Final answer:
The term for excessive calcium in the blood is hypercalcemia, which can cause various symptoms including lethargy and confusion, and is regulated by calcium homeostasis mechanisms within the body.
Step-by-step explanation:
The term that means excessive calcium in the blood is hypercalcemia. This condition is characterized by abnormally increased blood levels of calcium. It is important to maintain calcium homeostasis because imbalances can result in various health issues.
For example, hypocalcemia, which is the condition of abnormally low blood levels of calcium, can cause problems with blood coagulation, muscle contraction, nerve functioning, and bone strength. Conversely, hypercalcemia can lead to lethargy, sluggish reflexes, constipation and loss of appetite, confusion, and in severe cases, coma. Calcium homeostasis is controlled by parathyroid hormone (PTH), vitamin D, and calcitonin, which interplay with the skeletal, endocrine, digestive, and urinary systems.