BIOL 251 MODULE 4 EXAM: SKELETAL SYSTEM | BONE
HISTOLOGY, AXIAL & APPENDICULAR IDENTIFICATION 2026
MODULE 4: THE SKELETAL SYSTEM QUESTIONS AND
ANSWERS | PDF
Part 1: Bone Histology & Physiology
1. Which cell type is responsible for "building" new bone matrix?
A) Osteocyte
B) Osteoblast
C) Osteoclast
D) Chondrocyte
Explanation: Osteoblasts secrete osteoid (bone matrix). (Memory tip: Blasts Build).
2. What are the "giant, multinucleated" cells that break down bone matrix to
release calcium?
A) Osteocytes
B) Osteoblasts
C) Osteoclasts
D) Osteogenic cells
Explanation: Osteoclasts perform bone resorption. (Memory tip: Clasts Consume).
3. The structural unit of "Compact Bone" is called a(n):
A) Trabecula
B) Osteon (Haversian System)
C) Canaliculus
D) Lacuna
Explanation: An Osteon is a weight-bearing pillar consisting of a central canal
surrounded by concentric lamellae.
, 4. Where is "Red Bone Marrow" (the site of hematopoiesis) primarily found in
adults?
A) Medullary cavity of long bones
B) Spongy bone (Dipolë) of flat bones and epiphyses
C) Central canals
D) Periosteum
Explanation: Spongy bone contains trabeculae that house red marrow. In adults,
yellow marrow (fat) fills the medullary cavities of long bones.
5. The "shaft" of a long bone is anatomically known as the:
A) Epiphysis
B) Diaphysis
C) Metaphysis
D) Periosteum
Explanation: The Diaphysis is the long axis of the bone, while the Epiphyses are the
expanded ends.
6. Which hormone is released when blood calcium levels are LOW to stimulate
osteoclasts?
A) Calcitonin
B) Parathyroid Hormone (PTH)
C) Growth Hormone
D) Insulin
Explanation: PTH increases blood calcium by triggering bone resorption.
7. "Endochondral Ossification" describes bone developing from which
precursor?
A) Fibrous membranes
B) Hyaline cartilage
C) Adipose tissue
, D) Elastic fibers
Explanation: Most bones below the skull (except clavicles) form via Endochondral
ossification.
8. The "Epiphyseal Plate" is the site of:
A) Bone thickness growth (appositional)
B) Longitudinal bone growth (lengthening)
C) Fracture repair
D) Red marrow storage
Explanation: The Epiphyseal plate is a layer of hyaline cartilage in growing children; it
becomes the epiphyseal line once growth stops.
9. Which organic component provides bone with "flexibility" and tensile
strength?
A) Calcium salts
B) Collagen fibers
C) Hydroxyapatites
D) Phosphorus
Explanation: Collagen prevents bone from being too brittle. The mineral salts provide
hardness.
10. Tiny canals that connect lacunae to each other, allowing osteocytes to
communicate, are:
A) Perforating canals
B) Canaliculi
C) Central canals
D) Nutrient foramina
Explanation: Canaliculi ensure nutrients reach cells trapped in the hard matrix.
Part 2: The Axial Skeleton
HISTOLOGY, AXIAL & APPENDICULAR IDENTIFICATION 2026
MODULE 4: THE SKELETAL SYSTEM QUESTIONS AND
ANSWERS | PDF
Part 1: Bone Histology & Physiology
1. Which cell type is responsible for "building" new bone matrix?
A) Osteocyte
B) Osteoblast
C) Osteoclast
D) Chondrocyte
Explanation: Osteoblasts secrete osteoid (bone matrix). (Memory tip: Blasts Build).
2. What are the "giant, multinucleated" cells that break down bone matrix to
release calcium?
A) Osteocytes
B) Osteoblasts
C) Osteoclasts
D) Osteogenic cells
Explanation: Osteoclasts perform bone resorption. (Memory tip: Clasts Consume).
3. The structural unit of "Compact Bone" is called a(n):
A) Trabecula
B) Osteon (Haversian System)
C) Canaliculus
D) Lacuna
Explanation: An Osteon is a weight-bearing pillar consisting of a central canal
surrounded by concentric lamellae.
, 4. Where is "Red Bone Marrow" (the site of hematopoiesis) primarily found in
adults?
A) Medullary cavity of long bones
B) Spongy bone (Dipolë) of flat bones and epiphyses
C) Central canals
D) Periosteum
Explanation: Spongy bone contains trabeculae that house red marrow. In adults,
yellow marrow (fat) fills the medullary cavities of long bones.
5. The "shaft" of a long bone is anatomically known as the:
A) Epiphysis
B) Diaphysis
C) Metaphysis
D) Periosteum
Explanation: The Diaphysis is the long axis of the bone, while the Epiphyses are the
expanded ends.
6. Which hormone is released when blood calcium levels are LOW to stimulate
osteoclasts?
A) Calcitonin
B) Parathyroid Hormone (PTH)
C) Growth Hormone
D) Insulin
Explanation: PTH increases blood calcium by triggering bone resorption.
7. "Endochondral Ossification" describes bone developing from which
precursor?
A) Fibrous membranes
B) Hyaline cartilage
C) Adipose tissue
, D) Elastic fibers
Explanation: Most bones below the skull (except clavicles) form via Endochondral
ossification.
8. The "Epiphyseal Plate" is the site of:
A) Bone thickness growth (appositional)
B) Longitudinal bone growth (lengthening)
C) Fracture repair
D) Red marrow storage
Explanation: The Epiphyseal plate is a layer of hyaline cartilage in growing children; it
becomes the epiphyseal line once growth stops.
9. Which organic component provides bone with "flexibility" and tensile
strength?
A) Calcium salts
B) Collagen fibers
C) Hydroxyapatites
D) Phosphorus
Explanation: Collagen prevents bone from being too brittle. The mineral salts provide
hardness.
10. Tiny canals that connect lacunae to each other, allowing osteocytes to
communicate, are:
A) Perforating canals
B) Canaliculi
C) Central canals
D) Nutrient foramina
Explanation: Canaliculi ensure nutrients reach cells trapped in the hard matrix.
Part 2: The Axial Skeleton
