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

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

These are symptoms linked to changes in blood vessels that supply blood as a result of contraction or relaxation of the smooth muscles that line the walls of the vessels. —Joy Emeh, Health, 18 July 2024

To stretch that far, the smooth muscle wall that wraps around the bladder, called the detrusor, must relax. —Emily Underwood, Smithsonian Magazine, 5 June 2024

The receptors control constriction and dilation in the smooth muscle fibers in the walls of these blood vessels. —Kristen Rogers, CNN, 21 Mar. 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