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

Through a series of experiments, Dr. Murad discovered that nitroglycerin releases nitric oxide, which relaxes smooth muscle cells. —Michael S. Rosenwald, Washington Post, 11 Sep. 2023

Red Boost claims to optimize smooth muscle, allowing blood to flow into erectile tissue and remain firmly trapped there. —Jon Goodwin, Discover Magazine, 30 Dec. 2022

This dysfunction can cause major problems, such as in the esophagus, where the smooth muscles that line the organ don’t contract and move food effectively. —Rachael Zimlich, Bsn, Rn, Verywell Health, 13 July 2023

Horny Goat Weed, on the other hand, is said to contain a compound that supports the relaxation of smooth muscles, which may help increase blood flow and subsequently improve erectile dysfunction. —Amber Smith, Discover Magazine, 11 June 2023

The hormones have a similar effect on other smooth muscles in your body, like in your bowels. —Korin Miller, Health, 13 July 2023

For example, in addition to endothelial cells, Tian’s team tried the experiment in smooth muscle cells, neurons and cardiac cells. —IEEE Spectrum, 19 Dec. 2016

Movement of the third eyelid in cats is also partially regulated by the sympathetic nervous system and by smooth muscle cells within the third eyelid. —Paul Miller, Scientific American, 1 Sep. 2015

There are three main types of muscle tissue: smooth muscle lines the gut wall and organs, except the heart; cardiac muscle is striated and covers the heart; and skeletal muscle, which can be found in the arms and legs, is also striated. —Lauren J. Young, Scientific American, 2 July 2023

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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