Question

Which factor listed below directly contributes to what is seen in the dashed line above the "normal" operating line?

1) A higher QRS complex in the EKG
2) Increased myosin ATPase activity in ventricular cardiomyocytes
3) Norepinphrine binding to beta receptors in vascular smooth muscle
4) Phosphorylation of the ryanodine receptor in cardiomyocytes
5) Phosphorylation of the calcium ATPase pumps in ventricular cardiomyocytes

Answer 1

Increased myosin ATPase activity in ventricular cardiomyocytes directly contributes to what is seen in the dashed line above the "normal" operating line. Hence the correct answer is option 2

Step-by-step explanation:

The factor that directly contributes to what is seen in the dashed line above the "normal" operating line is 2) Increased myosin ATPase activity in ventricular cardiomyocytes.

Hence the correct answer is option 2