Final answer:
During hypocalcemia, nerves fire more easily, and during hypercalcemia, nerves are less able to fire. An imbalance either way affects nerve function and muscle physiology, leading to varying symptoms.
Step-by-step explanation:
During hypocalcemia, a condition characterized by abnormally low levels of calcium, nerves fire more easily because of increased excitability. Conversely, during hypercalcemia, where there is an abnormally high level of calcium, nerves are less able to fire due to decreased neuronal excitability, leading to symptoms like lethargy, sluggish reflexes, constipation, loss of appetite, confusion, and in severe cases, coma. The balance of calcium is crucial for proper nerve function as well as the physiology of other body systems such as cardiac and skeletal muscles.