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• Skeletal system


  System that includes bones and connective tissue like ligaments, tendons, and cartilage
• The human skeletal system has an important job of supporting the body, protecting organs, storing minerals, and enabling movement
• Axial skeleton


  Includes the bones in the skull, ears, throat, vertebral column, and ribcage
• Appendicular skeleton


  Includes the bones of the arms, shoulder girdle, legs, and pelvic girdle
• Types of bones by shape

  • Long bones
  • Short bones
  • Sesamoid bones
  • Flat bones
  • Irregular bones
• Compact bone tissue


  • Hard outer layer
  • Contains spongy bone tissue and bone marrow
• Osteoblasts


  Cells that make bone
• Osteocytes


  Cells that maintain bone structure
• Osteoclasts


  Cells that break down bone structure using lysosomes and acids
• Bone remodeling occurs where old bone is removed and new bone is rebuilt, with 5-10% of the skeleton remodeled each year
• Bones store minerals like calcium, which is important for processes like muscle contraction
• Chondroblasts


  Cells that make cartilage
• Chondrocytes


  Cells that maintain cartilage
• Bone fracture healing


  1. Fracture hematoma forms

  2. Internal and external callus forms

  3. Osteoclasts remove damaged bone

  4. Osteoblasts rebuild new bone
• Fractures can take 6-8 weeks to heal, depending on the type of fracture and other variables
• Severe bone fractures can lead to fat embolism syndrome, which requires emergency care
• Osteogenesis imperfecta


  Genetic disorder that affects collagen production, leading to brittle bones