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Questions and Answers

What is a primary complication of pyogenic osteomyelitis?

Angina pectoris

Tuberculosis osteomyelitis

Pseudomembranous colitis

Segmental bone necrosis (correct)

Which bacteria is most frequently associated with pyogenic osteomyelitis?

Klebsiella pneumoniae

Streptococcus pneumoniae

Escherichia coli

Staphylococcus aureus (correct)

What factor is likely to delay the healing of fractures?

Proper immobilization

Inadequate immobilization (correct)

Minimal displacement

Adequate nutrition

Which statement about tuberculous osteomyelitis is accurate?

It can spread to adjacent soft tissues, causing psoas muscle abscesses. Signup and view all the answers

What is the most common type of bone tumor?

Metastatic tumors Signup and view all the answers

What condition is characterized by severe osteopenia and an increased risk of fractures due to a decrease in bone mass?

Primary Osteoporosis Signup and view all the answers

Which of the following factors is NOT a characteristic of Paget disease?

Osteitis fibrosa cystica Signup and view all the answers

What role does parathyroid hormone (PTH) primarily play in the body?

Activates bone resorption and regulates calcium homeostasis Signup and view all the answers

Which of the following best describes the histological features of primary osteoporosis?

Histologically normal bone with decreased quantity Signup and view all the answers

In chronic renal failure, what is the primary consequence that leads to secondary hyperparathyroidism?

Decreased active form of vitamin D synthesis Signup and view all the answers

What is a common presentation of a brown tumor in patients with untreated hyperparathyroidism?

Mass of reactive tissue with hemorrhage and macrophage influx Signup and view all the answers

Which statement about the familial aspects of Paget disease is true?

50% of Paget disease cases have a familial link. Signup and view all the answers

Which feature is most indicative of osteitis deformans (Paget disease)?

Presence of prominent cement lines and mosaic patterns in bone Signup and view all the answers

What is the primary function of osteoblasts?

Form new bone cells Signup and view all the answers

Which type of bone is characterized by parallel collagen fibers and is found in the adult skeleton?

Lamellar bone Signup and view all the answers

What mutation is associated with achondroplasia?

Point mutation in FGFR3 Signup and view all the answers

What is the primary cause of the brittle bone disease known as osteogenesis imperfecta?

Defective synthesis of type I collagen Signup and view all the answers

Which ossification process is responsible for the development of long bones?

Endochondral ossification Signup and view all the answers

What is osteopetrosis primarily characterized by?

Defective osteoclast-mediated bone resorption Signup and view all the answers

What structural abnormality does woven bone exhibit?

Naphtazard arrangement of collagen fibers Signup and view all the answers

Which factor promotes osteoclast activity and bone turnover?

Glucocorticoids Signup and view all the answers

Which of the following characteristics is true for Fibrous Dysplasia?

It arises from GNAS mutations. Signup and view all the answers

What is the primary site of occurrence for Chordoma?

Sacrococygeal region Signup and view all the answers

Which type of lesion is characterized by a diameter of 5-6 cm?

Non-Ossifying Fibroma Signup and view all the answers

What is the primary diagnostic marker for Chordoma?

BRACHURY Signup and view all the answers

What is a defining symptom of Osteoarthritis?

Morning stiffness Signup and view all the answers

Which factor differentiates Rheumatoid Arthritis from Osteoarthritis?

Symmetrical joint involvement Signup and view all the answers

In which age group is Ewing Sarcoma most commonly diagnosed?

Under 20 years Signup and view all the answers

Which statement is true regarding bone metastases in adults?

Most originate from prostate, breast, kidney, and lung cancers. Signup and view all the answers

What is a defining characteristic of osteoid osteoma?

Responds to aspirin Signup and view all the answers

What type of bone lesion is associated with Gardner Syndrome?

Osteoma Signup and view all the answers

Which bone tumor is most commonly found in individuals under 20 years of age?

Osteosarcoma Signup and view all the answers

What distinguishes osteoblastoma from osteoid osteoma?

It is painful and non-localized Signup and view all the answers

In which region is an osteochondroma most likely to develop?

Metaphysis of long tubular bones Signup and view all the answers

What size characterizes chondromas as part of Soillier and Maffucci syndromes?

Greater than 5 cm Signup and view all the answers

What is the most common site for osteosarcoma?

Knee Signup and view all the answers

Which statement is true regarding chondrosarcoma?

It is a malignant tumor that produces neoplastic cartilage matrix. Signup and view all the answers

Study Notes

Bone Cells & Structure

Osteoblasts form bone cells
Osteocytes are mature bone cells
Osteoclasts break down bone matrix
Osteogenic cells are stem cells in periosteum & endosteum, giving rise to osteoblasts
Woven bone is produced rapidly during fetal development or fracture repair, with a haphazard arrangement of collagen fibers
Lamellar bone is the mature bone in adult skeletons, with slow formation and durability. It has parallel collagen fibers.

Bone Development

Endochondral ossification develops long bones.
Intramembranous ossification develops flat bones.
RANKL (on osteoblasts and marrow stromal) binds RANK (on osteoclast precursors)
Osteoprotegerin (OPG) produced by osteoblasts blocks RANK-RANKL interaction, regulating bone resorption/formation.
Parathyroid hormone (PTH), vitamin D, and sex hormones influence bone turnover.

Bone Diseases

Osteogenesis Imperfecta (OI): Brittle bone disease due to defective type I collagen synthesis.
Osteopetrosis: Stone/marble bone disorder, caused by defective osteoclast-mediated bone resorption.
Osteoporosis is characterized by low bone mass and bone fragility, increasing risk of fractures.

Hyperparathyroidism

Increased parathyroid hormone (PTH) leads to increased osteoclast activity, bone resorption, and bone loss.
Secondary hyperparathyroidism is often related to chronic renal failure, with low vitamin D production.
Brown tumors are a manifestation of severe hyperparathyroidism, characterized by extensive bone loss and micro-fractures.

Paget's Disease

Increased but disordered bone remodeling
Three phases: osteolytic, osteoblastic, osteosclerotic.
Osteoclast activity is abnormally elevated.

Bone Tumors

Benign (Osteoid osteoma, osteoblastoma): Painful, localized bone tumors.
Malignant (Osteosarcoma): Most common primary malignant bone tumor other than myeloma and lymphoma.

Other Bone Diseases

Osteomyelitis (infection of bone): Caused by bacteria, resulting in bone necrosis.
Osteochondroma: Benign bone tumor consisting of both cartilage and bone.
Chondroma/Chondrosarcoma: Benign/malignant cartilage tumors that develop in the medullary cavity primarily of long bones.
Fibrous cortical defect/Non-ossifying fibroma: Benign bone lesions, often asymptomatic, and typically found in the metaphysis of long tubular bones.
Giant cell tumor: Benign tumor characterized by multiple giant multinucleated cells in the bone.

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Description

Test your knowledge on bone cells and their functions, including osteoblasts, osteocytes, and osteoclasts. The quiz also covers bone development methods, diseases related to bone health, and the influence of hormones on bone turnover. Understand the differences between woven and lamellar bone in the process.