Prelims - NUTRIENT DIGESTION AND ABSORPTION (Dr. Lim) Flashcards
(267 cards)
1
Q
It is the enzymatic conversion of complex dietary substances to form that can be absorbed as initiated by sight, smell and taste of food.
A
Digestive Process
2
Q
Some digestion begins in __________ —> __________ —> __________
A
Mouth
Lumen of Stomach
Small Intestine
3
Q
Digestion within the SI can occur in both the
A
Lumen
SI Brush Border Membrane
4
Q
Digestion in SI LUMEN is mediated by
A
Pancreatic Enzymes
5
Q
Digestion in SI BRUSH BORDER MEMBRANE is by
A
Brush Border Enzymes
6
Q
TRUE or FALSE
Glucose may not require digestion
A
TRUE
*INTESTINAL CELLS may absorb the nutrient as ingested
7
Q
POLYMER (Protein) may be digested in lumen to its CONSTITUENT MONOMERS (AA) by __________ before absorption
A
Pancreatic Enzymes
8
Q
OLIGOMER (Sucrose) is digested into its CONSTITUENT MONOMERS (Monosaccharides) by __________ before absorption
A
Brush Border Enzymes
9
Q
TRUE or FALSE
OLIGOMER (Oligopeptide) may be directly absorbed by cell & then broken down into MONOMERS (AA) inside cell
A
TRUE
10
Q
TRUE or FALSE
TRIACYLGLYCEROL broken down into constituent components before absorption; cell may RESYNTHESIZE original molecule
A
TRUE
11
Q
__________ absorbs Carbohydrates, Proteins & Lipids
A
Entire SI
12
Q
Absorption is greatest in the ___________, less in ___________, much less in the __________.
A
Duodenum
Jejunum
Ileum
13
Q
CALCIUM, IRON AND FOLATE
Some substances are actively absorbed only in the
A
Duodenum
- CALCIUM: LOW ABSORPTION in Jejunum and Ileum
14
Q
There is LOW ABSORPTION of Calcium
A
Jejunum & Ileum
15
Q
BILE ACIDS are absorbed along the ENTIRE SI, but active absorption occurs only in the __________
A
Ileum
16
Q
COBALAMIN is absorbed only in the __________
A
Ileum
17
Q
What are the diseases in the ESOPHAGUS
A
(1) GERD
(2) Achalasia
(3) Cardia
(4) Barrett’s Esophagus
(5) Esophageal Cancer
“GA C BE”
18
Q
Diseases of the STOMACH
A
(1) Dyspepsia
(2) Gastritis
(3) Gastric Ulcer
(4) Gastric Cancer
“D GGG”
19
Q
Diseases of the DUODENUM, JEJUNUM & ILEUM
A
(1) Duodenal Ulcer
(2) Celiac Disease
(3) Crohn’s Disease (CD)
(4) Intestinal Tuberculosis (ITb)
“DC CI”
20
Q
Diseases of the COLON
A
(1) Diarrhea
(2) Constipation
(3) Inflammatory Bowel Syndrome (IBS)
(4) Inflammatory Bowel Disease (IBD)
(5) Colorectal Cancer (CRC)
“DCI IC”
21
Q
Organ site for CELIAC SPRUE
A
Duodenum
Jejunum
22
Q
Organ Site for CHRONIC PANCREATITIS
A
Exocrine Pancreas
23
Q
Organ site for SURGICAL RESECTION OF ILEUM; CHRON DISEASE OF ILEUM
A
Ileum
24
Q
Organ site for PRIMARY LACTASE DEFICIENCY
A
Small Intestine
25
Defective process in CELIAC SPRUE
Fat Absorption
| Lactose Hydrolysis
26
Defective process in CHRONIC PANCREATITIS
Fat Digestion
27
Defective process in SURGICAL RESECTION OF ILEUM; CHRON DISEASE OF ILEUM
Cobalamin and Bile Acid absorption
28
Defective process in PRIMARY LACTASE DEFICIENCY
Lactose Hydrolysis
29
CARBOHYDRATE DIGESTION provides % of total energy
45% of the total energy needs of Western diets
30
CARBOHYDRATES require __________ before absorption
Hydrolysis to Monosaccharides
31
What are the dietary carbohydrates?
