Figure 4

Oxygen delivery from a peritubular capillary into the surrounding tissue depending on its shape. (A) Predicted values of the partial pressure of oxygen (PO₂) along the edges of one periodic unit cell, relative to PO₂ at the capillary surface. Results are shown for three different, idealized capillary cross-sections: square, ellipse, and circle. The cross-sectional area of each capillary is fixed at 80 µm² in the physiological case and at 62.5 µm² in the pathological case. The size of the unit cell (i.e., the distance between the centers of 2 adjacent capillaries) is 20 µm in the physiological case and 25 µm in the pathological case. (B–D) Predicted PO₂ profile in the tissue surrounding a peritubular capillary in one unit cell under pathological conditions. The capillary cross-section is represented as either a square (B), an ellipse (C), or a circle (D). The PO₂ values are normalized by the PO₂ at the capillary surface. The length of the unit cell is 25 µm and capillary density is 0.10 for all shapes.