Test Your Knowledge: Which Hormone Opposes Parathyroid Hormone?
Think you know which hormone counters parathyroid action? Take the test now!
This quick quiz helps you identify which hormone opposes parathyroid hormone and how that choice affects calcium balance. Use it to check gaps before an exam and refresh core endocrine facts; when you're ready for more, try the endocrine practice set or visit the study hub .
Study Outcomes
- Identify the Counteracting Hormone -
Determine which hormone opposes the action of parathyroid hormone and learn its role in calcium regulation.
- Understand Parathyroid Hormone Function -
Describe parathyroid hormone function in maintaining blood calcium levels and its impact on bone health.
- Analyze Opposing Hormones -
Compare opposing hormones parathyroid hormone interactions and feedback loops to appreciate endocrine system balance.
- Apply Knowledge with Quiz Questions -
Engage with endocrine system quiz questions to test your grasp of hormone interactions and retention of key concepts.
- Leverage Endocrine Hormones Trivia -
Recall fascinating endocrine hormones trivia to reinforce your understanding of glandular signaling and regulation.
Cheat Sheet
- Calcitonin as the Primary Antagonist -
Calcitonin, secreted by thyroid parafollicular C-cells, opposes the action of parathyroid hormone by inhibiting osteoclast-mediated bone resorption and enhancing renal calcium excretion. This direct counterbalance helps maintain serum calcium within a narrow physiological range. Mnemonic: "Calcitonin Cuts Calcium" to recall its calcium-lowering effect.
- Parathyroid Hormone Function Recap -
Parathyroid hormone (PTH) raises blood calcium by stimulating osteoclasts, increasing renal calcium reabsorption, and activating vitamin D in the kidney (1α-hydroxylase). Understanding parathyroid hormone function is crucial for recognizing how opposing hormones restore balance. Tip: remember PTH's "3 D's" - Bones (deDuce), Kidneys (reDuce loss), and Gut (absoDption with vitamin D).
- Calcium Homeostasis Feedback Loop -
The feedback loop between PTH and calcitonin ensures tight control of extracellular calcium: low Ca2+ triggers PTH release, while high Ca2+ stimulates calcitonin secretion. This interplay illustrates opposing hormones parathyroid hormone dynamics, preventing hypercalcemia or hypocalcemia. Visualize a thermostat model: PTH "turns up" calcium, calcitonin "turns it down."
- Renal vs. Skeletal Effects Contrast -
PTH enhances renal Ca2+ reabsorption and phosphate excretion, whereas calcitonin decreases renal reabsorption of calcium and phosphate. In bone, PTH promotes osteoclast differentiation via RANKL upregulation, while calcitonin directly inhibits mature osteoclasts. Contrast chart suggestion: list each hormone's actions side by side for quick revision.
- Clinical Implications and Disorders -
Imbalances in PTH or calcitonin can lead to hyperparathyroidism, hypoparathyroidism, or medullary thyroid carcinoma (elevated calcitonin marker). Recognizing which hormone opposes the action of parathyroid hormone aids in diagnosing calcium disorders and guiding treatments such as bisphosphonates or calcimimetics. Example case: high serum Ca2+, low PTH, elevated calcitonin suggests malignancy-driven hypercalcemia.