Oxygen concentration, end capillary

Since the consumption of oxygen by the fetus is not considered in this study, a maternal blood velocity change to a zero velocity would result in a fetal end capillary oxygen concentration that is equal to the... 

Examination of the curves of Figure 21 shows that as the magnitude of the period of oscillation of the velocity function decreases (from 45 sec to 15 sec), the minimum fetal blood end capillary oxygen concentration increases from 26.3 mm Hg for a period of 45 sec to 27.8 mm Hg for a period of 15 sec. Additionally, the maximum fetal oxygen concentration decreases from 30 mm Hg (the normal value) for the 45-sec period to 28.6 mm Hg for the period of 15 sec. Thus, longer periods of contrac-... 

Unsteady-State Analysis Including Axial Dispersion. As in the previous unsteady-state analysis, the effects of placental barrier tissue oxygen consumption are neglected in this study. For the unsteady-state analysis of the model in which axial dispersion was included, one study was conducted. This study involved placing a step change on the maternal blood velocity to a new maternal blood velocity of 0.125 times the normal in an attempt to determine the effects of axial dispersion on the system at low maternal blood velocities. The discussion of this study is divided into the following two parts first, the effect of axial dispersion on the response of the fetal blood end capillary oxygen concentration, and second, the effect on the transient axial profiles. 

Electrical measurements were carried out with the capillary electrode immersed in a suitable solution contained in a cell of the type used in polarography. The other electrode was a mercury pool, and an auxiliary electrode of platinum gauze was fitted over the lower end of the capillary, flush with the end as shown in Fig. i [a). The solutions contained in-difierent electrolyte (KNO3, KCl, etc.) at molar concentration and a low concentration (of the order of io M.) of the ion under investigation. Atmospheric oxygen was expelled by a stream of nitrogen. The cell was placed in a thermostat at 25 rh 01° c. 

The partial pressure of O2 in the air is 0.2 atm, sufficient to allow these molecules to be taken up by hemoglobin (the red pigment of blood) in which it becomes loosely bound in a complex known as oxyhemoglobin. At the ends of the capillaries which deliver the blood to the tissues, the O2 concentration is reduced by about 50% owing to its consumption by the cells. This shifts the equilibrium to the left, releasing the oxygen so it can diffuse into the cells. 

The concentration of protein in plasma is much higher than the protein concentration of the interstitial fluid outside the blood vessels. This concentration difference results in an osmotic pressure of about 18 torr, which tends to move fluid into the bloodstream. However, the pumping action of the heart puts the blood under pressure (blood pressure) that is greater at the arterial end of a capillary (about 32 torr) than at the venous end (about 12 torr). Because the blood pressure at the arterial end is higher than the osmotic pressure, the tendency is for a net flow to occur from the capillary into the interstitial fluid (see > Figure 15.7). The fluid that leaves the capillary contains the dissolved nutrients, oxygen, hormones, and vitamins needed by the tissue cells. 

The concentration of hydrogen radicals is several orders of magnitude higher than that of hydroxy radicals. In the quartz tube, this occurs either in a flame burning at the end of an oxygen delivery capillary (for a flame-in-tube device) or at the beginning of the hot zone for an externally heated tube (above 600°C). Only a small portion of the volume of the atomizer is filled by the cloud, as determined by the gas dynamics, geometry of the tube and... 

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