1. Antegrade Impulse
    an impulse that travels through the conduction system in the correct direction
  2. Retrograde Impulse
    an impulse that travels through the conduction system in the reverse direction
  3. Ectopy
    a broad term indicating any kind of abnormal impulse
  4. Hyperkalemia
    As potassium levels rise (normal 3.5-5.0 mEq/L) T-waves become higher and more peaked
  5. Anastomosis
    communication between two or more vessels
  6. Poiseulle's Law
    a low of physiology stating that blood flow through a vessel is directly proportional to the radius of the vessel to the 4th power
  7. Cardiac Cycle
    the period of time from the end of one cardiac contraction to the end of the next
  8. Diastole
    Rest - the period of time when the myocardium is relaxed and cardiac filling and coronary perfusion occur
  9. Systole
    Contraction - the period of the cardiac cycle whrn the myocardium is contracting
  10. Ejection Fraction
    ratio of blood pumped from the ventricle to the amount remaining at the end of diastole
  11. Stroke Volume
    the amount of blood ejected by the heart in one cardiac contraction
  12. Preload
    the pressure within the ventricles at the end of diastole, commonly called the end-diastolic volume
  13. Starling's Law of the Heart
    law of physiology stating that the more the myocardium is stretched, up to a certain amount, the more forceful the subsequent contraction will be
  14. Afterload
    the resitance against which the heart must pump
  15. Factors Affecting Stroke Volume
    Preload Cardiac Contractility Afterload
  16. Cardiac Output
    the amount of blood pumped by the heart in 1 minute (Stroke Volume x heart rate = Cardiac Output)
  17. Chronotropy
    pertaining to heart rate
  18. Inotropy
    pertaining to cardiac contractile force (Strength)
  19. Dromotropy
    pertaining to the speed of impulse transmission (Electrical Conductivity)
  20. Intercolated Discs
    specialized bands of tissue inserted betwen myocardial cells that increase the rate in which the action potential is spread from cell to cell
  21. Syncytium
    group of cardiac muscle cells that physilogically function as a unit
  22. Electrolytes that effect cardiac function
    • Sodium (Na+)-Major role in depolarizing the myocardium,
    • Calcium (Ca++) takes part in myocardial depolarization and myocardial contraction
    • Potassium (K+) influences repolarization
    • Chloride (Cl-)
    • Magnesium (Mg++)
  23. Hypercalcemia
    • increase in serum calcium
    • increased myocardial contractility
    • shortens repolarization
    • ST segment shortens (sometimes T-wave looks as if it's on QRS)
  24. Hypocalcemia
    decrease in serum calcium, decreased myocardial contractility and increased electrical irratibility, prolongs repolarization, prolongs ST segment
  25. Hyperkalemia
    increase in Potassium, decreases automaticity and conduction
  26. Hypokalemia
    decrease in Potassium, increases irritability
  27. Repolarization
    return of a muscle cell to its preexcitation resting state
  28. Action Potential
  29. Excitability
    the ability to be simulated to contract, respond to electrical stimulus
  30. Conductivity
    the ability to transmit(propagate) an electrical impulse from one cell to the another
  31. Automaticity
    pacemaker cells capability to self-depolarize, the ability to selfgenerate an impulse
  32. COntractility
    the ability of the muscle fibers to contract, shortening of the muscle fibers (mechanical property)
  33. Internodal Atrial Pathways
    Connect the SA node to the AV node
  34. artifact
    deflection on the ECG produced by factors other than the hearts electrical activity, such as muscle tremors, shivering, patient movement, loose electrodes, 60 hertz interference, machine malfuntion
  35. Bipolar Limb Leads
    ECG leads applied to the arms and legs that contain 2 electrodes of opposite (+ & -) polarity. Leads I, II and III
  36. Einthoven's Triangle
    the triangle around the heart formed by the bipolar limb leads
Card Set
EMS-153 nova