ch. 6 Skeletal System Overview

Tissue Types in Bone

  • Bone consists of multiple tissue types:
    • Nervous tissue
    • Epithelial tissue
    • Connective tissue
  • Types of cartilage:
    • Hyaline cartilage (nose, joints, ribcage)
    • Elastic cartilage (ear, epiglottis)
    • Fibrocartilage (pubic symphysis, menisci)

Functions of the Skeletal System

  • Support: Endoskeleton that grows with the organism
  • Protection: Bones protect vital organs (e.g., skull protects the brain)
  • Anchorage: Muscle attachment for movement
  • Mineral Storage: Primarily calcium and phosphate for bone strength and bodily functions
  • Blood Cell Formation: Hematopoiesis occurs in red marrow of spongy bone
  • Fat Storage: Yellow marrow stores fat
  • Hormone Production: Osteocalcin regulates blood glucose levels

Skeleton Structure

  • Axial vs. Appendicular Skeleton
  • Bone Types:
    • Long bones
    • Short bones
    • Flat bones
    • Irregular bones
  • Sesamoid Bones: Increase joint strength (e.g., patella)

Bone Tissue Types

  • Compact Bone: Dense with osteons as functional units
  • Spongy Bone: Trabeculae, less dense, found in the interior of bones
  • Diploe: Term for spongy bone in flat bones

Bone Anatomy

  • Structure of Long Bones:
    • Diaphysis (shaft)
    • Epiphysis (ends)
    • Medullary cavity (yellow marrow)
    • Articular cartilage (joint surfaces)

Microscopic Anatomy of Bone

  • Types of Cells:
    • Osteogenic cells (stem cells)
    • Osteoblasts (bone-forming)
    • Osteocytes (mature bone)
    • Osteoclasts (bone-resorbing)
  • Bone Matrix Composition:
    • Organic components (collagen, ground substance)
    • Inorganic components (hydroxyapatites, calcium phosphate)

Bone Health and Disorders

  • Osteoporosis results from inadequate calcium deposits in bones leading to brittle, porous structures
  • Weight-bearing exercises help strengthen bones

Conclusion

  • Understanding bone structure and function is critical for learning about the skeletal system in health and disease.