Structure and Functions of Bone Tissue and Cartilage

Introduction

This study guide covers the essential concepts of bone and cartilage structure and function, as outlined in Chapter 6. It is designed to help Anatomy & Physiology students understand the skeletal system, including bone tissue, cartilage, bone growth, remodeling, and repair. The guide also addresses the gross anatomy of bones and their clinical significance.

Learning Outcomes

• Global Learning Outcomes:

  • Understand the principles of scientific inquiry and the impact of science on society.

  • Demonstrate the ability to think critically and employ scientific thinking skills.

• General Features of the Skeletal System:

  • Describe what makes a bone an organ.

  • Identify the general functions of the skeleton and bone tissue.

  • List and describe the major structural components of bones (e.g., bones, ligaments, tendons, articulations).

• Cartilage:

  • Describe the characteristics of the three types of cartilage in the skeletal system.

  • Compare the structure and function of the three kinds of cartilage tissue.

  • Explain how cartilage grows.

• Microscopic Components of Bone:

  • Describe the microscopic anatomy of bone tissue, including osteon composition.

  • Describe the structure of bone tissue and the general functions of its organic and inorganic components.

  • Describe the different types of bone cells and their roles in bone location and general function.

• Gross Anatomy of Bones:

  • List the types of bones based on shape and provide examples of each.

  • Describe the structure and location of compact and spongy bone.

  • Describe the gross anatomy of a typical long bone.

  • Compare the gross anatomy and typical function of red bone marrow and yellow bone marrow.

  • Explain how bone structure is adapted to withstand tension and compression.

  • Compare periosteum and endosteum.

  • Describe the major divisions of the skeletal system and list the bones contained in each (axial and appendicular).

  • Describe the types of markings found on bones.

• Bone Growth, Remodeling, and Repair:

  • Define osteogenesis.

  • Describe the two major forms of bone development: intramembranous ossification and endochondral ossification.

  • Explain appositional growth and bone remodeling.

  • Describe the stages of bone repair after a fracture.

Major Topics and Subtopics

I. The Skeletal System

• Functions: Support, protection, movement, mineral storage, blood cell production, and energy storage.

• Osseous Tissue: The primary tissue of bone, composed of cells and extracellular matrix.

• What Makes a Bone an Organ? Bones are organs because they contain multiple tissue types, including bone tissue, cartilage, blood vessels, nerves, and connective tissue.

II. Cartilage

• Locations: Found in joints, rib cage, ear, nose, bronchial tubes, and intervertebral discs.

• Types:

  • Hyaline cartilage: Most common; provides support with flexibility and resilience.

  • Elastic cartilage: Contains more elastic fibers; found in the ear and epiglottis.

  • Fibrocartilage: Highly compressible; found in intervertebral discs and knee menisci.

• Growth: Cartilage grows by appositional (from the outside) and interstitial (from within) mechanisms.

III. Bone Tissue

• Growth: Bones grow in length and width through endochondral and intramembranous ossification.

• Extracellular Matrix: Composed of organic (collagen fibers) and inorganic (hydroxyapatite crystals) components.

• Cells:

  • Osteoblasts: Bone-forming cells.

  • Osteocytes: Mature bone cells that maintain bone tissue.

  • Osteoclasts: Bone-resorbing cells.

IV. Gross Anatomy

• Divisions of the Skeleton:

  • Axial skeleton: Skull, vertebral column, and thoracic cage.

  • Appendicular skeleton: Limbs and girdles.

• Long Bone Structure:

  • Epiphysis: End of the bone, contains spongy bone.

  • Diaphysis: Shaft of the bone, contains compact bone.

  • Metaphysis: Region between diaphysis and epiphysis; contains the growth plate.

  • Periosteum: Outer fibrous covering. surrounding the bone

  • Endosteum: Lining of the medullary cavity.

  • Articular cartilage: Covers joint surfaces.

  • Vasculature: Blood supply to bone.

  • Innervation: Nerve supply to bone.

• Flat Bone Structure:

  • Composed of compact bone on the outside and spongy bone (diploë) inside.

  • Contains marrow, periosteum, endosteum, articulations, vasculature, and innervation.

• Bone Types: Long, short, flat, irregular, and sesamoid bones.

• Bone Markings: Projections, depressions, and openings that serve as sites for muscle attachment, joint formation, or passage of nerves and blood vessels.

V. Bone Growth, Remodeling, and Repair

• Osteogenesis: The process of bone formation.

  • Intramembranous ossification: Bone develops from a fibrous membrane (e.g., flat bones of the skull).

  • Endochondral ossification: Bone develops by replacing hyaline cartilage (e.g., long bones).

• Appositional Growth: Increase in bone thickness.

• Remodeling: Ongoing replacement of old bone tissue by new bone tissue; involves osteoblasts and osteoclasts.

• Clinical Correlation – Fracture Healing: Bone repair involves hematoma formation, fibrocartilaginous callus formation, bony callus formation, and bone remodeling.

Key Table: Types of Cartilage in the Skeletal System

Key Equations and Concepts

• Bone Matrix Composition:

  • Organic component: Collagen fibers (provide tensile strength)

  • Inorganic component: Hydroxyapatite crystals (provide hardness)

• Bone Growth Equation (Length):

• Bone Remodeling Equation:

Summary Table: Bone Cells and Their Functions

Additional info:

• Clinical applications may include understanding osteoporosis, bone fractures, and the effects of aging on bone tissue.

• Students are encouraged to review figures and tables from the textbook for visual reinforcement of these concepts.