L35. Physiology - Parathyroid

<p>Chief cells (A)</p> Signup and view all the answers

<p>Promotes its conversion to the active form (B)</p> Signup and view all the answers

<p>Increased bone resorption (B)</p> Signup and view all the answers

<p>Kidney (D)</p> Signup and view all the answers

<p>It stimulates calcium absorption from the gut (B)</p> Signup and view all the answers

<p>Parathyroid hormone (B)</p> Signup and view all the answers

<p>Low extracellular calcium relieves the inhibitory effect of PKC and intracellular calcium on PTH release (D)</p> Signup and view all the answers

<p>Directly enhances calcium reabsorption and increases phosphate excretion (C)</p> Signup and view all the answers

<p>Continuous PTH exposure leads to increased osteoclast activity, promoting bone breakdown and elevating blood calcium levels (C)</p> Signup and view all the answers

<p>PTH interacts with GPCRs linked to adenylate cyclase, resulting in intracellular calcium signaling (D)</p> Signup and view all the answers

<p>Directly increasing calcium absorption in the kidneys and indirectly acting on bone to increase calcium release (A)</p> Signup and view all the answers

<p>Activating Vitamin D synthesis, which enhances calcium absorption in the intestines (C)</p> Signup and view all the answers

<p>Inhibition of PTH release to decrease blood calcium levels (B)</p> Signup and view all the answers

<p>Both PKC and intracellular calcium inhibit PTH release (A)</p> Signup and view all the answers

<p>Modulating the balance between osteoclast and osteoblast activity (A)</p> Signup and view all the answers

<p>Increased bone resorption and elevated blood calcium levels (B)</p> Signup and view all the answers

<p>Mono-hydroxylated form (C)</p> Signup and view all the answers

<p>Liver and Kidney (D)</p> Signup and view all the answers

<p>The di-hydroxy form is about 10 times more active. (B)</p> Signup and view all the answers

<p>To act as a precursor to the active form of Vitamin D for hormone function. (A)</p> Signup and view all the answers

<p>Conversion from provitamin D by UV rays. (A)</p> Signup and view all the answers

<p>A steroid (D)</p> Signup and view all the answers

<p>Hydroxylation (B)</p> Signup and view all the answers

<p>To facilitate its transport in the bloodstream. (D)</p> Signup and view all the answers

<p>Increased secretion of parathyroid hormone (PTH) from the parathyroid glands (B)</p> Signup and view all the answers

<p>PTH promotes phosphate excretion by the kidneys (phosphaturia), thereby lowering plasma phosphate levels. (B)</p> Signup and view all the answers

<p>Increasing calcium absorption in the gut (C)</p> Signup and view all the answers

<p>Increased deposition of calcium-phosphate in bone and other tissues, leading to decreased plasma calcium. (D)</p> Signup and view all the answers

<p>PTH indirectly increases calcium absorption in the gut by stimulating the production of active vitamin D in the kidneys. (B)</p> Signup and view all the answers

<p>Stimulating osteoblasts to secrete factors that promote the differentiation of osteoblasts, leading to increased bone formation. (A)</p> Signup and view all the answers

<p>Increased excretion of phosphate, leading to decreased plasma phosphate levels (phosphaturia). (B)</p> Signup and view all the answers

<p>PTH indirectly increases plasma calcium by stimulating calcium reabsorption in the kidneys. (A)</p> Signup and view all the answers

<p>Insulin (A)</p> Signup and view all the answers

<p>1α hydroxylase (A)</p> Signup and view all the answers

<p>1α hydroxylase activity (C)</p> Signup and view all the answers

<p>Calcium transporters and binding proteins (B)</p> Signup and view all the answers

<p>Growth hormone (D)</p> Signup and view all the answers

<p>Promotes calcium influx into bone (D)</p> Signup and view all the answers

<p>Stimulates gene expression for calcium absorption (D)</p> Signup and view all the answers

