Digestion/Absorption of Biomolecule CCP Flashcards
necrotizing enterocolitis
risk factor: low birth weight enteral feeding bacterial colonization (after birth) intestinal ischemia
pathology NEC
terminal ileum, cecum, right colon
necrosis
due to irreversible cell damage
in this case ischemia
mechanism of necrosis
mitochondria failure
-cytochrome C release
premature baby
can't make mucus less peristalsis less gastric acid less immune response less tight junctions
allow bacteria to kill enterocyte
apoptosis
intrinsic - cytochrome c from mito
extrinsic - TLR to caspases
duod and prox jejunum
Na absorption - nutrient coupled and Na/H exchanger
Cl absorption - passive (voltage dependent)
-driven by Na/nutrient coupled
Cl secretion - throughout intestine CFTR
carb, protein, lipid absorption
calcium - active in duodi (VIt D)
Iron and Folate - exclusively duodenum
Fat-soluble vitamins A D E K
Mg and P
also, pancreatic enzymes and hormones
lieum
parallel Na/H and Cl/HCO3 exchnager
electroneurtal
enterotoxin sensitive
Cl absorption - electroneutral
K absorption -passive
little food and nutrients
bile salts - exclusive to ileum
cobalamin - exclusive to ileum
loss of ileum
Vit B12 deficiency (pernicous anemia)
steatorrhea (sudan III test)
colon
secrete K, absorb H2O Na Cl
Na absorption - parallel exchangers and epithelial Na channels
Cl absorption - passive and Cl HCO3 exchanger and parallel exchnager
K secretion - passive and active (Na)
K absorption - only distal colon
colon
absorb short chain fatty acid
loss of ileocecal valve
colonic bacteria in small intestine
results in D-lactic acidosis
small bowel adaptation
after resection changes occur
-epidermal growth factor important
SGLT1 - small intestine, colon
PepT1 - now in colon
NHE-3 - small intestine
weaning with SBS
30 50
60 60
100 100
