Blood ionic composition

Murugesan S, Mousa S, Vijayaraghavan A, Ajayan PM, Linhardt RJ (2006a) Ionic liquid-derived blood-compatible composite membranes for kidney dialysis. J Biomed Mater Res B Appl Biomater 79 298-304. 

Fig. 7.6. The dependence of the potential of an ammonium ion-selective electrode to anunonium ions alone (o) and in the presence of 0.15 M Na, 0.005 M K, which is the appropriate ionic composition of blood serum ( ). (After Scholer and Simon [186].)...

The ionic compositions of tissues and of body fluids vary substantially. Blood of marine organisms is similar to that of seawater in its content of Na+, CT, Ca2+, and Mg2+. Blood of freshwater and terrestrial organisms... 

Fig. 12.1 Main structural components of the nephron. Note particularly how the terminal part of the loop of Henle passes within cellular distances of the afferent arteriole. This forms the anatomical basis for the tubuloglomerular feedback mechanism by which the nephron regulates the incoming blood flow in response to variations in the ionic composition of the fluid that leaves the loop of Henle.

The interstitial volume is the extracellular volume outside of the blood vessels. Note that it is three times larger than the intravascular volume While its ionic composition closely resembles that of blood plasma (with which it is in equilibrium for all small solutesthat are not protein-bound), it has a considerably lower protein content. 

We have mentioned already that the maintenance of proper concentrations of sodium, potassium, calcium, and other ions is of considerable importance to the cell. This maintenance is assisted by the efforts the body as a whole makes to ensure that the ionic composition of the circulating bloodstream should be of constant composition. It achieves this by disposing of unwanted material, mainly by filtering and processing the blood in the kidneys and... 

Table 1 SBF and human blood plasma ionic composition and concentration (mM)...

A partial failure of kidney function consequently is reflected by the ionic composition, by the alkali reserve, and possibly by the pH of blood. The regulation by the lungs also may lose its effectiveness and permit corresponding shifts of the alkali reserve (= respiratory acidosis or alkalosis). Finally, a metabolic defect may cause overproduction of organic acids, as has been known longest in the case of diabetes mellitus. The last situation is termed metabolic acidosis. There are other pathological shifts of acid-base equilibria and of the electrolyte balance that are not discussed here. 

For blood at 37 C, the normal mean value is p/C P) = 6.103, with a normal biological standard deviation (SD) of about 0,0015, mainly caused by variations in ionic strength. The solubility coefficient for CO2 gas, a, also varies with the composition of the solution. For pure water at 37 °C, the solubility coefficient a = 0.0329 mmol x L x mmHg , and for normal plasma at 37 °C it is 0.0306 mmol x L X mmHg", with a biological SD of about 0.0003 mmol x L X mmHg ... 

If the ionic strength and pH of the perfusate do not match those of the extracellular environment the physiological conditions will be perturbed. Results from experiments performed under these conditions could then be a product of factors that are not accounted for experimentally. While this can be less important in a blood vessel than in the brain, where all processes are affected by electrolyte levels, the perfusate composition is very important in the reliability of the results. Analysis of microdialysis samples with mass spectrometric detection offers a special challenge because the high salt concentration of the dialysate could affect the sensitivity of the spectrometer. 

Q.15.1 What is the ionic strength of the serum component of blood What is the osmolarity of this component Normal Serum composition is Na 140 mil-liequivalents, K 4 milliequivalents, Cl 100 milliequivalents, HCOa 24 milliequivalents. 

---