🌟 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.