Digestion and Absorption of Shit Flashcards Preview

S&F IV: Exam One > Digestion and Absorption of Shit > Flashcards

Flashcards in Digestion and Absorption of Shit Deck (13):
1

Carbohydrate Absorption

Glucose and Galactose are absorbed via co-transport w/ Na+ and then cross to blood via GLUT 2
-Na+ gradient maintained by Na+/K+ on basolateral side

*Fructose undergoes facilitated diffusion on both sides via GLUT 5 and GLUT 2

2

Lactose intolerance

Lactase deficiency causing lactose to remain in GI tract w/ water
=>diarrhea, borborygmi, gas

*Undigested lactose metabolized by bacteria

3

Protein Digestion

Enterokinase activates trypsinogen, chymotrypsinogen, and proelastase

=> Hydrolyze interior peptide bonds to di and tripeptides

4

Peptide Absorption

Di and Tri-peptides use H+-dependent PEPT1 and are hydrolyzed to AAs in the enterocyte

-Reach blood via facilitated diffusion

5

Hartnup disease

Affects uptake of neutral AAs

6

Cystinuria

Affects uptake of basic AAs

7

Iron absorption

Gastric acid dissolves ferric iron and complexes it w/ Vit C

-Uses Dcytb to become ferrous iron

=>Crosses into enterocyte via DMT1 and gets stored as ferritin

8

Iron mobilization

Ferritin gets transported out of enterocyte via ferroportin and is converted to Fe3+

-Binds to transferrin and lives happily ever after

9

Hepcidin

Liver released enzyme that binds to ferroportin when plasma [Fe3+] is high

-Iron cannot be sent into blood and is lost when enterocyte dies

10

Hemochromatosis

Defect in HFE gene causes drop in hepcidin levels

=>Excess iron collects in liver, pancreas, arteries

11

Na+ absorption

Duodenum/Jejunum= Na+/glucose, AA, or H+

ileum= Na+/Cl-

Colon= Facilitated diffusion

12

Cl- absorption

Paracellular and HCO3- exchange

13

Carbohydrate Digestion

Converted to maltose, maltotriose, and dextrin by a-amylases

-Later hydrolyzed to glucose by brush-border enzymes