Dome-shaped muscular membranous partition separating the thoracic cavity from the abdominal cavity in mammals.
Note: The diaphragm plays a major role in breathing, as its contraction increases the volume of the thorax and so inflates the lungs.
Source:
PAC, 2016, 88, 713. 'Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)' on page 744 (https://doi.org/10.1515/pac-2015-1202)