Endocrine: Parathyroid Glands

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Questions and Answers

What is the primary function of the parathyroid glands?

Regulating pituitary hormone secretion

Enhancing neuromuscular excitability

Producing vitamin D

Exclusive control of calcium metabolism (correct)

How does the parathyroid gland regulate calcium levels?

By releasing hormones that inhibit calcium absorption

By directly sensing calcium levels in the blood (correct)

By stimulating the release of vitamin D

By responding to pituitary hormone signals

What is the effect of unregulated calcium on the muscular system?

Muscle cramps and weakness (correct)

Increased muscle strength and contraction

Enhanced neuromuscular excitability

Reduced bone resorption

What is the primary cause of secondary hyperparathyroidism?

Compensatory response to hypocalcemia Signup and view all the answers

What is the effect of hyperparathyroidism on bone health?

Osteoporosis and bone resorption Signup and view all the answers

What is the primary symptom of hyperparathyroidism related to the nervous system?

Muscle cramps and weakness Signup and view all the answers

What is the role of the bones in calcium metabolism?

They serve as a calcium storage system Signup and view all the answers

What is the effect of parathyroid hormone on calcium levels?

It increases calcium levels in the blood Signup and view all the answers

What is the effect of PTH on calcium reabsorption in the renal system?

PTH increases calcium reabsorption in the renal system Signup and view all the answers

What is the cause of secondary hyperparathyroidism?

Chronic renal failure and malabsorption Signup and view all the answers

What is the effect of PTH on vitamin D production in the kidneys?

PTH increases vitamin D production in the kidneys Signup and view all the answers

What is the treatment for severe hypercalcemia due to primary hyperparathyroidism?

Surgical removal of the parathyroid glands Signup and view all the answers

What is the effect of low PTH levels on bone resorption?

Decreased bone resorption Signup and view all the answers

What is the complication of hypoparathyroidism?

Paresthesia, muscle cramps, and tetany Signup and view all the answers

What is the effect of PTH on phosphate excretion in the renal system?

PTH increases phosphate excretion in the renal system Signup and view all the answers

What is the effect of PTH on calcium levels in the extracellular fluid?

PTH increases calcium levels in the extracellular fluid Signup and view all the answers

Study Notes

Parathyroid Glands

4 tiny glands with rich blood supply, interact with blood calcium
Exclusive for calcium metabolism
Produce hormones PTH
Measurement of PTH in blood indicates its function
Control calcium in blood and bones

Calcium Function

Provides electrical energy for the nervous system
Conducts electricity in the nervous system
Stabilizes neuromuscular excitability, making nerves less sensitive to stimuli
Provides energy for cells to contract in the muscular system
Strengthens skeletal system by making bones strong
Bones serve as calcium storage system

Hyperparathyroidism

Excess PTH secretion
Causes increased bone resorption/osteoporosis, hypercalcemia, and hypercalciuria
Types: Primary and Secondary
Primary: Tumor of parathyroid gland, failure, or chronic renal failure
Secondary: Compensatory response to hypocalcemia often due to chronic renal failure

Primary Hyperparathyroidism

Caused by parathyroid adenoma (one or more glands)
Leads to increased skeletal resorption, release of Ca2+ and Pi from bone
Increases Ca2+ and Pi absorption from small intestine
Enhances Ca2+ reabsorption and inhibits Pi reabsorption from renal, causing increased urine Pi excretion
Results in increased ECF calcium and decreased ECF phosphate

Secondary Hyperparathyroidism

Caused by chronic renal failure and malabsorption
Elevated PTH levels
Long-term activation causes hyperplasia of glands, loss of sensitivity to circulating calcium
Autonomous secretion of PTH even with normal calcium levels

Complications of Hyperparathyroidism

Death due to cardiac and neurological dysfunctions
Hypercalcemia, hypercalciuria, and osteoporosis

Treatment of Hyperparathyroidism

Medical emergency for severe hypercalcemia
Use diuretics to increase calcium excretion
Use drugs to inhibit bone resorption
Surgical removal of tumor or ectopic secretion due to tumor

Hypoparathyroidism

Abnormal or low PTH levels
Etiology: thyroid surgery, autoimmunity, genetic mechanism, and Di George syndrome
Clinical findings: depressed calcium, increased phosphate, decreased bone resorption, and hypocalciuria
Treatment: calcium and vitamin D replacement therapy, risk of kidney stones

Complications of Hypoparathyroidism

Paresthesia, muscle cramps, and spasms (tetany)
Fatigue, headaches, bone pain, and insomnia
Severe irregularities in normal heart beat
Spasm of airways causing respiratory failure

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Description

This quiz covers the functions of parathyroid glands, calcium metabolism, and calcium's role in the nervous system and muscle contractions.