Professor Long's Anatomy and Physiology Lecture Notes

Introduction

• Lecturer: Professor Bob Long
• Course: Anatomy and Physiology
• Content Focus: Bone formation and growth
• Purpose: Intended for Professor Long's students to learn the material in his teaching style.

Overview

• Recent lectures included:
  • Bone formation introduction
  • Long bone structure
  • Bone wedge model: Osteons, concentric lamellae, interstitial lamellae
  • Endochondral Ossification: Formation of long bones within a hyaline cartilage model

Intramembranous Ossification

• Definition: Formation of bone within a membrane, specifically the dermis of the skin.
• Process: Overview
  • Occurs during embryonic development within the dermis.
  • Mesenchymal (embryonic) tissue forms dermal or flat bones (e.g., skull, clavicle, sternum, ribs, scapula).
  • Involves osteoprogenitors differentiating into osteoblasts which lay down bone spicules.
  • Formation of osteoid (similar to bone) by laying down calcium salts.
  • Growth occurs along stress lines forming trabeculae (spongy bone).
  • Remodeling includes adding compact bone layers.
• Outcome: Formation of flat bones filled with spongy bone without marrow cavities, filled with red bone marrow instead.

Bone Growth

Interstitial Growth (Length)

• Process:
  • Growth occurs at the growth plate (metaphysis) between diaphysis and epiphysis.
  • Chondrocytes add cartilage on the epiphyseal side
  • Osteoclasts and osteoblasts on the diaphyseal side replace cartilage with bone.
  • Results in bones growing longer until growth plates close during late puberty.
• Key Terms:
  • Epiphyseal Edge: Side of growth plate near the epiphysis
  • Diaphyseal Edge: Side of growth plate near the diaphysis
  • Growth Plate Closure: Indicates end of bone length growth, leaving an epiphyseal line.

Appositional Growth (Diameter)

• Process:
  • Osteoclasts enlarge marrow cavity by digesting spongy bone.
  • Osteoblasts add circumferential lamellae, increasing bone diameter.
  • Balances bone weight support with maintaining thickness.
• Key Features:
  • Occurs concurrently with interstitial growth
  • Diameter grows while thickness remains relatively constant.

Nutritional and Hormonal Influence

• Upcoming topics include:
  • Nutrition's role in bone health
  • Hormonal effects on bone growth
  • Importance of diet and exercise for skeletal health

Conclusion

• Summary: Interstitial growth increases bone length, while appositional growth increases diameter.
• Additional Learning: Students are encouraged to understand and teach these concepts for mastery.
• Next Steps: Future lectures will cover nutrition and hormonal effects on bones.