Liver Function and Metabolic Roles - Anatomy and Physiology
- Which liver process makes new glucose from noncarbohydrate sources such as amino acids, lactate and glycerol?
- Gluconeogenesis. It helps keep blood glucose up during fasting.
- Which liver process converts excess blood glucose into a storage form after a meal?
- Glycogenesis, the synthesis of glycogen from glucose.
- Which plasma protein made by the liver contributes most to plasma colloid osmotic pressure?
- Albumin. Low albumin in liver disease lets fluid leave capillaries and contributes to edema.
- Which vessel delivers nutrient-rich blood from the digestive tract to the liver?
- The hepatic portal vein. It supplies most of the liver's blood; the hepatic artery supplies oxygen-rich blood.
- Which organ produces bile, and which organ stores and concentrates it?
- The liver produces bile; the gallbladder stores and concentrates it between meals.
- Into which vessel do the hepatic sinusoids of each liver lobule drain?
- The central vein, which leads to the hepatic veins and then the inferior vena cava.
- What are Kupffer cells?
- Macrophages lining the hepatic sinusoids that remove bacteria, debris and worn-out red blood cells from portal blood.
- Which water-soluble vitamin does the liver store in amounts that can last several years?
- Vitamin B12. The liver also stores iron and the fat-soluble vitamins A and D.
- Which clotting factors require vitamin K for their synthesis in the liver?
- Factors II (prothrombin), VII, IX and X.
- What does the liver do to bilirubin before excreting it in bile?
- It conjugates bilirubin with glucuronic acid, making it water-soluble so it can be secreted into bile.
- Into what compound does the liver convert toxic ammonia from amino acid breakdown?
- Urea, made through the urea cycle and then excreted by the kidneys.
- Which enzyme family in the smooth endoplasmic reticulum of hepatocytes oxidizes many lipophilic drugs?
- Cytochrome P450 enzymes. They make drugs more water-soluble so they can be excreted.