Deck 5: Osteogenesis

Question 1

Which of the following is true of intramembranous, rather than endochondral, ossification?

A) A hyaline cartilage model is used
B) Long bones are formed
C) Mesenchymal cells differentiate into osteoblasts within connective tissue
D) Periosteal buds invade the lacunae left behind by dead chondrocytes
E) Secondary ossification centers form in the epiphyses

Answer 1

C
Mesenchymal cells differentiate into osteoblasts within connective tissue

Question 2

During the lengthening of long bones, the zone in which cartilage cells undergo cell division and become organized into rows of isogenous cells is the

A) Calcification zone
B) Hypertrophic zone
C) Proliferative zone
D) Reserve zone
E) Vascular invasion zone

Answer 2

C
Proliferative zone

Question 3

Parathyroid hormone

A) Decreases calcium levels in the blood
B) Increases calcium excretion in the kidneys
C) Inhibits osteoclast activity
D) Is released by the thyroid gland
E) Stimulates osteoclast activity

Answer 3

E
Stimulates osteoclast activity

Question 4

When the epiphyseal plate is replaced by bone

A) Appositional bone growth begins
B) Interstitial bone growth begins
C) Long bones have reached their adult length
D) Puberty begins
E) The bone becomes more brittle

Question 5

Secondary ossification centers are found

A) At the outer surface of the diaphysis
B) At the surface of the epiphyses
C) In the center of the epiphyses
D) In the dermis of the skin
E) In the medullary cavity of the diaphysis

Question 6

The hormone calcitonin functions to

A) Decrease the rate of calcium absorption
B) Decrease the rate of calcium excretion
C) Increase the level of calcium ion in the blood
D) Stimulate both osteoblast and osteoclast activity
E) Stimulate osteoclast activity

Question 7

What occurs in the hypertrophic zone during endochondral ossificiation?

A) Chondrocytes in the center of the cartilage undergo mitosis and growth
B) Invasion of empty lacunae by osteoprogenitor cells
C) Penetration of calcified septa by blood vessels
D) Programmed cell death of chondrocytes
E) Proliferating chondrocytes organize into parallel columns

Question 8

Each of the following statements about epiphyseal plates is correct EXCEPT

A) Appositional growth occurs on the epiphyseal side
B) Bone replaces cartilage on the diaphyseal side
C) Mitotically active chondrocytes are distributed throughout the zone of reserve cartilage
D) These chondrocytes are required for lengthening of long bones
E) They contain a portion of healthy hyaline cartilage

Question 9

In bone remodeling, osteoclasts perform lamellar resorption just prior to

A) Maturation of osteoblasts into osteocytes
B) Mineralization of osteoid tissue
C) Osteoclast activation
D) Osteoclast to osteoblast reversal
E) Trapping of osteoblasts in bony matrix

Question 10

Each of the following statements about epiphyseal plates is correct EXCEPT

A) Appositional growth occurs on the epiphyseal side
B) Bone replaces cartilage on the diaphyseal side
C) Mitotically active chondrocytes are distributed throughout the zone of reserve cartilage
D) Epiphyseal plates are required for lengthening of long bones
E) Epiphyseal plates contain a portion of healthy hyaline cartilage