Week 6 - Introduction to the Skeletal System

Overview of the Skeletal System

• The skeletal system is composed of more than just bones.
  • Functions include protection, support, movement, blood formation, calcium regulation, triglyceride regulation.
• Essential for overall health and homeostasis.

Classifying Bones by Shape

1. Long Bones
   • Example: Femur (thigh bone), longest and strongest.
2. Short Bones
   • Nearly equal in length and width (square or circular shape).
   • Examples: Carpals (wrist bones) and Tarsals (ankle bones).
3. Flat Bones
   • Thin and flat.
   • Examples: Scapula and skull bones.
4. Irregular Bones
   • Irregular shapes.
   • Examples: Vertebrae and parts of the scapula.
5. Sesamoid Bones
   • Not directly attached to other bones; embedded in tendons.
   • Example: Patella (knee cap).

Anatomy of a Long Bone

• Medullary Cavity: Contains bone marrow and fat; reduces bone weight.
• Diaphysis: The shaft of the bone.
• Epiphyses: The ends of the bone, where joint articulation occurs.
• Metaphyses: Regions between the diaphysis and epiphyses, critical for growth.

Surface Tissues of Long Bones

• Endosteum: Inner surface of the bone, lining the medullary cavity.
• Periosteum: Outer surface, with perforating fibers (Sharpe's fibers).
• Articular Cartilage: Hyaline cartilage on joint surfaces, aids in shock absorption.

Bone Marrow

• Red Marrow:
  • Found in children and specific adult bones (skull, ribs, pelvis).
  • Hematopoietic: Produces blood cells.
• Yellow Marrow:
  • Found in adults.
  • Fatty, produces triglycerides.
  • Limited blood production as it replaces red marrow.

Conclusion

• Next video will discuss bone cells and tissues, focusing on the bone matrix.
• Review ground substance and matrix concepts for the next session.