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The Musculoskeletal System - Coggle Diagram
The Musculoskeletal System
Organization
Axial Skeleton
Skull, Vertebral Column, Ribs, Sternum
Function: Protection and Posture
Appendicular Skeleton
Upper & Lower Extremities, Shoulder/Pelvic Girdles
Function: Movement and Locomotion
Interconnecting Tissues
Tendons (Muscle to Bone)
Ligaments (Bone to Bone)
Bones (Osteology)
Types by Shape
Long Bones (e.g., Femur, Humerus) - Weight-bearing & levers
Short Bones (e.g., Carpals, Tarsals) - Stability & limited movement
Flat Bones (e.g., Sternum, Skull) - Protection & muscle attachment
Irregular Bones (e.g., Vertebrae) - Complex shapes
Sesamoid Bones (e.g., Patella) - Reduce friction in tendons
Substantial Components
Inorganic Matrix (65%)
Hydroxyapatite (Calcium Phosphate crystals)
Function: Hardness and compressional strength
Organic Matrix (35%)
Osteoid (Type I Collagen fibers)
Function: Flexibility and tensile strength
Bone Cells
Osteoblasts (Bone-forming)
Osteocytes (Mature bone maintenance)
Osteoclasts (Bone resorption/breakdown)
Role of Calcium
Binds with phosphate to form Hydroxyapatite
Mineralization/Calcification process
Converts soft osteoid into rigid, solid bone structure
Joints (Arthrology)
Synovial Joint Components
Articular (Hyaline) Cartilage: Shock absorption, reduces friction
Articular Capsule: Fibrous outer layer & Synovial membrane
Synovial Fluid: Lubrication and cartilage nutrition
Supporting Structures: Ligaments, Menisci, Bursae
Types by Shape & Movement
Hinge (Uniaxial): Flexion/Extension (e.g., Elbow / Biceps & Triceps)
Pivot (Uniaxial): Rotation (e.g., Atlantoaxial / SCM muscle)
Ball-and-Socket (Triaxial): All movements (e.g., Shoulder / Deltoid & Rotator Cuff)
Saddle (Biaxial): Flex/Ext, Abd/Add (e.g., Thumb CMC / Opponens pollicis)
Condyloid (Biaxial): Oval in depression (e.g., Wrist / Flexor carpi radialis)
Planar: Gliding movements (e.g., Intercarpal joints)
Skeletal Muscles (Myology)
Structural Hierarchy
Epimysium (Wraps entire muscle)
Perimysium (Wraps Fascicles / muscle fiber bundles)
Endomysium (Wraps individual Muscle Fibers / cells)
Myofibrils (Intracellular cylindrical structures)
Sarcomere (Functional contractile unit from Z-line to Z-line)
Thick Filaments (Myosin)
Thin Filaments (Actin, Troponin, Tropomyosin)
Excitation-Contraction Coupling (Mechanism)
Excitation: ACh released at Neuromuscular Junction, depolarizes sarcolemma
Propagation: Action potential travels down T-tubules
Calcium Release: Sarcoplasmic Reticulum releases Ca2+ into sarcoplasm
Binding: Ca2+ binds to Troponin-C, moving Tropomyosin away from Actin binding sites
Cross-Bridge Cycle: Myosin heads bind to Actin, execute power stroke (requires ATP)
Relaxation: Ca2+ pumped back into SR (SERCA pump), Tropomyosin covers sites
Energy Sources
Creatine Phosphate: Direct phosphorylation, ultra-fast, lasts ~15 seconds
Anaerobic Glycolysis: No oxygen, produces lactic acid, fast, lasts ~2 minutes
Aerobic Respiration: Requires oxygen, highly efficient (32-36 ATP), sustains prolonged activity
Adaptation
Hypertrophy: Increase in muscle mass/fiber diameter (more actin & myosin) due to mechanical overload
Atrophy: Decrease in muscle mass/fiber diameter due to disuse (bedrest/casting) or denervation (nerve damage)
Chaidir Akbar Nugroho - 2606777515