Calcium Regulation

In which of the following would parathyroid hormone be present in greater quantities? Would it be in A) a breast-feeding mother or B) an infant?

A) a breast-feeding mother

Which hormone is derived from Vitamin D3? Is it A) calcitriol or B) calcitonin?

A) calcitriol. Calcitriol is derived from Vitamin D3 while calcitonin is produced by the thyroid.

Which bone cells release calcium into the bloodstream? Are they A) osteoclasts or B) osteoblasts?

A) osteoclasts. Osteoclasts release calcium into the bloodstream by dissolving bone matrix.

The three hormones responsible for maintaining calcium homeostasis are calcitonin, parathyroid hormone, and A) calreticulin or B) calcitriol.

B) Calcitriol

Which form of calcium most affects your normal body function? Is it A) calcium bound to blood proteins or B) free calcium in blood?

B) Free calcium in blood. The calcium ions that travel freely through the blood, called free calcium, are critical to the functioning of all body cells.

Which hormone is PTH's opposite in the negative feedback loop of calcium regulation? Is it A) calcitriol ob B) calcitonin?

B) calcitonin. Calcitonin acts to decrease free calcium levels, the opposite action of PTH.

Which of the following hormones is produced in the thyroid gland? Is it A) PTH or B) calcitonin?

B) calcitonin. Calcitonin is produced in the thyroid gland, and parathyroid hormone (PTH) is produced in the parathyroid gland.

What would happen to you if you had a functioning thyroid but a non-functioning parathyroid gland? Would you A) survive by taking large quantities of calcium supplements or B) develop several fatal pathologic conditions due to the lack of free calcium?

B) develop several fatal pathologic conditions due to the lack of free calcium. You would no longer be able to regulate levels of free calcium in your body, resulting in fatal effects on your nervous system and skeletal muscles.

Low calcium concentrations in the blood can lead to a condition called A) hypercalcemia or B) hypocalcemia.

B) hypocalcemia.

Which of the following is not a symptom of hypocalcemia? Is it A) loss of appetite or B) memory loss?

B) memory loss. Memory loss is a symptom of hypercalcemia, not hypocalcemia.

Which hormone is responsible for regulating calcium levels in three ways? Is it A) calcitonin or B) parathyroid hormone?

B) parathyroid hormone. Parathyroid hormone regulates calcium levels by acting on bone cells, the small intestine, and the kidneys.

Calcitriol increases free calcium concentrations by A) signaling the kidneys to excrete excess calcium or B) signaling the intestines to reabsorb more calcium.

B) signaling the intestines to reabsorb more calcium. Calcitriol signals the intestines to absorb more calcium from your dietary intake.

True or False? The free calcium in your blood makes up 99 percent of the total calcium in your body?

False

When calcitonin acts on free calcium levels, how does it affect them?

It decreases them.

True or false? Parathyroid hormone becomes active when the levels of free calcium need to increased.

True

True or False? Calcium is the most abundant ion in your body.

True

Calcitriol is derived from what vitamin?

Vitamin D3