Parathyroid Hormone and Calcium Regulation Flashcards

Flashcards to review key concepts related to parathyroid hormone, calcium regulation, and related drugs.

What is Parathyroid Hormone (PTH)?

A hormone that plays a central role in maintaining calcium homeostasis.

Why is calcium important for various physiological processes?

Nerve function, muscle contraction, blood clotting, and bone health.

What are the three main target organs of PTH?

Bones, kidneys, and intestines.

How does PTH affect bones?

Stimulates the release of calcium and phosphate from bone.

How does PTH affect the kidneys?

Increases calcium reabsorption and promotes phosphate excretion.

How does PTH affect the intestines?

Increases calcium absorption by stimulating active vitamin D production.

How is PTH secretion primarily regulated?

Negative feedback loop involving blood calcium levels.

What happens to PTH secretion when blood calcium levels rise?

PTH secretion is inhibited.

What happens to PTH secretion when blood calcium levels fall?

PTH secretion is stimulated.

What is hyperparathyroidism?

Overproduction of PTH, leading to hypercalcemia.

What is hypoparathyroidism?

Underproduction of PTH, leading to hypocalcemia.

What are parathyroid hormone analogues?

Synthetic forms of PTH or PTHrP used to stimulate bone formation.

Give an example of a recombinant human parathyroid hormone.

Teriparatide and Natpara.

Give an example of an analogue of human PTHrP.

Abaloparatide.

What are parathyroid hormone analogues used to treat?

Severe osteoporosis with a high risk of fracture and hypocalcemia in patients with hypoparathyroidism.

What do calcimimetics do?

Mimic the action of calcium on the calcium-sensing receptor (CaSR).

What is the effect of activating the CaSR?

Decreases the secretion of PTH.

Give an example of a calcimimetic.

Cinacalcet and Etelcalcetide.

What are calcimimetics used to treat?

Secondary hyperparathyroidism in adults with chronic kidney disease on hemodialysis.

What is the mechanism of action of Vitamin D analogs?

Increase calcium absorption in the gut and reduce PTH secretion.

What is Calcitriol?

The active form of Vitamin D.

Name a synthetic Vitamin D analog.

Paricalcitol and Doxercalciferol.

What is Alfacalcidol?

A vitamin D precursor converted to calcitriol in the body.

What condition are Vitamin D analogs used to treat?

Secondary hyperparathyroidism in patients with chronic kidney disease

What is the primary role of calcitonin?

Lowers blood calcium levels.

Where is calcitonin produced?

Parafollicular cells (C-cells) of the thyroid gland.

What stimulates the release of calcitonin?

High levels of calcium in the blood.

How does calcitonin lower blood calcium levels?

Inhibition of osteoclasts, increased calcium excretion by the kidneys, and inhibition of intestinal calcium absorption.

What is salcatonin?

A synthetic form of calcitonin with a more potent and longer-lasting effect.

What conditions are synthetic calcitonins used to treat?

Paget's disease of bone, postmenopausal osteoporosis, and hypercalcemia.

What are some side effects of calcitonin?

Abdominal pain, altered taste, musculoskeletal pain, and arthralgia.

What is calcium homeostasis?

The process of maintaining stable calcium levels in the blood.

What are osteoclasts?

Cells that break down bone tissue.

What converts alfacalcidol into calcitriol?

An enzyme that catalyzes the conversion of vitamin D to its active form.

How are Vitamin D analogs related to PTH secretion?

Through negative feedback loops affecting PTH release and renal calcium handling.