Physiology Flashcards
(26 cards)
What is the function of Endopeptidases?
Hydrolyze interior peptide bonds of polypeptides and proteins
What is the function of trypsin?
Attacks peptide bonds involving basic amino acids; yields products with basic amino acids at C-terminal end
What is the function of chymotrypsin?
Attacks peptide bonds involving aromatic amino acids, leucine, glutamine, and methionine; yields peptide products with these amino acids at C-terminal end
What is the function of elastase?
Attacks peptide bonds involving neutral aliphatic amino acids; yields products with neutral amino acids at C-terminal end
What is the function of exopeptidases?
Hydrolyze external peptide bonds of polypeptides and protein
What is the function of Carboxypeptidase A?
Attacks peptides with aromatic and neutral aliphatic amino acids at C-terminal end
What is the function of Carboxypeptidase B?
Attacks peptides with basic amino acids at C-terminal end
Which intestinal enzyme activates the rest of the intestinal enzymes?
Trypsin
What is the name of the enzyme that turns trypsinogen into its active form?
Enterokinase
What is the defect in Hartnup disease?
There is no apical amino acid transport for L-Phenylalanine
What is the defect in Cystinuria?
There is no apical amino acid transport for L-arginine or cystine
What is the defect in lysinuric protein intolerance?
There is a defect in the basolateral amino-acid transport of lysine (SLC7A7 defect)
What does lingual, gastric, and pancreatic lipase turn triglycerides into?
Monoglycerides and 2 fatty acids
What does cholesterol ester hydrolase turn cholesterol ester into?
Cholesterol and fatty acid
What does Phospholipase A2 turn phospholipids into?
Lysolecithin and fatty acid
What are the 5 Lipid digestive and absorptive abnormalities that can cause steatorrhea?
- Pancreatic insufficiency
- Acidity of duodenal contents
- Deficiency of bile salts
- Bacterial overgrowth
- Decreased intestinal cells for absorption
- Failure to synthesize apoproteins
What soluble vitamins are dependent of what type of transporter?
Na+-dependent cotransport (exception Vit. B12)
What is the pathway for absorption of vitamin B12?
(1) Dietary vitamin B12is released from foods by the digestive action of pepsin in the stomach. (2) Free vitamin B12binds toR proteins,which are secreted in salivary juices. (3) In the duodenum, pancreatic proteases degrade the R proteins, causing vitamin B12to be transferred to intrinsic factor, a glycoprotein secreted by the gastric parietal cells. (4) The vitamin B12–intrinsic factor complex is resistant to the degradative actions of pancreatic proteases and travels to the ileum, where there is a specific transport mechanism for its absorption
What is osmotic diarrhea?
Presence of nonabsorbable solutes in the lumen of the intestine.
What is secretory diarrhea?
Excessivesecretionof fluid by crypt cells
Why Oral Rehydration Solution is used to treat diarrhea?
Oral rehydration solutionis beneficial in the treatment of diarrheal disease worldwide.
It contains glucose, Na+, Cl−, and HCO3−, which stimulate intestinal absorption of fluid and electrolytes
(i.e., Na+-glucose cotransport), thus offsetting the massive secretion of fluid and electrolytes.
What are some common causes for gallstones?
- Too much absorption of water from bile
- Too much absorption of acids from bile
- Too much cholesterol in bile
- Inflammation of epithelium
What are the most common causes of pancreatitis that are gender specific?
Women-gallstones
Men-alcohol
Which ligament is used as a clinical dividing line between the upper and lower GIT?
The Suspensory muscle (ligament) of duodenum (ligament of treitz)
