Musculoskeletal Anatomy Key Term Review
|
Key Term |
Definition |
|
myofiber |
single muscle cell |
|
myofibril |
myofiber contractile units |
|
sarcomere |
a single contractile unit |
|
motor unit |
one neuron and the muscle fibers it innervates |
|
Type I |
Slow-twitch; dominant fiber type for endurance/posture; |
|
Type II |
Fast-twitch; dominant fiber type for agility, quick actions |
|
neutralizers |
muscles that function to maintain motion within a target plane of motion |
|
stabilizers |
muscles that function to provide support a region while another area moves |
|
fascia |
loose, ubiquitous connective tissue |
|
tendon |
thick connective tissue that attaches muscle to bone. Myotendinous junction (where muscle connects to tendon) is the most common site of muscle strain |
|
ligaments |
thick connective tissue that connects bones across joints; contributes to proprioception and pain perception |
|
articular cartilage |
avascular viscoelastic material that provide a smooth frictionless surface for joint motion |
|
fibrocartilage |
blend of fibrous and cartilaginous tissue that provides flexibility, toughness, and elasticity |
- Major contractile proteins in myofibrils are actin and myosin
- Concentric muscle contraction (shortening) relies on ATP as its energy source to catalyze the myosin head bond to actin filaments.
- Eccentric contraction involves the physical "breaking" of cross links between actin and myosin due to an applied load.
- Hundreds of thousands of myofibrils use energy and interactions between actin and myosin to produce a shortening contraction resulting in isometric, single joint, or functional movement.
- Muscle function and training will determine the efficiency and effectiveness of Type I and Type II fibers.
