Question

Choose the true statements about skeletal muscle. There may be more than one correct answer.

A. blocking the calcium ATPase would inhibit relaxation
B. epinephrine is the most important neurotransmitter for skeletal muscle
C. blocking all ion channels on the t-tubules would block contraction
D. ATP must remain high for the muscle to contract and relax

Answer 1

Blocking the calcium ATPase inhibits relaxation, blocking all ion channels on the T-tubules blocks contraction, and ATP must remain high for muscle to contract and relax.

Step-by-step explanation:

According to the information provided, the true statements about skeletal muscle are:

A. Blocking the calcium ATPase would inhibit relaxation. This is because the calcium ATPase is responsible for actively pumping calcium ions out of the cytoplasm and back into the sarcoplasmic reticulum, which is required for muscle relaxation.

C. Blocking all ion channels on the T-tubules would block contraction. The T-tubules are responsible for transmitting the action potential deep into the muscle fiber, which triggers the release of calcium ions from the sarcoplasmic reticulum and initiates muscle contraction.

D. ATP must remain high for the muscle to contract and relax. ATP provides the energy necessary for cross-bridge cycling, which is the interaction between myosin and actin filaments that causes muscle contraction. Without ATP, muscle contraction cannot occur.