This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nerve Muscle Physiology, Subject name: Physiology
All of the following is true about excitation contraction coupling in skeletal muscle, except: 
Select and explain. 
A. Acetylcholine is released at nerve terminals, B. Ca++ is pumped backed into SERCA during relaxation, C. Ca++ is binds to tropomyosin to initiate contraction, D. Unlike cardiac muscle that has electrochemical coupling, skeletal muscle shows electromechanical coupling
C: Ca++ is binds to tropomyosin to initiate contraction
Answer: C: Ca++ is binds to tropomyosin to initiate contraction 
Explanation: Calcium binds to troponin C Ach is released at neuromuscular junction when action potential arrives at nerve terminal to produce end plate potential at post synaptic muscle membrane. Also, small quanta (packets) of acetylcholine are released randomly from the nerve cell membrane at rest. Each produces a minute depolarizing spike called a miniature endplate potential, which is about 0.5 mV in amplitude. Removal of troponin-tropomyosin complex from active site by calcium: Mechanism of Calcium removal that leads to relaxation Electromechanical coupling in skeletal muscle: Action potential causes mechanical change in DHPR receptor that opens RYR receptor of SERCA Electrochemical coupling in myocardium: AP causes opening of Ca++ channel associated with DHPR receptor. This calcium influx causes calcium induced calcium release from RYR.