Absorption Flashcards
What monomers are absorbed in the ileum?
glucose and fats
How is sodium maintained as a lwo concentration in the ileum epithelial cell?
Sodium actively transported out of ileum epithelial cells and into blood by sodium/potassium pump which uses ATP
This creates a lower concentration of sodium in ileum epithelial cells and higher in ileum contents
How are glucose / amino acids transported into epithelial cells?
co-transported with Na+
through co-transport protein
glucose / aa move against conc. gradient while Na+ moves down conc. gradient
symport mechanism as Na+ and glucose go in same direction
How are glucose / amino acids moved into blood from ileum epithelial cells?
by facilitated diffusion using carrier protein
How are micelles formed?
products of lipase digestion (emulsification) that remain in association with bile salts to from micelles
What happens to micelles upon contact of surface of ileum epithelium cells
break down into monoglycerides and fatty acids upon contact with brush border
What happens to monoglycerides and fatty acids at the membrane?
diffuse across membrane into cell via simple diffusion
What happens to monoglycerides and fatty acids at the smooth endoplasmic reticulum?
are recombined to form triglycerides
What happens to monoglycerides and fatty acids at the golgi?
triglycerides associate with cholesterol and lipoproteins to form chylomicrons
What happens to the chylomicrons after being packaged?
transported by vesicle to cell membrane and released by exocytosis
chylomicrons then enter lacteal and transport the lipids via lymphatic vessels into the blood vessels
What happens to the chylomicrons after exocytosis?
enter lacteal and transport the lipids via lymphatic vessels into the blood vessels
Why are there numerous mitochondria in ileum epithelial cells?
to form ATP for active transport
What are the advantages of lipid droplet and micelle formation?
increase surface area so faster hydrolysis
micelles carry fatty acids + glycerol
