Nutrient Digestion II (Fats, Vitamins and Minerals) Flashcards
what does ingested fat form?
triacyglycerol
what enzyme is fat digestion in small intestine carried out by?
pancreatic lipase
what is lipase?
water soluble enzyme
what do triacyglycerols present as?
large lipid droplets
where can digestion only take place with regards to fat?
surface of the droplet
what is emulsification?
dividing large lipid droplets into smaller droplets
what does emulsification require?
mechanical disruption and emulsifying agent
what is mechanical disruption?
disruption of large droplets into small droplets
smooth muscle contraction grinds and mixes lumenal contents
what does emulsifying agent do?
prevents small droplets reforming into large droplets
the formation of what enhances absorption?
micelles
what is micelles?
bile salts and monoglycerides and fatty acids and phospholipids
what happens in a micelle breakdown?
release of small amounts of free fatty acids (FFA) and monoglycerides into solution
diffusion across plasma membrane of absorbing cells
after entering epithelial cells, fatty acids and monoglycerides go where?
smooth endoplasmic reticulum
what happens when fatty acids and monoglycerides enter smooth endoplasmic reticulum
reformed into triacylglycerols
what are triacylglycerol droplets coated with and what does this achieve?
amphiphatic protein
emulsification
what are extracellular fat droplets?
chylomicrons
what are the classes of vitamins?
fat soluble vitamins- A, D, E, K
water-soluble vitamins- B and C and folic acid
how are water-soluble vitamins absorbed?
passive diffusion or carrier- mediated transport
how much of ingested iron absorbed cross intestine into blood?
10%
what does iron in blood bind to?
transferrin
what is hyperaemia?
increased ferritin levels
more iron bound in enterocytes
what is anaemia?
decreased ferritin levels
more iron released to blood
