Cartilage Overview and Types

Cartilage Overview

• Cartilage is an avascular connective tissue (CT) with a firm, rubbery matrix, providing resilience.
• It functions in support, maintaining airway patency, providing smooth joint surfaces, and acting as a shock absorber.

Learning Objectives

• Define cartilage.
• Classify cartilage types.
• Locate cartilage in the human body.
• Understand the microstructure of cartilage.

Cartilage Cell Types

• Chondrogenic cells: The precursor cells for all cartilage cells.
• Chondroblasts: Immature cartilage cells located on the cartilage surface and perichondrium. They produce the cartilage matrix and fibers.
• Chondrocytes: Mature cartilage cells that secrete the matrix and are encased within lacunae. Often found in isogenous groups.

Cartilage Fibers

• Collagen and elastic fibers, the type varying depending on the cartilage type.

Cartilage Matrix

• Rubbery and basophilic (staining darkly).
• Composed of glycosaminoglycans (GAGs), glycoproteins, and water.

Cartilage Types

• Hyaline cartilage: Found in fetal skeletons, articular surfaces, costal cartilage, and respiratory passages (e.g., nose, trachea). It contains Type II collagen fibers.
• Elastic cartilage: Found in the ear pinna, Eustachian tube, epiglottis, and external auditory canal. It contains elastic fibers.
• Fibrocartilage: Found in intervertebral discs, symphysis pubis, mandibular joints, sternoclavicular joints, and acetabulum. It contains Type I collagen fibers.

Hyaline Cartilage Structure

• Surrounded by perichondrium (except at articular surfaces).
• Contains Type II collagen fibers.

Elastic Cartilage Structure

• Contains perichondrium.
• Contains elastic fibers.
• Matrix less abundant than hyaline cartilage.

Fibrocartilage Structure

• Lacks perichondrium.
• Contains thick, parallel bundles of Type I collagen fibers.
• Matrix is very scant.
• Chondrocytes are arranged in rows between the collagen bundles.

References

• Junqueira's Basic Histology (2013, 13th Edition by Anthony L. Mescher)

This quiz explores the fundamental aspects of cartilage, a vital avascular connective tissue in the human body. You'll learn to define cartilage, classify its different types, and understand its unique cell types and microstructure. Discover the crucial roles cartilage plays in support and joint function.