What are the four fundamental properties of muscle tissue?

• A. Excitability, Contractility, Extensibility, Elasticity
• B. Conductivity, Permeability, Mobility, Plasticity
• C. Viscosity, Rigidity, Elasticity, Ductility
• D. Absorption, Secretion, Metabolism, Growth

Answer: (A)

Muscle tissue is defined by its ability to respond to signals and to generate movement. The four properties that make this possible are excitability, contractility, extensibility, and elasticity. Excitability means muscle fibers respond to nerve or hormonal signals with changes in membrane potential, which starts the process that leads to contraction. Contractility is the ability to shorten actively, producing force and movement. Extensibility allows muscles to be stretched beyond their resting length when necessary, such as when opposing muscles pull. Elasticity is the tendency to recoil back to the original length after being stretched, helping restore proper length after movement or stretch. Other terms like conductivity, permeability, or viscosity don’t capture these functional capabilities of muscle tissue, and terms such as rigidity or plasticity describe material properties that don’t reflect how muscles operate in the body.