<p>Inhibition of its own production (A)</p> Signup and view all the answers

<p>Monohydroxylated form (D)</p> Signup and view all the answers

<p>PTH (Parathyroid hormone) (A)</p> Signup and view all the answers

<p>High calcium levels (B)</p> Signup and view all the answers

<p>Dihydroxy form (B)</p> Signup and view all the answers

<p>Ultraviolet radiation exposure (A)</p> Signup and view all the answers

<p>It limits further production of Vitamin D. (B)</p> Signup and view all the answers

<p>It is responsible for the di-hydroxylation of Vitamin D. (A)</p> Signup and view all the answers

<p>Liver and kidney (B)</p> Signup and view all the answers

Parathyroid hormone that regulates calcium levels in the blood.

The balance of calcium levels in the blood and body.

The excretion of phosphate in the urine stimulated by PTH.

The process of releasing calcium from bone into the bloodstream.

The form of vitamin D that enhances calcium absorption in the gut.

The process where excess phosphate leads to calcium deposits in tissues and bone.

Cells that help form new bone by secreting substances like calcium.

Low calcium levels trigger the parathyroid gland to secrete PTH.

The amount of calcium within cells, generally around 10 nM, which is very low.

The amount of calcium outside cells, especially in plasma, which is much higher at about 1 mM.

Most calcium in the body, around 1000 g, is stored in bones.

The average daily intake of calcium is about 1 g, necessary for health.

A hormone produced by parathyroid glands that regulates calcium levels by stimulating reabsorption and vitamin D conversion.

Vitamin D helps regulate calcium levels, enhancing absorption from the gut and synergizing with PTH.

Cells activated by high levels of PTH that promote the resorption (breakdown) of bone.

The process facilitated by intermittent PTH that leads to the formation of new bone.

The process stimulated by PTH that increases calcium retention from urine back into blood.

The conversion of provitamin D to vitamin D3 via UV rays exposure.

Provitamin D found in the skin, converted to vitamin D3.

The principal circulating form of Vitamin D in the blood.

The more active form of vitamin D, 10 times more active than the mono form.

Biochemical processes in liver and kidney converting vitamin D forms.

Protein that transports vitamin D in the bloodstream.

The biologically active versions of vitamin D produced in the body.

Initiates the process of vitamin D synthesis in the skin.

PKC is activated by a Gq GPCR pathway leading to increased intracellular calcium.

Calcium outside cells that affects the secretion of PTH.

PKC and high intracellular calcium inhibit the release of PTH from secretory granules.

Low extracellular calcium levels relieve inhibition, resulting in increased PTH release.

PTH raises blood calcium levels by acting on bone, kidneys, and indirectly through Vitamin D.

PTH stimulates bone remodeling by promoting resorption and mineralization.

In kidneys, PTH increases calcium reabsorption and excretion of phosphate, sodium, and bicarbonate.

PTH activates the conversion of Vitamin D to its active form.

Chronic high PTH increases osteoclasts, promoting bone resorption and raising calcium levels.

Short bursts of PTH promote healthy bone growth and remodeling.

7-dehydrocholesterol, the precursor to vitamin D, found in skin.

The principal circulating form of vitamin D in the blood, bound to globulin.

The active form of vitamin D, about 10 times more active than mono-hydroxylated form.

An enzyme stimulated by PTH to convert inactive vitamin D to its active di-hydroxy form.

PTH stimulates vitamin D production; inhibited by high calcium levels and feedback mechanisms.

Vitamin D inhibits its own production when levels are sufficient to maintain balance.

Low plasma phosphate stimulates the 1α hydroxylase enzyme for active vitamin D production.

Insulin, sex steroids, and growth hormone trigger the production of active vitamin D.

Proteins that facilitate the absorption of calcium from the gut, activated by vitamin D.

Vitamin D enhances calcium and phosphate absorption in the gut via the VDR.

A receptor that vitamin D binds to in order to exert its effects on gene expression.

Vitamin D promotes calcium flow into bones by increasing gut absorption.

Vitamin D also stimulates phosphate absorption in the intestines, aiding in bone health.