nutrient digestion Flashcards
digestion
enzymatic conversion of complex dietary substances to a form that can be absorbed
types of digestion
luminal and membrane
What is luminal digestion mediated by
pancreatic enzymes secreted into duodenum
what is membrane digestion mediated by
enzymes sitauted at the bruhs border of epithelial cells
absorption
process by which absorbale products of digestion are transferred across apical and basolateral membranes of enterocytes
what are enterocytes
absorptive cells of the intestinal epithelium
name of overall process of digestion and absorption
assimilation
what is the main energy source
starch
what is starch stored as
carbohydrate
what is starch composed of
amylase and amylopectin; polysacharides
difference between poly and mono sachhardies
long chain of carbs composed of monos v simplest form of carbs
what are monosacharides as chemicals
aldehydes/ ketones
what are amylose and amylopectin broken down to
oligosaccharides
what are oligos broken down to
monosachharides
what are examples of monos
fructose and glucose
what breaks the bonds in amylose
alpha amylose
what breaks down oligosaccharides
oligosaccharidases
how do monos get into the cell
via transporters
how are proteins broken down
via enzymes in the lumen a little in th elumen then further at bruhs border into a fragment of a peptide
what are peptides broken down into and where do they go
brooken down into amino acids and go straight into the blood
what are exopeptidases
broken down into an amino acid starigth away
what are endopeptidases
broken down into a fragment before amino acids
how are glucose and galactose absorbed into mucosa of gi tract
via secondary active mediated by SGLT1
how is fructose absorbed
via facilitated diffusion by glut5
how do monosaccharides exit GI mucosa
via facilitated diffusion through GLUT5
How are proteins brokoen down in the stomach
HCL denatures them and pepsin cleaves proteins into peptides
what breaks down the peptides
trypsin, chymotrypsin, elastase, carboxypeptidase A and B
how are fat soluble vitamins absorbed
via passive diffusion into enterocytes where they are incorporated into chylomicrons for release into lymphatics
what are fat soluble vitamins
A,D,E,K
