Final answer:
High blood calcium levels in hypercalcemia cause sluggish deep tendon reflexes by decreasing the excitability of nerve and muscle cells, indicating an underactive nervous system.
Step-by-step explanation:
Hypercalcemia, characterized by abnormally high levels of calcium in the blood, leads to an underactive nervous system. This can cause a range of symptoms from lethargy and confusion to severe cases of coma. In terms of motor function, hypercalcemia affects deep tendon reflexes by making them sluggish. Deep tendon reflexes, also known as stretch reflexes, are an indicator of motor neuron function and are typically elicited by a strong tap to a tendon.
In the setting of hypercalcemia, the increased calcium concentration can decrease the excitability of nerve and muscle cells, leading to sluggish reflexes. This can also eventually impair cardiac function, if not corrected. Understanding the impact of calcium levels on reflexes is crucial in differentiating between upper and lower motor neuron disorders and for assessing overall neuromuscular health.