The hydrogen indicator of blood and, especially, the brain is maintained at a fairly stable level, and its changes significantly affect the activity of many enzyme systems. Despite the fact that the release of acidic metabolic products into the blood varies, the slightly alkaline blood reaction characteristic of humans is maintained within narrow limits. Several mechanisms associated with the buffering properties of blood, gas exchange in the lungs, and excretory function of the kidneys are involved in the regulation of CRR.
Buffer properties are determined by the content in the blood or other liquids of bicarbonates, inorganic phosphates and proteins, which combine with an excess of acids or bases and form substances that do not affect pH.
The regulation of pH by gas exchange is as follows. Depending on the condition of the coronary artery, the respiratory cycle changes in such a way that normalization of the acid-base balance of the brain is normalized through an increase or decrease in the supply of oxygen and carbon dioxide emission. In systemic metabolic disorders, pH is well controlled by modulation of the respiratory cycle. The respiratory cycle is transformed under the influence of an extracellular concentration of hydrogen ions, which affect the chemoreceptors of the medulla oblongata . Changes occur quickly enough – in a few minutes.
The kidneys regulate ASR by increasing or decreasing the concentration of HCO 3 – and H in body fluids. Changes in pH occur slowly – over several hours or even days.
In a number of pathological conditions, such large amounts of acids or bases accumulate in the blood that the described regulatory mechanisms cannot maintain the pH at the optimal level.