Effect of Parathyroid Hormone (PTH): Functions, Disorders & OPRA Exam Guide 2025

Learn the effects of parathyroid hormone (PTH) on bones, kidneys, and intestines. Understand hyperparathyroidism, hypoparathyroidism, symptoms, mnemonics, FAQs, and key takeaways for OPRA exam preparation in 2025.

Krupa

9/27/20252 min read

Key Takeaways:

  • Two major glands of the endocrine system are Thyroid gland and parathyroid glands.

  • Thyroid gland is responsible for metabolism, calcitonin lowers calcium.

  • Parathyroid glands is responsible for balancing calcium-phosphate levels in blood

  • PTH(Parathyroid hormone) raises calcium and lowers phosphate.

  • Increased release of PTH hormone results in Hyperparathyroidism. It causes hypercalcemia, kidney stones, bone fragility.

  • Reduced release of PTH hormone results in Hypoparathyroidism causing hypocalcemia, tetany, neuromuscular symptoms.

  • Best Mnemonics related to this topic is “Stones, Bones, Groans, Moans” & “CATS go numb”

There are two major glands in the endocrine system - The thyroid and parathyroid glands. These are crucial parts for normal functioning of a body. Normal metabolism is the major function of the thyroid gland and the parathyroid glands keeps the balance between calcium and phosphate in the body through the release of PTH (Parathyroid hormone).

These high yield topics such as these crucial hormones are very important for competitive exams like OPRA (Overseas Pharmacist Readiness Assessment) exam. It assesses the knowledge and skills of international candidates to work effectively and safely in Australia. ParaThyroid Hormone is an important hormone. It regulates calcium thus it maintains bone health, overlooking the renal function, checks the neuromuscular stability, and manages endocrine disorders.

This blog provides comprehensive details regarding parathyroid hormone, its actions, mnemonics to remember, FAQs, and key takeaways to boost your preparation.

About Thyroid Gland: For a quick check

It is a butterfly shaped gland located in the front side of neck

Thyroid gland excretes mainly three hormones

  • Thyroxine (T4)-it controls metabolism and growth

  • Triiodothyronine (T3) - which is more active form of thyroid hormone

  • Calcitonin-which lowers calcium by increasing deposition in bones.


Function of thyroid gland:

  • It regulates bodily metabolism, temperature, and heart rate

  • It works opposite to parathyroid hormone to balance calcium levels in body


About the Parathyroid gland:

  • These are small-four glands located behind the thyroid gland

  • Main role of parathyroid gland is to secrete parathyroid hormone (PTH)

  • Main function of PTH is to regulate the calcium and phosphate levels in blood

  • It is essential for bone and kidney functions, but has no influence on metabolism

Effects of Parathyroid Hormone:

Effect on bones

  • it stimulates resorption of calcium to bones

  • Releases calcium and phosphates into the blood as per the need


Effect on kidneys

  • It increases calcium reabsorption from urine

  • It also promotes phosphate excretion

  • It also activates an enzyme, 1α-hydroxylase enzyme which converts vitamin D into active calcitriol


Effect on Intestine

It will increase the absorption of calcium via calcitriol

What are the conditions related to parathyroid hormone imbalances?

Mnemonics for The OPRA exam preparation

Symptoms of abnormal PTH levels

Low Calcium (Hypocalcemia) in the blood causes Hypoparathyroidism

It results in:

  • Brain fog or confusion

  • Dry skin, brittle nails

  • Muscle cramps

  • Tingling (paresthesias) in lips, fingers, feet


High Calcium (Hypercalcemia) in the blood causes Hyperparathyroidism

It results in:

  • Fatigue

  • Headaches

  • Joint and bone pain

  • Frequent urination, excessive thirst

Thyroid vs Parathyroid gland functions

Conclusion

In our body, the thyroid and parathyroid glands are responsible for maintaining metabolic and mineral balance. The thyroid gland regulates metabolism and reduces calcium by resorption via calcitonin, the parathyroid increases calcium and reduces phosphate via PTH.

For OPRA exam success, remember:

  • What are the effects of PTH on bones, kidneys, intestines?

  • What are the main features of Hyper- and hypoparathyroidism?

  • Mnemonics for revision
    Mastering these topics ensures you are well-prepared for clinical and theoretical exam questions.

About the Author

Krupa Karamchand

Content Writer | Elite Expertise

Krupa Karamchand is a B. Pharm graduate and KAPS-qualified pharmacist with over 7 years of experience in the pharmaceutical field. As an experienced SEO content writer, she combines her in-depth healthcare knowledge with proven digital strategies to create informative, engaging, and search engine–optimized blogs. Krupa is passionate about making complex medical topics easy to understand and accessible to all readers.

Follow On