D312 Section 3 Lab Questions on Skeletal Anatomy and Structure

Student Name

Western Governors University

D312 Anatomy and Physiology I with Lab

Prof. Name

Date

Lab Questions Section 3 – Skeletal Anatomy and Structure of Bones and Bones of the Head and Neck

This laboratory section focuses on foundational concepts related to skeletal anatomy and bone physiology. The questions presented below examine bone cell types, structural components of bone tissue, classifications of bones, and the organization of the axial and appendicular skeletons. Each question is answered as presented in the lab content, with expanded explanations to reinforce conceptual understanding and reduce ambiguity. Tables are incorporated where comparison or clarification is beneficial.

Bone Cells and Bone Matrix

Which bone cells are entrapped in the bone matrix?

Among the various bone cell types, only one becomes permanently enclosed within the mineralized matrix of bone tissue.

Answer Choice	Explanation
a. Osteoclast cells	Incorrect. Osteoclasts are large, multinucleated cells that function in bone resorption. They operate on the bone surface and are not embedded within the matrix.
b. Osteogenic cells	Incorrect. Osteogenic cells are undifferentiated stem cells located in the periosteum and endosteum. Their role is to divide and differentiate into osteoblasts rather than become trapped in bone tissue.
c. Osteoblast cells	Incorrect. Osteoblasts actively synthesize and secrete bone matrix but remain on the surface of the bone. Once they become enclosed by the matrix they produce, they differentiate into another cell type.
d. Osteocyte cells	Correct. Osteocytes are mature bone cells that originate from osteoblasts that have become embedded in the bone matrix. They maintain bone tissue and regulate mineral exchange.

Osteocytes are uniquely positioned within lacunae of the bone matrix, allowing them to communicate through canaliculi and play a critical role in maintaining bone integrity and metabolic balance.

Components of the Bone Matrix

Label the components of the bone matrix (Questions 2–5)

These questions require identification of specific bone tissues based on a labeled diagram. Each answer corresponds directly to a structural component commonly observed in long bones.

Question	Label	Correct Identification
Question 2	A	Spongy bone
Question 3	B	Bone marrow
Question 4	C	Compact bone
Question 5	D	Periosteum

Spongy bone provides structural support with reduced weight, bone marrow is responsible for hematopoiesis or fat storage, compact bone offers strength and protection, and the periosteum serves as a connective tissue covering that supports growth and repair.

Structure of Long Bones

Which statement is true about the diaphysis labeled D in the long bone diagram?

The diaphysis refers to the shaft of a long bone and is structurally specialized to support body weight and resist stress.

Answer Choice	Explanation
a. The diaphysis is comprised of compact bone and cartilage.	Correct. The diaphysis is primarily composed of compact bone, while cartilage is present at the epiphyseal plates near its junctions with the epiphyses during growth.
b. The diaphysis is comprised mostly of compact bone.	Partially correct. While compact bone predominates, this option does not acknowledge the role of cartilage associated with growth regions.
c. The diaphysis is comprised of spongy bone and cartilage.	Incorrect. Spongy bone is primarily found in the epiphyses rather than the shaft of long bones.
d. The diaphysis is comprised mostly of spongy bone.	Incorrect. The shaft must be dense and strong, a function served by compact bone.

Overall, the diaphysis provides rigidity and leverage, making compact bone its most prominent structural component.

Bone Shape Classification

Which image is classified as an irregular-shaped bone?

Bone classification is based on shape, which directly relates to function.

Answer Choice	Explanation
a. A – Long bones	Incorrect. Long bones are elongated and primarily function in movement.
b. B – Sesamoid bone	Incorrect. Sesamoid bones are small, round bones embedded in tendons.
c. C – Flat bones	Incorrect. Flat bones are thin and provide protection, such as the ribs and cranial bones.
d. D – Irregular bones	Correct. Irregular bones have complex shapes designed for specialized functions, such as vertebrae that protect the spinal cord.

Which type of bone is labeled A?

Answer Choice	Explanation
a. Irregular bones	Incorrect. Irregular bones do not display the elongated structure shown in the image.
b. Short bones	Incorrect. Short bones are cube-shaped and lack a distinct shaft.
c. Long bones	Correct. Long bones possess a shaft and two expanded ends and are designed to support movement and weight-bearing.
d. Flat bones	Incorrect. Flat bones are thin and broad rather than elongated.

Bones that surround the spinal cord are classified as ________ bones.

Answer Choice	Explanation
a. Flat	Incorrect. Flat bones protect organs such as the heart and brain, not the spinal cord.
b. Irregular	Correct. Vertebrae are irregular bones with complex structures that protect the spinal cord.
c. Short	Incorrect. Short bones are found in the wrists and ankles.
d. Sesamoid	Incorrect. Sesamoid bones are embedded in tendons and do not form protective enclosures.

What is the classification of bones labeled A and B in the human skeleton image?

Answer Choice	Explanation
a. Long bone	Correct. Bones such as the femur, humerus, and phalanges fall into this category due to their elongated shape.
b. Flat bone	Incorrect. Flat bones are broad and thin, such as the sternum.
c. Irregular bone	Incorrect. Irregular bones include vertebrae and facial bones.
d. Short bone	Incorrect. Short bones are roughly cube-shaped.

Axial and Appendicular Skeleton

What is part of the axial skeleton?

Answer Choice	Explanation
a. Thigh bones	Incorrect. Thigh bones belong to the appendicular skeleton.
b. Vertebral column	Correct. The axial skeleton includes the skull, vertebral column, and thoracic cage.
c. Foot bones	Incorrect. Foot bones are appendicular.
d. Shoulder bones	Incorrect. Shoulder girdle bones are part of the appendicular skeleton.

The appendicular skeleton ________.

Answer Choice	Explanation
a. forms the vertical axis of the body	Incorrect. This function belongs to the axial skeleton.
b. includes all bones of the body trunk and limbs	Incorrect. The trunk bones are part of the axial skeleton.
c. consists of 126 bones	Correct. The appendicular skeleton includes 126 bones associated with the limbs and girdles.
d. is comprised of the bones of the lower and upper limbs	Correct. This includes the limbs and the pectoral and pelvic girdles.

Summary Table of Bone Classifications

Bone Type	Description	Examples
Long Bones	Longer than they are wide; primarily compact bone with spongy bone at the ends	Femur, humerus, radius
Short Bones	Cube-shaped; mostly spongy bone with a thin compact bone covering	Carpals, tarsals
Flat Bones	Thin and flattened; two layers of compact bone with spongy bone between	Sternum, ribs, cranial bones
Irregular Bones	Complex shapes adapted for specialized functions	Vertebrae, sphenoid, ethmoid
Sesamoid Bones	Small bones embedded within tendons to reduce friction	Patella

References

Martini, F. H., Nath, J. L., & Bartholomew, E. F. (2017). Fundamentals of anatomy & physiology (11th ed.). Pearson.

Tortora, G. J., & Derrickson, B. (2017). Principles of anatomy and physiology (15th ed.). Wiley.

D312 Section 3 Lab Questions on Skeletal Anatomy and Structure

Saladin, K. S. (2020). Anatomy & physiology: The unity of form and function (9th ed.). McGraw-Hill Education.