Explain the Diaphragm
The diaphragm is a muscular membranous partition separating the abdominal and thoracic cavities and functioning in respiration. It consists of a central tendon from which the muscle fibres radiate.
When the diaphragm contracts, its muscle fibres shorten and the central tendon is pulled downwards. Thus, the thoracic cavity is enlarged in length. The diaphragm is supplied by phrenic nerves. Phrenic nerves are a pair of nerves that arises from cervical spinal roots and passes down the thorax to innervate the diaphragm and control breathing.
The muscles of the diaphragm and the intercostal muscles contract simultaneously. Thus, the thoracic cavity is enlarged in all directions (antero-postenor and vertical). Next, let us study about the third set of muscles involved in respiration, i.e., abductor muscles.