A&P 1 101 - Portage Learning
Module 4 Exam: The Skeletal System (Tissue, Cells, &
Physiology)
Questions & Rationale
Q1: Which cell type is responsible for breaking down bone matrix during bone
remodeling?
● A. Osteoblast
● B. Osteocyte
● C. Osteoclast [CORRECT]
● D. Osteogenic cell
Correct Answer: C
Rationale: Osteoclasts are large, multinucleated cells derived from monocyte lineage
that secrete hydrochloric acid and lysosomal enzymes to dissolve the mineralized
matrix (hydroxyapatite) and digest organic components. This resorption is essential for
calcium homeostasis and bone remodeling. Osteoblasts (A) build bone by secreting
osteoid. Osteocytes (B) are mature bone cells that maintain matrix and sense
mechanical stress. Osteogenic cells (D) are stem cells that differentiate into
osteoblasts.
Q2: The central canal of an osteon contains:
● A. Dense, irregular connective tissue
● B. Blood vessels and nerves [CORRECT]
● C. Only osteocytes in lacunae
● D. Red bone marrow exclusively
Correct Answer: B
, Rationale: The central (Haversian) canal runs longitudinally through the center of each
osteon and contains neurovascular structures—blood vessels (nutrient supply, waste
removal) and nerves (sensory innervation). These connect to perforating (Volkmann's)
canals. Dense irregular tissue (A) forms the periosteum. Osteocytes reside in lacunae
within concentric lamellae, not the central canal (C). Red marrow (D) fills medullary
cavities of certain bones, not central canals.
Q3: Which type of bone tissue is characterized by trabeculae and is found at the ends of
long bones?
● A. Compact bone
● B. Spongy (cancellous) bone [CORRECT]
● C. Woven bone
● D. Lamellar bone
Correct Answer: B
Rationale: Spongy (cancellous/trabecular) bone consists of an open, lattice-like network
of trabeculae (thin bony spicules) that provide strength along stress lines while being
lightweight. It is found in epiphyses of long bones, between flat bones of the skull, and
lining the medullary cavity. Compact bone (A) is dense and forms the diaphyseal shaft.
Woven bone (C) is immature, unorganized bone formed during development or repair.
Lamellar bone (D) refers to the organized, layered structure of mature bone.
Q4: During endochondral ossification, what happens to the original hyaline cartilage
model?
● A. It remains as articular cartilage permanently
● B. It is completely removed and replaced by dense connective tissue
● C. It is gradually replaced by bone tissue [CORRECT]
● D. It calcifies and becomes the permanent bone matrix
Module 4 Exam: The Skeletal System (Tissue, Cells, &
Physiology)
Questions & Rationale
Q1: Which cell type is responsible for breaking down bone matrix during bone
remodeling?
● A. Osteoblast
● B. Osteocyte
● C. Osteoclast [CORRECT]
● D. Osteogenic cell
Correct Answer: C
Rationale: Osteoclasts are large, multinucleated cells derived from monocyte lineage
that secrete hydrochloric acid and lysosomal enzymes to dissolve the mineralized
matrix (hydroxyapatite) and digest organic components. This resorption is essential for
calcium homeostasis and bone remodeling. Osteoblasts (A) build bone by secreting
osteoid. Osteocytes (B) are mature bone cells that maintain matrix and sense
mechanical stress. Osteogenic cells (D) are stem cells that differentiate into
osteoblasts.
Q2: The central canal of an osteon contains:
● A. Dense, irregular connective tissue
● B. Blood vessels and nerves [CORRECT]
● C. Only osteocytes in lacunae
● D. Red bone marrow exclusively
Correct Answer: B
, Rationale: The central (Haversian) canal runs longitudinally through the center of each
osteon and contains neurovascular structures—blood vessels (nutrient supply, waste
removal) and nerves (sensory innervation). These connect to perforating (Volkmann's)
canals. Dense irregular tissue (A) forms the periosteum. Osteocytes reside in lacunae
within concentric lamellae, not the central canal (C). Red marrow (D) fills medullary
cavities of certain bones, not central canals.
Q3: Which type of bone tissue is characterized by trabeculae and is found at the ends of
long bones?
● A. Compact bone
● B. Spongy (cancellous) bone [CORRECT]
● C. Woven bone
● D. Lamellar bone
Correct Answer: B
Rationale: Spongy (cancellous/trabecular) bone consists of an open, lattice-like network
of trabeculae (thin bony spicules) that provide strength along stress lines while being
lightweight. It is found in epiphyses of long bones, between flat bones of the skull, and
lining the medullary cavity. Compact bone (A) is dense and forms the diaphyseal shaft.
Woven bone (C) is immature, unorganized bone formed during development or repair.
Lamellar bone (D) refers to the organized, layered structure of mature bone.
Q4: During endochondral ossification, what happens to the original hyaline cartilage
model?
● A. It remains as articular cartilage permanently
● B. It is completely removed and replaced by dense connective tissue
● C. It is gradually replaced by bone tissue [CORRECT]
● D. It calcifies and becomes the permanent bone matrix
