BIO 201 Exam 2 V2 | 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 and breakdown of the
bone matrix?
A. Osteoblast
B. Osteoclast
C. Osteocyte
D. Osteoprogenitor cell
Answer: B
Rationale: Osteoclasts are large, multinucleated cells derived from monocytes that
dissolve the bone matrix through the secretion of acids and enzymes. This process, known
as resorption, is critical for calcium homeostasis and bone remodeling. Osteoblasts, in
contrast, are responsible for bone formation by secreting the organic components of the
matrix.
2. The structural unit of compact bone is known as a(n):
A. Trabecula
B. Lacuna
C. Canaliculus
,D. Osteon
Answer: D
Rationale: An osteon, also called a Haversian system, is the fundamental functional unit of
compact bone consisting of concentric lamellae. These units are aligned parallel to the long
axis of the bone to provide weight-bearing strength. Each osteon contains a central canal
that houses blood vessels and nerve fibers.
3. Which hormone is released by the parathyroid gland in response to low blood calcium
levels?
A. Parathyroid Hormone (PTH)
B. Thyroxine
C. Growth Hormone
D. Calcitonin
Answer: A
Rationale: Parathyroid Hormone (PTH) is secreted when blood calcium levels drop below
the physiological set point. It stimulates osteoclast activity to release calcium from the bone
into the bloodstream and increases calcium reabsorption in the kidneys. This mechanism
ensures that vital neurological and muscular functions have adequate calcium available.
4. In endochondral ossification, the precursor to bone is:
A. Fibrocartilage
, B. Elastic cartilage
C. Dense regular connective tissue
D. Hyaline cartilage
Answer: D
Rationale: Endochondral ossification is the process where a hyaline cartilage model is
gradually replaced by bone tissue. Most bones of the skeleton, including long bones, are
formed via this complex multi-step process. Intramembranous ossification, by contrast,
develops directly from mesenchymal connective tissue without a cartilage stage.
5. The presence of an epiphyseal plate indicates that:
A. Longitudinal growth has ceased
B. The bone is increasing in diameter
C. The bone is increasing in length
D. The person has reached full maturity
Answer: C
Rationale: The epiphyseal plate is a band of hyaline cartilage located between the
epiphysis and diaphysis where longitudinal growth occurs. As long as this plate exists, the
bone can continue to grow longer under the influence of growth hormone and IGFs. Once
the plate ossifies into an epiphyseal line, height growth is complete.
StraighterLine | Q&A with Rationale (BIO
201 Exam 2)
1. Which type of bone cell is primarily responsible for the resorption and breakdown of the
bone matrix?
A. Osteoblast
B. Osteoclast
C. Osteocyte
D. Osteoprogenitor cell
Answer: B
Rationale: Osteoclasts are large, multinucleated cells derived from monocytes that
dissolve the bone matrix through the secretion of acids and enzymes. This process, known
as resorption, is critical for calcium homeostasis and bone remodeling. Osteoblasts, in
contrast, are responsible for bone formation by secreting the organic components of the
matrix.
2. The structural unit of compact bone is known as a(n):
A. Trabecula
B. Lacuna
C. Canaliculus
,D. Osteon
Answer: D
Rationale: An osteon, also called a Haversian system, is the fundamental functional unit of
compact bone consisting of concentric lamellae. These units are aligned parallel to the long
axis of the bone to provide weight-bearing strength. Each osteon contains a central canal
that houses blood vessels and nerve fibers.
3. Which hormone is released by the parathyroid gland in response to low blood calcium
levels?
A. Parathyroid Hormone (PTH)
B. Thyroxine
C. Growth Hormone
D. Calcitonin
Answer: A
Rationale: Parathyroid Hormone (PTH) is secreted when blood calcium levels drop below
the physiological set point. It stimulates osteoclast activity to release calcium from the bone
into the bloodstream and increases calcium reabsorption in the kidneys. This mechanism
ensures that vital neurological and muscular functions have adequate calcium available.
4. In endochondral ossification, the precursor to bone is:
A. Fibrocartilage
, B. Elastic cartilage
C. Dense regular connective tissue
D. Hyaline cartilage
Answer: D
Rationale: Endochondral ossification is the process where a hyaline cartilage model is
gradually replaced by bone tissue. Most bones of the skeleton, including long bones, are
formed via this complex multi-step process. Intramembranous ossification, by contrast,
develops directly from mesenchymal connective tissue without a cartilage stage.
5. The presence of an epiphyseal plate indicates that:
A. Longitudinal growth has ceased
B. The bone is increasing in diameter
C. The bone is increasing in length
D. The person has reached full maturity
Answer: C
Rationale: The epiphyseal plate is a band of hyaline cartilage located between the
epiphysis and diaphysis where longitudinal growth occurs. As long as this plate exists, the
bone can continue to grow longer under the influence of growth hormone and IGFs. Once
the plate ossifies into an epiphyseal line, height growth is complete.
