Liver Function 1 Flashcards
Describe the liver
Largest solid organ Protected by ribs RUQ Diaphragm ‘roof’ 2, 4 lobes, 8 segments Hepatic artery, portal vein, hepatic veins, bile duct
Which ligament runs between the right and left lobes of the liver?
Falciform ligament
Which ligament is at the end of the falciform ligament?
Round ligament
What cells make up the liver?
Hepatocytes (60%) Kupffer cells (30%) Stellate Cells Endothelial cells Biliary epithelium
What is the role of hepatocytes?
Hepatocytes are involved in synthesizing protein, cholesterol, bile salts, fibrinogen, phospholipids and glycoproteins.
They ensure that our blood coagulates so we don’t bleed to death, that cell communication s good and that we are able to carry fats in the bloodstream.
Other functions of the hepatocytes include the transformation of carbohydrates (from alanine, glycerol and oxaloacetate), protein storage, start of the formation and secretion of bile and urea, and detoxification and excretion of substances.
Thanks to these main cells, we are able to fight off disease, produce waste, transport materials throughout the body and process everything from drugs and insecticides to steroids and pollutants.
What is the role of liver endothelial cells?
Since they do not have tight membranes, these cells act as “scavengers” of nearby cells - collecting and circulating hepatocytes in the blood, for instance.
Responsible for transporting white blood cells and other material from the blood to the liver and for increasing the immune system’s tolerance of the liver.
They can absorb ligands, which serve as biological markers and binders for pharmaceutical drugs. When stimulated, endothelial cells secrete cytokines, which is a form of cellular communication signal.
What is the role of Kupffer cells?
Kupffer cells are located within the sinusoidal lining of the liver and hold a quarter of the liver lysosomes.
The lysosomes digest and dispose of dying cells, unnecessary proteins, bacteria and foreign microbes. If stimulated, kupffer cells secrete mediators of the immune response system, and they can perform a complex array of functions–from disarming foreign substances to removing damaged red blood cells from circulation.
In a way, the kupffer cells are like bodyguards and assassins for the hepatocytes, protecting them from invaders and cell refuse.
What is the role of hepatic stellate cells?
The livers reserve army.
Most of the time, this 5 to 8 percent of the liver’s cells just sit around in an inactive “quiescent” state, storing vitamin A and a number of important receptors.
When activated (by an event like liver injury), the cell promotes ion movement, the production of antibodies, genesis of natural killer T-cells and the proliferation of chemical responses to stress.
Researchers believe that hepatic stellate cells play a key role in releasing collagen scar tissue and encouraging liver scarring.
What is bile?
Green/yellow fluid made up of water, electrolytes and organic molecules (bilirubin, bile acids, phospholipids and cholesterol)
What do epithelial cells in the bile ducts secrete?
Water and bicarbonate
How is bile secreted?
Bile is secreted by hepatocytes Through canaliculi Small ducts Left/right hepatic duct Common hepatic duct Common bile duct
What are the functions of bile?
Responsible for fat digestion and absorption
Bile and pancreatic juice neutralise gastric juice
Gets rid of waste products of blood such as bilirubin and cholesterol
What does the liver produce?
Proteins, lipoproteins, coagulation factors (fibrinogen, prothrombin, clotting factors. Vitamin K s essential for formation of prothrombin and factors II,VII,IX,X)
Hormones and pro-hormones
Carrier proteins (transferrin)
What does the liver store?
Carbohydrates, fat, ADEK, B12, folate, ferritin, metals
What are the roles of the liver?
Production, storage, metabolism, excretion
How does the liver metabolise proteins?
- Transamination: one amino acid is converted to another (adding/removing elements from R group)
- Deamination: getting rid of excess amino acids by removing amino group (NH2). NH2 is converted to NH3 (ammonia) and NH3 enters the urea cycle. Urea is then excreted in urine.
What proteins are synthesised by the liver?
Fibrinogen, albumin, globulin, CRP, complement proteins C1-4
What is the role of the liver in response to high blood glucose levels?
Insulin released by pancreas, glucose is converted to glycogen and stored in the liver, decreased gluconeogenesis, decreases glycogenolysis
What is the role of the liver in response to low blood glucose?
Glucagon released by pancreas, glycogen converged into glucose and released, increases gluconeogenesis and increases glycogenolysis
What are lipids metabolised by the liver?
Triglycerides are oxidised in hepatocytes to produce energy
Excess proteins and carbohydrates are converted into fatty acids and triglycerides and stored in adipose tissue
Liver produced lipoproteins
Synthesises cholesterol and phospholipids
What happens to cholesterol in the liver?
Cholesterol s excreted in bile or converted to bile acids
How does the liver metabolise alcohol?
Alcohol dehydrogenase converts ethanol to acetaldehyde
Acetaldehyde dehydrogenase converts acetaldehyde to acetate
Acetate is broken down to water and carbon dioxide for easy elimination
Which enzyme converts ethanol to acetaldehyde?
Alcohol dehydrogenase
Which enzymes converts acetaldehyde to acetate?
Acetaldehyde dehydrogenase
