Question

fill in the blank question nodal cells in the sa initiate a heartbeat by spontaneously depolarizing to generate an action potential. need help? review these concept resources.

Explanation:

The sino - atrial (SA) node contains nodal cells which are pacemaker cells. These cells spontaneously depolarize, changing the electrical potential across their cell membranes, which initiates the heartbeat and generates an action potential that spreads through the heart to cause contraction.

Answer:

depolarizing