MONOSACCHARIDES - monomers
OLIGOSACCHARIDES - short polymers
POLYSACCHARIDES - long polymers
32
TRUE or FALSE
Small intestine cannot directly absorb monomers
FALSE
* Small Intestine can directly absorb monomers but NOT polymers
33
TRUE or FALSE
Small Intestine can directly absorb MONOMERS by NOT POLYMERS
TRUE
34
TRUE or FALSE
Some polymers are DIGESTIBLE
TRUE
* Some POLYMERS are DIGESTIBLE: body can digest them from MONOMERS that SI can absorb
35
TRUE or FALSE
Other polymers are NONDIGESTIBLE
TRUE
* Other polymers are nondigestible: "FIBER"
36
Polymer that is nondigestible
Fiber
37
45-60% of dietary carbohydrates come from
Starch (Polysaccharide)
38
Storage form of carbohydrates in plants
Starch (Amylose & Amylopectin)
39
Storage form of carbohydrates in animal
Glycogen
40
Straight chain glucose polymer multiple glucose residues
Amylose
41
Massive branched glucose polymer contain 1M glucose residues
Amylopectin
42
TRUE or FALSE
Amylose > Amylopectin
FALSE
* AMYLOPECTIN > Amylose
43
Most dietary oligosaccharides are
Disaccharides
44
SUCROSE & LACTOSE make up __________ of dietary carbohydrates
30-40%
45
Table sugar from SUGAR CANE & SUGAR BEETS
Sucrose
46
Sugar found in MILK
Lactose
47
Carbohydrate digestion begins by the action of __________, OLIGOSACCHARIDES are then broken down by __________ to DISACCHARIDES (Maltose, Sucrose, Lactose), then the __________ breaks it down to MONOSACCHARIDES (Galactose, Glucose, Fructose)
Salivary Amylase
Pancreatic Amylase
Brush Border Enzymes
48
Monossacharides account for __________ of total carbohydrate intake
5-10%
49
CARBOHYDRATE DIGESTION
SI can absorb _________
ONLY Monosaccharides
* all dietary carbohydrates must be digested to monosaccharides before absorption
50
CARBOHYDRATE DIGESTION
COLON __________
CANNOT absorb monosaccharides
51
Two Steps of Digestive Process of dietary CARBOHYDRATES
(1) Intraluminal Hydrolysis
| (2) Membrane Digestion
52
__________ of starch to Oligosaccharides by __________
Intraluminal Hydrolysis
Salivary & Pancreatic Amylases
53
__________ of Oligosaccharides to Monosaccharides by _________
Membrane Digestion
Brush Border Disaccharides
54
LUMINAL DIGESTION begins with action of __________ & finishes with __________
Salivary Amylase
Pancreatic Amylase
55
Initiates starch digestion; inactivated by gastric acid
Salivary Amylase
56
Completes starch digestion in lumen of small intestine; endoenzyme that hydrolyzes internal alpha 1,4 linkages
Pancreatic a-Amylase
57
Salivary & Pancreatice alpha Amylase are
Endoenzymes
58
Salivary & Pancreatic alpha Amylase CAN DIGEST __________, but CANNOT BREAK __________
LINEAR INTERNAL ALPHA 1,4 LINKAGES between glucose residues
TERMINAL ALPHA 1,6 LINKAGES (between the last two sugars in the chain)
59
Salivary & pancreatic alpha amylase CANNOT SPLIT __________ at branch points of Amylopectin or ___________
a-1,6 linkages
adjacent a-1,4 linkages
60
Products of a amyase action are
(1) Linear glucose oligomers
(2) Maltotriose
(3) Maltose
(4) a-limit dextrins
"LMMA"
61
__________ splits LACTOSE, then both monomers are transported via __________
Lactase
SLGT1
62
___________ removes glucose monomers for transport
Glucoamylase (MALTASE)
63
___________ are 2 enzymes
___________ splits Sucrose, Maltose & Maltotriose
Sucrase-isomaltase
Sucrase moiety
64
__________ are intrinsic membrane proteins with catalytic domains facing lumen
Brush Border Oligosaccharides
65
__________ splits a-limit dextrins, maltose & maltotriose
Isomaltase moiety
66
Na-COUPLED TRANSPORTER mediates uptake of GLUCOSE or GALACTOSE
SGLT1
67
Mediates FACILITATED DIFFUSION of FRUCTOSE
GLUT5
68
Mediates EFFLUX across BASOLATERAL membrane
GLUT2
69
GLUT5 transport is thru?
