Nutrients, Digestion and Absorption Flashcards
What is Lactose ?
glucose + galactose (lactase)
What is Sucrose ?
glucose + fructose (sucrase)
What is Maltose ?
glucose + glucose (maltase)
What border contaisn enzymes for diasach breakdown?
Brush border of mebranes
What is the result of unbroken Lactase in SI?
Osmotic drop, diarrhea and LActose INtolerance
WHat is Alpha amylose?
glucose linked in straight chains
WHat is amylopectin?
glucose chains highly branched
What is Cellulose?
Unbranched, linear chains of glucose monomers linked by A-1,4 glycosidic bonds
How does Glu enter from lumen to Blood?
Epi cells have SGLT1 transporters, enters epithelium then Glu can go through GLUT-2 transporters and Na is pumped across to allow H2O to follow conc gradient
How does Fructose cross epi to blood?
No blood fructose control it is just metabolised directly,
Enters epi via Glut 5 and exits via Glut2
What percentage of amino acids are dipeptodes or tripeptides?
66 percent
What are Enzymes which hydrolyse peptide bonds and reduce proteins called?
Peptides and proteases
What are the two types of peptidases?
Endo and Exco
What are the 2 type sof excopeptidases?
Aminopeptidases and carboxypeptidases
How does amino acids enter from epi to blood?
SAAT1
allows amino acids and na to cross epi-lumen barrier after which amino acid is transported out and NA/K pump allows na out into blood
How do di/tri peptides cross?
PepT1 pumps H ion and Dipeptide in to cell and Dipeptide is excreted out of cell to blood via own spec channe,
H ion pumped back out in exchange for Na which goes through Na/K.
This H creates a microclimate of acidity
What form are almost all digested fats in?
triacylglycerol
What digests fat in SI?
Pancreatic lipase
Triacylglycerol goes to monoglyceride and 2 fatty acids
What does emulsification require?
Mechanical Disruption - caused by smooth muscle contraction
Emulsifying Agents - Prevents re-aggregation e.g Bile salts + Phosopholipids (amiphatic - polar and non polar)
What 4 things constitute a micelle?
Bile Salt + Monoglycerides + Fatty Acids + Phospholipids
What does a chylomicron contain?
Phospholipid, Cholesterol, and fat soluble vits
How do Chylomicrons eneter into blood?
Between Endothelial cells as can not pass through capillaries
Pass through LACTEALS
Which vitamins are fat soluble?
ADEK
Which are water soluble?
B, C and folic
What does vit B12 bind to in the stomach?
Intrinsic factor so can be absorbed in distal ileum
What is the result of B12 insfficency?
Pernicious anemia, failure of RBC to mature
Which part of the membrane does Iron get transported through and via which transporter into duodenal enteocytes?
Via DMT1 across brush border (H coupled)
What complex is iron stored as intracellulary?
Ferritin (protein-iron complex)
What membrane does iron cross to get to blood?
serosal membrane
what is hyperaemia?
Increased ferritin levels more iron bound in enterocytes
What is anemia?
Decreased ferritin, more iron in blood
