Pancreas and Liver Physiology Flashcards
What occurs in the endocrine part of the pancreas?
Produces hormones such as insulin or glucagon
What is the exocrine function of the pancreas?
Acts on the small intestine to assist with the initial stages of digestion
What is the function of pancreatic juice?
Breaks down macromolecules so they can be more easily absorbed by the small intestine
In what species does the pancreatic duct join with the bile duct before joining the duodenum?
Sheep and Goats
What makes up pancreatic juice?
HCO3- and Cl-
What enzymes are found in the pancreatic juice?
Lipase, amylase and Protease
What is the function of Trypsin?
To activate all the enzymes (it’s secreted in its inactivated form trypsinogen)
What is Autocatalysis?
the process where the reaction product is also the catalyst for the reaction
Where is trypsin firmed?
Trypsin is formed in the duodenum by enteropeptidase
Whya re enzymes secreted in their inactive forms?
so taht they don’t break down tissue
What is the function of HCO3-
to make the ingesta alkaline when it enters the duodenum
Why is it important the ingesta from stomach is alkaline?
-Preventing injury to mucosa
-Providing optimal pH for enzymatic activity
What is the Cephalic phase?
changes in digestive activity that takes places before the ingesta enters the stomach
What is the gastric phase?
Changes in the digestive tract and motility/ secretion in the stomach
What is there an increase of in pigs and horses when there is increased enzyme secretion?
an increase of ion and water secretion
What occurs during the intestinal phase?
Chyme entering the duodenum causes increases in pancreatic secretion
- This is regulated by CCK and secretin
Where is Secretin released?
By S cells in the duodenum as a response to increased acidity in the gut (stimulates HCO3- secretion)
What is Cholecystokinin (CCK)?
» released when FAs and peptides/amino
acids increase in duodenum
» stimulates pancreas to increase enzyme
secretion
» increased enzymes = increased ingesta
degradation
» = increased products of digestion
What other organ does Cholecystokinin (CCK) act on?
The bile duct, causing it to release more bile secretion
What is the role of the liver?
absorbs nutrients from the small intestine and releases them into the bloodstream, it also inactivates substances such as drugs/ alcohol
What is the role of the gall bladder?
site of storage of bile when there is no digestuion
Whata re bile salts prodcued from?
cholesterol
Sphincter of Oddi
Band of muscle that controls entry into the duodenum from the bile duct
What is the function of bile salts?
Help to digest fat in the small intestine
What happens to bile salts in the small intestine?
Bile salts are not lipid soluble = not
absorbed by diffusion from the SI
- They function throughout the entire
length of the SI before being
absorbed at its end
- Absorbed bile salt molecules are
returned to the liver
= enterohepatic circulation
What regulates bile secretion?
Parasympathetic activity, mediated via vagal nerves and secretin
Most important factor determining the volume of bile is
the amount of bile salts in the bile canaliculi
- when the concentration of bile salts in the portal
blood rises the amount of bile released from the
hepatocytes increases
What stimulates the release of secretin?
Release stimulated by acidic duodenal content
* Causes increase of HCO3
-
from pancreas
* Causes increase of bile production
Why is there a constant rate of secretion of pancreatic juice in ruminants?
The abomasum receives a continuous flow of food
When do cats and dogs have the largest increase in pancreatic juice production?
Straight after eating
What does the bicarbonate concentration in horses provide the ideal conditions for?
Fermentation in the colon and caecum
Why may horses struggle to secrete enzymes?
Produce 35-40 L of pancreatic juice so the flow rate is too high
When is bile production highest?
When the bile salts recirculate after a meal
Why is it important that dogs/cats have a gallbladder
They have intermittent meals so they need to store their bile