Passive Diffusion
70
SGLT1 is a?
Na-coupled transporter
71
TRUE or FALSE
SUCRASE activity is greatly reduced much more by fasting than LACTASE ACTIVITY
TRUE
72
__________ is more susceptible to enterocyte injury, it is also SLOWER TO RECOVER from damage than other oligosaccharide activity
Lactase Activity
73
REDUCED LACTASE ACTIVITY is a consequence of __________ & ___________
Genetic Regulation
Environmental Effects
74
Symptoms of Lactose Intolerance
```
✅ Bloating
✅ Pain or cramps in lower belly ✅ Gurgling sounds
✅ Gas
✅ Loose stools
✅ Diarrhea
```
75
___________ RISES after glucose or lactose ingestion
and
H2 in the breath is _________
Plasma glucose
Low
76
___________ can split lactose into glucose and galactose and can absorb the two monosaccharides
SI
77
Product of lactose metabolism by colonic bacteria which metabolize lactose that enters colon
H2
78
What metabolizes lactose that enters colon
Colonic Bacteria
* large amounts of H2 is excreted in the breath
79
3 Monosaccharide products of Carbohydrate Digestion
Glucose
Galactose
Fructose
80
Monosaccharides are absorbed in the SI in two-step process
(1) UPTAKE across the APICAL MEMBRANE into epithelial cell
| (2) Coordinated EXIT across the BASOLATERAL MEMBRANE
81
PROTEIN DIGESTION
Digestion-absorption involve ___________
4 Major Pathways
82
In protein digestion, __________ enzymes come from __________
Luminal Enzymes
Stomach & Pancreas
83
4 Major Pathways of Protein Digestion
(1) HYDROLYZE proteins -> peptides -> AA -> absorbed
(2) DIGEST proteins -> peptides, but enzymes present at BRUSH BORDER digest peptides -> AA -> absorbed
(3) DIGEST proteins -> peptides then taken up as OLIGOPEPTIDES by ENTEROCYTES -> further digestion of oligopeptides -> AA -> moved into BLOOD
(4) DIGEST dietary proteins -> OLIGOPEPTIDES taken up by ENTEROCYTES -> moved DIRECTLY INTO BLOOD
84
Proteins come from
Dietary & Endogenous sources
85
Protein is encoded by __________ & it consist of __________ AA
mRNA
20
86
How many AA's are not synthesized in adequate amounts by the body
9 AA's
87
TRUE or FALSE
Protein derived from plant sources are digested more completely than animal protein
FALSE
* Protein derived from animal sources digested more completely than plant protein
88
These are secreted as proenzymes and require conversion to their active form for protein hydrolysis to occur
Gastric & Pancreatic Proteases
89
Pancreatic enzymes are secreted as __________
Inactive Proenzymes
90
What are the 5 pancreatic enzymes participate in PROTEIN DIGESTION
(1) Trypsinogen
(2) Chymotrypsinogen
(3) Proelastase
(4) Procarboxypeptidase A
(5) Procarboxypeptidase B
"TC PPP"
91
_________ & _________ hydrolyze proteins to single AA or to oligopeptides
Pepsin from Stomach
5 - Pancreatic Proteases
92
_________ in cytoplasm hydrolyze oligopeptides into their consistuent AA
Peptidases
93
Peptides exit across BASOLATERAL MEMBRANE through one of three __________
Na-INDEPENDENT AA transporters
94
Oligopeptide uptake occurs via
H/oligopeptide cotransporter (PepT1)
95
If _________ present in lumen as free AA, enterocyte absorbs it through apical AA transporters
Glycine
96
Glycine is absorbed through
Apical AA Transporters
97
If same amount of GLYCINE is present in lumen in form of dipeptide GLYCYLGLYCINE, rate kf appearance in blood is _______
twice as high
98
__________ which moves several AA monomers for each turnover of transporter, is an effective mechanism for absorbing "AA"
PepT1
99
AA enter enterocytes through 1 or more group-specific _________
Apical Membrane Transporters
100
Predominant apical AA transport system is _________ results in _________
SYSTEM Bo
Na-dependent uptake of neutral AA
101
SYSTEM Bo results in
Na-dependent uptake of neutral AA
102
SYSTEM Bo gene in humans?
