Oxygen in blood

Hemoglobin, a protein with a molecular weight of 68 000 Da, consists of four subunits with a molecular weight of 17 000 Da. Oxygenation proceeds in the following four steps  

From the practical point of view, the following empirical equation of Hill [6] is more convenient. 

plotting experimental values of the left-hand side of Equation 15.3b against those of log p gives the values of H and n, which are functions of pH and temperature. 

---

Lack of oxygen in blood or tissues. Tissue hypoxia can be caused by injury, inflammation, or tumor growth, due to disruption of blood supply. Tissue hypoxia is normally associated with acidosis, as anaerobic metabolism leads to production of lactic acid. 

Figure 15.4 Diffusivity of oxygen in blood Dg (a) and kinematic viscosity of blood Vg (b) at 37 °C.

In cattle, a thiamine deficiency causes podioencephalomalcia (PEM), characterized by blindness, decreased feed intake, incoordination, failure of rumen to contract, spasms, and paralysis. In swine, a deficiency retards growth and sometimes causes cyanosis (insufficient oxygen in blood), enlarged heart, accompanied by fatly degeneration of heart muscles. Chicks suffer from paralysis of peripheral nerves, causing polyneuritis (head drawn back). 

Several nonmetallic inorganic species may act as toxicants that affect ecosystems. Spills of salts of cyanide ion, CN, from mining operations have temporarily sterilized small streams. Nitrate ion, NO3, in contaminated well water may be reduced to nitrite ion, N02, in the stomachs of ruminant animals and infants. The nitrite converts the iron(II) in blood hemoglobin to iron(III), thus producing methemoglobin, which is useless for transporting oxygen in blood. In extreme cases, fatalities have resulted in livestock and human infants. Excessive levels of carbon dioxide, C02, in water or air can be detrimental or even fatal. 

They are also more than curiosities. The space in the middle with the four inward-pointing nitrogen atoms is just right for complex formation with divalent metals such as Fe(II). With more varied substituents, this structure forms the reactive part of haemoglobin, and the iron atom in the middle transports the oxygen in blood. 

A dropping mercury electrode was used for the determination of oxygen in blood [29-32] in lymph [31] during various enzymatic processes [33-35] and in various gases [36-38]. 

To carry out metabolic functions, the body depends on the solubility of gases in blood, which, in turn, depends on the pressure of that gas and not any other. So the solubility of oxygen in blood depends on the pressure of oxygen in the inhaled air, and the solubility of oxygen in the cells depends on the pressure of oxygen in the cell. As metabolism takes place in the cell, oxygen is used up and carbon dioxide is produced. When... 

K. Feldscher, A Novel Way to Measure Oxygen in Blood, The Northeastern Voice, www.voice.neu.edu/970123/oxygen.html, 7/12/1999. 

Another interesting example is the dissoluhon of molecular oxygen in blood. Normally, oxygen gas is only sparingly soluble in water (see Practice Exercise in Example 12.6). 

It is this process that accounts for the high solubility of molecular oxygen in blood. The Chemistry in Action essay on p. 480 explains a natural disaster with Henry s... 

---