BIO105 Anatomy and Physiology 1 Exam 2 Version
1 Questions with Correct Answers and Expert
Explanation for Each Question
1. Which cell type is primarily responsible for the resorption or breakdown of bone
matrix?
A. Osteoblasts
B. Osteoclasts
C. Osteocytes
D. Chondrocytes
Correct Answer: B
Expert Explanation: Osteoclasts are specialized multinucleated cells that dissolve
the bone matrix by secreting acid and enzymes. This process is essential for calcium
mobilization and bone remodeling throughout the human lifespan. In contrast,
osteoblasts are responsible for bone formation by secreting the organic components
of the matrix. Osteocytes are mature bone cells that maintain the matrix rather than
breaking it down. Understanding the balance between these cell types is critical for
diagnosing metabolic bone diseases.
2. What is the name of the structural unit of compact bone?
A. Trabeculae
,B. Osteon
C. Canaliculi
D. Lamellae
Correct Answer: B
Expert Explanation: The osteon, or Haversian system, is the fundamental
functional unit of compact bone tissue. Each osteon consists of concentric layers of
calcified matrix known as lamellae surrounding a central canal. While trabeculae are
found in spongy bone, the osteon is unique to the dense structure of compact bone.
Canaliculi are small channels that connect lacunae, but they are only a component of
the larger osteon structure. Mastering this microscopic anatomy is vital for
understanding how bones resist mechanical stress.
3. The shaft of a long bone is anatomically referred to as the:
A. Epiphysis
B. Diaphysis
C. Periosteum
D. Metaphysis
Correct Answer: B
,Expert Explanation: The diaphysis is the long, tubular shaft that forms the main
axis of a long bone. It is composed primarily of compact bone and contains the
medullary cavity filled with yellow marrow. The epiphysis refers to the expanded
ends of the bone, while the periosteum is the outer fibrous covering. Between the
diaphysis and epiphysis lies the metaphysis, which contains the growth plate in
developing children. Recognizing these anatomical landmarks is essential for
identifying fracture locations in clinical imaging.
4. Which hormone is released when blood calcium levels are too low to stimulate
bone resorption?
A. Parathyroid Hormone (PTH)
B. Insulin
C. Calcitonin
D. Thyroxine
Correct Answer: A
Expert Explanation: Parathyroid Hormone (PTH) is secreted by the parathyroid
glands in response to low serum calcium levels. It increases blood calcium by
stimulating osteoclast activity to release calcium from the bone matrix. Conversely,
calcitonin is released by the thyroid gland to lower blood calcium levels by
inhibiting osteoclasts. Insulin and thyroxine play roles in general metabolism but do
, not directly regulate calcium homeostasis in this manner. Mastery of this feedback
loop is a core requirement for understanding endocrine control of the skeletal
system.
5. Which of the following bones is considered part of the axial skeleton?
A. Femur
B. Sternum
C. Scapula
D. Clavicle
Correct Answer: B
Expert Explanation: The sternum is a central bone of the chest and is a key
component of the axial skeleton. The axial skeleton includes the skull, vertebral
column, and thoracic cage, totaling eighty bones. The femur and scapula belong to
the appendicular skeleton, which facilitates movement and locomotion. Similarly,
the clavicle is part of the pectoral girdle, which attaches the upper limbs to the axial
frame. Distinguishing between these two divisions is fundamental for any nursing or
medical student.
6. What type of bone formation involves the replacement of a hyaline cartilage
model?
A. Intramembranous ossification
1 Questions with Correct Answers and Expert
Explanation for Each Question
1. Which cell type is primarily responsible for the resorption or breakdown of bone
matrix?
A. Osteoblasts
B. Osteoclasts
C. Osteocytes
D. Chondrocytes
Correct Answer: B
Expert Explanation: Osteoclasts are specialized multinucleated cells that dissolve
the bone matrix by secreting acid and enzymes. This process is essential for calcium
mobilization and bone remodeling throughout the human lifespan. In contrast,
osteoblasts are responsible for bone formation by secreting the organic components
of the matrix. Osteocytes are mature bone cells that maintain the matrix rather than
breaking it down. Understanding the balance between these cell types is critical for
diagnosing metabolic bone diseases.
2. What is the name of the structural unit of compact bone?
A. Trabeculae
,B. Osteon
C. Canaliculi
D. Lamellae
Correct Answer: B
Expert Explanation: The osteon, or Haversian system, is the fundamental
functional unit of compact bone tissue. Each osteon consists of concentric layers of
calcified matrix known as lamellae surrounding a central canal. While trabeculae are
found in spongy bone, the osteon is unique to the dense structure of compact bone.
Canaliculi are small channels that connect lacunae, but they are only a component of
the larger osteon structure. Mastering this microscopic anatomy is vital for
understanding how bones resist mechanical stress.
3. The shaft of a long bone is anatomically referred to as the:
A. Epiphysis
B. Diaphysis
C. Periosteum
D. Metaphysis
Correct Answer: B
,Expert Explanation: The diaphysis is the long, tubular shaft that forms the main
axis of a long bone. It is composed primarily of compact bone and contains the
medullary cavity filled with yellow marrow. The epiphysis refers to the expanded
ends of the bone, while the periosteum is the outer fibrous covering. Between the
diaphysis and epiphysis lies the metaphysis, which contains the growth plate in
developing children. Recognizing these anatomical landmarks is essential for
identifying fracture locations in clinical imaging.
4. Which hormone is released when blood calcium levels are too low to stimulate
bone resorption?
A. Parathyroid Hormone (PTH)
B. Insulin
C. Calcitonin
D. Thyroxine
Correct Answer: A
Expert Explanation: Parathyroid Hormone (PTH) is secreted by the parathyroid
glands in response to low serum calcium levels. It increases blood calcium by
stimulating osteoclast activity to release calcium from the bone matrix. Conversely,
calcitonin is released by the thyroid gland to lower blood calcium levels by
inhibiting osteoclasts. Insulin and thyroxine play roles in general metabolism but do
, not directly regulate calcium homeostasis in this manner. Mastery of this feedback
loop is a core requirement for understanding endocrine control of the skeletal
system.
5. Which of the following bones is considered part of the axial skeleton?
A. Femur
B. Sternum
C. Scapula
D. Clavicle
Correct Answer: B
Expert Explanation: The sternum is a central bone of the chest and is a key
component of the axial skeleton. The axial skeleton includes the skull, vertebral
column, and thoracic cage, totaling eighty bones. The femur and scapula belong to
the appendicular skeleton, which facilitates movement and locomotion. Similarly,
the clavicle is part of the pectoral girdle, which attaches the upper limbs to the axial
frame. Distinguishing between these two divisions is fundamental for any nursing or
medical student.
6. What type of bone formation involves the replacement of a hyaline cartilage
model?
A. Intramembranous ossification
