| Dictionary, Encyclopedia and Thesaurus - The Free Dictionary 3,918,147,433 visitors served. |
Dictionary/ thesaurus | Medical dictionary | Legal dictionary | Financial dictionary | Acronyms | Idioms | Encyclopedia | Wikipedia encyclopedia | ? |
Sphincter |
Also found in: Dictionary/thesaurus, Medical, Wikipedia | 0.01 sec. |
|
|
sphincter
Anatomy a ring of muscle surrounding the opening of a hollow organ or body and contracting to close it sphincter [′sfiŋk·tər] (anatomy) A muscle that surrounds and functions to close an orifice. Sphincter a ringlike muscle that constricts to close a natural orifice such as the oral or anal opening, or to narrow the passage from one part of a hollow tubular organ to another, for example, from the stomach and bile duct to the duodenum and from the bladder to the urethra. The sphincter is always in a tonic state. The orbicular muscle of the iris is a sphincter. Some sphincters consist of striated muscle and others of smooth muscle innervated by the autonomic nervous system. Want to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit the webmaster's page for free fun content. |
|
| Encyclopedia |
| Free Tools: |
For surfers:
Free toolbar & extensions |
Word of the Day |
Help
For webmasters: Free content | Linking | Lookup box | Double-click lookup |
|---|