Biol 251 Human Anatomy & Physiology I W/Lab | Module 3 Exam Questions And Correct Answers With Rationales Graded A+

BIOL 251 HUMAN ANATOMY & PHYSIOLOGY I W/LAB |
MODULE 3 EXAM QUESTIONS AND CORRECT ANSWERS
WITH RATIONALES GRADED A+


1. Which of the following is the primary structural unit of compact bone?
A. Trabeculae
B. Osteon
C. Lacuna
D. Canaliculi
Answer: B. Osteon
Rationale: Osteons (Haversian systems) are the cylindrical units of compact bone,
containing central canals and concentric lamellae. Trabeculae are in spongy bone.


2. During endochondral ossification, the primary ossification center appears in
the:
A. Epiphysis
B. Diaphysis
C. Periosteum
D. Articular cartilage
Answer: B. Diaphysis
Rationale: Endochondral ossification begins in the diaphysis, where cartilage is
replaced by bone. Secondary ossification centers appear in the epiphyses.


3. A patient has low blood calcium levels. Which bone cell type will be primarily
activated to release calcium into the blood?
A. Osteocyte
B. Osteoblast
C. Osteoclast
D. Chondroblast

,Answer: C. Osteoclast
Rationale: Osteoclasts resorb bone, releasing calcium into the bloodstream;
osteoblasts build bone, lowering blood calcium.


4. Which of the following bones contains the foramen magnum?
A. Temporal
B. Occipital
C. Sphenoid
D. Ethmoid
Answer: B. Occipital
Rationale: The foramen magnum, where the spinal cord passes, is located in the
occipital bone.


5. Identify the bone type: A carpal bone in the wrist is classified as:
A. Long bone
B. Short bone
C. Flat bone
D. Irregular bone
Answer: B. Short bone
Rationale: Short bones are roughly cube-shaped; carpals and tarsals are examples.


6. Scenario: A 12-year-old boy breaks the distal end of his radius. X-ray shows the
fracture passes through the growth plate. What type of fracture is this?
A. Greenstick
B. Comminuted
C. Epiphyseal
D. Stress
Answer: C. Epiphyseal
Rationale: Growth plate fractures occur at the epiphysis and can affect bone
development.

,7. Which of the following is true about red bone marrow?
A. Found in diaphysis of long bones in adults
B. Main site of hematopoiesis
C. Replaces yellow marrow in aging
D. Found exclusively in the skull
Answer: B. Main site of hematopoiesis
Rationale: Red marrow produces blood cells; in adults, it is found in axial
skeleton, pelvic bones, and proximal epiphyses of humerus/femur.


8. Which structure allows for nutrient passage into bone tissue?
A. Canaliculi
B. Perforating (Volkmann’s) canal
C. Lamellae
D. Lacunae
Answer: B. Perforating (Volkmann’s) canal
Rationale: Volkmann’s canals connect blood vessels from periosteum into central
canals of osteons, supplying nutrients.


9. Lab identification: You observe a bone with trabeculae forming irregular
latticework. This is:
A. Compact bone
B. Spongy bone
C. Periosteum
D. Osteon
Answer: B. Spongy bone
Rationale: Spongy bone consists of trabeculae that provide strength while
minimizing weight.

, 10. Which hormone increases calcium deposition in bones?
A. Parathyroid hormone (PTH)
B. Calcitonin
C. Calciferol
D. Thyroid hormone
Answer: B. Calcitonin
Rationale: Calcitonin, released by the thyroid, lowers blood calcium by promoting
osteoblast activity and bone deposition.


11. Which of the following bones is part of the axial skeleton?
A. Scapula
B. Sternum
C. Clavicle
D. Humerus
Answer: B. Sternum
Rationale: The axial skeleton includes skull, vertebral column, ribs, and sternum;
the others are appendicular.


12. The proximal end of the humerus articulates with the:
A. Ulna
B. Radius
C. Scapula
D. Clavicle
Answer: C. Scapula
Rationale: The head of the humerus fits into the glenoid cavity of the scapula,
forming the shoulder joint.