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CV - Cardiostimulatory - Coggle Diagram

- - - - ↑ Contractility of cardiac myocytes
        
        ↑ Force of contraction
        
        ↑ CO
- - - - Inhibits the Na+/K+ ATPase in the plasma membrane
      - This causes increased intracellular Na+
      - This drives the plasma membrane Na+ / Ca2+ exchanger to allow influx of Ca2+
      - Increased intracellular Ca2+ activates ryanodine receptors on the sarcoplasmic reticulum and allows Ca2+ release from the SR
      - This Ca2+ binds to myofibrils and causes increased contraction
      - Positive inotropic effect
    - - Increases PNS on AV/ SA node
  - - - a. Decreases HR
      - b. Decreases AV conduction velocity (negative dromotropic effect)
      - c. Increases AV refractory period
      - d. Decreases automaticity of AV node
      - e. Increases automaticity of His-Purkinje conduction system
- - - - a. Activation of CA2+ channels on plasma membrane allow Ca2+ influx, which induce release of Ca2+ from SR by RyR
      - b. Inhibition of phospholamban allows SERCA to reuptake of Ca2+ and increase release on excitation
      - c. Phosphorylation of Myosin light chains - increased affinity of filaments for Ca2+
- - - - a. Phospholamban, allowing SERCA to reuptake Ca2+ for release
      - b. Plasma Ca2+ channels, allowing Ca2+ influx, activating RyR and increasing contraction
      - c. Myosin light chain, increasing affinity for Ca2+
- - - - Increase sensitivity of troponin for Ca2+
      - Increased interactions between actin + myosin without increased ATP or O2 consumption
      - Increased strength of contraction
    - - Opens ATP sensitive K+ channels on plasma membrane
      - Hyperpolarises membrane
      - Reduced contraction