digestion and absorption of macronutrients Flashcards
what is digestion?
the breakdown of complex food stuffs unto smaller absorbable units
what bonds does amylase break down?
alpha 1-4 but not alpha 1-6
what is lactose intolerance and what causes it?
intolerance to milk products
due to enzyme deficiency
lactose should be broken down in small intestine but no lactase means it travels intact to large intestine leading to bacterial fermentation leading to diarrhoea and flatulence
carbohydrate digestion.
carbohydrate digestion begins in the ______ by the action of _____ ______ . The pancreas secretes ______ ______ to produce oligo and disaccharides.
carbohydrate digestion begins in the (mouth) by the action of (salivary) (amylase). The pancreas secretes (pancreatic) (amylase) to produce oligo and disaccharides.
carbohydrate digestion.
_____ and ______ are absorbed via cotransport with ______ ions. _______ passes via facilitated diffusion.
(glucose) and (galactose) are absorbed via cotransport with (sodium) ions. (fructose) passes via facilitated diffusion.
carbohydrate absorption.
monosaccharides leave the ______ cells via _____ ______, enter the ______ blood in the villi and are transported to the _____ via the ____ ____ vein.
monosaccharides leave the (epithelial) cells via (facilitated) (diffusion), enter the (capillary) blood in the villi and are transported to the (liver) via the (hepatic) (portal) vein.
protein digestion.
Protein digestion begins in the _____ by the action of _______. This produces large polypeptides. Pancreatic enzymes in the _____ ______ then break these down into small polypeptides.
protein digestion begins in the (stomach) by the action of (pepsin). This produces large polypeptides. Pancreatic enzymes in the (small) (intestine) then break these down into small polypeptides.
protein absorption.
Amino acids are absorbed via ______ with _____ ions. Some dipeptides and tripeptides are absorbed via _____ with ____ ions and are _____ to amino acids within cells. Amino acids leave the cell by _____ _____, enter the ____ blood in the villi, and are transported to the _____ via the ____ ____ vein.
Amino acids are absorbed via (cotransport) with (sodium) ions. Some dipeptides and tripeptides are absorbed via (cotransport) with (hydrogen) ions and are (hydrolysed) to amino acids within cells. Amino acids leave the cell by (facilitated) (diffusion), enter the (capillary) blood in the villi, and are transported to the (liver) via the (hepatic) (portal) vein.
what is the function of enteropeptidase?
to convert trypsinogen to trypsin
what is the function of bicarbonate?
neutralizes acid so the enzymes can work
what is the function of trypsin and chymotrypsin?
hydrolyses peptide bonds to produce oligopeptides
which cytoplasmic peptidases are epithelial cells rich in?
carboxypeptidases
aminopeptidases
dipeptidases
what is the problem with digestion and absorption of lipids? What is the solution?
they have poor water solubility
the solution is increasing the interface between lipid and aqueous phase and stabilisation with detergents such as bile acids
digestion of triglycerides.
Digestion begins in the ____ by the action of _____ _______. Digestion continues in the ____ by the action of ____ ____. Lipids are then _____ by the detergent action of ____ _____ ducted in from the _____. The pancreas then also releases ____ ____ to produce monoglycerides and fatty acids.
Digestion in the (mouth) by the action of (lingual) (lipase). Digestion continues in the (stomach) by the action of (gastric) (lipase). Lipids are then (emulsified) by the detergent action of (bile) (salts) ducted in from the (liver). The pancreas then also releases (pancreatic) (lipase) to produce monoglycerides and fatty acids.
Fatty acid absorption.
Fatty acids and monoglycerides enter the intestinal cells via _____. They are then recombined to form ______ which combine with other _____ and _____ within the cell. This forms _____ which enter the _____ of the villi and are transported across the _____ membrane into the _____ system.
Fatty acids and monoglycerides enter the intestinal cells via (diffusion). They are then recombined to form (triacylglycerols) which combine with other (lipids) and (proteins) within the cell. This forms (chylomicrons) which enter the (lacteals) of the villi and are transported across the (basolateral) membrane into the (lymph) system.
