BIO 201 Exam 2 V1 | BIO 201 A&P |
StraighterLine | Q&A with Rationale (BIO
201 Exam 2)
1. Which type of bone cell is primarily responsible for the resorption of bone tissue during the
remodeling process?
A. Osteoclasts
B. Osteocytes
C. Osteoblasts
D. Osteoprogenitor cells
Answer: A
Rationale: Osteoclasts are large, multinucleated cells derived from monocytes that break
down bone matrix by secreting enzymes and acids. Osteoblasts are responsible for building
bone, while osteocytes maintain the bone matrix. This balance is critical for calcium
homeostasis and structural integrity within the skeletal system.
2. Which hormone is released when blood calcium levels are too low, stimulating osteoclast
activity?
A. Calcitonin
B. Thyroxine
C. Parathyroid Hormone (PTH)
,D. Insulin
Answer: C
Rationale: Parathyroid Hormone (PTH) is secreted by the parathyroid glands in response
to low serum calcium levels. It stimulates osteoclasts to resorb bone, releasing calcium into
the bloodstream. Calcitonin, on the other hand, is secreted by the thyroid gland to lower
blood calcium levels when they are too high.
3. The structural unit of compact bone is known as a(n):
A. Trabeculae
B. Canaliculus
C. Osteon
D. Lacuna
Answer: C
Rationale: An osteon, or Haversian system, consists of concentric lamellae surrounding a
central canal. Trabeculae are characteristic of spongy (cancellous) bone rather than
compact bone. Lacunae are the small spaces that house osteocytes, and canaliculi are the
tiny channels connecting them.
4. In the epiphyseal plate, which zone is characterized by older chondrocytes dying and the
matrix becoming calcified?
A. Zone of proliferation
, B. Zone of calcification
C. Zone of hypertrophy
D. Zone of resting cartilage
Answer: B
Rationale: The zone of calcification is where the cartilage matrix hardens and
chondrocytes die off due to a lack of nutrients. This stage provides a scaffold for osteoblasts
to deposit new bone tissue. The zone of hypertrophy precedes this, where cells enlarge but
are not yet calcified.
5. Which type of ossification involves the replacement of a hyaline cartilage model with bone
tissue?
A. Endochondral ossification
B. Intramembranous ossification
C. Appositional growth
D. Interstitial growth
Answer: A
Rationale: Endochondral ossification is the process used to form most bones in the body,
such as long bones, starting from a cartilage model. Intramembranous ossification occurs
when bone develops directly from mesenchymal connective tissue, typically in flat bones of
the skull. This distinction is fundamental to understanding skeletal development in A&P.
StraighterLine | Q&A with Rationale (BIO
201 Exam 2)
1. Which type of bone cell is primarily responsible for the resorption of bone tissue during the
remodeling process?
A. Osteoclasts
B. Osteocytes
C. Osteoblasts
D. Osteoprogenitor cells
Answer: A
Rationale: Osteoclasts are large, multinucleated cells derived from monocytes that break
down bone matrix by secreting enzymes and acids. Osteoblasts are responsible for building
bone, while osteocytes maintain the bone matrix. This balance is critical for calcium
homeostasis and structural integrity within the skeletal system.
2. Which hormone is released when blood calcium levels are too low, stimulating osteoclast
activity?
A. Calcitonin
B. Thyroxine
C. Parathyroid Hormone (PTH)
,D. Insulin
Answer: C
Rationale: Parathyroid Hormone (PTH) is secreted by the parathyroid glands in response
to low serum calcium levels. It stimulates osteoclasts to resorb bone, releasing calcium into
the bloodstream. Calcitonin, on the other hand, is secreted by the thyroid gland to lower
blood calcium levels when they are too high.
3. The structural unit of compact bone is known as a(n):
A. Trabeculae
B. Canaliculus
C. Osteon
D. Lacuna
Answer: C
Rationale: An osteon, or Haversian system, consists of concentric lamellae surrounding a
central canal. Trabeculae are characteristic of spongy (cancellous) bone rather than
compact bone. Lacunae are the small spaces that house osteocytes, and canaliculi are the
tiny channels connecting them.
4. In the epiphyseal plate, which zone is characterized by older chondrocytes dying and the
matrix becoming calcified?
A. Zone of proliferation
, B. Zone of calcification
C. Zone of hypertrophy
D. Zone of resting cartilage
Answer: B
Rationale: The zone of calcification is where the cartilage matrix hardens and
chondrocytes die off due to a lack of nutrients. This stage provides a scaffold for osteoblasts
to deposit new bone tissue. The zone of hypertrophy precedes this, where cells enlarge but
are not yet calcified.
5. Which type of ossification involves the replacement of a hyaline cartilage model with bone
tissue?
A. Endochondral ossification
B. Intramembranous ossification
C. Appositional growth
D. Interstitial growth
Answer: A
Rationale: Endochondral ossification is the process used to form most bones in the body,
such as long bones, starting from a cartilage model. Intramembranous ossification occurs
when bone develops directly from mesenchymal connective tissue, typically in flat bones of
the skull. This distinction is fundamental to understanding skeletal development in A&P.
