Cartilage Overview

Cartilage Overview

• Cartilage is a specialized connective tissue, avascular (no blood vessels)
• Matrix is firm/rubbery, resilient
• Functions include support, maintaining airway patency, providing smooth joint surfaces, shock absorption

Learning Objectives

• Define cartilage
• Classify cartilage types (hyaline, elastic, fibro)
• Identify locations of cartilage in the human body
• Describe microstructure of cartilage

Cartilage Cells

• Chondrogenic cells: Stem cells for all cartilage cell types
• Chondroblasts: Immature cartilage cells found on the surface of cartilage and perichondrium, producing cartilage matrix and fibers.
• Chondrocytes: Mature cartilage cells, produce matrix, then become trapped (imprisoned) within lacunae. Appear in isogenous groups (clusters).

Cartilage Fibers

• Composition varies according to cartilage type.
• Collagen and elastic fibers are present.

Cartilage Matrix

• Rubbery and basophilic (stains dark with basic dyes)
• Composed of glycosaminoglycans (GAGs), glycoproteins, and water.

Types of Cartilage

• Hyaline cartilage:
  • Found in fetal skeleton, epiphyseal plates, articular surfaces, costal cartilage, and respiratory passages (e.g., nose, trachea)
  • Matrix is primarily collagen type II
• Elastic cartilage:
  • Found in the ear pinna, Eustachian tube, epiglottis, and external auditory canal.
  • Matrix contains elastic fibers for flexibility.
• Fibrocartilage:
  • Found at intervertebral discs, symphysis pubis, mandibular joint, sternoclavicular joint, and acetabulum (and the femur) – provides strength for high-stress points
  • Matrix has dense collagen fibers (type I), more structure/strength. Less ground substance than Hyaline.

Cartilage Structure

• Perichondrium: A layer of dense irregular connective tissue surrounding cartilage (except articular cartilage).
• Fibers: Collagen (type II in hyaline, type I in fibro) and elastic fibers (elastic cartilage).
• Matrix: Varies in amount depending on type of cartilage. Hyaline matrix abundant & conspicuous; Elastic matrix less.
• Cartilage cells: Chondrocytes housed in lacunae.

Reference

• Junqueira's Basic Histology (13th edition, 2013).

This quiz explores the structure, types, and functions of cartilage, a specialized connective tissue in the human body. You'll learn how to classify different types of cartilage and identify their locations. Additionally, you'll dive into the cellular components and matrix of cartilage.