endocardium
/ˌɛndoʊˈkɑrdiəm/
noun
- The thin, smooth membrane that lines the inside of the heart chambers and covers the heart valves.
- The doctor explained that the endocardium is only one cell layer thick.
- An infection of the endocardium is called endocarditis.
- The endocardium helps blood flow smoothly through the heart.