Gastro 6 - Enterocytes And Absroption Flashcards
Where are Crypts of Liberkuhn located?
Between the villi in the small intestine.
How are Glucose, Galactose, and Fructose absorbed?
Glucose and Galactose are absorbed by Na-dependent transport. Fructose is done by facilitated diffusion.
What does the pancreatic lipase hydrolyzes triacylglycerol to?
Fatty acids. 2-Monoacylglycerol.
Where is iron absorbed? What are optimal environments for iron absorption?
It is absorbed in duodenum. It requires an acidic environment to be absorbed. Avoid eating things in excess like cereals, milk, eggs, antiacids, quinolone, tetracycline, coffee, gastric bypass surgery.
Where is Folate absorbed? What are the causes of deficiency?
Absorbed in duodenum and jejunum. Causes of deficiency are poor nutrition, alcoholism, babies feed exclusively on goat’s milk.
Where is B12 absorbed?
Absorbed in terminal ileum and requires intrinsic factor, which is produced by parietal cells. Deficiency leads to megaloblastic anemia.
What is the Schilling test?
A test to gauge Vitamin B12 levels: Radiolabeled cyanocobalamin given orally to determine if it was absorbed by the ileum. In normal circumstance, over 8% of the oral dose is recovered in the urine.
What is Abetalipoproteinemia?
Autosomal recessive, due to lack of apoprotein B. Causes defective chylomicron assembly that leads to enterocytes filled w/ chylomicron particles. This causes no chylomicrons, VLDL, LDL, abnormal star-shaped RBCs (acanthocytes), Presents in early childhood with malabsorption, failure to thrive, ataxia.
What is Celiac disease?
An autoimmune disorder, caused by intolerance to gliadin; wheat protein cross-reacts w/ small bowel tissue, leading to inflammation and Ab against gliadin and tissue transglutaminase. This leads to impaired absorption, causing foul-smelling pale stools, stunted growth, failure to thrive. Associated w/ HLA-DQ2, and HLA-DQ8. Can predispose to T-cell lymphoma, GI cancer, Breast cancer.
What does lactase do?
Breaks down lactose into glucose and galactose.
What is Whipple disease?
A systemic disease caused by Tropheryma whipplei, a G(+). Causes weight loss, lymphadenopathy, hyperpigmentation, cardiac symptoms, arthralgias, neurologic symptoms. Causes PAS-positive foamy macrophages in the intestinal lamina propria.
What are three causes of pancreatic insufficiency?
Chronic pancreatitis. Cystic fibrosis. Obstruction of pancreatic duct (gallstones, cancer).
What are the symptoms of pancreatic insufficiency?
Steatorrhea. Fat-soluble vitamin deficiencies.
What serum antibodies are associated w/ celiac sprue?
Tissue transglutaminase. Gliadin antibodies.
What organism is associated with Whipple disease?
Tropheryma whipplei.
