Hypoxia and oxidative stress: The role of the anaerobic gut, the hepatic arterial buffer response and other defence mechanisms of the liver

Figure 1 Schematic diagram of countercurrent blood flow within the small intestinal villus allowing diffusion of O₂ from the arteriole to the venule, creating a luminal hypoxia from the crypt to the villous tip. PO₂ is shown in mmHg.

Figure 2 Schematic representation of a hepatic acinus within a conventional hepatic lobule. The demarcation of the hepatic acinus is shown by the dashed lines. Arrows indicate the direction of blood flow within hepatic sinusoids in a periportal-to-perivenous direction, giving rise to zones 1, 2 and 3 (numbered) within the acinus. Note that all three zones are represented in a single sinusoid.

Figure 3 Production of adenosine from adenine nucleotides. ATP: Adenosine triphosphate; ADP: Adenosine diphosphate; AMP: Adenosine monophosphate; Pi: Inorganic phosphate; AK: Adenosine kinase.

Figure 4 Liver as the “chemical smithy” of the body.

Figure 5 Protective adaptations of the liver against oxidative stress. HABR: Hepatic arterial buffer response.