Liver (D3)

• 2 blood vessels supply blood to the liver. Hepatic artery brings oxygenated blood & hepatic portal vein carries blood from the gut which contains digested food. The liver regulates carbohydrate, protein & lipid levels in the blood. Excess glucose is stored as glycogen after a meal & glycogen is broken down to glucose during fasting. Excess amino acids are deaminated & utilized as E sources. The liver processes the resulting nitrogenous waste. Surplus cholesterol is converted into bile
• In the liver, arterial blood mixes w that from the hepatic portal vein as it flows through blood-filled channels aka sinusoids, past lines of hepatocytes & then on to a branch of the hepatic vein. Sinusoids merge w venules that lead to hepatic vein, a vein that carries blood away from the liver to the vena cava. 
• Numerous mitochondria, endoplasmic reticulum & golgi apparatus are found in liver hepatocytes. The ER & golgi apparatus produces plasma proteins (eg fibrinogen & albumin) & high no. of mitochondria provides ATP for the synthesis process. 
• Detoxification:

  Most foreign substances (eg: medicine, alcohol & toxins) are removed from the blood by the liver & detoxified. Eg, alcohol is converted into a less toxic substance by the enzyme ethanol dehydrogenase. Fatty liver, steatosis, is the most common type of alcoholic liver disease where fat builds up in the liver, which stops the liver from working properly. 
• Recycling:

  Old & dmg erythrocytes undergo Δ in their plasma membrane which make them susceptible to recognition by macrophages. At the end of their 120 day lifespan, they are removed from circulation & broken down in the liver. Most of the breakdown products are recycled.
• Worn-out erythrocytes are taken up via phagocytosis by phagocytes called Kupffer cells. The globin (protein) & heme (non-protein part containing Fe ions) of haemoglobin are split apart. From the breakdown of the heme, Fe in the form of Fe3+ ions is removed & attached to a carrier protein. In this form, Fe is stored in the liver cell. The Fe is then exported via the blood plasma to the bone marrow where it is reused to make new haemoglobin in new red blood cells. Also, radioactive particles can be taken up by Kupffer cells.