Monogastric pt 7 Flashcards
What are the steps in membranous phase of digestion?
- Enzymes synthesized in the enterocytes
- Enzyme reaches apical surface
- Substrate contacts enzyme
What are the products of amylose and amylopectin in the luminal phase digestion?
- Maltose
- Isomaltose
- Maltotriose
What is the end absorbed product after the membranous phase of digestion?
- Glucose
- Fructose
- Galactose
What can GLUT 5 transport?
Fructose and glucose
What can SGLT1 carry?
Glucose and galactose
Describe the membranous digestion of poly peptides?
Apical transporters move them into the enterocyte (PepT1). Intracellular peptidases digest them into aa which are transported across the basolateral membrane
Where is the absorption phase of digestion?
Enterocytes that absorb products of luminal and membranous phase of digestion
What are the ground rules for the movement of nutrients?
- Move down electrochemical gradient
- Move towards opposite charge
Transport of what depends on the Na gradient?
- Glucose
- Galactose
- AA
What GLUT channel accepts all forms of sugars on the basolateral side?
GLUT 2
Which sugar transporter uses passive transport?
GLUT 5
Which sugar transporter is secondary active transport?
SGLT 1
Is Na important of nah?
It’s pretty important dawg. Lots of co-transporters
What are the types of fats?
- Triglycerides (plant and animal)
- Cholesterol and cholesterol ester (plant, animal ,waxes)
- Phospholipid (plant and animal)
- Vitamins (A,D,E,K)
What type of diet leads to more digestion of lipids?
Carnivores
Fat digestion relies on…
Mechanical processes (emulsification) and chemical processes (hydrolysis)
What are the steps in digestion of fats?
- emulsification
- Hydrolysis
- Micelle formation
- Absorption
What is emulsification?
Lipids are reduced in size to make a stable suspension and in the SI bile is released and the bile salt surrounds it and reduces surface tension and particle size
What is hydrolysis?
Pancreatic lipase and co-lipase cleave
-Triglycerides -> fatty acids and monoglycerides
What is micelle formation?
Product of lipid hydrolysis ( much smaller) with bile acids and phospholipids. Tranfer the components to the apical membrane to be absorbed
How do micelles enter enterocytes?
Go through the unstirred layer and get close to the apical membrane and fatty acid binding proteins on the apical surface that brings in the lipids.
What happens to lipids once they enter the enterocyte?
RER repackages them (much bigger) to make chylomicrons and they then enter the circulation through the lymphatics to then enter the vena cava
How are bile acids absorbed?
Takin in by apical Na-BA transporter and the taken out by organic solute transporter on the basolateral side
