COMPARISON OF THE ACTION POTENTIAL OF THE NATURAL PACEMAKER (THE SA) NODE AND THE ACTION POTENTIAL OF THE CONTRACTILE MYOCYTES​

Pacemaker cells generate spontaneous action potentials that are also termed "slow response" action potentials because of their slower rate of depolarization. ... Another difference between cardiac and nerve and muscle action potentials is the role of calcium ions in depolarization.

explanation:

for example, code 28039 - excision, tumor, soft tissue of foot or toe, subcutaneous, 1.5 cm or greater, appears before 28043 - excision, tumor, soft tissue of foot or toe, subcutaneous; less than 1.5 cm.