BRS Histology - Cartilage & Bone Flashcards
Which of the following statements characterizes osteoclasts?
(A) They are enucleated cells.
(B) They produce collagen.
(C) They secrete osteoid.
(D) They are derived from osteoprogenitor cells.
(E) They occupy Howship’s lacunae.
E.
Osteoclasts are multinucleated cells that produce proteolytic enzymes and occupy Howship’s lacunae. They are not derived from osteoprogenitor cells but from monocyte precursors
Which one of the following statements is correct concerning the periosteum?
(A) It is devoid of a blood supply.
(B) It produces osteoclasts.
(C) It is responsible fo rinterstitial bone growth.
(D) Its inner layer contains osteoprogenitor cells.
(E) Its outer layer is devoid of fibers.
D.
The inner layer of the periosteum possesses osteoprogenitor cells, whereas the outer layer of the periosteum is fibrous. The periosteum functions to distribute blood vessels to the bone; thus, appositional bone growth takes place here
Which one of the following statements is characteristic of osteocytes?
(A) They communicate via gap junctions between their processes.
(B) They contain large amounts of RER.
(C) They are immature bone cells.
(D) They are housed as isogenous groups in lacunae.
(E) They give rise to osteoclasts.
A.
Osteocytes communicate with each other via gap junctions on narrow cytoplasmic processes that extend through canaliculi. They are mature bone cells that occupy individ- ual lacunae as mature resting bone cells
Which one of the following statements concerning hyaline cartilage is correct?
(A) It is vascular.
(B) It contains type IV collagen.
(C) It undergoes appositional growth only.
(D) It is located at the articular ends of long bones.
(E) Its chondrocytes are aligned in rows.
D.
Hyaline cartilage is avascular, contains type II collagen, and grows both interstitially and appositionally. It is located at the articulating ends of long bones
A 7-year-old boy is seen by his pediatrician because the child broke his humerus as he tripped and fell while walking. The pediatrician asked about the child’s diet and learned that he might have a dietary deficiency. Which of the following may be lacking in his diet?
(A) Potassium
(B) Calcium
(C) Iron
(D) Carbohydrates
(E) Protein
B.
Because calcium must be maintained at a constant level in the blood and the tissues, a diet deficient in calcium leads to calcium loss from the bones. As a result, the bones become fragile
A 22-year-old woman is seen for the first time by her new physician, who notes that she has very thick bones in her extremities and face. The physician suspects acromegaly, caused by which of the following?
(A) Hypervitaminosis A
(B) Excess growth hormone
(C) Hypovitaminosis A
(D) Hypervitaminosis D
(E) Hypovitaminosis D
B.
Excessive growth hormone causes acromegaly. Excessive vitamin D causes bone resorption. Both an excess and a deficiency of vitamin A result in short stature
Which of the following statements is characteristic of bone?
(A) Bone matrix contains primarily type II collagen.
(B) About 65% of the dry weight of bone is organic.
(C) Haversian canals are interconnected via Volkmann canals.
(D) Bone growth occurs via interstitial growth only.
(E) Bone growth occurs via appositional growth only.
C.
Haversian canals run longitudinally, parallel to the long axis of bone. They are connected to one another by Volkmann canals that run perpendicular (or obliquely) to them
Which one of the following inhibits histogenesis of cartilage?
(A) Thyroxine
B) Hypervitaminosis A
(C) Hypovitaminosis D
(D) Hydrocortisone
(E) Hypovitaminosis C
D.
Hydrocortisone inhibits cartilage growth and matrix formation
Which one of the following stimulates cartilage histogenesis?
(A) Thyroxine
(B) Hypervitaminosis A
(C) Hypovitaminosis D
(D) Hydrocortisone
(E) Hypovitaminosis C
A.
Thyroxine, testosterone, and somatotropin stimulate cartilage growth and matrix
formation
Which one of the following accelerates epiphyseal ossification?
(A) Thyroxine
(B) Hypervitaminosis A
(C) Absenceofvitamin D
(D) Hydrocortisone
(E) Hypovitaminosis C
B.
Hypervitaminosis A accelerates ossification of epiphyseal plates, whereas hypovitaminosis A reduces the width of the epiphyseal plates
Which one of the following makes epiphyseal cartilage matrix fail to calcify?
(A) Thyroxine
(B) Hypervitaminosis A
(C) Hypovitaminosis D
(D) Hydrocortisone
(E) Hypovitaminosis C
C.
In the absence of vitamin D, epiphyseal chondrocytes continue to proliferate, but their matrix does not calcify, which leads to rickets
A 25-year-old patient, anemic for several years, complains of failing eyesight and hearing loss. During a physical examination, it is determined that the patient has lost function of some of the cranial nerves.
The diagnosis could be which one of the following?
(A) Osteoporosis
(B) Osteomalacia
(C) Rickets
(D) Acromegaly
(E) Osteopetrosis
E.
Osteopetrosis is a genetic defect involving the osteoclasts. Persons with this defect possess osteoclasts without ruffled borders, which prohibit them from resorbing bone. Therefore, bone forms but is not resorbed. This leads to increased bone density, anemia, blindness, deafness, and cranial nerve involvement because the nerves are impinged upon as they exit the cranium via their foramina
