GI digestion and absorption Flashcards
(128 cards)
1
Q
___: process whereby complex nutrients are broken down into simpler nutrients
A
digestion
2
Q
___ ___: consists of all the physical movements of the digestive tract breaking apart the food particles into smaller particles
A
mechanical digestion
3
Q
___ ___: consists of all the changes in chemical composition that foods undergo in their travel through the digestive tract
A
chemical composition
4
Q
chemical digestion usually occurs through ____
A
hydrolysis
5
Q
20% of alcohol is absorbed in ___
A
stomach
6
Q
80% of alcohol is absorbed in the ____
A
jejunum
7
Q
water is absorbed at the junction of ___ and ___
A
jejunum
ileum
8
Q
alcoholic gastritis stimulates ___ secretion and destroys the ___ ____
A
HCl
mucosal barrier
9
Q
____ used for the absorption of B12
A
coballenin
10
Q
villi and micovilli increase absorption by ___ fold
A
10000
11
Q
__ __ of villi is a lymphatic capillary for fat absorption
A
central lacteal
12
Q
blood capillaries of villi can absorb __ ___ if they are small enough
A
fatty acids
13
Q
carbs account for approx ___% of ingested calories
A
50
14
Q
carbs are present in __ and __ chains
A
straight
branched
15
Q
2 major sources of carbs in the human diet
A
sucrose
lactose
starches
16
Q
__ ___ can hydrolyze up to 30-40% of ingested starch into oligosaccharides
A
salivary amylase
17
Q
salivary amylase normally hydrolyes less than __% in the mouth
A
5
18
Q
salivary amylase can only hydrolyze ___ __:___ linkages to maltose, maltotriose, and dextrans
A
alpha 1:4
19
Q
pancreatic amylase is highest in concentration in the ___ lumen
A
duodenal
20
Q
pancreatic amylase rapidly hydrolyzes starch to ___, ___ and ___
A
oligosaccharides
maltose
maltotriose
21
Q
oligosaccharide hydrolases are present in the brush border with highest concentration in ____ and ___ ___
A
mid jejunum
proximal ileum
22
Q
oligosaccharide hydrolases: hyrolysis is the ____-___ step in digestion/absorption
A
rate-limiting
23
Q
___ has the lowest specific gravity
A
lactase
24
Q
carbs are broken down to glucose, galactose and fructose are transported to the liver by ___ ___ vein
A
hepatic portal
25
carb absorption is through ___ ___
active transport
26
glucose absorption in ___ and __ ___
duodenum
| proximal jejunum
27
fructose is absorbed by ___ ___ which may be carrier-mediated
facilitated diffusion
28
___ follows movement of carbs
water
29
some carb movement by ___ ___
solvent drag
30
Na+ is symported with ___ and ___ from the lumen to the epithelial cell of the small intestine
glucose
| galactose
31
the symporter of Na+, glucose and galactose is through ____ ___
SGLT 1
32
frustose is brought in the epithelial cell of the small intestine by ___ __
GLUT 5
33
glucose, galactose, and frustose is taken out of the epithelial cell to the blood by ___ _
GLUT 2
34
proteins are digested to __ ___ monomers
amino acid
35
gastric digestion:
| - __-__% of protein is broken down to amino acid
10-20
36
gastric digestion:
| - ___ splits protein into proteases, peptones, and large polypeptides
pepsin
37
pepsin is the active form of ___
pepsinogen
38
pepsinogen is activated by ____
acid
39
pepsin functions best at pH __-__
2-3
40
pepsin has ability to digest ___
collagen
41
intestinal digestion:
| - most protein (___-___%) digestion occurs in the __ ___ __ due to ___ enzymes
80-90
upper small intestinal
pancreatic
42
____ and ___: digest proteins into peptides
trypsin
| chymotrypsin
43
___: cleaves from C-terminus (carboxyl end of polypeptides)
carboxypeptidase
44
___: converted to elastase, digesting elastin fibers
proelastase
45
small percent of proteins are digested to ___ ____
amino acids
46
intestinal digestion:
| - digestion of peptides by ____
peptidases
47
inside the cytosol of the intestine, the tripeptides and dipeptides of proteins are broken down to ___ ___
amino acids
48
__% of proteins are absorbed as ___ ___
amino acids
49
trypsinogen is activated by ____ to trypsin
enterokinase
50
enterokinase is found in ___
enterocytes
51
amino acids appear rapidly in the ___ ___ system
hepatic portal
52
dipeptides and tripeptides are brought into the epithelial cells of the small intestine and can either get changed into ___ ___ or go directly into the ___
amino acids
53
dipeptides and tripeptides gets changed into amino acids by ____
peptidase
54
___ are a major constituent in foods of animal origin
triglycerides
55
____: hydrophillic and hydrophobic ends
amphipathic
56
cholesterol is not considered fat because its not made of ____ ____
fatty acids
57
____ digestion occurs in the stomach
little
58
gastric digestion normally occounds for ___% of fat hydrolysis through gastric and lingual lipase
10
59
gastric digestion begins emulsification of fat through ____ and ___
churning
| mixing
60
stomach empties chyme __ into small intestine
slowly
61
fats are insoluble in ___ and ___
water
| chyme
62
fats are solubilized in ___ by ____, __ ___, and __ ___
lecithin
bile salts
fatty acids
63
emulsion in the intestine is stable at pH of ___-___
6 - 8.5
64
luminal concentration of pancreatic lipase is highest within ____ hour after meal
first
65
