Unlike contractile cardiac muscle cells, specialized pacemaker cells in various

Question

Unlike contractile cardiac muscle cells, specialized pacemaker cells in various locations in the heart depolarize and generate action potentials spontaneously. The diagram below shows the currents responsible for action potentials in the sinoatrial (SA) node of the right atrium. Note that the subscript "f" refers to "funny" channels SA Node +30 IK 0 0 3 -30 Threshold 4 4 60 The rapid depolarization phase of the SA node cell's membrane potential is caused by movement of... (More than one answer may be correct.) sodium through funny channels calcium through L-type (long) calcium channels calcium through T-type (transient) calcium channels potassium through funny channels potassium through K channels

Explanation / Answer

Changes in membrane potential during the different phases are brought by changes in movement of ions mainly ca++,Na+ across membrane through ion channels.

1. Depolarization tion phase of SA node cells membrane potential caused by.

Calcium through L type (long) calcium channel increases. And ca++ through T-type receptor channels decline

2.

Following things are responsible for repolarization phase of SA node cell membrane potencial

-decreased calcium current through L-type calcium channels

-increased in potassium current through voltage gated k channels.

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