Musculoskeletal System Lecture Notes

Overview

• Provides mechanical support and protection for the body
• Permits movement
• Composed of:
  • Bones
  • Cartilage
  • Skeletal muscles
  • Joints
  • Connective tissues (tendons and ligaments)

Functions of the Musculoskeletal Components

Bones

• Main mineral reservoir (stores and releases calcium and phosphate)
• Production center for blood cells in red bone marrow
• Act as levers for movement
• Articulate with each other via joints
• Classified by shape:
  • Long bones (movement)
  • Short bones (limited motion)
  • Flat and irregular bones (protective/supportive)

Cartilage

• Provides padding for ends of bones within joints

Connective Tissues

• Tendons: connect muscles to bones
• Ligaments: connect bones to each other

Bone Tissue

• Composed of bone cells and extracellular matrix
• Extracellular matrix:
  • Organic component: collagen (flexibility)
  • Inorganic component: minerals, primarily calcium (stiffness)

Bone Remodeling

• Continuous renewal of bone tissue
• Involves:
  • Reshaping bones
  • Repairing micro-damages and fractures
• Regulates plasma calcium and phosphate levels
• Performed by:
  • Osteoclasts (dissolve bone matrix)
  • Osteoblasts (form new bone tissue)
• Controlled by signaling pathways and hormones (e.g., parathyroid hormone, vitamin D)

Bone Diseases

Osteoporosis

• Common bone disease (loss of bone mass and strength)
• Increased risk of fractures
• Causes:
  • Age
  • Hormone imbalances
  • Deficiency in calcium, vitamin D, proteins
  • Sedentary lifestyle

Joint Types and Disorders

Synovial Joints

• Most common and movable joint type
• Features a cavity with synovial fluid (lubricant)
• Bursae: sacs with synovial fluid, cushion movements

Arthritis

• Most common joint disease
• Two main types:
  • Osteoarthritis: wear and tear, loss of cartilage, bone spurring
  • Rheumatoid arthritis: joint inflammation, immune-related

Muscular Tissue and Disorders

Muscle Structure

• Consists of elongated muscle cells (muscle fibers)
• Fibers bundled into fascicles, wrapped in connective tissue
• Connective tissue continuous with tendon

Muscle Disorders

• Commonly caused by injury or overuse
• Includes:
  • Sprains
  • Strains
  • Cramps
  • Tendonitis