Particularities of the diaphragmatic muscle cell

The diaphragm is the main inspiratory muscle, accounting for more than 50% of the tidal volume during quiet breathing. It works continuously, contract ing rhythmically and generally at a law intensity. In this respect, it is c lose to the myocardium, being the only vital skeletal muscle. Front a gener al point of view, functional and biochemical characteristics of the diaphra gm are similar to those of other skeletal muscles with a similar fiber type composition. However, the diaphragm presents some specificities allowing a high supply of metabolic substrates. This could serve To presence contract ile function in different physiological and physiopathological situations. Such specificities concern muscular vascularization, the microvascular netw ork and the content of mitochondria and myoglobin. These characteristics ar e detailed and compared to those of other striated muscles.