Skeletal System

• What are the primary components of the skeletal system?

  Bones, cartilage, and ligaments
• What are the five primary functions of the skeletal system?

  • Support and attachment of soft tissues & organs
  • Storage of minerals & lipids (e.g., Ca, lipids in yellow bone marrow)
  • Blood cell production (e.g., RBC, WBC in red bone marrow)
  • Protection of vital organs (e.g., brain, spinal cord)
  • Leverage to alter forces produced by skeletal muscles
• What shape are long bones and where are they located?

  Long and slender; located in the upper arm, forearm, thigh, lower leg, hands, and feet
• What is the appearance of short bones?

  Box-like in appearance; examples include carpal and tarsal bones

  
• What is the function of flat bones?

  Protection for underlying soft tissues and attachment of muscles
• What are irregular bones and where can they be found?

  Complex shapes with short, flat, notched, or ridged surfaces; found in vertebrae, pelvis, and several skull bones

  
• What is the composition of the bone matrix?

  • Dense matrix containing calcium deposits
  • $Ca_3(PO_4)_2$ makes up 2/3 of bone weight
  • Interacts with $Ca(OH)_2$ to form hydroxyapatite crystals
  • Collagen fibers make up 1/3 of bone weight
  • Periosteum covers the outer surface of bones
• What are osteocytes?

  Mature bone cells that occupy a lacuna and do not divide
• What is the function of canaliculi in bone tissue?

  They form a network for the exchange of nutrients and waste products
• What do osteoblasts do?

  They produce new bone matrix through ossification or osteogenesis
• What are osteogenic cells?

  Progenitor cells that divide to produce osteoblasts

  
• What is the role of osteoclasts?

  They absorb and remove bone matrix and regulate calcium and phosphate concentrations

  
• How does the skeleton function as a calcium reserve?

  • Important for intracellular activities of neurons and muscle cells
  • Maintains calcium homeostasis through parathyroid hormone and calcitonin
  • Related conditions: Osteopaenia and Osteoporosis
• What are the stages of fracture repair?

  1. Haematoma formation: Closes off injured vessels and produces a fibrous meshwork
  2. Callus formation: Internal and external callus stabilize the fracture
  3. Spongy bone formation: Osteoblasts replace callus with spongy bone
  4. Compact bone formation: Fracture area is remodeled by osteoblasts and osteoclasts

  
• How many bones are in the axial skeleton?

  80 bones

  
• What bones are included in the skull?

  8 cranial bones and 14 facial bones
• What is the function of the axial skeleton?

  It supports and protects the brain, spinal cord, and thoracic and abdominal organs
• What are sinuses and their functions?

  Air-filled chambers that lessen bone weight, produce mucus, and serve as resonating chambers in speech
• How many bones are in the appendicular skeleton?

  126 bones

  
• What are the types of joints and their movement capabilities?

  • Immoveable: Sutures of the skull
  • Slightly moveable: Bones connected by ligaments
  • Freely moveable: Synovial joints at the ends of long bones

  
• What are the components of synovial joints?

  • Joint capsule surrounds the joint
  • Synovial membrane and articular cartilage
  • Synovial fluid acts as lubricant and shock absorber
  • Accessory ligaments support the joint
  • Bursa reduce friction

  
• What are the types of synovial joints?

  • Gliding/plane: Slight movement (e.g., sacroiliac joint)
  • Hinge: Motion in a single plane (e.g., elbow, knee)
  • Condylar: Oval face in a depression (e.g., radiocarpal joint)
  • Saddle: Complex faces fit together (e.g., carpometacarpal joint of thumb)
  • Pivot: Permits rotation (e.g., atlantoaxial joint)
  • Ball & socket: Rotation (e.g., shoulder, hip joint)

  
• What are the degenerative changes to joints?

  • Arthritis: Joint inflammation
  • Osteoarthritis: Cumulative wear and tear
  • Rheumatoid arthritis: Autoimmune disease

  
• What is the role of ligaments?

  • Connect bones to other bones
  • Stabilize joints and limit movements
  • Viscoelastic properties allow gradual strain and return to original shape
• What are tendons and their function?

  • Connect muscle to bone
  • Capable of withstanding tension
  • Composed of Type 1 collagen
• What is the recommended additional reading for this topic?

  Martini 11th edn. Chapters 6-9