Term
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Definition
* approximately the size of your fist
* Location
- Superior surface of diaphragm
- Left of the midline
- Anterior to the vertebral column
- Posterior to the sternum |
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Term
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Definition
* a double walled sac around the heart composed of:
- superficial fibrous pericardium
- a deep 2 layer serous pericardium
- the parietal layer lines the internal surface of the
fibrous pericardium
- visceral layer or epicardium lines the surface of the heart
- they are separated by the fluid filled pericardial cavity |
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Term
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Definition
* Protects and anchors heart
* prevents overfilling of the heart with blood
* allows for the heart to work in a relatively friction-free environment |
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Term
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Definition
* Epicardium
* myocardium
* Fibrous skeleton of the heart
* endocardium |
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Term
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Definition
| visceral layer of the serous pericardium |
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Term
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Definition
| cardiac muscle layer forming the bulk of the heart |
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Term
| Fibrous skeleton of the heart |
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Definition
| crisscrossing interlacing layer of connective tissue |
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Term
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Definition
| endothelial layer of the inner myocardial surface |
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Term
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Definition
* receiving chambers of the heart
* pectinate muscles mark atrial walls
* blood enters right atria from superior and inferior venae cavae
* blood enters left atria from pulmonary veins |
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Term
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Definition
* discharging chambers of the heart
* papillary muscles and trabeculae muscles mark vetricular walls
* right ventricle pumps blood into the pulmonary trunk
* left ventricle pumps blood into the aorta |
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Term
| Pathway of blood trough heart and lungs |
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Definition
* Right atrium > tricuspid valve > right ventricle
* Right ventricle > Pulmonary valve > Pulmonary arteries >
Lungs
* Lungs > Pulmonary veins > Left atrium
* Left atrium > bicuspid/matrovalve > Left ventricle
* Left ventricle > Aortic valve > Aorta
* Aorta > Systemic circulation |
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Term
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Definition
* Functional blood supply to the heart muscle itself
* collateral routes ensure blood blood delivery to heart even
if major vessels are occluded |
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Term
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Definition
| * ensure unidirectional blood flow through the heart |
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Term
| Atrioventicular (AV) valve |
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Definition
* lie between the atria and the ventricles
* prevent backflow into the atria when ventricles contract
* chordae tendineae anchor AV valves to papillary muscles |
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Term
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Definition
| prevent backflow of blood into ventricles |
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Term
| microscopic anatomy of heart muscle |
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Definition
* cardiac muscle is striated, short, fat, branched, and interconnected
* intercalated discs anchor cardiac cells together and allow free passage of ions |
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Term
| cardiac muscle contraction |
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Definition
* stimulated by nerves and is self-excitable
* contracts as a unit
* has a long absolute refractory period |
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Term
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Definition
* Sinoatrial (SA) node generates impulses about 75 times a min
* SA pace maker of the heart
* Atrioventricular (AV) node delays the impulse approximately 0.1 second
* impulse passes from atria to ventricles via the atrioventicular bundle |
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Term
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Definition
*AV bundle splits into 2 pathways in the interventricular septum
*bundle branches carry the impulse toward the apex of the heart
*purkinje fibers carry the impulse to the heart apex and ventricular walls |
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Term
| Extrinsic innervation of the heart |
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Definition
*Heart is stimulated by the sympathetic cardioacceleratory center
*heart is inhibited by the parasympathetic cardioinhibitory center |
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Term
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Definition
*electrical activity is recorded by electrocardiogram (ECG)
*P wave corresponds to depolarization
*T wave corresponds to ventricular repolarization
*Atrial repolarization record is masked by the larger QRS complex |
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Term
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Definition
| Sinus Node SN > interatrial tracts > atrium > AV node > bundle of his > bundle branches > purkinje fibers > ventricle |
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Term
| congestive heart failure: def |
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Definition
| Condition in which the pumping of the heart is depressed so that circulation is inadequate to meet tissue needs |
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Term
| CHF: right side of the heart failure |
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Definition
*Ineffective RV contractility
*failure of RV pumping
*decreased cardiac output to lungs
*Blood backs up into RA + peripheral circulation |
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Term
| CHF: left sided heart failure |
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Definition
*Ineffective LV contractility
*failure of LV pumping
*decreased CO to the body
*blood backs up into left atrium and lungs
*pulmonary congestion, dyspnea, activity intolerance |
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Term
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Definition
| normal beating of the heart |
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Term
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Definition
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Term
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Definition
| rate of more than 100 bpm |
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Term
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Definition
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Term
