Proteins → amino acids→ sulphate, urea + H +Īcids can be divided into two groups: (1) volatile acids (respiratory acids), (2) non-volatile acids (metabolic acids). Triacylglycerol → fatty acids, ketone bodies + H + Organism is acidified by these processes: 1) Complete oxidationĬarbon skeleton → CO 2 + H 2O → HCO 3 – + H + 2) Incomplete oxidationĬarbohydrates → glucose → pyruvate, lactate + H + Human organism (healthy or not) every day produces great quantities of acids – source of protons. Examples follow: 1) Proton-productive reactionsĪ) Anaerobic glycolysis in muscles and erythrocytesī) Ketogenesis – production of ketone bodiesĬO 2 + 2 NH + 4 → urea + H 2O + 2 H + 2) Proton-consumptive reactionsī) Neutral and dicarboxylic amino acids oxidation 3) Proton-neutral reactions (1) proton-productive, (2) proton-consumptive, (3) proton-neutral. Three types of reactions can be distinguished from point of view of the acid-base balance. lactate to glucose in gluconeogenesis, lactate to pyruvate and oxidation in cardiomyocytes), or (2) excretion from body. Source of acids in the body is chiefly metabolism, source of bases is predominantly nutrient.Īcids and bases undergo either (1) metabolic conversion (e.g. Base is au contraire molecule that can cleave off OH – (Arrhenius) or acceptor of H + (Brönsted). Acids and bases in the bodyĪcid is defined as molecule that can cleave off H + (Arrhenius) or donor of H + (Brönsted). Therefore it is not surprising that venous pH and pH of interstitial fluid is lower (i.e. This concentration gradient drives the movement of H + from cells to blood. This corresponds to fact that there is 2,5 fold difference between intracellular and arterial H + concentration. Intracellular pH compared to arterial pH gives difference 0,4. There is quite variable and lower pH value intracellular, it is about 7,0 ( = 100 nmol/l). Values differ in different body compartments hence there are different H + concentrations. Values mentioned above apply for arterial blood. lower than 6,8 are incompatible with life. Value of pH in arterial blood higher than 7,8, resp. enzymes), membranes permeability, and electrolyte distribution. For example change of protein structure (i.e. Extensive deviations of pH value can cause serious consequences. Value of pH higher than 7,44 in arteries is denoted as alkalemia, pH lower than 7,36 is acidemia. Physiologic range of the pH is 7,36-7,44. pH could be easily calculated as follows: = 140 mmol/l or = 25 mmol/l, are three orders of magnitude higher). There is 40 nmol/l of protons in the arterial blood physiologically (note that concentrations of other plasma ions, e.g. Plasma and extracellular space concentrations of the protons are held in very narrow physiologic range. pH is used for express concentration of the protons: Maintaining of constant proton (H +) concentration is isohydria. Maintaining of stable anion and cation concentrations in blood plasma is denoted as isoionia. In Subchapter 7/6 is pointed out that maintenance of stable pH, also called isohydria, is one of the basic components of the internal environment: (1) isohydria, (2) isovolumia (stable volume), (3) isoosmolarity (stable tonicity), and (4) isoionia (stable ion composition). Maintenance of the internal environment is one of the vital functions (it has same importance as circulation or respiration). Basic disorders of the acid-base balance and means of compensation Laboratory tests of the acid-base balance status 4. Systems responsible for the maintenance of the acid-base balance 3.
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