Chyme, Pancreas And Liver

Question 0

Describe the digestive functions of the liver and the components of bile

Answer 0

Liver:
Secretion of bile, excretion of bile pigments (bilirubin)
Bile:
Bile acid dependent - bile acids, bile pigments
Bile acid independent - alkaline juice, water

Question 1

Describe the key properties of chyme leaving the stomach and how they are conditioned

Answer 1

Acid - HCO3- secreted from pancreas, liver, duodenum
Hypertonic - osmotic movement of water across duodenal wall
Partly digested - enzymes from pancreas and small intestinal mucosa, bike acids

Question 2

Describe the secretion of bile acids and the entero-hepatic circulation of bile acids

Answer 2

Bile secreted from liver in canaliculi

Liver –> duodenum –> terminal ileum –> hepatic portal blood –> liver

Question 3

Give three examples of bile acids

Answer 3

Cholic acid
Chenodeoxycholic acid
Cholesterol

Question 4

Describe the function of the gall bladder and the relationship to the formation of gallstones

Answer 4

To store bile
In gall bladder, bile has a high concentration (transport of salt and water across epithelium) so stones may precipitate out

Question 5

List the secretions of the exocrine pancreas

Answer 5

Enzymes - amylase, lipase, protease (trypsin, chymotrypsin, elastase, carboxypeptidase)
Alkaline juice (water, ions, HCO3-)

Question 6

Relate the structure of the endocrine pancreas to its secretions

Answer 6

Insulin from B cells –> break down glucose
Glucagon from a cells –> stimulates glucose production
Somatostatin from delta cells –> inhibit gastrin, CCK, secretin
Pancreatic polypeptide from F cells –> reduces appetite and food intake

Question 7

Describe the mechanisms of secretion of alkaline juice

Answer 7

Duct secretion

Na+/K+ATPase, NHE, CO2 enters cell, HCO3- leaves into lumen

Question 8

Describe the control of pancreatic and biliary secretion

Answer 8

Acinar secretion activated by enzymatic cleavage

Stimulated by CCK, hypertonicity, fats, release of ACh

Question 9

Describe the mechanisms of digestion of fats

Answer 9

Bile acids travel in micelles

They emulsify fats and increase the SA for lipases

Question 10

Describe the gross anatomy of the liver

Answer 10

Right and left lobes divided by falciform ligament (ends in Ligamentum Teres)
Caudate lobe next to IVC
Quadrate lobe next to gall blessed
Bare area of liver on right, anterior edge

Question 11

Describe the biliary tree

Answer 11

Right and left hepatic ducts –> common hepatic duct -cystic duct-> common bile duct -pancreatic duct-> ampulla of Vater –> sphincter of Oddi

Question 12

Describe the functions of the liver in relation to blood

Answer 12

Energy metabolism
Detoxification
Creation of plasma proteins

Question 13

Interpret basic liver function tests

Answer 13

Hepatocellular damage:
ALT - specific to liver, AST - liver, brain, kidney 
AST:ALT 2 = alcoholic liver disease 
Cholestasis:
Billirubin
Alkaline phosphatase 
Synthetic function:
Albumin
Prothrombin time

Question 14

Describe the causes and effects of jaundice

Answer 14

Pre-hepatic - excessive haemolysis e.g. sickle cell anaemia, lover unable to cope with excess billirubin
Hepatic - deranged hepatocyte function, liver unable to eliminate billirubin e.g. cirrhosis
Post-hepatic - obstruction of biliary system, passage of conjugated billirubin blocked e.g. gallstone
Yellow discolouration of sclera, skin, mucous membranes

Question 15

Describe the effects of excessive alcohol consumption on the liver, and the key features of alcoholic liver disease

Answer 15

Alcohol is toxic to hepatocytes
Fatty liver –> alcoholic liver disease –> cirrhosis
Key features:
Palmar erythema, jaundice, anaemia, bruising, Dupuytren’s contracture

Question 16

Describe the process of cirrhosis

Answer 16

Hepatocyte necrosis –> nodular regeneration and fibrosis

Question 17

Describe how liver disease may lead to portal hypertension, and appreciate the associated pathology these may lead to

Answer 17

Portal hypertension due to inability of hepatocytes to function effectively
Backlog of blood reopens portosystemic shunts
Oesophageal varices (oesophageal branches off left gastric artery)
Caput medusa (ligamentum teres)
Anal haemorrhoids

Question 18

Describe the causes and consequences of gallstones

Answer 18

Causes - precipitation of bile acids (mixed/cholesterol/calcium pigment) in gall bladder due to loss of water and salt, gallstone impaction in Hartman’s pouch
Consequences - biliary colic, pain after eating

Question 19

Describe the causes and consequence of acute and chronic pancreatitis

Answer 19

Acute:
Gallstones, trauma, autoimmune, iatrogenic, drugs 
Chronic:
Alcoholism, calcification 
Consequences - steatorrhoea, jaundice

Question 20

Describe the presentation of carcinoma of the pancreas

Answer 20

Jaundice
Dark urine
Pale stools
Generalised itch (bile in bloodstream)