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HSF II Cardio III
Question | Answer |
---|---|
Artery vs Vein flow | Artery away from heart, vein to heart |
Pulmonary Circulation Pressure | low pressure system |
Systemic Circulation Pressure | high pressure system |
Mean Arterial Pressure | average pressure in an artery during one cardiac cycle |
Heart Orientation in Mediastinum | base is superior, apex inferior. Rotated counterclockwise, lies on right side |
Heart and Rib Location | base of heart at 2nd intercostal space, apex at the 5th intercostal, 2.5-3 inches left of midline |
Serous Fluid | in pericardial space lubricates and eliminates friction between the heart and adjacent tissues as the heart beats |
Aerobic Respiration | heart relies on this respiration, unable to pump in ischemic environments. supplied by coronary arteries |
Cardiomyocytes | contain large numbers of mitochondria, enabling continuous aerobic respiration and production of ATP |
Myoglobin | heart contains large concentrations, an oxygen-storing protein |
Striated Cardiac Muscle | contains sarcomeres, contains actin, myosin, troponin, and tropomyosin, contraction explained by the sliding filament model, excitation/contraction coupling via Ca++ |
Intercalated Discs | interconnecting cardiac muscle cells, have gap junctions causing myocardium to function as a syncytium |
Myocardial Contraction Regulation | intrinsically by pacemaker activity, and extrinsically by ANS and endocrine systems |
Contractile Cardiomyocytes | bulk of myocardium, specialized for contraction, stable membrane potential, dont show pacemaker activity |
Pacemaker Cardiomyocytes | specialized for conduction, and are responsible for coordinated contraction between the contractile cells |
Pacemaker Potentials | action potentials that initiate the action potentials in contractile cells, resulting in contraction, slow inflow of Na+ without compensating outflow of K+ |
Intrinsic Contractile Rate | inherent pacemaker activity determine |
Intrinsic Conduction System | connected pathway of pacemaker cells, comprised of SA node, internodal pathways, AV node, bundle branches, Purkinje Cells |
SA node | Sinoatrial node, posterior wall of right atrium, primary driver of heart rate, known as cardiac pacemaker |
AV node | atrioventricular node, at junction between atria and ventricles. gets stimulus from SA node and through branches, acts as backup to SA node |
Internodal Pathways | in atrial walls, |
Authorhythmic cells | pacemaker and conducting, control and coordinate the heartbeat |
5 Steps of Prepotential | 1) K+ permeability decreases 2) Na+ permeability increases 3)Ca++ T Channels open at -50 mV 4) Ca++ L Channels open at -40mV 5) at max depol L channels close and K+ open for repol. |
Overdrive Suppression | when slower depolarizing events (AV node and purkinje fibers) are inhibited by the SA node because it is fastest |
Heart Block | when the link between SA node and pacemaker cells in vent are broken, atria and vents myocardia beat independently |
Ectopic Focus | group of cells that transiently depolarizes more rapidly than the normal pacemaker, an out of place pacemaker, causes: fatigue, caffeine, ANS irreg |
Fibrous Trigone | delays transmission of the beat from AV node to bundle of his, causing atria and vent to beat at different times ~200msec slower |
Contractile Potential | depol via influx of Na+, plateau phase by prolonged Ca++ influx , L Ca channels |
ECG (EKG) | represents summation of all the electrical activity associated with one heartbeat |
End-Systolic Volume | volume of blood in a ventricle at the end of contraction |
End-Diastolic Volume | volume of blood in ventricle at the end of filling/diastole, or end of atrial systole |
Strove Volume | EDV-ESV = SV, volume of blood ejected into the aorta |
Isovolumetric Ventricular Contraction | ventricles contract with no pressure change, when all heart valves are still closed |
Ventricular Ejection | when the pressure in the vents is higher than the aorta and pulmonary arteries, |
Ejection Fraction | SV/EDV, normalizes the number because hearts are different. Should be above 50% |