Muscle Physiology: Types, Contractions, and Mechanisms

These flashcards cover the different types of muscle fibers, their functions, and the processes involved in muscle contraction.

Type 1 Muscle Fiber

Slow Twitch or Slow Oxidative (SO) muscle fiber, primarily uses aerobic respiration.

Type 2A Muscle Fiber

Fast Twitch or Fast Oxidative (FO) muscle fiber, can switch to anaerobic respiration.

Type 2B Muscle Fiber

Fast Twitch or Fast Glycolytic (FG) muscle fiber, primarily uses anaerobic glycolysis.

Multiunit Smooth Muscle

Unorganized cells that contract as individual cells, located in the iris of the eye and walls of blood vessels.

Visceral Smooth Muscle

Forms sheets of muscle, where cells are connected by gap junctions and contract as a group.

Calmodulin

A calcium-binding messenger protein that activates myosin light chain kinase in smooth muscle contraction.

Skeletal Muscle Contraction Process

Involves the arrival of action potential at the axon terminal and the release of ACh, which prompts the opening of Na+ and K+ channels.

Excitation-Contraction Coupling

The process by which an action potential leads to muscle contraction by causing Ca2+ release from the sarcoplasmic reticulum.

Sliding Filament Theory

Describes how myosin heads bind to actin to perform a power stroke, resulting in muscle fiber contraction.

Power Stroke

The action in which the myosin head pulls the actin filament during muscle contraction after forming a cross bridge.