emulsifying agents break fat into smaller particles in order to ___ surface area for absorption
increase
66
bile salts enter the duodenum with gallbladder contraction usually within ___ ___ of a meal
30 minutes
67
TGs broken into monoglycerides and FAs by ___, ____ and ___ lipases
lingual
gastric
pancreatic
68
cholesterol esters broken into cholesterol and FA by __ ___ ____
cholesterol ester hydrolase
69
phospholipids broken into lysolecithin and FA by ____ ___
phopholipase A2
70
FAs and monoglycerides associated with ___ in intestinal lumen
micelles
71
FAs and monoglycerides resulting fron fat digestion leave ___ and enter epithelial cell by ___
micelle
| diffusion
72
FAs are used to synthesize TGs in ___ ___ ____
smooth endoplasmic reticulum
73
fatty globules are combined with proteins to form ___ within the ___ ___
chylomicrons
| golgi apparatus
74
vesicles containing chylomicrons migrate to the ____ membrane, extruded from the ___ cell, and enter a ___
basal
epithelial
lacteal
75
lymph in the lacteal transports ____ from the intestine
chylomicron
76
___: excessive fat in the stool
steatorrhea
77
___ ___ disease decreases fat absorption by 50%
biliary tract
78
____ deficiency decreases fat absorption by 66%
pancreatic
79
ileal defect causes __ ___ malabsorption
bile salt
80
DNA and RNA are hydrolyzed to their nucleotide monomers by ___ ___
pancreatic nucleases
81
nucleotides are then broken apart by ___ and ___ releasing free bases, pentose sugars, and phosphate ions
nucleosidases
| phosphatases
82
nitrogenous bases, pentose sugars, and phosphate ions are transported ___ across the epithelium by special carriers in the ___ epithelium, then entering the ___
actively
villus
blood
83
most electrolytes are absorbed along the ___ length of the small intestine
entire
84
iron and calcium absorption is largely limited to the ___
duodenum
85
active transport of Na+ out of the cell into the blood pulls ___ in from the bush border of the intestine due to a concentration gradient
Na+
86
some ___ is absorbed with sodium ions
Cl-
87
negatively charged Cl- are ___ ___ by positive electrical charges of sodium
dragged passively
88
___ is actively secreted into the lumen in exchange for chlorine
bicarbonate
89
___ move across intestinal mucosa by facilitated diffusion in response to changing osmotic gradients
K+
90
as water is absorbed from the lumen, ___ is absorbed as well
K+
91
K+ absorption ____ if water absorption is hindered, as in diarrhea
decreases
92
iron and calcium absorption is intimately related to the __ ___
bodys need
93
ionic iron is ___ transported into mucosal cells, binding to ___
actively
| ferritin
94
intracellular iron ferritin complexes serve as ___ ___ for iron
local storehouses
95
ferrous iron
+3
96
ferric ion
+2
97
calcium is locally regulated by the active form of VitD, which acts as a cofactor to facilitate active ____ absorption
calcium
98
____ stimulates activation of vit D by the Kidneys
PTH
99
approximately ___L of water enter the small intestine daily
9
100
water absorbed mostly by osmosis via ___ and ___ pathways
transcellular
| paracellular
101
normal rate of water absorption is ___-___mL/hr
300-400
102
if bile salts arent enough, 4 vits wont be absorbed
A, E, K, and D
103
vit ___ binds to R protein produced by saliva
B12
104
R protein-B12 complex hydrolyzed by pancreatic enzymes and B12 binds with ___ ____
intrinsic factors
105
B12-IF complex binds to receptor site triggering ___
endocytosis
106
ileal flow is slowest ___ and peaks after ___
overnight
| meals
107
reabsorption of __, __ and ___ dominates in the colon
Na
Cl
H20
108
large intestine absorb max of __-__L of fluid and electrolyte
5-8
109
colon is able to digest small amounts of ___
cellulose
110
formation of vitamin __ and ___ happen in the colon
K
| B12
111
overuse of antibiotics can kill the colons ___
fluora
112
3 gases formed in the colon
CO2
H2
CH4
113
composition of feces: ___ water, ___ solid mass
3/4
| 1/4
114
comp of feces
- __% dead bacteria
- __-__% fat
- __-__% inorganic matter
- __-__% protein
- __% undigested roughage
```
30
10-20
10-20
2-3
30
```
115
brown color of feces related to ___ and ___
stercobilin
| urobilin
116
bilirubin is oxidized to ___ and ___
stercobilin
| urobilin
117
some ____ and ___ is absorbed by the blood and excreted by urine
stercobilin
| urobilin
118
odor of feces is caused by products of ____ action
bacterial
119
____ regulate small intestine, colonic fluid, and electrolyte transport
glucocorticoids
120
____ stimulate Na+ absorption and inhibit secretion in ileum
opiates
121
___ stimulates Na+ absorption and decreases motility
somatostatin
122
___ increase Na+ and Cl- absorption
cholinergics
123
___ stimulates fluid secretion via cAMP
VIP
124
___ reduces water absorption
gastrin
125
___/____ decrease Na, K. and Cl absorption in jejunum
secretin/CCK
126
___ stimulate cAMP and thereby decrease Na and water absorption
toxin
127
___ ___: tropical countries; infection; not specific; flattening of villi and atrophy of cell
tropical spew
128
___ ____: commin in temperate regions; autoimmune; reaction of immune system; destruction of epithelial cells (decreases absorption)
celiac spew
