Which Is TRUE About the Comparison of Excitation-Contraction Coupling in Cardiac

question 15

Multiple Choice

Which is TRUE about the comparison of excitation-contraction coupling in cardiac muscle with that in skeletal muscle?

• A)Extracellular Ca²⁺ plays a major role in cardiac but not skeletal muscle.
• B)The mechanism  for Ca²⁺ release from the sarcoplasmic reticulum is the same in both types of muscle.
• C)Troponin sites are completely saturated immediately after Ca²⁺ release in both types of muscle.
• D)There is no net change in total intracellular Ca²⁺ concentration in either muscle.
• E)Intracellular Ca²⁺ stores are necessary for contraction in skeletal muscle,but not in cardiac muscle.