9 Chyme, Pancreas and Liver Secretions Flashcards
Why is it important that water moves into the duodenum?
Chyme entering duodenum is hypertonic- water deals with hypertonicity
When the chyme leaves the duodenum is it hypertonic, isotonic or hypotonic?
Isotonic (generally)
What are the Brunner’s glands and what do they do?
Why is it important that chyme release into the duodenum is controlled?
Stomach impermeable to water
Duodenum is relatively permeable to water
Hypertonic chyme draws water from ECF/circulation into duodenum
Must be controlled so as not to overwhelm duodenum
Secretions from the pancreas and liver allow for further digestion of chyme, what are these secretions (in general terms)?
What 2 hormones does the duodenum secrete in response to the presence of chyme and what effects do these hormones have?
Pancreatic secretions are stimulated by secretin and CCK. What else are they stimulated by?
Autonomics
Sympathetic inhibits
Parasympathetic (vagus) stimulates
The following diagram shows an acinus found within the pancreas. Which cells release the enzymatic components and which cells release the aqueous bicarbonate component?
Label the parts of the pancreas:
CCK and the vagus stimulate acini within the pancreas to produce enzymes. What enzymes and state whether they are active of inactive?
Proteases:
- Trypsin
- Chymotrypsin
- Elastase
- Carboxypeptidase
If proteases become activated whilst inside the pancreas, what will they cause?
Pancreatitus
How much bile does the liver secrete per day?
250ml-1000mL per day
In general terms, what does bile consist of? (3)
- Bile acids
- Bile pigments
- Alkaline solution
Through which vein does all of the blood from the gut drain into the liver?
Through portal vein
Identify each of the anatomical lobes in the following image and where the falciform ligament is.
What are the components of the portal triad?
Where do the central veins running through the centre of the liver lobules drain into?
Hepatic veins
Outline the flow of blood and the flow of bile within the liver lobules
Which zone in the acinus in the following diagram is most vulnerable to:
ischaemic damage?
toxic damage?
Ischaemic: zone 3
Toxic: zone 1
In which cells is bile created?
Hepatocytes and duct cells in liver
Why does bile need to be stored in the gall bladder?
Bile= continuously produced but only needed intermittently so stored
What are the functions of bile?
Emulsify fats- increase SA- aiding digestion
Allows waste products from blood to be excreted
Why are bile acids converted to bile salts? How do the bile salts aid lipid digestion?
(Converted by addition of amino acids eg glycine and taurine)
Bile acids- not very soluble in stomach acid
Bile salts have amphipathic structure so act as oil/water interface- create micelles with products of lipid breakdown
Micelles transport digested lipids to luminal membrane of enterocyte- lipids diffuse in, bile salts do not
Outline the recycling of bile salts.
Bile salts remain in gut (not taken up by enterocytes)
Reabsorbed in terminal ilium
Return to liver via portal blood
What is steatorrhoea and how might it be caused?
- Steatorrhoea: undigested fat appearing in faeces
- Pale, floating, foul smelling
- Causes:
- Lipid not emulsified with bile
- Bile not getting into duodenum
- Problem with enzymes in pancreas
- Lipid not emulsified with bile
