Question

Chemical ions responsible for muscle contraction are

• A. $C{a}^{++}$ and $K^{+}$
• B. $N{a}^{+}$ and $K^{+}$
• C. $N{a}^{+}$ and $C{a}^{++}$
• D. $C{a}^{++}$ and $M{g}^{++}$ ions

Answer 1

The correct option is D $C{a}^{++}$ and $M{g}^{++}$ ions

• When a nerve impulse reaches the neuromuscular junction, the calcium ions are released from the sarcoplasmic reticulum. Then the calcium ions trigger muscle contraction cycle by binding to the protein complex troponin, exposing the active-binding sites on the action. and this enables the myosin molecule heads to “grab and swivel” their way along the thin filament. This is the driving force of muscle contraction.
• Magnesium ions also play a role in regulating muscle contractions. The magnesium acts as a natural calcium blocker to help muscles relax.
  
• Hence Chemical ions responsible for muscle contraction are Ca++ and Mg++ ions.
• So, the correct answer is 'Ca++ and Mg++ ions'.