Skeletal

• Skeleton split into 2 parts:

  Appendicular- Associated with movement + a lot of flexibility in joints

  Axial- Associated with stability and protection
• Function of skeletal system:

  1. Support
  2. Protection
  3. Movement
  4. Storage of minerals
  5. Production of blood cells
• Different parts of long bone:

  • Diaphysis
  • Metaphysis
  • Epiphysis
  • Articular cartilage
  • Medullary cavity (Bone marrow, fat, blood cells)
  • Spongy bone
  • Compact bone
  • Periosteum
• Diaphysis: The shaft of a long bone, which is the part that extends from epiphysis to epiphysis (Middle). Only has compact bone
• Metaphysis: Where Epiphysis meets diaphysis, contains the growth plate during childhood
• Epiphysis: the end part of a long bone that is wider (Increased SA) to spread the weight. Mainly spongy bone with a thin layer of compact bone
• Articular cartilage: Protects the bone, provides cushioning, and reduces friction between bones.
• Medullary cavity: Where bone marrow is found, includes fat and blood cells
• Spongy bone: Inside bone, much lighter than compact bone, honeycomb arrangement
• Compact bone: Outer surfaces, thickest in diaphysis, heavier than spongy bone, made up of osteons
• Periosteum: Attaches tendons to ligaments, cells that turn to bone which is important to heal fractures
• Compact and spongy bone are both made up of ECM and cells but are arranged differently.

  ECM- Collagen and hydroxyapatite
• Four different types of bone cells:

  • Osteogenic
  • Osteoblast
  • Osteocyte
  • Osteoclast
• Osteogenic cells: Creates new bone cells and develops into osteoblasts
• Osteoblast cells: Makes new bone (Secretes collagen needed to make the new bone) Once it's wrapped in all the collagen it turns into osteocytes
• Osteocyte: Maintains bone, located inside the bone matrix and signals to the other 3 (Osteos) whether to create, make, or resorb bone
• Osteoclast: Resorbs (eats away) bone and is found on surfaces but more so internal
• 3 types of joint classifications:

  Axial

  • Fibrous (Fibula-Tibia) Very little movement
  • Cartilaginous (Rib-sternum) Slightly more movement

  Appendicular

  • Synovial Free moveable
• Joints are found where two or more bones join together to allow movement
• Synovial joints have 4 basic features:

  • Joint space (To move)
  • Joint capsule (Connect the joints)
  • Articular cartilage (Cushion and reduce friction between joints)
  • Synovial fluid (Lubrication for joints)
• Osteoporosis (Brittle bones): A condition when more bone is being removed than being made
• Osteoarthritis: When there is no space between joints
• Appositional growth: growth of bone tissue in response to mechanical stress. (Increase of bone tissue as we grow)