Chemical Control of Respiration


During tissue metabolism, Carbon Dioxide[c02] and Water [h2o] are produced


In the presence of a substance called Carbonic Anhydrase, they are converted to Carbonic acid [h2co3]=co2 + h2o = h2co3


Carbonic acid quickly breaks down into Hydrogen ions and Bicarbonate ions co2 + h2o = h2co3 which breaks down to [h+]+[hc0-3.


Any increase in co2= an increase in h


Homeostasis- = The respiratory system tries to maintain proper levels of Carbon Dioxide and oxygen and are also extremely sensitive any changes.


The normal Partial pressure of oxygen in arterial blood is105 mmhg


Receptors = There are receptors located within the Medulla which is the central Chemosensative area and they monitor any changes in the Hydrogen ion concentrations in the blood


Within the Carotid and Aortic bodies are the Peripheral Chemoreceptors and they are sensitive to any changes in Hydrogen ions, Carbon Dioxide and oxygen levels in the blood


An increase in the Carbon Dioxide level [called Hypercapnia] stimulates the Central Chemosensative area and the Peripheral Chemoreceptors which send impulses to the Inspiratory area to increase the rate and depth of breathing. This is called Hyperventilation, and will normally eliminate Carbon Dioxide and return the Partial pressure of Carbon Dioxide and Hydrogen ions to their normal levels


A fall in the Partial pressure of Carbon Dioxide will not affect the breathing and does not stimulate the receptors. The breathing remains the same until normal levels are attained.


Home page