SLC6A19
* solute carrier family 6 member 19
103
Mediates epithelial resorption of neutral AA across apical membrane in kidneys & intestines
SLC6A19 gene in humans
104
Mutation in SLC6A19 gene
Hartnup disease
105
Defects in APICAL amino acid transport
(1) Hartnup Disease
| (2) Cystinuria
106
Defects in BASOLATERAL amino acid transport
(1) Lysinuric Protein Intolerance
107
HARTNUP DISEASE is a
Autosomal Recessive Disorder
108
CYSTINURIA is an
Autosomal Recessive Disorder
109
LYSINURIC PROTEIN INTOLERANCE is a
Rare Autosomal Recessive Disorder
110
This disease is associated with SI abnormalities in absorption of neutral amino acids (L-phenylalanine)
Hartnup Disease
111
What is defective in Hartnup Disease
Apical System Bo (SLCA19)
112
Manifestations of Hartnup Disease
Pellagra
Cerebellar Ataxia
Psychiatric Abnormalities
113
This disease is associated with renal tubule abnormalities of cationic amino acids (L-arginine) & L-cystine
Cystinuria
114
What is defective in Cystinuria
Apical Ststem Bo+ (SLC7A9/SLC3A1 dimer)
115
Manifestation of Cystinuria
Formation of Kidney Stones
116
What is defect in Lysinuric Protein Intolerance
System y+L
* which is solely located on BASOLATERAL MEMBRANE
117
This disease is when urinary excretion of cationic AA is increased & poorly absorbed from intestine
Lysinuric Protein Intolerance
118
Lysinuric Protein Intolerance is characterized by
LYSINE DEFICIENCY - skeletal & immunological abnormalities
119
Lysinuric Protein Intolerance is present in
SI, Hepatocytes, Kidney Cells
120
Organic compounds of biological origin sparingly soluble in water
Natural Lipids
121
Lipids as NONPOLAR compounds
Completely INSOLUBLE in water (cholesterol esters, carotene)
122
Lipids as POLAR compounds
Amphiphilic, having both polar & nonpolar groups
123
Body's only source of essential fatty acids
Dietary fat
124
Acts as vehicle for absorption of fat-soluble vitamins
Dietary fat
125
Major nutrient responsible for postprandial satiety
Dietary fat
126
TRUE or FALSE
Ratio of SATURATED to UNSATURATED fatty acids in TAGs: LOW in animal fats & HIGH in plant fats
FALSE
* HIGH in animal fats & LOW in plant fats
127
_________ of dietary lipids from cell membranes & are _________
5%
Phospholipids
128
Most phospholipids are
Glycerophospholipids
129
Glycerophospholipids have
GLYCEROL backbone
130
It is a predominant phospholipid
Phosphatidylcholine (Lecithin)
131
Has SERINE rather than a glycerol backbone
Sphingolipid
132
DIETARY LIPIDS are disrupted mechanically in _________
mouth & stomach
133
Resulting lipid particles from dietary lipids are stabilized as
EMULSION
134
Central process in digestion of lipids is
HYDROLYSIS in aqueous milieu of the intestinal lumen
135
Central process in digestion of lipids is catalyzes by
LIPASES
* secreted by glands & cells of upper GI tract
136
KEY STEP PRELIMINARY to lipid digestion is
Transformation of ingested solid fat & oil masses into an EMULSION of fine oil droplets in water
137
Emulsification of dietary fats begin with?
