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42 Cards in this Set
- Front
- Back
What are the functions of the liver? |
Detoxifier
Hormone processor Protein creator - albumin and clotting agents Heat production |
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What is the blood supply for the liver? |
Hepatic - 30%, oxygenated blood from heart, 12 kPa
Portal Vein- 70%, deoxygenated blood rich in nutrients, 1.3 kPa Drains through hepatic vein |
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Where is the liver located? |
Right upper quadrant of the abdominal cavity |
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What are the features of sinusoids? |
Fenestrated vessel Wide capillaries Lined with endothelia with fenestrae Selective sieve No basal lamina |
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What is the journey of bile?
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Transported in hepatocytes
Secreted in bile canaliculi to bile ductules Drained in small intestine |
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What is the structure of the portal venule? |
Large lumen, collapsed structure and attenuated wall
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What is the structure of the hepatic arteriole? |
Single layer of smooth muscle cells
Small lumen |
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What is the structure of the bile ductule? |
Simple cuboidal to columnar ciliated epithelium (to move bile)
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What is the structure of the lobules in the liver? |
80% - parenchyma
20% - stroma 50-100k lobules |
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What is the structure of hepatocytes? |
Cuboidal Epithelial Cell Single cell columns radiate from central vein Rich in: Tight junctions, microvilli, Mi, peroxisomers, RER, SER, glycogen |
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What does the liver metabolise? |
Metabolise fats, carbohydrates and proteins
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How are fats metabolised in the liver? |
Triglyceride Oxidation for energy production Plasma lipoprotein synthesis Cholesterol and phospholipid synthesis |
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How are carbohydrates metabolised in the liver? |
Carbohydrates are converted into fatty acids and triglycerides Glucose concentration regulation: glycogenolysis--gluconeogenesis |
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How are proteins metabolised in the liver? |
Amino acid synthesis, Plasma protein synthesis – albumin/clotting factors Detoxification of metabolism waste products e.g.Amino acid deamination- Urea formation |
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What does the liver detoxify? |
Alcohol and other drugs |
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What else does the liver secrete? |
Bile - contains products of metabolism - billirubin Acts a detergent to emulsify fats |
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What is acinus? |
Constructed around portal triad with Central vein as corners |
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What occurs in the three zones of the liver acinus? |
Zone 1 - receives oxygen, nutrients, hormones first. Hepatocytes synthesizeglycogen and plasma proteins Zone 3 - hypoxic, drug detoxification |
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What is the function of the endothelial cells? |
Contain large fenestrae Passage of large plasma-proteins - chylomicrons Lacks BM Endocytosis and transcytosis |
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What are Kupffer cells? |
Mononuclear phagocytes
Found on the luminal endothelial face Phagocytosis of bacteria, virus particles, damaged erythrocytes, immune complexes |
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What are hepatic stellate cells? |
Quiescent; fat-containing/storing; Vitamin A storage; found in the space of Disse |
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What is the function of Canals of Hering? |
Contain a reserve compartment of hepatocyte and bile duct progenitor cells – stem cell location |
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Where is the space of Disse? |
Between hepatocytes and sinusoidal endothelial cells with fenestrae of 100 nm which are dynamic with Ca |
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How are fenestrae linked to arteriosclerosis? |
Cannot take up cholesterol-rich chylomicrons Stay in circulation |
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What affects size of fenstrae? |
Actin disruption increases fenestrae numbers and size Calcium addition yields fenestrae contraction Serotonin and drugs |
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How does alcohol affect the liver sinusoidal endothelial cells? |
Yields endothelium defenestration Sinusoidal porocity decreases Yields Hyperlipoproteinemia |
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Why is some alcohol considered good for you? |
Enlarges fenestrae Dietary lipid clearance by the liver |
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What is the function of Sphincter of Oddi |
Smooth muscle ring Controls entry of both bile and pancreatic juice into the duodenum |
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What is gall bladder concentrated in? |
Bile is highly concentrated 20x fold increase in bile salt concentration |
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What is bile composed of? |
Bile salts (50%) Bile pigments (e.g. bilirubin) (2%) - colour Phospholipids (40%) Cholesterol (4%) |
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What are the precursors of bile salts? |
Bile acids |
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What are primary bile acids? |
Cholic Acid (CA; 31%) and Chenodeocholic acid (CDCA; 45%) Synthesised in liver from cholesterol |
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What are primary bile acids conjugated to? |
Conjugated to aa like taurine (tauroconjugates) or glycine (glycoconjugates) to be excreted |
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Where are primary bile acids reabsorbed? |
95% reabsorbed Distal ileum and returned to the liver via portal vein |
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Are bile acids hydrophobic or hydrophilic? Why is it important? |
Both - amphipathic Key feature for the emulsification of fat |
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What is the difference between primary and seccondary bile acids? |
Secondary are more hydrophilic - more OH groups |
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What is the function of bile? |
Contains Bile Acids that aid in fat absorption Transports material (drugs, bilirubin etc.) to the intestine for excretion |
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What is an issue of too much secondary bile acids? |
Colon cancer, gallstones, GI diseases |
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What do conjugated bile acids in the small intestine prevent? |
Bacterial overgrowth Bile salts - Bacteriostatic agents |
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Which direct does blood and bile flow in ? |
oppositedirections |
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Where are portal triads |
Periphery |
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How are bile salts excreted? |
95% of bile salts are reabsorbed by small intestine. 5% lostin faeces |