13. Breakdown Of Food Flashcards
D scribe breakdown of carbs
1 Polysacc>disacc
2 disacc>monosacc
& enzymes involved
- Starch&glycogen>maltose (amylase)
- Maltose>Glucose(maltose)
Sucrose>fructose&glucose(sucrase)
Lactose>galactose&glucose(lactase)
Describe absorption of monosaccharides
- Na+ cotransporter w glucose or galactose into cell
- Fructose transported into cell by GLUT5
- Fructose and either glucose or galactose cotramsported out by GLUT2
- Na+/K+ATPase pumps Na+ out to maintain low Na+ conc in cell
Production and absorption of short chain fatty acid occurs in (5,9)
Large intestine
Breakdown and absorption of protein flow diagram
Exogenous (dietary) & endogenous protein
+pepsin
+pancreatic proteases
(Also membrane bound peptidase)
Di&tri peptides and amino acids
Route 1:di/tri peptides
Enter villus epithelial cell via PEPT1
Intra cell peptidases break down into aa
Na+independent channel transports it to capillary
Route 2
Na+ in/dependent channel transports aa into cell
Na+ independent channel transports aa to capillary
Na+/k+ ATPase maintains low Na+conc in cell
Describe production of pepsin
1 what cell & where in body
2 activation
- Gastric gland in stomach: Chief cell makes pepsinogen
- Parietal cell makes HCl
Activates pepsinogen to pepsin away from the chief cells
Trypsin activation
- Where
- Activation process
- What trypsin does
- duodenum
- Pancreatic duct releases pancreatic zymogen, trypsinogen
Enterokinase on brush border activates to trypsin - Protease
Digestion and absorption of lipids
- Outside cell
- Inside cell
- Once inside body system
- Large lipid droplet
+mixing with bile Salts=micelles
+pancreatic lipase=monoglyceride+fatty acid
Enter mucosal cell of small intestine - ER converts them back to triglyceride
Form chylomicrons
Exocytosed into lymphatic vessel
3a. Chylomicron travels lymph>blood
3b. Adipose tissue’s lipoprotein lipase convert to fatty acid>+glycerol3p (not g3p)>triacylglycerol
3c. Chylomicron remenant>liver
Liver: remnant>cholesterol&(+glucose=)triacylglycerol
TGL & chow transported via v large dense lipoprotein>muscle +fat(3b)
3d. After adipose, remaining tgl/chol>liver
Fat soluble vits
- Which ones (4)
- How they absorbed
- ADEK
- D absorbed into chylomicron & fit d binding protein
Others (AEK) passively absorbed into small intestine (facilitated by bile)>join chylomicrons
Other names for fit ADEK
Role & associated conditions
A=retinol
D=colecalciferol
E=tocopherol
A=epithelial tissue maintenance,vision; night blindness & xerophthalmia (impaired immunity)
D=bone calcification, PTH;rickets, osteomalacia
E=antioxidant; neuromusc problems, anaemia retinopathy, dysarthria (speech not clear)
K=blood clotting;bleeding
*****B12 absorption
- Dietary intake; is bound to animal protein; transcobalamin/salivary r protein>??
- In stomach separated and binds to R protein made by parietal cell. This goes into duodenum w intrinsic factor (made by parietal)
Note Cbl-r protein also secreted in bile - Pancreatic proteases break down r protein and in jejunum, Cbl binds with IF
- Ileal mucosal cell: receptor/transporter cubilin transport into cell
Cbl&IF separated, cbl now bound to transcobalamin and transported via portal system bound to TC1,2 or 3 - When reaches cell, cbl separated from tc and converted to methyl and adenosyl cb
Role of water soluble vitamins (B1,2,3,6,12 & folic acid)
Include other names (no need to include associated conditions)
B1; thiamine; carb metabolism B2; riboflavin; H transfer B3; niacin; H transfer B6; pyridoxine; protein metabolism B12; cyanocobalamin; rbc formation Folic acid; singer carbon metabolism (low of this=foetal neural tube defect)
**iron absorption
.
Ca2+ absorption
.
Role of minerals
.
What is absorbed where
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