Henderson-Hasselbalch Equation - Calculator

to calculate pH from PCO2 and HCO3-

Henderson-Hasselbalch Equation - Calculator

to calculate HCO3- and Base Excess from pH and PCO2

Henderson-Hasselbalch Base Excess Calculator

Inward Rectifying Potassium Current

http://tmedweb.tulane.edu/pharmwiki/doku.php/introduction_to_cardiac_physiology_
electrophysiology

The inward potassium rectifying current (Ik) is what distinguishes a cardiac muscle cell from other muscle cells and nerve cells.  It causes a delay in the refractory period which allows for the crucial entry of calcium during the plateau phase of the action potential.

How does it work?

Ionic basis for the resting and action potential in a ventricular heart cell. The action potential is divided into phases 0 through 4. Each phase results from a change in the balance of inward and outward ionic currents that become activated upon membrane depolarization. The primary currents underlying each phase are: phase 0: Na current (I_Na); phase 1: transient outward K current (I_to); phase 2: L-type Ca current(I_Ca); phase 3: delayed rectifier K currents (I_Kr & I_Ks); phase 4: inwardly rectifying K current (I_K1). The change in dominant conductance during each phase produce either net depolarization or hyperpolarization, and give the action potential its characteristic shape.