Quick Study Index, Cardiac Muscle: Module 0

Cardiac Muscle vs. Skeletal and Smooth Muscle (Discussion points)

  • Electrophysiology:

    Two Kinds of Myocardial Cells

    Electrophysiologic changes during the cardiac cycle (Figure 1)

    The Five Phases of Myocardial Cell Electrophysiology (a listing of events in Fig. 1)

    Fast and Slow Ion Channels

    The Three Slow Channel states (Figure 2)

    Na and Ca gates opening / closing in follower cells (Table 1)

    The Various Cell Ion Pumps (Figure 3)

    The Fast Na and Slow Ca Channels (Figure 4)

    Na and Ca gate opening / closing in S-A nodal & A-V nodal cells (Table 2)
    Changes in Transmembrane Potential in Various Myocardial Cells (Figure 5)

    Mechanisms for Changing Pacemaker Cell Automaticity

    Factors Determining Action Potential Conduction Velocity
    Factors Affecting AV Junction Conduction

    Refractory Period

    Right: Myofibril with sarcomeres, and the Sliding Filament Model of muscle contraction, with myosin & actin.

  • Mechanics:

    The Cardiac Muscle Contraction Cycle

    Various Conditions of Muscle Contraction
    Isometric and Isotonic Muscle Twitches (Figure 6)

    Comparing Isometric and Isotonic Contractions

    Effects of Afterload and Preload on Velocity of Shortening (Figure 8)
    Effect of Preload on Isometric Twitch Tension (Figure 9)
    Velocity of Shortening vs. Afterload (Figure 10)
    Length-Tension Curves for Skeletal and Cardiac Muscle (Figure 11)

    Effects of Increased Preload

    Effects of Afterload on Shortening Velocity

    Effects of Increased Inotropicity

    Factors Affecting Cardiac Muscle Inotropic State (Table 3)
    Norepinephrine's Effect on Isometric Twitches Tension (Figure 12)
    Norepinephrine's Effect on Velocity of Shortening (Figure 13)
    The Bowditch Effect (Treppe, Staircase) (Figure 14)
    Summary: Mechanisms for Altering Tension in Cardiac vs Skeletal Muscle (Figure 7)

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