Sat27November0556PM 34

Which hormone is responsible for the regulation of blood calcium levels?

(Please select 1 option)

Thyroid hormone

Adrenaline

Glucagon

Cortisol

Parathyroid hormone Correct

Explanation

Blood calcium levels are regulated by parathyroid hormone.

Calcium has many important roles in the human body:

Major component of bone, playing a fundamental role in support and movement

Required for blood clotting

Required for contraction of muscles, including the heart

Required for nervous transmission

Required for intracellular signalling pathways

Required for the production and release of some hormones.

The regulation of calcium levels in the blood and interstitial fluid is very important as excessively low or high levels of calcium can cause arrhythmias and cardiac arrest.

The parathyroid hormone works directly on bone. The actions of PTH on bone are complex as it can stimulate bone production and/or resorption (loss) depending on the concentration and duration of exposure. It also works directly on the kidney:

Increases loss of phosphate in the urine

Decreases loss of calcium in the urine, and

Promotes activity of the enzyme 1-alpha hydroxylase which activates vitamin D.

Additionally, parathyroid hormone works indirectly on the gut through the action of activated vitamin D.

Answer Statistics

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1%

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4

99%

Times answered: 265