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Definition
| there is a pause in the rate in the AV node between P-R |
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Term
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Definition
| some QRS complexes are missing |
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Term
| PVC: Premature Ventricular Contraction |
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Definition
irregular heart beat in which the ventricle contracts prematurely
the wave is lower that zero |
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Term
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Definition
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Term
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Definition
| uncoordinated contraction of the cardiac muscle of the ventricles in the heart, making them tremble rather than contract properly |
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Term
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Definition
| No cardiac electrical activity |
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Term
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Definition
| no cardiac electric activity > death |
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Term
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Definition
*rapid and sometimes irregular heart beat
*saw tooth appearance between QRS complexes |
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Term
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Definition
*The heart's atria quiver instead of beating effectively
*Blood isn't pumped completely out of them, so it may pool and clot |
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Term
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Definition
*associated with closing of heart valves
*first sound occurs as AV valves close > beginning of systole
*second sound occurs when SL valves close at the beginning of ventricular diastole |
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Term
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Definition
| *all events associated w/ blood flow through the heart |
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Term
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Definition
| contraction of the heart muscle |
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Term
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Definition
| relaxation of heart muscle |
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Term
| *ventricular filling > mid-to-late diastole |
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Definition
*heart blood pressure is low as blood enters atria and flows into ventricles
*AV valves are open, then atrial systole occurs |
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Term
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Definition
*atria relax
*rising ventricular pressure results in closing of AV valves
*isovolumetric contraction phase
*ventricular ejection phase opens semilunar valves |
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Term
| isovolumetric relaxation > early diastole |
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Definition
*ventricles relax
*backflow of blood in aorta and pulmonary trunk closes semilunar valves |
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Term
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Definition
| brief rise in aortic pressure caused by backflow of blood rebounding off semilunar valves |
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Term
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Definition
*amount of blood pumped by each ventricle in one min
*it is the product of heart rate (HR) and stroke volume (SV) |
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Term
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Definition
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Term
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Definition
| amount of blood pumped out by a ventricle with each beat |
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Term
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Definition
| is the difference between resting and maximal CO |
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Term
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Definition
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Term
| factors affecting stroke volume |
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Definition
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Term
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Definition
*amount ventricles are stretched by contained blood
*Stretch |
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Term
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Definition
*back pressure exerted by blood in the large arteries leaving the heart
*Resistance |
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Term
| Frank-Starling law of the heart |
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Definition
*Preload, or degree of stretch, of cardiac muscle cells before they contract is the critical factor controlling stroke volume
*Slow heartbeat and exercise increase venous return to the heart, increasing SV
*Blood loss and extremely heart beat decrease SV |
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Term
| Extrinsic factors influencing SV |
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Definition
| *Contractility is the increase in contractile strength,independent of stretch and End Diastolic Volume (EDV) |
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Term
| increase in contractility comes from: |
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Definition
-Increased sympathetic stimuli
-certain hormones
-Ca2+ and some drugs |
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Term
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Definition
-acidosis
-increased extracellular K+
-Calcium channel blockers |
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Term
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Definition
-Positive chronotropic factors > increase heart rate
-Negative chronotropic factors decrease heart rate |
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Term
| Regulation of heart rate: Autonomic Nervous System |
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Definition
-Sympathetic nervous system stimulation is activated by stress, anxiety, excitement, or evercise
-Parasympathetic nervous system stimulation is mediated by acetylcholine and opposes the SNS
-PNS dominates the autonomic stimulation, slowing heart rate and causing vagal tone |
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Term
| Atrial (Bainbridge) reflex |
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Definition
-sympathetic reflex initiated by increased blood in the atria
-Causes stimulation of the SA node
-Increased SNS stimulation |
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Term
| Chemical regulation of the heart |
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Definition
-hormones epinephrine and thyroxine increase hear rate
-intra- and extracellular ion concentrations must be maintained fro normal heart function |
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Term
| Congestive Heart Failure CHF causes |
|
Definition
-Coronary atherosclerosis
-persistent high blood pressure
-multiple myocardial infarcts
-dilated cardiomyopathy DCM |
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