muscler system

Myosin

Thick myofilaments involved in muscle contraction.

Actin myofilaments

Thin myofilaments composed of actin and accessory proteins, containing active sites for attachment.

Sarcomere

The functional unit of muscle fibers, composed of myofilaments organized into repeating sections.

Sliding Filament Model

Theory explaining muscle contraction in which myosin filaments slide past actin filaments.

Action potential

A temporary change in the membrane potential that propagates along the muscle fiber, leading to contraction.

Neuromuscular Junction

The synapse between a motor neuron and a muscle fiber where nerve impulses trigger muscle contraction.

Excitation-Contraction Coupling

The physiological process of converting an electrical stimulus into a mechanical response in muscle fibers.

Relaxation

The process where muscles return to their resting state, requiring ATP for detaching myosin heads and pumping calcium back.

Motor Units

A single motor neuron and the muscle fibers it innervates, involved in muscle contraction and force generation.

All-or-None Law

Principle stating that a muscle fiber will contract fully or not at all in response to a stimulus.

Tetanus

Sustained muscle contraction resulting from rapid stimulation, can be fused or unfused.

Isometric Contraction

Muscle contraction where the length remains the same while tension increases.

Isotonic Contraction

Muscle contraction where the muscle changes length while maintaining constant tension.

Fast glycolytic (FG) fibers

White muscle fibers that are fast, powerful, and fatigue easily.

Curare

A paralytic toxin that blocks acetylcholine receptors, preventing muscle contraction.

Rigor Mortis

Stiffness of muscles post-death due to ATP depletion.

Agonist/prime mover

Muscle that provides the primary force for a specific movement.

Tendons

Connect muscle to bone.

Muscle Fiber Types

Include slow oxidative (SO), fast oxidative glycolytic (FOG), and fast glycolytic (FG) fibers, characterized by endurance and power.

Muscle Tone

State of partial contraction in a muscle, can be hypotonia (low) or hypertonia (high).