Question

If breathing rate increases, what happens to pH.

What causes respiratory acidosis and alkalosis.

Answer 1

1. The lungs are important regulators of blood pH because they excrete carbon dioxide (CO2).Carbon dioxide increases in H+ in body fluids because it combines with water to form carbonic acid, which then dissociates into a bicarbonate ion and a hydrogen ion. The lungs, therefore, help to control blood pH by regulating levels of excreted CO2. The brain detects rising H+ in the blood and stimulates breathing, causing increased CO2 loss and a fall in H+. Conversely, if blood pH becomes too alkaline, the brain can reduce the respiration rate to increase CO2 levels and increase H+, restoring pH towards normal.

2. Acidosis and alkalosis are both dangerous, particularly to the central nervous system and the cardiovascular system. In practice, acidotic conditions are commoner than alkalotic ones, because the body tends to produce more acid than alkali. Acidosis may follow respiratory problems, if the lungs are not excreting CO2 as efficiently as normal, or if the body is producing excess acids (e.g. Diabetic Ketoacidosis) or in kidney disease, if renal H+ excretion is reduced.

On the other hand Alkalosis may be caused by loss of acidic substance through vomiting, diarrhoea, endocrine disorders or diuretic therapy, which stimulates increased renal excretion. Rarely, it may follow increased respiratory effort, such as in an acute anxiety attack where excessive amounts of CO2 are lost through overbreathing (hyperventilation).