GI-3 Flashcards
epithelial cell bicarbonate secretion depends on ______
CFTR
proenzymes secreted by acini in the pancreas
zymogens
Prevent pancreatic gland cells from self digestion (autodigestion)
zymogen granules
pancreatic fluid is rich in
bicarbonate
damage of acinar cells leads to_____
autodigestion
main causes of pancreatitis
gallstones, alcohol, drug reactions
Food leaves the small intestines via ____
mesenteric vein, then the portal vein to the liver
end products of starches
glucose, galactose, fructose
End products of proteins
amino acids
End products of triglycerides
Free fatty acids and glycerol
end products of phospholipids
free fatty acids and lysophosphlipids
end products of cholesterol esters
cholesterol and free fatty acids
why is lipid digestion more complicated than carbohydrate or protein?
Requires healthy function of liver, pancreas, and enterocytes
what prevents further aggregation of fat droplets
amphipathic bile salts
what enzymes attach to fat cells after bile salt?
lipase and colipase
ferries fat digestion products to brush border
micelles
how are water-soluble vitamins absorbed?
membrane transporters
Vitamin B12 binds to _____ in the small intestine
intrinsic factor
where is vitamin B12/IF complex absorbed
terminal ileum to portal blood and then throughout body/bone marrow
Iron absorption is dependent on: __
Divalent ion membrane transporter-1 (DMT-1)
Common Mechanisms of diarrhea (4)
- secretory
- malabsorptive
- Osmotic
- Inflammatory
Common example of malabsorptive diarrhea
celiac disease
loss of gut surface area
malabsorptive
lactase deficiency
osmotic mechanism - lactose ingestion results in osmotic pull of lactose remaining in the gut.
Example of secretory diarrhea
cholera, E. coli
example of inflammatory diarrhea
IBD - direct damage to the mucosa or intestinal wall
lab test (histology) found in celiac disease
CD4+T cells and activated intraepithelial lymphocytes
In celiac disease, ingestion and partial digestion of gluten produces ______
gliadin peptides which increases antigenicity and stimulate CD4 T-helper cells creating adaptive immune response.
Hereditary nonpolyposis colon cancer
Lynch Syndrome
Hallmark of lynch syndrome
numerous polyps
Autosomal dominant - increases risk of other cancers
Lynch syndrome
Most common cause of pediatric gastroenteritis
rotovirus and norovirus
Parasitic gastroenteritis
Giardia
cryptosporidium
common signs of GERD in infants and charildren
pain, recurrent vomiting, dysphagia, food refusal.
Most common cause of bowel obstruction in children
Intussusception (ages 6 months-3 years)
Compression of bowel and blockage of blood flow
intussusception - leads to ischemia
Hirschsprung disease
failure of enteric neurons to innervate a segment of large intestine
Causes lack of motility/failure to defecate shortly after birth
Hirschsprung disease
hypertrophy of circular and longitudinal muscle layers or pylorus
Hypertrophic pyloric stenosis
diagnosed by repeated vomiting, weight loss, dehydration. Present at birth. Surgery may be needed
Hypertrophic pyloric stenosis
