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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% |