Calcium and Phosphate Regulation Quiz

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Questions and Answers

What is the main component of bone matrix responsible for providing tensile strength?

Type 1 collagen fibers (correct)

Proteoglycans

Calcium ions

Bone marrow

Which cells are primarily responsible for bone remodelling?

Chondrocytes

Adipocytes

Osteoclasts and osteoblasts (correct)

Fibroblasts

What biological functions do bones provide?

Hormone production, immune response, and waste elimination

Hematopoiesis, energy storage, and mineral regulation

Neurotransmission, muscle contraction, and heat generation

Support, protection, movement, and mineral storage (correct)

What is the primary role of PTH (parathyroid hormone) in bone physiology?

Stimulate bone resorption to release calcium into the bloodstream Signup and view all the answers

What is the primary component of human bone?

Compact bone Signup and view all the answers

Where is trabecular bone primarily found?

At the ends of long bones Signup and view all the answers

At what age does the growth plate fuse with the metaphysis?

Around age 18 Signup and view all the answers

What is the microstructure of cortical bone composed of?

Osteons Signup and view all the answers

Which cells promote bone formation by laying down osteoid?

Osteoblasts Signup and view all the answers

What is the role of osteoclasts in bone?

Promote bone reabsorption Signup and view all the answers

What is the function of osteocytes in bone?

Transfer minerals and sense mechanical load Signup and view all the answers

How are bones constantly balanced?

Through activation of osteoblasts and osteoclasts Signup and view all the answers

What is the primary role of calcium in bone physiology?

All of the above Signup and view all the answers

In what forms is calcium found in body fluids?

Ionized (free), bound to protein, and bound to small anions Signup and view all the answers

Which hormone is released from the parathyroid glands in response to low plasma [Ca$^{2+}$] and is the major controller of free Ca$^{2+}$ in the body?

Parathyroid hormone (PTH) Signup and view all the answers

What is the daily calcium regulation that involves dietary intake of 1000 mg, gastrointestinal absorption of approximately 600 mg, and urinary excretion of 150 mg?

Dietary intake of 900 mg, gastrointestinal absorption of 400 mg, and urinary excretion of 250 mg Signup and view all the answers

What can lead to increased free [Ca$^{2+}$] in acidosis and decreased free [Ca$^{2+}$] in alkalosis?

Increased [H$^+$] displacing Ca$^{2+}$ from protein in acidosis and alkalosis Signup and view all the answers

What is the process that involves 1$α$-hydroxylation in the kidney and promotes Ca$^{2+}$ absorption from the gut and mineralization of bone?

Active vitamin D production Signup and view all the answers

What does osteoporosis cause in adults due to vitamin D deficiency?

Bone fragility and susceptibility to fracture Signup and view all the answers

What does PTH regulate in the kidney?

Stimulates Ca$^{2+}$ reabsorption Signup and view all the answers

What is the process that involves the increased synthesis of components such as Ca$^{2+}$ channels and phosphate absorption in the gut, and reabsorption of Ca$^{2+}$ and PO$_4^{3-}$ in kidney tubules?

Active vitamin D production Signup and view all the answers

What can vitamin D deficiency lead to in children and adults?

Rickets in children and osteomalacia in adults Signup and view all the answers

What are the cells that mediate bone turnover throughout life?

Osteoblasts, osteoclasts, and osteocytes Signup and view all the answers

Study Notes

Calcium and Phosphate Regulation in the Body

The major physiological functions are mediated by the ionized form of calcium (Ca2+).
Acid-base status can affect levels of bound Ca2+ where increased [H+] displaces Ca2+ from protein, leading to increased free [Ca2+] in acidosis and decreased free [Ca2+] in alkalosis.
Daily calcium regulation involves dietary intake of 1000 mg, gastrointestinal absorption of approximately 600 mg, and urinary excretion of 150 mg.
Parathyroid hormone (PTH) is released from the parathyroid glands in response to low plasma [Ca2+] and is the major controller of free Ca2+ in the body.
PTH regulates plasma Ca2+ by stimulating bone reabsorption and promoting bone mineral reabsorption through the increase production of a mixture of cytokines.
PTH also stimulates the reabsorption of Ca2+ in the kidney's thick ascending limb of the loop of Henle and inhibits phosphate reabsorption in the proximal and distal tubules.
Active vitamin D production involves 1α-hydroxylation in the kidney, which is an important regulatory site, and promotes Ca2+ absorption from the gut and mineralization of bone.
Vitamin D promotes the increased synthesis of components such as Ca2+ channels and phosphate absorption in the gut, and reabsorption of Ca2+ and PO43- in kidney tubules.
Osteoporosis is a systemic skeletal disease characterized by low bone mass, microarchitectural deterioration, bone fragility, and susceptibility to fracture.
Vitamin D deficiency can lead to rickets in children and osteomalacia in adults, causing abnormal amounts of unmineralized osteoid and bone weakness.
Bone growth stops with the fusing of the epiphyseal plate in the long bones, while bone turnover continues throughout life and is mediated by osteoblasts, osteoclasts, and osteocytes.
The aging population increases the risk of osteoporosis, with women being more likely to suffer a hip fracture than develop breast cancer.

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Description

Test your knowledge of calcium and phosphate regulation in the body with this quiz. Explore the role of parathyroid hormone, vitamin D, and the impact of aging on bone health. Learn about conditions such as osteoporosis, rickets, and osteomalacia, and understand the physiological functions of calcium and phosphate in the body.