Chewing & gastric churning caused by antral peristalsis against a closed pylorus
138
Chewing & gastric churning is caused by
Antral peristalsis against a closed pylorus
139
LIPID DIGESTION
Mechanical processes will:
(1) REDUCE SIZE of lipid droplets
(2) INCREASE RATIO of surface area to volume
(3) INCREASE AREA of oil-water interface
140
__________ initiate lipid digestion
Lingual & Gastric (Acid) Lipase
141
In some species small amount of lipid digestion begins in _________, mediated by __________
Mouth
Lingual Lipase
142
In STOMACH, both _________ secreted by gastric CHIEF CELL digest substantial amounts of lipid
Lingual Lipase & Gastric Lipase
143
Process of fat digestion begins in
Stomach
144
Fat digestion is completed in _________, by enzymes synthesized & secreted by __________
Proximal SI
Pancreatic Acinar Cells
145
Fat digestion is carried into DUODENUM by
Pancreatic Juice
146
TRUE or FALSE
As LIPASES hydrolyze TAGs at surface, TAGs from core replace them, causing droplet to grow
FALSE
* As LIPASES hydrolyze TAGs at surface, TAGs from core replace them, causing droplet to shrink
147
CORE LIPIDS include
(1) Triacylglycerols
(2) Diacylglycerols
(3) Cholesterol Esters
148
SURFACE LIPIDS include
(1) Fatty Acid Soaps
(2) Monoacylglycerols
(3) Lysolecithins
(4) Cholesterol
(5) Bile Salts
149
Products of lipolysis enter bulk water phase of intestinal lumen as vesicles, mixed _________ & __________
Micelles
Monomers
150
Process of how Lipids cross enterocyte brush border
(1) Lipids as mixed MICELLES & MONOMERS
(2) Diffuse across unstirred water layer on surface of JEJUNAL MUCOSA
(3) Cross enterocyte brush border
151
To reach interior of enterocyte, lipolytic products must cross these barriers
(1) MUCOUS GEL LAYER - lines intestinal epithelial surface
(2) UNSTIRRED WATER LAYER (Disequilibrium Zone) - contiguous with enterocyte's apical membrane
(3) APICAL MEMBRANE
"MUA"
152
This barrier lines intestinal epithelial surface
Mucous gel layer
153
This barrier is contiguous with enterocyte's apical membrane
Unstirred Water Layer (Disequilibrium Zone)
154
_________ carry lipids through the acidic unstirred layer to surface of enterocyte
Mixed micelles
155
__________ leave mixed micelle & enter an acidic microenvironment created by APICAL Na-H EXCHANGER
2-MAG
FA
Lysophospholipids
Cholesterol
156
2-MAG, FA, LYSOPHOSPHOLIPIDS & CHOLESTEROL leave mixed micelle & enter an acidic microenvironment created by _________
Apical Na-H Exchanger
157
Enterocyte re-esterifies lipid components & assembles them into
Chylomicrons
158
Largest of lipoprotein particles
Chylomicrons
159
Consist primarily of TAGs with smaller amounts of phospholipids, cholesteryl esters, cholesterol & apolipoproteins
Chylomicrons
160
_________ re-esterifies lipid components & assembles them into CHYLOMICRONS
Enterocyte
161
Enterocyte secretes ________ into lymphatic circulation during FEEDING
Chylomicrons
162
Enterocyte secretes ________ during FASTING
VLDL
163
Enterocyte secretes VLDL during
Fasting
164
Enterocytes secretes chylomicrons into lymphatic circulation during
Feeding
165
TRUE or FALSE
Chylomicrons are too large to pass through fenestrate of blood capillaries
TRUE
166
Chylomicrons enter lymph through
