90 Questions
Which of the following is responsible for bone degradation and remodeling?
Osteoclasts
What is the composition of bone primarily made up of?
Extracellular matrix
Which bone classification is characterized by spicules and trabeculae?
Cancellous bone
What is the function of osteoblasts?
Protein production and bone growth
What is the clinical term for an imbalance between bone resorption and bone formation?
Osteoporosis
Which cells are responsible for bone resorption?
Osteoclasts
Which cells are responsible for resorbing bone?
Osteoclasts
What is the main component of the extracellular matrix in bone?
Minerals
What is the function of osteoclasts in bone remodeling?
Phagocytose bone matrix
What is the role of glycosaminoglycans in the extracellular matrix of bone?
Attract water
What are the two major factors governing bone remodeling?
Mechanical stress and calcium homeostasis
What happens to bone when it is not subjected to weight-bearing or mechanical stress?
It weakens
Which hormone is responsible for increasing plasma calcium levels?
PTH
What is the active form of vitamin D?
Calcitriol
What is the main factor determining peak bone mass?
Genetics
What is the effect of intermittent PTH compared to continuous PTH?
Continuous PTH has stronger effects
What are the signs and symptoms of hypercalcemia?
Constipation
What can cause chronic hypocalcemia?
Parathyroid dysfunction
Which substance inhibits osteoclast-mediated bone resorption related to inorganic pyrophosphate?
Alendronate
What is the molecular mechanism of osteopetrosis?
Defective Vacuolar proton pump
Which drug is a monoclonal antibody that targets RANKL to prevent osteoclast maturation?
Denosumab
What is the purpose of Teriparatide in the treatment of osteoporosis?
Encourage osteoblast formation of bone
What is the function of Carbonic Anhydrase in osteoclasts?
Secrete acid for bone resorption
During which phase of fracture healing does lamellar bone replace woven bone?
Hard Callus Formation
Which of the following is NOT a learning outcome of the Structures & Cells of bone section?
Pathologies of Calcium Regulation
What is the main focus of the chapter 'Bone Tissue' in the book 'Tortora' (14th ed.)?
Pathologies of Bone Remodeling
Which hormone plays a role in calcium regulation?
All of the above
What is the main focus of the chapter 'Calcium' in the book 'Guyton & Hall' (13th ed.)?
Calcium homeostasis
What is a common cause of osteoporosis?
Introduction to Drugs for Osteoporosis
Which cells are responsible for maintaining the bone?
Osteoblasts
What is the main inorganic component of bone?
Hydroxyapatite
What is the function of osteoclasts in bone degradation?
Resorbing bone
Where do osteocytes live within the bone?
Lacuna
Which cells are responsible for bone resorption?
Macrophages
Which component of bone provides its tensile strength?
Collagen
What is the primary function of osteoblasts?
Bone formation
What is the main role of osteoclasts in bone remodeling?
Bone resorption
What is the main focus of the chapter 'Calcium' in the book 'Guyton & Hall' (13th ed.)?
The physiology of calcium regulation
What is the main factor determining peak bone mass?
Genetics and heredity
What is a common cause of osteoporosis?
Smoking and alcohol consumption
What is the function of osteoclasts in bone remodeling?
Bone resorption
Which cells detect mechanical stress in bone?
Osteocytes
What happens to bone when it is not subjected to weight-bearing or mechanical stress?
It undergoes rapid turnover
What are the two major factors governing bone remodeling?
Gravity and calcium homeostasis
What is the function of bisphosphonates in the treatment of osteoporosis?
They inhibit osteoclast-mediated resorption
Which substance in the extracellular matrix of bone attracts water and provides squishiness and resistance to compression?
Glycosylated glycans
Which cells are responsible for releasing growth factors in the extracellular matrix of bone?
Osteoblasts
What is the process called when bone cells recognize bone stresses and stimulate the remodeling process?
Activation
What is the main function of hydroxyapatite in the extracellular matrix of bone?
Acts as a reinforcement like steel in reinforced concrete
What is the main focus of the chapter 'Bone Tissue' in the book 'Tortora' (14th ed.)?
