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 the thyroid gland:
- It regulates bodily metabolism, temperature, and heart rate
- It works opposite to parathyroid hormone to balance calcium levels in the body
About the Parathyroid gland:
- These are four small glands located behind the thyroid gland
- The main role of the parathyroid gland is to secrete parathyroid hormone (PTH)
- The main function of PTH is to regulate the calcium and phosphate levels in the blood
- It is essential for bone and kidney functions, but has no influence on metabolism
Effects of Parathyroid Hormone:
Effect on bones
- It stimulates the resorption of calcium into the bones
- Releases calcium and phosphates into the blood as per the need
Effect on the kidneys
- It increases calcium reabsorption from the urine
- It also promotes phosphate excretion
- It also activates an enzyme, 1α-hydroxylase enzyme, which converts vitamin D into active calcitriol
Effect on the Intestine
It will increase the absorption of calcium via calcitriol
What are the conditions related to parathyroid hormone imbalances?
Parathyroid Disorders – Hyper vs Hypo
| Condition | PTH Level | Blood Calcium | Blood Phosphate | Causes | Common Symptoms |
|---|---|---|---|---|---|
| Hyperparathyroidism | High | Increases → Hypercalcemia | Decreases → Hypophosphatemia | Parathyroid adenoma (common) Parathyroid cancer (rare) Kidney disease |
Fatigue, headaches Joint/bone pain Frequent urination & thirst Kidney stones |
| Hypoparathyroidism | Low | Decreases → Hypocalcemia | Increases → Hyperphosphatemia | Accidental surgical removal/damage (75% cases) Genetic disorders Autoimmune disease |
Muscle cramps Tingling (lips/fingers/feet) Dry skin, brittle nails Brain fog, confusion |
Mnemonics for the OPRA exam preparation
Parathyroid Disorders – Mnemonics
| Condition | Mnemonics | Meaning / Symptoms |
|---|---|---|
| Hyperparathyroidism | “Stones, Bones, Groans, Moans” | Stones → kidney stones Bones → bone pain, osteoporosis Groans → abdominal pain Moans → fatigue, depression |
| Hypoparathyroidism | “CATS go numb” | C → Convulsions A → Arrhythmias T → Tetany S → Spasms/Seizures Go numb → Tingling lips, fingers, toes |
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
Thyroid vs Parathyroid Glands| Key Features | Thyroid Gland | Parathyroid Gland |
|---|---|---|
| Hormones | T3, T4, Calcitonin | PTH |
| Primary Role | Metabolism, growth, decreases calcium (via calcitonin) | Calcium & phosphate regulation |
| Effect on Calcium | Decreases calcium | Increases calcium |
| Disorders | Hypo/Hyperthyroidism | Hypo/Hyperparathyroidism |
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.