Breath Control

Control of breathing is quite complex And if you really check the specs You find all kinds of balances and checks Within the medulla, cells playing their role The DRG, inspirational control Using cyclic neurons for their goal. Actions potentials from the DRG These cells are cyclic and fire intermittently. Then muscle contract to the best of their ability. To the external intercostals and diaphragm they talk And these muscles, at the neurons’ stalk Follow orders and they do not balk. And when they stop, the muscles relax. Air is forced out as muscle slacks. Volume decreases and Boyle’s Law acts. So breathing in costs ATP That means the use of energy But calm expiration? It’s just free. But when you need to force air out Or at something, really shout The VRG is what it’s all about. It talks to abdominal muscles as well As internal intercostals to make pressure swell And air in the lungs can no longer dwell. The Apneustic center in the pons is a source Of a center dealing with force Of an inspiration’s course. The pneumotaxic center deals with duration And both centers talk to each medullary station And help regulate breathing condition. The limbic system has some sway In breathing fast or slow at bay More than most realize, an important say. And the hypothalamus, always of import With its influence never falls short In aiding ventilation, it lends its support. For other than limbic, it deals with fever When it tips the temperature lever And makes ventilation a greater achiever. Lastly there’s the cortex of the brain, Whose job most think, is always to reign. But when it comes to breathing, it is quite plain. You can’t stop breathing by your will. The lower centers always still Make breathing a reflex, cortex input almost nil. And just what drives this reflex to ventilate? From where does the need originate? From the chemoreceptors, it does emanate. Receptors monitoring proton concentration. Then messages sent without cessation To the brainstem for increasing ventilation. And hydrogen ions, where are they from? Carbon dioxide and water, voila, they come. The magic formula, carbonic acid does succumb.