Which of the following is both a structural and functional protein?

The anaerobic contraction of skeletal muscle causes deposition or accumulation of

Sarcoplasmic reticulum is present in which structure:

Where are calcium ions stored in muscle cells?

Select the correct statements regarding the mechanism of muscle contraction.
$A.$ It is initiated by a signal sent by $\text{CNS}$ via a motor neuron,not a sensory neuron.
$B.$ Neurotransmitter generates an action potential in the sarcolemma.
$C.$ Increased $Ca^{++}$ level leads to the binding of calcium with troponin on actin filaments.
$D.$ Masking of the active site of actin prevents contraction; unmasking leads to contraction.
$E.$ Utilising the energy from $\text{ATP}$ hydrolysis to form a cross-bridge.

What is the value of the action potential in a muscle fibre?