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Cardiomyocyte calcium regulation (load independent inotropy: positive and negative inotropes concept map)
Cardiomyocyte calcium regulation (load independent inotropy: positive and negative inotropes concept map)

Cardiomyocyte calcium regulation (load independent inotropy: positive and negative inotropes concept map)

Inotropy is basically a fancy scientific word for how strong or weak a contraction is, in this case in we are discussing inotropy regulation that is INDEPENDENT of loading.

Since action potentials (movement of sodium and potassium) are “all or nothing” phenomenon. When it comes to regulating inotropy at the cellular level it mostly revolves around calcium regulation. Which works via three main pathways: ligand interactions, voltage gated confirmational changes, and active transport mechanisms that control how much calcium is in the cell.

MAP SUMMARY

PKA acts on Troponin 1 and Phospholambon. The latter to inhibit or activate Calcium ATPases at the sarcoplasmic reticulum and the former to influence the stability of myosin and actin interactions via changes in Troponin 1’s calcium affinity. L-Type DHPs are voltage gated calcium channels on the sarcoplasmic reticlulum. Finally we have Primary and Secondary active transport controlling the overall movement of calcium in and out of the cell along with the movement of calcium in and out of the sarcoplasmic reticulum.

For further reference material in understanding the concept map above here are some videos: