How do pacemaker cardiac muscle cells differ from contractile cardiac muscle cells? What is autorhythmicity?

Video transcript

Hi, everyone. Let's take a look at this practice problem. Together, choose which statement is correct about the heart. I'll read the possible answer choices first and then together we'll go through the two statements provided. The answer options are a statement one only B, statement two, only C, both statements one and two and D neither statement one or two. So the first statement is the heart contracts without any external stimulation due to auto rhythmicity, recall the definition of out of rhythmicity and it's that the cardiac muscle tissue in the heart has the ability to contract without any neural or hormonal stimulation. So statement one is the definition of automic. So statement one is true. Now, statement two is the pacemaker cells of the heart do not contribute to the contractile force of the heart. So recall that it is specialized cardiac muscle tissue that helps the heart to contract pacemaker cells control the heart rate and they do not contribute to the contractile force of the heart. So again, that contractile force comes from specialized cardiac muscle cells. So statement two is also a correct statement. Therefore, the correct answer is option C both statements. One and two. All right, everyone. I hope you found this helpful and I'll see you soon for the next practice problem.