Hepatic portal system vena cava (thus bypassing the liver). Blood flow to the liver is unique in that it receives both oxygenated and (partially) deoxygenated blood. As a result, the partial gas pressure of oxygen (pO) and perfusion pressure of portal blood are lower than in other organs of the body. Blood passes from branches of the portal vein through cavities between "plates" of hepatocytes called sinusoids. Blood also flows from branches of the hepatic artery and mixes in the sinusoids to supply the hepatocytes with oxygen. This mixture percolates through the sinusoids and collects in a central vein which drains into the
Protocol Relating to the Status of Refugees the temporal and geographic restrictions. This was needed in the historical context of refugee flows resulting from decolonisation. However, the Protocol gave those states which had previously ratified the 1951 Convention and chosen to use the geographically restricted definition the option to retain that restriction. Protocol Relating to the Status of Refugees The Protocol Relating to the Status of Refugees is a key treaty in international refugee law. It entered into force on 4 October 1967, and 146 countries are parties. Where the 1951 United Nations Convention Relating to the Status of Refugees had restricted refugee status to those whose