Muscular Function Overview

Vocabulary flashcards related to muscular functions and mechanics.

Motor Units

Functional groupings of muscle fibers innervated by a single motor neuron.

All-or-None Principle

The principle stating that if a motor neuron fires, all muscle fibers in that motor unit contract fully.

Hypertrophy

An increase in muscle size due to an increase in the size of existing muscle fibers.

Atrophy

A decrease in muscle size, typically due to disuse or immobilization.

Isometric Contraction

A type of muscle contraction where the muscle maintains the same length while contracting.

Isotonic Contraction

A type of muscle contraction that produces movement; it can be either concentric or eccentric.

Sliding Filament Theory

The theory explaining muscle contraction based on the sliding movement of actin and myosin filaments.

Type I Muscle Fibers

Slow-twitch muscle fibers that are fatigue-resistant and ideal for endurance activities.

Type II Muscle Fibers

Fast-twitch muscle fibers that are used for power and explosive movements.

Calcium Ions

Essential for muscle contraction; they bind to troponin to expose binding sites on actin.

Agonist

The muscle that contracts to produce a movement.

Antagonist

The muscle that opposes the action of the agonist and can slow or control the movement.

Synergist

A muscle that assists the agonist in performing a movement.

Fixator

A muscle that stabilizes one part of the body while another part moves.

Cross-Bridge Cycle

The cyclical process of myosin heads attaching to actin, tilting, and pulling to produce muscle contraction.

Excitation-Contraction Coupling

The process by which a nerve impulse leads to muscle contraction.