Characteristics of Skeletal Muscle

CHARACTERISTICS OF SKELETAL MUSCLE

Skeletal muscle, with its associated connective tissue, constitutesapproximately 40% of body weight. Skeletal muscle is so named because most of the muscles are attached to the skeletal system. It is also called striated muscle because transverse bands, or striations, can be seen in the muscle under the microscope.

  Skeletal muscle has four major functional characteristics: contractility, excitability, extensibility, and elasticity.

1.Contractility (kon-trak-til′ i-tē) is the ability of skeletal muscle to shorten with force. When skeletal muscles contract, they cause the structures to which they are attached to move. Skeletal muscles shorten forcefully during contraction, but they lengthen passively. Either gravity or the contraction of an opposing muscle produces a force that pulls on theshortened muscle, causing it to lengthen.

2.Excitability (ek-sı̄′tă-bil′i-tē) is the capacity of skeletalmuscle to respond to a stimulus. Normally, the stimulus is from nerves that we consciously control.

3.Extensibility (eks-ten′sı̆-bil′i-tē) means that skeletal muscles stretch. After a contraction, skeletal muscles can be stretchedto their normal resting length and beyond to a limited degree.

4.Elasticity (ĕ-las-tis′i-tē) is the ability of skeletal musclesto recoil to their original resting length after they have been stretched.