An essay on the mechanism of breathing and its control The basic mechanisms involved in inspiration and expiration are as follows; 1)Inspiration The contraction of the diaphragm and external intercostals muscles leading to an expansion of the lungs. This expansion means there is an increase in the volume of the thorax and a decrease in intrapulmonary pressure. A pressure gradient is therefore established from the atmosphere to alveoli, hence air being suck into the lower …showed first 75 words of 1100 total…

…showed last 75 words of 1100 total…ventilation work antagonistically. Stimulation of the heart by the sympathetic system increases the heart rate, but stimulation by the parasympathetic system decreases the rate. The two centres located in the pons involved in the control of ventilation also work antagonistically; the apneustic area capable of activating the inspiratory centre and prolonging its action, and the pneumotaxic area, acting on the inspiratory centre to turn it off when the lungs become overstretched or full of air.