Question

Which statement(s) best describe(s) the regulation of contraction strength of myocardial cells?

1) The higher the intracellular concentration of Ca , the stronger the force of contraction will be.
2) Catecholamines make voltage-gated Ca channels more likely to open, thus allowing higher concentrations of Ca inside the cell.
3) A and B are true

Answer 1

The regulation of contraction strength in myocardial cells involves the influx of calcium ions and the role of catecholamines.

Step-by-step explanation:

The regulation of contraction strength of myocardial cells involves the influx of calcium ions (Ca2+) through slow calcium channels. The higher the intracellular concentration of Ca2+, the stronger the force of contraction will be. Additionally, catecholamines, such as adrenaline, enhance the opening of voltage-gated Ca2+ channels, allowing higher concentrations of Ca2+ inside the cell. Therefore, both statement 1 and 2 are true, and the correct answer is option 3 (A and B are true).