GI 5 Flashcards
Three main categories of pancreatic secretion
- Endocrine secretion
- Digestive enzyme secretion
- Bicarbonate secretion
Pancreas are composed of
Contains endocrine secretory epithelium
Exocrine secretory epithelium
Digestive enzymes and NaHCO3
How are pancreatic enzymes released
by zymogens
how are pancreatic zymogens activated
Tripsinogen converted to trypsin by enteropeptidase (Brush border enzyme)
Trypsin activates zymogens
Role of bicarbonate in pancreas
They are produced in duct cells and neutralizes acid entering from stomach
Cystic fibrosis alters
Pancreas secretion
gallbladder
Storage redevoir for liver
Liver secretes
Bile
What id bile secreted by
Hepatocytes
What is bile
non enzymatic solution
3 main components:
bile salts
bile pigments
cholestrol
Main role of bile is
Lipid Digestion
Bile
Dissociates the lipid molecule (takes it apart)
What inhibits gastric acid secretion
Somatostatin
Steps of Fat absorption
- Bile salts from live coat fat droplets
- Pancreatic lipase and collapse break down fats into monoglycerides and fatty acids stored in micelles
Cholesterol are packed in
Chylomicrons
How are chylomicrons released
By the lymphatic system
Bile
It recycles
Gallstones
hardened deposits likely due to excess cholesterol or bilirubin
Upper right abdominal pain, jaundice
Steps of carbohydrates digestion
Amylase (salivary and pancreatic) break down glucose polymers to disaccharides (maltose)
Disaccharides are broken down into monosaccharides
two categories of protein digestion
Endopeptidases
Exopeptidases
Endopeptidases
Cleave proteins to smaller peptides
Attack Peptide bonds in the amino acid chain forming fragments
- Released as zymogens
- Pepsin, trypsin and chymotrypsin
Exopeptidase
Release single amino acids for peptides one at a time
Aminopeptidase
Amino terminal end enzyme
Carboxypeptidase
Carboxy terminal end
(most of it)
Digestive enzymes in the stomach are produced in
Chief cells
ECL cells secrete
histamine
Protein absorption
Mostly free amino acids
olingopeptide transporter
H+ cotransporter
Larger peptides are transported
By transcytosis
(Relatively small)
Vitamin and Mineral absorption
Fat soluble vitamins (A, D, E and K absorbed with fats
Water soluble C and B are absorbed by mediated transport
B12 is absorbed in the ileum after forming a complex with intrinsic factor released from parietal cells
Mineral absorption is usually by active transport
