the AV bundle |
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Term
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Definition
| -contracts from superior to inferior so that the atria express blood to the ventricles |
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Term
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Definition
| -contracts from inferior to superior, expelling blood from the ventricles into the aorta and pulmonary arteries |
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Term
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Definition
| -ability of the cells to respond to an electrical stimulus |
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Term
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Definition
| -ability of the cells to propagate the electrical impulse from one cell to another |
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Term
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Definition
| -pacemaker cells' ability of self-depolarization |
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Term
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Definition
| -ability of muscle cells to contract |
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Term
| Internodal atrial pathways |
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Definition
-connect the SA node to the AV node
-conduct the depolarization impulse to the atrial muscle mass and through the atria to the AV junction |
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Term
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Definition
-"Gatekeeper"
-slows the depolarization impulse from the internodal atrial pathways to allow the ventricles time to fill
-then allows the impulse to pass through into the AV node and onto the AV fibers into the ventricles. |
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Term
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Definition
-formation of the AV fibers in the ventricle
-divides into the right and left bundle branches |
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Term
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Definition
-delivers depolarization impulse to the apex of the right ventricle
-then impulse continues into the Purkinje system which spreads it across the myocardium |
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Term
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Definition
| -divides into anterior and posterior fascicles that terminate in the Purkinje system |
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Term
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Definition
-primary pacemaker cell located high in the right atrium
-depolarizes at 60-100 beats per minute |
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Term
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Definition
-backup pacemaker
-depolarizes at 40-60 beats per minute |
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Term
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Definition
-wicked backup pacemaker
-depolarizes at 15-40 beats per minute |
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Term
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Definition
-the graphic recording of the heart's electrical activity
-amplifies electrical impulses of the heart and records them on graph paper
-positive impulses appear as upward deflections
-negative impulses appear as downward deflections
-the absence of any electrical impulse produces an isoelectric line, which is flat
-generally uses one lead to monitor, most common is lead II or the modified chest lead 1 (MCL1) |
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Term
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Definition
-deflection on the ECG produced by factors other than the heart's electrical activity
*muscle tremors, shivering, patient movement, loose electrodes, 60-hertz interference, machine malfunction |
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Term
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Definition
-ECG leads applied to the arms and legs that contain two electrobes of opposite polarity
-leads I, II and III |
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Term
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Definition
| -the triangle around the heart formed by the bipolar limb leads |
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Term
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Definition
-another term for unipolar limb leads, reflecting the fact that the ground lead is disconnected, which
increases the amplitude of deflection on the ECG tracing |
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Term
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Definition
| ECG leads applied to the arms and legs, consisting of one polarized electrode and a non-polarized reference point that is created by the ECG machine combining two additional electrodes; also called augmented limb leads; leads aVR, aVL and aVF |
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Term
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Definition
| -electrocardiogram leads applied to the chest in a pattern that permits a view of the horizontal plane of the heart; leads V1, V2, V3, V4, V5 and V6. |
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Term
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Definition
-can provide info including:
*heart rate
*regularity of the heartbeat
*time it takes to conduct the impulse through the various parts of the heart
-cannot provide:
*presence or location of an artifact
*axis deviation or chamber enlargement
*right to left differences in conduction or impulse formation
*quality or presence of pumping action |
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Term
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Definition
-standardized
-moves across the stylus at a standard rate of 25 mm/sec
-light lines are 1mm apart and heavy lines are 5mm apart
-1 small box = 0.04 sec
-1 large box = 0.2 sec
-two large boxes = 1 millivolt |
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Term
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Definition
-first component of the ECG
-corresponds to atrial depolarization |
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Term
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Definition
-reflects ventricular depolarization
-not all 3 waves are always present |
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Term
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Definition
| -the first negative deflection after the P wave |
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Term
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Definition
| -the first positive deflection after the P wave |
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Term
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Definition
| -first negative deflection after the R wave |
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Term
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Definition
| -reflects repolarization of the ventricles |
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Term
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Definition
-PRI
-the distance from the beginning of the P wave to the beginning of the QRS complex
-represents the time the impulse takes to travel from the atria to the ventricles
-normal is 0.12-0.2 seconds |
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Term
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Definition
-distance from the first deflection of the QRS complex to the last
-represents the time necessary for ventricular depolarization
-normal is between 0.08-0.12 seconds
-less than 0.12 seconds means the ventricles depolarize in a normal amount of time |
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Term
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Definition
-period from the beginning of the QRS complex to the end of the T wave
-normal is 0.33-0.42 seconds
-QT intervals and the heart rate have an inverse relationship |
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Term
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Definition
| -the period of time when myocardial cells have not yet completely repolarized and cannot be stimulated again |
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Term
| Absolute refractory period |
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Definition
-the period of the cardiac cycle when stimulation will not produce any depolarization whatsoever
-beginning of the QRS to the apex of the T wave |
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Term
| Relative refractory period |
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Definition
-the period of the cardiac cycle when a sufficiently strong stimulus may produce depolarization
-usually corresponds to the T waves downward slope |
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Term
| 5 step procedure to analyzing EKG's |
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Definition
-rate
-rhythm
-P waves
-PR interval
-QRS complex |
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Term
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Definition
-count the number of complexes in a 6-second period
-mark of a 6-second interval by noting two 3 second marks at the top of the ECG strip, then multiply the number of complexes by 10 |
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Term
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Definition
-measure the R-R interval, should be fairly regular
-if it is irregular note whether it fits one of the following:
*occasionally irregular (only one or two R-R intervals on the strip are irregular)
*regularly irregular (patterned irregularity or group beating)
*irregularly irregular (no relationship among R-R intervals) |
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Term
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Definition
-are they present?
-are they regular?
-is there one for every QRS complex?
-are they upright or inverted (compared to the QRS complex)?
-do they all look alike? |
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Term
| Analyzing the PR interval |
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Definition
-0.12 to 0.2 seconds
-3 to 5 small boxes
-any deviation is abnormal
-should be consistent across the strip |
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Term
| Analyzing the QRS complex |
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Definition
-do they all look alike?
-what is the duration?
-0.04 to 0.12 seconds (1-3 boxes) |
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Term
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Definition
-rate between 60-100
-regular rhythm (both P-P and R-R)
-P waves are normal in shape, upright and appear before each QRS complex
-the PR interval lasts 0.12 to 0.2 seconds and is constant
-the QRS complex has a normal morphology and its duration is less than 0.12 seconds |
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Term
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Definition
| -any deviation from the normal electrical rhythm of the heart |
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Term
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Definition
-the absence of cardiac electrical activity
-often used interchangeably with dysrhythmia |
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