Cartilage and Bone: Structure and Function

A 16-year-old track and field athlete asks for advice on protecting her knee joints from “wear-and-tear" injury. In this connection, articular cartilage acts as an excellent shock absorber and provides resilience against load. This critical biomechanical function is attributed chiefly to which of the following components of cartilage?

For the patient described in Question 1, which of the following cartilage components plays the most important role in binding extracellular (interstitial) water?

A 59-year-old obese woman (BMI = 33 kg/m²) complains of sharp pain and stiffness of her knee joints. The pain is typically worse following exercise and prolonged use of her joints. She is diagnosed with degenerative osteoarthritis. Which of the following best describes the pathogenesis of joint pain in this patient?

The knee joint of a 68-year-old woman is examined at autopsy. The articular cartilage shown in the image differs from hyaline cartilage in which of the following ways?

Which of the following types of collagen is the principal protein forming the intricate, three-dimensional meshwork found in hyaline cartilage throughout the body?

The collagen molecules of the type described in Question 5 self-aggregate to form which of the following structures in hyaline cartilage?

Which of the following proteins is the most abundant proteoglycan core protein found in hyaline cartilage?

Which of the following components of hyaline cartilage links the chondrocyte cell surface with the surrounding extracellular matrix and thereby helps regulate the turn-over, degeneration, and repair of hyaline cartilage?

A 64-year-old man with a history of smoking presents with chest pain and hemoptysis. Chest x-ray demonstrates a bronchial mass, and a CT-guided needle biopsy reveals squamous cell carcinoma. The tumor and tissue margin containing bronchial cartilage are resected, and the specimen is examined by light microscopy (shown in the image). The matrix of the hyaline cartilage appears heterogeneous in color. Which of the following best describes the region indicated by the arrows?

For the patient described in Question 9, what is the principal collagen type found within the region indicated by the arrows?

For the surgical specimen described in Question 9, which of the lettered arrows on the photomicrograph identifies the interterritorial matrix?

For the surgical specimen described in Question 9, which of the following patterns of cartilage growth is demonstrated (evidenced) by the heterogeneous distribution of proteoglycans, glycoproteins, and collagens within the hyaline cartilage matrix?

A surgical specimen containing normal cartilage is examined by light microscopy (shown in the image). The tissue/substance present within the rectangular box is best described as which of the following?

A 70-year-old woman with a mediastinal mass is diagnosed with primary lung cancer. The surgical specimen includes normal bronchial cartilage tissue and malignant cells. Slides are examined in the department of pathology (shown in the image). Identify the cells/structures indicated by the circles?

For the surgical specimen described in Question 14, the nuclei indicated by the arrows shown in the image belong to which of the following types of connective tissue cells?

Which of the following cells is responsible for appositional growth of hyaline cartilage during growth and development?

The parents of a 3-year-old boy complain that their child has a high fever, sore throat, and hoarse voice. On physical examination, the child's epiglottis appears swollen and erythematous. The boy is diagnosed with acute bacterial epiglottitis. In considering this case, you recall that the epiglottis at the entrance to the larynx is composed primarily of which of the following types of connective tissue?

Cartilage obtained at autopsy of a 50-year-old woman is examined by light microscopy (shown in the image). Which of the following histologic features in this photomicrograph is most useful for determining the specific type of cartilage?

A herniated intervertebral disc was removed surgically from the lumbar region of a 48-year-old man. Which of the following types of connective tissue is located within the peripheral annulus of this patient's intervertebral disc?

Fibrocartilage is a type of connective tissue characterized by resistance to tearing and compression. It combines which of the following basic histologic features?

Which of the following types of cartilage or bone is found in the epiphyseal growth plates of children and adolescents?

A 58-year-old man with a history of ischemic heart disease is scheduled for coronary artery bypass graft surgery. Before cutting the costal cartilage to open the chest cavity, the surgeon is mindful that healing of cartilage is problematic. She understands that hyaline cartilage has a limited capacity to undergo repair and regeneration due to which of the following intrinsic attributes?

A 55-year-old man complains of bone pain affecting his right femur. X-ray of the leg reveals a thickened bone shaft and a mass with poorly defined borders. Biopsy of the mass is examined by light microscopy (shown in the image). Based on morphology, which of the following is the most likely diagnosis for this malignant neoplasm?

