Digestion Of Protein And Carbohydrates Flashcards
What stimulates the secretion of pancreatic amylase?
CCK
Which enzymes are involved in the digestion of starch to oligosachharides?
Salivary amylase
Pancreatic amylase
Which Oligosaccharides are produced form the hydrolysis of starch?
Alpha limit dextrins
Maltose
Maltotriose
What are the three brush border oligosaccharides?
- lactase
- maltase
- sucrase-isomaltase
Where does brush border digestion for oligosaccharides mainly occur?
Proximal Jejunum
Which enzymes are involved in the digestion of alpha limit dextrins?
Isomaltase
Maltase
What are the products of lactose digestion?
Galactose
Glucose
What are the products of sucrose digestion?
Glucose
Fructose
How does the absorption of glucose, galactose and fructose occur in the small intestine?
- Uptake across the apical membrane into the epthelial cell
- Glucose, Galactose- Na/glucose transporter SLGT1
- secondary active transport, glucose inlux occurs against glucose concentration gradient, Na+ gradient maintained by basolateral Na-K pump
- Fructose- GLUT5 transporter- facilated diffusion
- Glucose, Galactose- Na/glucose transporter SLGT1
- Exit across the basolaterla membrane
- facilated sugar transporter GLUT2
What transporter is involved in the transport of glucose and galactose across the apical cell membrane?
SLT-1
What does SLT-1 transporter do?
Transport glucose and galactose across apical cell membrane
What transporter is involved in the transport of fructose across apical cell membrane?
GLUT-5
What is the transport of glucose and galactose called and why?
secondary active transport because its Na driven
How does the three monosaccharides exit the basolateral membrane
through GLUT-2 transporter
What are the symptoms of lactase deficiency after ingestion of lactose
GI symptoms, diarrhea and cramps
Why does individuals with primary lactase deficiency have increased breath H2
Non absorbed lactose is metabolised by colonic bacteria to form H2, which is absorbed into the blood and excreted by the lungs
Which dietry proteins are absorbed intact?
Antigenic proteins
Who can absorb intact proteins in substantial amounts?
Neonates- up to 6 months. From colostrum through endocytosis
What is the first pathway for digestion of proteins
Digestion of proteins into peptides by luminal enzymes. Digestion of peptides into amino acids by luminal enzymes
What is the second pathway for digestion of proteins
Digestion of protein into peptides by luminal enzymes Digestion of peptides into amino acids by brush border enzymes
What is the third pathway for digestion of proteins
Digestion of proteins into oligopeptides by luminal enzymes Oligopeptides are taken up by enterocyte Digestion into intracellular amino acids by cytosolic enzymes Transport across the basallateral membrane into the blood by transporter
What is the fourth pathway for digestion of proteins
Digestion of proteins into oligopeptides by luminal enzymes Oligopeptides are taken up by enterocyte Move directly into the blood
What does gastric chief cells secrete
Pepsinogen