Term
| Where is the heart located? |
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Definition
| thoracic cavity between two lungs: 2/3 to left of midline |
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Term
| What surrounds the heart? |
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Definition
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Term
| List and describe the two types of pericardium |
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Definition
-Fibrous pericardium:inelastic and anchors heart
-Serous pericardium:inside fibrous;double layer around heart
-parietal layer fused to fibrous pericardium
-inner visceral layer adheres tightly to heart
-filled with pericardial fluid:reduces friction during beat |
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Term
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Definition
-epicardium:outer layer
-myocardium:cardiac muscle(two separate networks via gap junctions in intercalated discs-atrial ventricular)
-endocardium:squamous epitherlium(lines inside of myocardium) |
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Term
| List and describe the chambers of the heart |
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Definition
-4 chambers
-2 upper chambers=atria(between interatrial septum and contains fossa ovalis)
-2 lower chambers=ventricles(between interventricular septum) |
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Term
| How does the thickness of the walls of the heart differ in individuals? |
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Definition
-wall thickness depends on workload
-atria thinnest
-right ventricle pumps to lungs & thinner than left |
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Term
| Describe the great vessels of the heart(right) |
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Definition
-superior and inferior vena cavae delivers deoxygenated blood to right atrium from body
-coronary sinus drains heart muscle veins
-right atrium>>>right ventricle
-pumps through pulmonary trunk
right and left pulmonary arteries>>>lungs |
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Term
| Describe the vessels of the heart(left) |
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Definition
pulmonary veins from lungs(oxygenated blood)>>>left atrium>>left ventricle>>ascending aorta>>>body
-between pulmonary trunk & aortic arch is ligamentum arteriosum
-fetal ductus arteriosum remnant |
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Term
| What is an electrocardiogram? |
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Definition
| recording of currents from cardiac conduction of skin(EKG or ECG) |
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Term
| List and describe the waves seen in an electrocardiogram |
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Definition
-P wave=atrial depolarization(contraction begins right after peak,repolarization is masked in QRS)
-QRS complex=ventricular depolarization(contraction of ventricle)
-T Wave=ventricular repolarization(just after ventricles relax) |
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Term
| Describe the cardiac cycle |
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Definition
-after T wave>>ventricular diastole
-ventricular pressure drops below atrial & AV valves open>>ventricular filling occurs
-after p wave>>atrial systole(finishes filling ventricles)
-after QRS>>ventricular systole
-pressure pushes AV valves closed
-pushes semilunar valves open and ejection occurs
-ejection until ventricle relaxes enough for arterial pressure to close semilunar valves |
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Term
| Describe how the heart rate is controlled |
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Definition
-pacemaker adjusted by nerves(cardiovascular center is medulla)
-parasympathetic:ACh slows(via vagus nerve)
-sympathetic:norepinephrine speeds
-sensory input for control:baroreceptors(aortic arch & carotid sinus)
-chemoreceptors:O2,CO2,pH |
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Term
| Describe the other important controls for the body |
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Definition
-hormones:epinephrine & norepinephrine increase heart rate
-thyroid hormones stimulate heart rate(called tachycardia)
-ions:increasesd NA+ or K+ decrease heart rate and contraction force;increased CA2+ increase heart rate & contraction force |
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Term
| Describe how exercise affects the heart |
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Definition
-aerobic exercise:longer than 20 mins strengthens cardiovascular system
-well trained athlete>>doubles maximum
-resting C.O about the same but resting H.R. decreased |
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Term
| Describe how blood is supplied to the heart |
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Definition
-blood flow through vessels in myocardium=coronary circulation
-left & right coronary arteries(branch from aorta to carry blood throughout muscle)
-deoxygenated blood collected by coronary sinus (posterior)
-empties into right atrium |
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Term
| Describe the conduction system of the heart |
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Definition
-1% of cardiac muscle generate action potentials=pacemaker & conduction system
-normally begins at sinoatrial(SA) node
-atria & atria contract>>AV node slows>>AV bundle(bundle of his)>>bundle branches>>purkinje fibers>>apex and up-then ventricles contract |
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Term
| Describe how a pacemaker works |
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Definition
-depolarize spontaneously
-sinoatrial node:100times/min
-also AV node:40 to 60 times/min
-in ventricle:20 to 35/min
-fastest one run runs the heart=pacemaker
-normally the sinoatrial node |
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