Digestion and Absorption Flashcards
1
Q
digestion in the mouth
A
- lipids - lingual lipase
- carbs - alpha amylase
- protein - none
2
Q
digestion in the stomach
A
- lipids - gastric lipase
- carbs - none
- protein - HCl denatures secondary and tertiary structures, pepsin is activated
3
Q
digestion in the intestine
A
- lipids - pancreatic lipase, colipase, cholesterol esterases, phospholipase A2
- carbs - pancreatic amylase, glucoamylase, sucrase-isomaltase, trehalase, lactase-glucosylceramidase
- protein - trypsin, chymotrypsin, elastase, carboxypeptidase, aminopeptidases
4
Q
characteristics of salivary alpha amylase
A
- endoglucosidase
- hydrolyzes alpha 1,4 bonds
- inactivated by low pH of the stomach
5
Q
characteristics of glycoamylase
A
- exoglucosidase
- specific for alpha 1,4
- starts at non-reducing end
6
Q
characteristics of sucrase-isomaltase complex
A
- most of the intestines ability to hydrolyze alpha 1,6
7
Q
characteristics of trehalase
A
- breaks down alpha 1,1 bonds
8
Q
characteristics of beta- glycosidase
A
- breaks beta 1,4 bonds between galactose and glucose
- lactose site
- active in young children
- susceptible to injury
9
Q
pepsinogen activation
A
- low pH (high H concentration)
10
Q
trypsinogen activation
A
- enteropeptidase
11
Q
chymotrypsinogen activation
A
- trypsin
12
Q
proelastase activation
A
- trypsin
13
Q
procarboxypeptidase activation
A
- trypsin
14
Q
function of colipase
A
- binds to fat and lipase activating pancreatic lipase
15
Q
ApoE
A
- recognized by liver cells
- digestion by lysosomes
16
Q
ApoCII
A
- activates lipoprotein lipase
- digestion of TGs in muscle and adipose
17
Q
vitamin B12
A
- requires binding parters such as IF
- absorbed in the ileum by transcobolamin
18
Q
sources and absorption of iron
A
- heme - from red meats, nonheme from plants
- absorbed in duodenum and jejunum
- transferrin binds for transport and ferritin binds for storage
19
Q
absorption of calcium
A
- duodenum absorption regulated by vitamin D and parathyroid hormone
20
Q
absorption of sodium
A
- over 50% absorbed in jejunum
- absorbed by cotransporters
21
Q
absorption of bicarbonate
A
- reabsorbed in duodenum and jejunum
- Cl/HCO3 exchanger
22
Q
complication of cystic fibrosis
A
- blocked pancreatic duct resulting in decreased secretion of pancreatic enzymes
- malabsorption
- treat with pancreatic enzymes
23
Q
gallstones
A
- precipitated bilirubin
- fats are not digested
- deficiencies of fat soluble vitamins
24
Q
abetalipoproteinemia
A
- lack of microsomal triglyceride transfer protein (MTP)
- limited synthesis of chylomicrons (ApoB-48) or VLDL (ApoB-100)
- steatorrhea, caloric and vitamin deficiencies
25
Hartnup's disease
- absence of neutral amino acid transporter
- high levels of amino acid in urine
- niacin deficiencies
- di and tri peptide absorption can compensate
