NEETZoologyLocomotion and Movement
How does the increase in calcium ion level lead to muscle contraction?
Options
- ABy increasing the cross-bridge formation between actin and myosin
- BBy binding with a subunit of troponin on actin filaments and thereby removing the masking of active sites for
- CBy causing the return of ‘Z’ lines back to their original position
- DBy pumping calcium ions back to the sarcoplasmic cisternae
Correct answer
B. By binding with a subunit of troponin on actin filaments and thereby removing the masking of active sites for
Step-by-step solution
Muscle contraction is initiated by a signal sent by the central nervous system (CNS) via a motor neuron.The junction between a motor neuron and the sarcolemma of the muscle fibre is called the neuromuscular junction or motor-end plate.When a neural signal reaches the neuromuscular junction, it releases a neurotransmitter (Acetylcholine) which generates an action potential in the sarcolemma. Increase in Ca²⁺ level leads to the binding of calcium with a subunit of troponin on actin filaments and thereby remove the ma