The composition of bone tissue
What is the main function of osteoblasts?
To produce protein in the extracellular matrix
What is the difference between lamellar bone and woven bone?
Lamellar bone is more mature and organized than woven bone
What are the three types of bone cells and their functions?
Osteoblasts - bone formation, Osteocytes - bone growth, Osteoclasts - bone resorption
Which of the following is a function of inorganic phosphate in bone metabolism?
It accumulates on bone and interferes with osteoblast metabolism
What is the effect of bisphosphonates like alendronate on osteoclasts?
They inhibit osteoclast-mediated bone resorption
What happens to osteoclasts when inorganic phosphate interferes with bone turnover?
They become less active
What is the main role of osteoblasts in bone metabolism?
To stimulate bone formation
What is the effect of bisphosphonates on osteoblasts?
They inhibit osteoblast-mediated bone resorption
What is the role of inorganic phosphate in bone turnover?
To interfere with osteoblast metabolism
Which of the following is NOT a symptom/sign of acute hypocalcaemia?
Low mood
Which of the following is a symptom/sign of chronic hypocalcaemia?
Carpopedal spasm
Which of the following is a symptom/sign of acute hypercalcaemia?
Diarrhoea
Name one function of the skeleton.
Haematopoiesis
Name one organ that is affected by PTH.
Heart
What is the cause of autosomal dominant osteopetrosis?
Vitamin D deficiency
What is the primary molecule responsible for bone's compressive strength?
Hydroxyapatite
What is the main function of osteocytes in bone?
Bone maintenance and stress detection
What is the main difference between intramembranous and endochondral bone formation?
Intramembranous begins with ossification while endochondral begins with cartilage
What is the main function of osteoblasts in bone metabolism?
Bone formation
What is the name of the depression formed around an osteoclast when it is degrading bone?
Howship's lacuna
What is the main role of glycosaminoglycans in bone?
Bone lubrication
What is the main function of osteoclasts in bone remodeling?
To secrete acid and digest hydroxyapatite
What is the main function of osteoblasts in bone metabolism?
To lay down bone and increase bone density
What is the main factor determining peak bone mass?
Genetic material
What is the primary function of osteocytes?
To maintain osteoid and provide mechanical support
What is the main focus of the chapter 'Calcium' in the book 'Guyton & Hall' (13th ed.)?
Calcium regulation
What are the signs and symptoms of hypercalcemia?
Bleeding and cardiac arrhythmias
Which of the following is the main reason why bisphosphonates accumulate to a high concentration only in bones?
Bisphosphonates have a high affinity for calcium ions
Why is the oral bioavailability of bisphosphonates low?
Bisphosphonates have a highly negative charge
What is the main effect of Teriparatide on bone remodeling?
Increased osteoblast activity
What is the net effect of intermittent PTH administration on bone remodeling?
Increased osteoblast number and activity
What is the role of osteoblasts in bone metabolism?
Laying down bone and activating osteoclast precursors
What is the main effect of bisphosphonate-based drugs on calcium ions?
They bind to calcium ions
Which of the following pharmacological treatments for osteoporosis mimics pyrophosphate in bone and leads to osteoclast apoptosis or protein trafficking defects?
Bisphosphonates
Which of the following drugs is a monoclonal antibody that binds to the RANK ligand and prevents activation and differentiation of osteoclasts?
Denosumab
Why is the high percentage of inorganic material in bone unusual in a living system?
Inorganic material cannot be manipulated directly by enzymatic activity.
How do calcium phosphate crystals form where bone is needed?
Calcium and phosphate are at a high concentration and can crystalize out of solution.
Why doesn't calcium phosphate fall out of solution in plasma?
There are crystallization inhibitors in the plasma.
Why does hypocalcemia lead to convulsions and why are its effects on the ECG 'paradoxical'?
Hypocalcemia makes membranes 'more excitable' and 'less stable', leading to convulsions. The effects on the ECG are 'paradoxical' because hypocalcemia decreases the QT interval.
Test your knowledge on osteoclasts and their role in bone resorption with this quiz. Learn about their structure, function, and key characteristics.
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