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Ca^(2+)" and "Mg^(2+)...

`Ca^(2+)" and "Mg^(2+)`

A

Reduce excitability of nerves and muscles

B

Increase excitability of nerves and muscles

C

Conduct nerve impulses

D

Both B and C.

Text Solution

AI Generated Solution

The correct Answer is:
To answer the question regarding the effects of calcium ions (Ca²⁺) and magnesium ions (Mg²⁺) on the excitability of nerves and muscles, we can follow these steps: ### Step-by-Step Solution: 1. **Understanding Calcium and Magnesium Ions**: - Calcium (Ca²⁺) and magnesium (Mg²⁺) are essential cations in the body that play significant roles in various physiological processes, including muscle contraction and nerve function. 2. **Effects of High Concentrations**: - High levels of calcium and magnesium ions lead to a decrease in the excitability of nerves and muscles. This means that when the concentrations of these ions are elevated, the ability of nerve and muscle cells to respond to stimuli is reduced. 3. **Mechanism of Reduced Excitability**: - The reduction in excitability occurs because high levels of these ions raise the threshold for stimulation. This means that a stronger stimulus is required for the nerve or muscle to respond. 4. **Effects of Low Concentrations**: - Conversely, low levels of calcium and magnesium ions increase the excitability of nerves and muscles. In this case, the cells become more responsive to stimuli, allowing for easier conduction of nerve impulses and muscle contractions. 5. **Conclusion**: - Based on the above understanding, the correct statement regarding the effects of Ca²⁺ and Mg²⁺ is that they reduce the excitability of nerves and muscles when present in high concentrations. ### Final Answer: The correct option is: **It reduces the excitability of nerves and muscles.** ---
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