Small Bowel: Physiology Flashcards
(18 cards)
Where are carbohydrates broken down?
Carbohydrates are broken down in the duodenum and proximal jejunum.
In the duodenum and proximal jejunum, what is starch broken down into?
Maltose and other small glucose polymers
What enzyme is responsible for breaking down carbohydrates/starch?
Amylase, from salivary glands and pancreas
What enzymes split disaccharides into monosaccharides?
Lactase, Maltese, sucrose
Where are lactase, Maltese, and sucrose found?
At the brush border
How are monosaccharides absorbed?
Via active transport involving sodium glucose cotransporters.
Where are proteins denatured?
By gastric acid in the stomac
Name three pancreatic proteases
Trypsinogen, chymotrypsin, and elastase
What do trypsinogen, chymotrypsin, and elastase act on? What remains after their action?
These pancreatic proteases act on peptide bonds to produce peptides.
What do exopepditdases do?
Serially remove amino acids from the carboxyl end of peptides
What serially removes amino acids from the carboxyl end of peptides?
Exopeptidases
Exopeptidases serially remove amino acids from which end of peptides?
The carboxyl end
How are protein molecules absorbed?
By sodium mediated active transport
What proportion of protein absorption occurs in the jejunum?
80-90% of protein absorption occurs in the jejunum
Where are most peptides absorbed>
80-90% of protein absorption occurs in the jejunum.
What are the three stages of fat absorption?
Emulsification, Michelle formation, and enterohepatic circulation
What agents emulsify fats?
Bile salts and lecithin
Bile salts and lecithin
