Which term describes the ability of a muscle to shorten forcibly when stimulated?

Which term describes the ability of a muscle to shorten forcibly when stimulated?

• A. Excitability
• B. Contractility
• C. Extensibility
• D. Elasticity

Answer: (B)

Contractility is the ability of a muscle to actively shorten when it’s stimulated. In skeletal muscles, a motor neuron triggers Ca2+ release, enabling myosin heads to grab actin and perform cross-bridge cycling with energy from ATP. As these interactions continue, the sarcomeres shorten, pulling the muscle ends closer together to produce movement. This active shortening is different from excitability (responding to a stimulus), extensibility (being stretched), and elasticity (recoiling after stretch). During contraction you can have isotonic shortening or isometric tension, but the defining feature is the forceful, active shortening of the muscle.

Contractility is the ability of a muscle to actively shorten when it’s stimulated. In skeletal muscles, a motor neuron triggers Ca2+ release, enabling myosin heads to grab actin and perform cross-bridge cycling with energy from ATP. As these interactions continue, the sarcomeres shorten, pulling the muscle ends closer together to produce movement. This active shortening is different from excitability (responding to a stimulus), extensibility (being stretched), and elasticity (recoiling after stretch). During contraction you can have isotonic shortening or isometric tension, but the defining feature is the forceful, active shortening of the muscle.