Buffer in blood

Tin metabolic acidosis (p. 652) there is an increase in glutamine processing by the kidneys. Not all the excess NH4 thus produced is released into the bloodstream or converted to urea some is excreted directly into the urine. In the kidney, the NH% forms salts with metabolic acids, facilitating their removal in the urine. Bicarbonate produced by the decarboxylation of a-lcetoglutarate in the citric acid cycle can also serve as a buffer in blood plasma. Taken together, these effects of glutamine metabolism in the kidney tend to counteract acidosis. ... 

Phosphate, present to an extent of 0.01 M, is one of the main buffers in blood plasma, whose pH is 7.45. Would phosphate be as useful if the plasma pH were 8.5 ... 

In mammals the bicarbonate ion, IICOT, is used as a buffer in blood and is catalysed by the zinc-containing enzyme carbonic anhydrase ... 

Buffers in Blood Your blood is a slightly alkaline solution with a pH of approximately 7.4. To be healthy, that pH must be maintained within narrow limits. A condition called acidosis occurs if the pH falls more than 0.3 units below 7.4. An equally serious condition called alkalosis exists if the pH rises 0.3 units. You may have experienced a mild case of acidosis if you have overexerted and developed a cramp in your leg. Cramping results from the formation of lactic acid in muscle tissue. 

For efficient transport of relatively insoluble CO2 from the tissues where it is formed to the lungs where it must be exhaled, the buffers of the blood convert CO2 to the very soluble anionic form HCOJ (bicarbonate ion). The principal buffers in blood are bicarbonate-carbonic acid in plasma, hemoglobin in red blood cells, and protein functional groups in both. The normal balance between rates of elimination and production of CO2 yields a steady-state concentration CO2 in the body fluids and a relatively constant pH. 

Write the pH control reactions for the carbon dioxide-based buffer in blood. 

BICARBONATE BUFFER Bicarbonate buffer, one of the more important buffers in blood, has three components. The first of these, carbon dioxide, reacts with water to form carbonic acid ... 

The hydrogencarbonate buffer in blood would soon become exhausted if there was not a way for the body to get rid of waste. Excess carbon dioxide and excess acid are removed by the lungs and kidneys, respectively. In this way, the hydrogencarbonate ions in the blood are released to act as a buffer once again. 

Less than 1% of the dissolved carbon dioxide exists as carbonie acid or its dissociation products. Carbonic acid, a weak acid with a pAl of 6.38, serves as an important buffer in blood. 

Within minutes, Brianna determines that the patient s blood pH is 7.30 and the partial pressure of CO2 gas is above the desired level. Blood pH is typically in the range of 7.35-7.45, and a value less than 7.35 indicates a state of acidosis. Respiratory acidosis occurs due to an increase in the partial pressure of CO2 gas in the bloodstream which prevents the biochemical buffers in blood from making a change in the pH. 

Maintaining the proper pH in blood is important to one s health. To find out how the body maintains a normal pH in blood, go to the Focus On feature for Chapter 17, Buffers in Blood, on the MasteringChemistry site. 

There is a buffer system (H2P04 -HP042 ) in blood that helps keep the blood pH at about 7.40. (IQ H2P04" = 6.2 X 10 ). 

Buffer systems are so vital to the existence of living organisms that the most immediate threat to the survival of a person with severe injury or burns is a change in blood pH. One of a paramedic s first steps in saving a life is to administer intravenous fluids. 

The main buffer in the blood consists primarily of hydrogen carbonate ions (HC03 ) and H30 + ions in equilibrium with water and C02 ... 

Higher than normal quantities of ketone bodies present in the blood or urine constitute ketonemia (hyperke-tonemia) or ketonuria, respectively. The overall condition is called ketosis. Acetoacetic and 3-hydroxybutyric acids are both moderately strong acids and are buffered when present in blood or other tissues. However, their continual excretion in quantity progressively depletes the alkah reserve, causing ketoacidosis. This may be fatal in uncontrolled diabetes mellitus. 

Buffers in your body are constantly working to prevent harmful increases or decreases in the pH of your blood, urine, and other fluids. In order to resist such changes, a buffer is composed of —... 

Figure 8.6 Positive ion LD TOF mass spectra of P. falciparum parasite sample (upper trace), and a control (uninfected blood) sample (lower trace). Protocol D is used for sample preparation. Both samples—in vitro cultured P. falciparum parasites in whole blood, and the whole blood control—are diluted to 5% hematocrit (10-fold) in PBS buffer. In the infected sample the estimated number of deposited parasites per sample well is approximately 100. A commercial LD TOF system is used, and both spectra are normalized to the same (40 mV) detector response value. Each trace represents the average of one hundred single laser shot spectra obtained from linear scanning of an individual well (no data smoothing). The characteristic fingerprint ions of detected heme in the upper trace are denoted.

Valproic acid has been determined in human serum using capillary electrophoresis and indirect laser induced fluorescence detection [26], The extract is injected at 75 mbar for 0.05 min onto a capillary column (74.4 cm x 50 pm i.d., effective length 56.2 cm). The optimized buffer 2.5 mM borate/phosphate of pH 8.4 with 6 pL fluorescein to generate the background signal. Separation was carried out at 30 kV and indirect fluorescence detection was achieved at 488/529 nm. A linear calibration was found in the range 4.5 144 pg/mL (0 = 0.9947) and detection and quantitation limits were 0.9 and 3.0 pg/mL. Polonski et al. [27] described a capillary isotache-phoresis method for sodium valproate in blood. The sample was injected into a column of an EKI 02 instrument for separation. The instrument incorporated a conductimetric detector. The mobile phase was 0.01 M histidine containing 0.1% methylhydroxycellulose at pH 5.5. The detection limit was 2 pg/mL. 

Moreover, several buffer systems exist in the body, such as proteins, phosphates, and bicarbonates. Proteins are the most important buffers in the body. Protein molecules contain multiple acidic and basic groups that make protein solution a buffer that covers a wide pH range. Phosphate buffers (HPO T /H2P07) are mainly intracellular. The pK of this system is 6.8 so that it is moderately efficient at a physiological pH of 7.4. The concentration of phosphate is low in the extracellular fluid but the phosphate buffer system is an important urinary buffer. Bicarbonate (H2C03/HC0 3) is also involved in pH control but it is not an important buffer system because normal blood pH 7.4 is too far from its pK 6.1 [144],... 

Our human health depends on a balanced and buffered blood pH. For instance, human blood is slightly basic with a pH between 7.3 and 7.5. If the blood pH drops below 7.3, acidosis occurs. If the blood pH rises above 7.5, alkalosis occurs. Adverse events including death will occur if a significant change in the blood pH goes below 6.8 or above 7.8. pH levels in blood are frequently determined in clinical laboratories [145],... 

This reaction is essential in maintaining a constant pH in blood by the bicarbonate buffer system. Carbonic anhydrase, which contains a single zinc atom in its structure, has a molecular weight of about 30,000. In this structure, zinc is surrounded tetrahedrally by three histidine molecules and one water molecule. The exact role of the catalyst is not known, but it is believed to involve hydrolysis that can be represented as... 

Henderson-Hasselbalch Equation Titration Curves p/—Isoelectric Point The Bicarbonate Buffer Imbalance in Blood pH Acidosis and Alkalosis... 

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