PH, of blood

This difference in behavior for acetic acid in pure water versus water buffered at pH = 7 0 has some important practical consequences Biochemists usually do not talk about acetic acid (or lactic acid or salicylic acid etc) They talk about acetate (and lac tate and salicylate) Why Its because biochemists are concerned with carboxylic acids as they exist in di lute aqueous solution at what is called biological pH Biological fluids are naturally buffered The pH of blood for example is maintained at 7 2 and at this pH carboxylic acids are almost entirely converted to their carboxylate anions... 

CycHc adenosine monophosphate (cAMP), produced from ATP, is involved in a large number of ceUular reactions including glycogenolysis, Hpolysis, active transport of amino acids, and synthesis of protein (40). Inorganic phosphate ions are involved in controlling the pH of blood (41). The principal anion of interceUular fluid is HP (Pig. 3) (41). 

The pH scale is widely used in biological applications because hydrogen ion concentrations in biological fluids are very low, about 10 M or 0.0000001 M, a value more easily represented as pH 7. The pH of blood plasma, for example, is 7.4 or 0.00000004 M H. Certain disease conditions may lower the plasma pH level to 6.8 or less, a situation that may result in death. At pH 6.8, the H concentration is 0.00000016 M, four times greater than at pH 7.4. 

The relevant pAj for carbonic acid, has a value far removed from the normal pH of blood plasma (pH 7.4). (The pAlj for HgCOj at 25°C is 3.77 (Table 2.4), but at 37°C, pAli is 3.57.) At pH 7.4, the concentration of HgCOj is a minuscule fraction of the HCO3 concentration, and thus the plasma appears to be poorly protected against an influx of OH ions. 

Blood is buffered mainly by the HC03 -H2C03 buffer system. The normal pH of blood is 7.40. 

Patients who have suffered traumatic injuries must receive an immediate intravenous solution to combat the symptoms of shock and help maintain the pH of blood. 

Healthy humans do not suffer these ailments, because blood pH is tightly regulated by a pair of reactions that involve H2 CO3 and HCO3. Hydronium ions that enter the bloodstream react with hydrogen carbonate, and hydroxide anions react with carbonic acid. These reactions work together to maintain the pH of blood at HC03 + H3 0+ H2 CO3 + H2 O... 

The dye Is colorless at the pH of blood, but purple when made alkaline during the assay. 

The pH of blood is a variable, and loss of carbon dioxide and the resultant change in pH can be avoided by leaving the stopper of the blood collection tube in place during processing steps such as centrifugation and storage. 

We need to introduce a word of caution. Most modem calculators cite an answer with as many as ten significant figures, but we do not know the concentration to more than two or three significant figures. In a related way, we note how the pH of blood is routinely measured to within 0.001 of a pH unit, but most chemical applications... 

We see how the pH of blood plasma is higher than 7, so the concentration of hydroxide ions exceeds their concentration in super-pure water. We derive the generalization aqueous solutions in which the concentration of hydroxide is greater than the concentration of solvated protons have a pH higher than 7. The pH is lower than 7 if the concentration of hydroxide is less than the concentration [H30+(aq)]. 

Why does the pH of blood not alter after eating pickle ... 

While the pH of blood must be maintained within strict limits, the pH of urine can vary. The sulfur in foods, such as eggs, is oxidized in the body and excreted in the urine. Does the presence of sulfide ions in urine tend to increase or decrease the pH Explain. 

In humans, the pH of blood is held at a remarkably constant value of 7.4 0.05. hi severe diabetes, the pH can drop to pH 7.0 or below, leading to death from acidotic coma. Death may also occur at pH 7.7 or above, because the blood is unable to release CO2 into the lungs. The pH of blood is normally controlled by a buffer system, within rather narrow limits to maintain life and within even narrower limits to maintain health. 

If the pH of blood rises, [HC03 ] temporarily increases. The pH is rapidly restored when atmospheric CO2 is absorbed and converted into H2CO3. It is a reservoir of CO2 that enables the blood pH to be maintained so rigidly. This reservoir of CO2 is large and can be altered quickly via the breathing rate. 

The regulation of hematopoiesis in the bone marrow is not only controlled by the cytokine composition, the cells microenvironment and the oxygen tension, but, as shown recently [55], also by the local pH. For cells of different Hneages deviating pH optima have been described. While CFU-GM proliferate best in a pH range 7.2 - 7.4 (the normal pH of blood), for erythroid cells an optimum of pH 7.6 was found. Below an acidic pH of 6.7 no differentiation or proUferation of any hematopoietic cell was observed. Cells of the erythroid lineage are even strongly inhibited at a pH below 7.1 [56]. 

The fluorescent dye hydroxypyrenetrisulfonic acid (3.27), described in section 3.5.1.6, is used in medical monitoring devices for the pH of blood. Absorption (excitation) bands occur at 405 nm (acid form) and 475 nm (basic form) with emission (fluorescence) at 520 nm. 

One of the most important buffer systems in the human body is that which keeps the pH of blood around 7.4. If the pH of blood fall below 6.8 or above 7.8, critical problems and even death can occur. There are three primary buffer systems at work in controlling the pH of blood carbonate, phosphate, and proteins. The primary buffer system in the blood involves carbonic acid, H COj and its conjugate base bicarbonate, HCO3. Carbonic acid is a weak acid that dissociates according to the following reaction ... 

Chemicals may be sequestered and accumulated in tissues (compartments) depending on certain factors (e.g., lipid solubility pKa) distribution can change with pH of blood or tissue. Some tissues are poorly accessible (brain). 

Measurement of pH is one of the most important and frequently used procedures in biochemistry. The pH affects the structure and activity of biological macromolecules for example, the catalytic activity of enzymes is strongly dependent on pH (see Fig. 2-21). Measurements of the pH of blood and urine are commonly used in medical diagnoses. The pH of the blood plasma of people... 

---