Cues

• Structure of Cartilage
• Three Types of Cartilage
• Structure of Bone
• Types of Bone Cells
• Two Types of Bone

Notes

Cartilage:

• Hyaline Cartilage:
  • Common sites: trachea, bronchi, costal cartilage, articular surfaces, epiphyseal plate, fetal skeleton.
  • Structure: Perichondrium (outer fibrous & inner chondrogenic layer), cartilage matrix (collagen type II, chondroitin sulphate, glycoprotein), chondrocytes in lacunae.
• Elastic Cartilage:
  • Common sites: ear pinna, external auditory canal, epiglottis, Eustachian tube.
  • Structure: similar to hyaline, but with elastic fibers.
• Fibrocartilage:
  • Common sites: intervertebral discs, symphysis pubis.
  • Structure: lacks perichondrium, contains both hyaline cartilage and dense connective tissue with type I collagen.

Bone:

• Structure of Bone:
  • Periosteum (outer fibrous, inner osteogenic layer).
  • Endosteum (lines bone marrow cavities, rich in osteogenic cells).
  • Bone matrix (organic: collagen type I, chondroitin sulphate, inorganic: calcium and phosphorus crystals).
• Bone Cells:
  • Osteoblasts: synthesize bone matrix.
  • Osteocytes: maintain bone matrix, deposit calcium.
  • Osteoclasts: resorb bone, remodel, remove debris.
• Types of Bone:
  • Compact bone: found in diaphysis of long bones, Haversian systems (osteons).
  • Spongy bone: found in epiphysis, no Haversian systems, irregular trabeculae.

Summary

This lecture covers the structure and types of cartilage and bone. Cartilage is categorized into three types—hyaline, elastic, and fibrocartilage—based on structure and location. Bone has a more complex structure, including periosteum, endosteum, and bone matrix, and is made up of four types of cells: osteoblasts, osteocytes, osteoclasts, and osteogenic cells. Bone also exists in two forms: compact and spongy, each with distinct structural features.