SA nodal cells are unique in that they exhibit autorhythmicity, meaning they are capable of depolarizing and firing an action potential spontaneously without any external influence.

1. True

2. False

1) True

Explanation:

Cells of Sinoatrial (SA) node make up the auto rhythmic cells of heart as in normal physiological conditions, SA-node is responsible to set the pace of the rest of the heart (pacemaker) at a rate of 70 to 80 beats per minute.

The cells of SA node has the ability to self-excite thus able to generate action potential without external stimulation by nerve cells. Thus they initiate the cardiac cycle providing the conduction system.

Hence the statement, SA nodal cells are unique in that they exhibit autorhythmicity, meaning they are capable of depolarizing and firing an action potential spontaneously without any external influence, is true.