smooth muscle

noun

: muscle tissue that lacks cross striations, is made up of elongated spindle-shaped cells having a central nucleus, and is found especially in vertebrate hollow organs and structures (such as the digestive tract and bladder) as thin sheets performing functions not subject to direct voluntary control and in all or most of the musculature of invertebrates other than arthropods compare striated muscle

Examples of smooth muscle in a Sentence

Recent Examples on the Web

The fluid moves because of the micro-contractions of smooth muscle between lymphatic nodes. —Matt Benoit, Discover Magazine, 6 Dec. 2024

Usually, when food enters your stomach, smooth muscle tissues in the gallbladder contract to push bile out of your gallbladder and into the small intestine, helping digest fat. —Lindsay Curtis, Health, 1 Oct. 2024

When activated, these receptors relax the smooth muscles of the bladder. —Matthew Wosnitzer, Verywell Health, 23 Sep. 2024

Her uterus was riddled with fibroids, benign tumors consisting of smooth muscle that were both inside and outside the lining of her uterus. —Ed Stannard, Hartford Courant, 26 July 2024

Word History

First Known Use

circa 1890, in the meaning defined above

Kids Definition

smooth muscle

noun

: muscle that is made up of long thin cells with a single nucleus and no cross stripes, that is found especially in hollow organs and parts (as the bladder and blood vessels), and that is not under voluntary control

called also involuntary muscle

compare striated muscle

Medical Definition

smooth muscle

noun

: muscle tissue that lacks cross striations, that is made up of elongated spindle-shaped cells having a central nucleus, and that is found especially in vertebrate hollow organs and structures (as the small intestine and bladder) as thin sheets performing functions not subject to direct voluntary control and in all or most of the musculature of invertebrates other than arthropods

called also nonstriated muscle, unstriated muscle

compare cardiac muscle, striated muscle