THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -Answer and Explanation: As a result of the long refractory period, cardiac muscle cannot exhibit (b) tetanus. Cardiac muscles cannot exhibit tetanus due to a long refractory period.

Detailed explanation-2: -The refractory period of cardiac muscle is dramatically longer than that of skeletal muscle. This prevents tetanus from occurring and ensures that each contraction is followed by enough time to allow the heart chamber to refill with blood before the next contraction.

Detailed explanation-3: -As a result of the long refractory period in the cardiac action potential, cardiac muscle cannot exhibit tonus.

Detailed explanation-4: -After an action potential initiates, the cardiac cell is unable to initiate another action potential for some duration of time (which is slightly shorter than the “true” action potential duration). This period of time is referred to as the refractory period, which is 250ms in duration and helps to protect the heart.