Which of the following osteocyte-derived biomolecules is the major structural component present in bone matrix?

Which of the following connective tissue cells initiates the mineralization of the bone matrix during growth and bone remodeling throughout life?

A 57-year-old woman undergoes spine fusion surgery. Following the procedure, the surgeon prescribes osteogenic protein-1 (OP-1) to promote bone growth and healing. OP-1 (also referred as bone morphogenic protein-7) has been shown to stimulate the differentiation of mesenchymal stem cells to yield which of the following cell types?

Bone obtained at the autopsy of a 68-year-old man is examined by light microscopy (shown in the image). Identify the structures indicated by the circles.

A ground (polished) section of bone from the patient described in Question 27 is examined under high magnification (shown in the image). Identify the features indicated by the arrows.

A higher magnification figure is obtained from the bone specimen described in Question 28 (shown in the image). Identify the thin lines indicated by the arrows and the structures that occupy this space.

A 21-year-old man is brought to the emergency room in a coma 1 hour after hitting his head against a metal pole while skate boarding. CT scan of the head reveals a skull fracture and epidural hemorrhage (shown in the image, note arrow). The epidural hematoma developing in this patient forms between which of the following two anatomic structures?

The function of the periosteum in supporting new bone growth is determined fundamentally by paracrine/endocrine signals that regulate the differentiation of which of the following connective tissue cells?

Spongy bone is examined by light microscopy (shown in the image). Which of the following best describes the epithelium (indicated by arrows) that lines the surface of bone spicules in spongy bone and the internal surface of compact bone?

A portion of the skull was obtained at the autopsy of a fetus with trisomy 21 (Down syndrome). A developing bone spicule is shown in the image. The light-stained line indicated by the arrows represents which of the following bone structures?

For the autopsy specimen described in Question 33, the arrowheads shown in the image identify which of the following types of connective tissue cells?

A bone biopsy taken from a 12-year-old girl was examined by light microscopy (shown in the image). Identify the cells indicated by the arrows.

Osteoclasts are derived from which of the following types of cells?

A 6-year-old boy with mild hydrocephalus suffers chronic infections and dies of intractable chronic anemia. At autopsy, his bones are dense and misshapen. The femur in particular shows obliteration of the marrow space. Hematopoietic bone marrow cells are sparse. The diagnosis is osteopetrosis, a rare genetic disorder caused by dysfunction of which of the following cell types?

A 58-year-old woman fractures her hip after slipping on an icy sidewalk. An x-ray reveals generalized osteopenia (reduced bone density). A femoral head obtained from another patient with this condition reveals attenuated bony trabeculae (shown in the image on the right). Normal bone is shown in the image on the left. Which of the following best explains the pathogenesis of osteopenia in this postmenopausal woman?

A 42-year-old woman presents to the emergency room with a spontaneous fracture of her humeral head. She has suffered from malabsorption secondary to Crohn disease for 20 years. Histologically, the humeral head shows bony trabeculae that are covered by a thicker than normal layer of osteoid (shown in the image). In this section, the osteoid is stained red, and mineralized bone is stained black. Which of the following best describes the pathogenesis of osteomalacia in this patient?

For the patient described in Question 39, impaired mineralization of the new bone matrix was most likely caused by a chronic deficiency of which of the following vitamins?

Which of the following bones forms via the intramembranous ossification pathway during embryonic and fetal development?

A 16-year-old girl is seen for her annual health checkup. Measurements taken in the office indicate that the patient has grown 15 cm over the past year. Which of the following cells in epiphyseal growth plates was chiefly responsible for the longitudinal growth of long bones in this patient?

A 28-year-old man with achondroplasia is admitted to the hospital for hip replacement due to severe osteoarthritis. He has short arms and legs and a relatively large head. Which of the following pathogenetic mechanisms is most likely responsible for this patient's inherited condition?

For the patient described in Question 43, which of the following mechanisms best explains the fact that the patient's head appears unusually large?

The distal end of the femur is examined at the autopsy of a 3-month-old child with Edward syndrome (trisomy 18). Longitudinal sections of the epiphyseal growth plate reveal evidence of zonation (shown in the image). Which of the labeled areas represents the zone of hypertrophy?