Accessory Organs of the Digestive System Flashcards
How does the pancreases connect to the small intestine?
connects to the upper portion of the small intestine via 2 ducts where the juices come into contact with the chyme
What are some of the exocrine cells of the pancreas?
ductal
acinar
Where are alpha, beta and delta cells found?
not connected to the pancreatic duct
-in the islets?
What are acinar cells?
At the end of the duct is there region with the cells that start to form the duct
What are the 8 exocrine secretions from the pancreases?
- Bicarbonate
- Pancreatic amylase
- Pancreatic lipase
- Trypsinogen
- Chymotripsinogen
- Procarboxypeptidase
- Prophospholipase
- Procolipase
What is the function of bicarbonate when secreted from the pancreases?
Released from ductal cells
- helps neutralize stomach acid
- can function right away
What is the function of pancreatic amylase when secreted from the pancreases?
Released from acinar cells
- Digests carbs
- functions right away
What is the function of pancreatic lipase when secreted from the pancreases?
Released from acinar cells
-digests lipids
What is the function of trypsinogen when secreted from the pancreases?
Released from acinar cells
- digest protein
- inactive form inside pancreases but out side it converted to active enzyme trypsin
What is the function of chymotrypsin when secreted from the pancreases?
Released from acinar cells
- digest protein
- inactive form inside pancreas and transformed into active form outside
What is the function of prophospholipase when secreted from the pancreases?
Released from acinar cells
- Digests phospholipids (foods with membranes)
- incactive form inside pancreases and transforms to active form phospholipase outside
What is the function of Procolipase when secreted from the pancreases?
Inactive then transforms into collapse which is not an enzyme but helps an enzyme to digest fats
What are zymogens?
inactive form of enzymes
How is trypsinogen activated?
When released from pancreatic duct, it combines with enteropeptidase in thee brush border of SI lumen which converts it to trypsin.
Why is the conversion of trypsin so important?
It functions as an enzyme to turn all zymogens into their active form
What re the endocrine secretions of the pancreases?
Coming from the islets of langerhaus:
- Insulin- released by beta cells
- Glucagon- released by alpha cells
- Somatostaitin- released by delta cells
What are the main cell types of the liver?
Hepatocytes
What are the function of hepatocytes?
secrete a bile solution that aids in digestion and therefore the absorption of lipids
What are cancliculi?
Small ducts in between hepatocytes which secrete bile solution
What to all caniculi eventually merge into?
right and left hapatic duct and then those two merge into the common hepatic duct
What are sinusoids?
Vessels surrounding hepatocytes. They are permeable blood capillaries that receive blood from hepatic artery which is O2 rich and hepatic portal vein which is nutrient rich
What do hepatocytes retrieve from sinusoids?
Substances, like absorbed macronutrients and then metabolize them before they are secreted back into the blood.
What is the path of the flow of blood through the liver?
Aorta> Hepatic Artery> Liver capillaries> Hepatic vein> Inferioir vena cava
Aorta> Digestive tract Arteries> Digestive capillaries> Hepatic portal vein> Liver capillaries> Hepatic vein> Inferior vena cava
What are the 4 main functions of the liver?
- Synthesis of bile salts to help break down lipids
- Excretion of bilirubin-waste products derived from hemoglobin (aren’t good for us)
- Metabolism of carbs, lipids and proteins- stores them or converts them
- Processing of drugs- process for body to use and excrete
Where is the bile solution produced?
By hepatocytes
Where is bile stored ?
In the gall bladder until it is stimulated for release into the small intestine
Does bile salt have any enzymatic properties?
NO
-they do help in the digestion of lipids but only to help expose more lipid to the enzymes(lipase) that digest them
How does bile help in digestion of lipids?
Lipids are hydrophobic and do not dissolve well in aqueous environment. Bile salts help make lipids more soluble = emulsification
What are the 4 components of bile salt?
- BIle salts- helps lipid digestion
- Cholesterol-excess is excreted because we make a lot
- Bile pigments-bilirubin gives it the yellow colour
- Water and ions- make solution less viscous, ions so it can live in the body
What why is it a good thing for bile to sit in the gallbladder for a long time?
It becomes more concentrated as some of the water and ions are reabsorbed.
-concentrated bile is better able to help in the digestion of fats
How do you release bile?
Hormonal control to secrete bile through the common bile duct into the duodenum by a muscular contraction fo tissue surrounding the gallbladder
