D3 The Liver Flashcards
ALCOHOL YUMMY WYUMYA
Liver position
Second largest organ in the human body
Under the diaphragm,
Liver function
Remove and add substances from the blood to maintain homeostatic levels.
Hepatic portal vein
Blood from the capillaries of the small intestine
The blood is deoxygenated
Low pressure within the vein
Can have lots or little nutrient content
Hepatic artery
Blood from the heart
Oxygenated blood
High pressure in artery
Low nutrient content
Hepatic vein
Blood from the liver
Deoxygenated blood / Low pressure
Nutrient levels are stabilised (osmoregulation)
Hepatocyte: Liver Cells // Sinusoids
Sinusoids are wider than capillaries
Sinusoids have fenestrations as opposed to tight junctions
Sinusoids have Kupffer Cells, cells that break down haemoglobin
Gallbladder
Stores bile, has a bile duct that drains to the intestine
Regulation of Nutrients in the Blood (STORAGE FUNCTIONS)
If nutritent high, liver uptake and store
If low, liver adds nutrients to system
Hepatocytes can store:
Glucose => as Glycogen
Iron => haemoglobin recycling
Vitamin A => As lipid droplets
Vitamin D => Supplies the bodies need in winter.
Protein Synthesis in Hepatocytes
bloodplasma
Endoplasmic reticulum and Golgi apparatus in hepatocytes produces plasma proteins
Synthesis of Albumins and Globulins and Fibrinogens
- Produce 90% of proteins in the blood plasma
Conversion of excess aminoacids to glucose or lipids but can also synthesize them back
Converts ammonia to urea
Lipid Metabolism in Liver
Liver hepatocytes synthesise a very high amount of cholesterol
Liver converts excess carbs into triglycerides and then shipped to adipose cells
Liver can break apart fatty acids to synthesise other types
Can create lipoproteins allowing them to move through water
Liver synthesises a great amount of lipid
Lipoproteins (GOOD CHOLESTEROL)
Lipoproteins are lipids on the inside (hydrophobic) and proteins on the outside engulfed in phospholipids
Lipoproteins are classified based on the relative amounts of lipid molecules compared to protein molecules.
Their classifications are as follows:
Chylomicron, Very Low Density Lipoprotein (VLDL), Intermediate Density Lipoprotein (IDL), Low Density Lipoprotein (LDL) and High Density Lipoprotein (HDL)
Recycling Erythrocytes
Red blood cells that live only up to 120 days
At the end of their life cycle the rupture
Kupffer cells ingest haemoglobin
Broken into Iron carrying Heme and Globin
1) Hydrolyses the polypeptide (globin) into amino acid (stores for the future)
2) The iron is send to the bone marrow (stored with a protein shell of ferritin to prevent oxidation) to form new haemoglobin molecules
3) The rest of the heme group is turned into bilirubin (bile pigment) and that’s later turned into bile
Bile Formation
Bile emulsifies fats (increasing the surface area of lipids)
Bile is made of water, bile salts, bilirubin and fats
Hepatocytes produce bile
They turn extra (surplus) cholesterol into similar molecules called bile salt.
Mixing bilirubin with the bile salt
Toxin Removal
Such as pesticides, preservatives, alcohol, bilirubin and ammonia.
Role of Kupffer Cells:
- Use phagocytosis to remove old red blood cells and bacteria from the blood
- Contain lots of lysosomes
Role of Hepatocytes:
- Most common cell in sinusoids
- They chemically change toxins and make them water-soluble so that they can pass through the urinary system
Liver Repair Problems
1) Inflammation
Swelling of the damaged liver tissue due to alcohol
2) Fat accumulation
Fat takes the place of normal liver tissue
3) Cirrhosis
Scar tissue left when areas are destroyed