Larger interendothelial channels of lymphatic capillaries
167
In fed & fasted states, intestine secretes ________ which are smaller than chylomicrons
VLDLs
168
Intestinal absorption of FAT-SOLUBLE VITAMINS follows pathways of __________
Lipid Absorption & Transport
169
In contract to water-soluble counterparts, FAT-SOLUBLE VITAMINS
(1) do not form classical coenzyme structures or prosthetic groups with soluble apoproteins
(2) can also be stored in fat depots in body
170
Vitamin A is also called as
Retinol
171
Vitamin D is also called as
1,25 cholecalciferol
172
Vitamin E is also called as
a-Tocopherol
173
Vitamin K is also known as
K1=phylioquinone
| K2=various menaquinones
174
Role of Vitamin A
Retinal pigment
175
Role of Vitamin D
Ca+ absorption
176
Role of Vitamin E
Antioxidant: thought to prevent oxidation of unsaturated fatty acids
177
Role of Vitamin K
Clotting: necessary for synthesis by liver of prothrombin and favtors VII, IX and X
178
RDA of Vitamin A
Male: 1000 ug
Female: 800 ug
179
RDA of Vitamin D
5-10 ug
180
RDA of Vitamin E
Male: 10 mg
Female: 8 mg
181
RDA of Vitamin K
Male: 70-80 ug
Female: 60-65 ug
182
Effect of deficiency of Vitamin A
Follicular hyperkeratosis
| Night blindness
183
Effect of deficiency of Vitamin D
Rickets
184
Effect of deficiency of Vitamin E
Peripheral Neuropathy
185
Effect of deficiency of Vitamin K
Hemorrhagic Disease
186
Fat-Soluble vitamin deficiency occurs in various fat malabsorption states:
(1) Induced by malabsorptive BARIATRIC SURGERY
(2) Drugs (ORLISTAT) that impair TAG hydrolysis
(3) Drugs (CHOLESTYRAMINE) that bind bile acids
(4) Reduction of bile acids by IMPAIRED HEPATOBILIARY FUNCTION
(5) UNABSORBABLE dietary fat substitutes
187
Drug that IMPAIR TAG HYDROLYSIS
Orlistat
188
Drug that BIND BILE ACIDS
Cholestyramine
189
Dietary Folate (PteGlu7) other names
Folate or Folic Acid or Pteroylmonoglutamate (PteGlu1)
190
Dietary Folate
PteGlu7
191
Dietary Folate (PteGlu7) must be deconjugated by _________ before absorption by an anion exchanger at APICAL MEMBRANE
Brush Border Enzyme
192
A cofactor in biochemical reactions involving transfer of 1-carbon fragment
Tetrahydrofolate (THF)
193
Reduced form of Folate
Tetrahydrofolate (THF)
194
Tetrahydrofolate is essential for synthesis of ________ & ________
THYMINE & PURINES
* which are components of DNA
195
Essentia for synthesis of Thymine & Purines
Tetrahydrofolate
196
This reduces the risk of neural tube defects
Folic acid supplementation in Pregnancy
197
Folate Deficiency is most clinically noticeable in
Bone Marrow
198
RNA & protein synthesis are not impaired in Folic Acid Deficiency, instead
Large RBCs (Megaloblasts) are produced
199
Tetrahydrofolate has three parts:
(1) Active pteridine moiety
(2) p-aminobenzoate
(3) Glutamate
"APG"
200
Oxidized form of folate
PteGlu1
* biologically INACTIVE
* MEDICINAL FORM of folate
* Monoglutamate
201
In PROXIMAL SI, ___________ removes glutamate residues from dietary folate
Brush Border Peptidase
202
Enterocyte absorbs PteGlu1 using _________
folate-OH exchanger
203
_________: reduce some of PteGlu1 to DHF -> THF (active form of folate)
Enterocyte
* may methylate some of THF to form N5-methyl-THF
204
PteGlu1 exits across
Basolateral Membrane (Unknown Transporter)
205
form of folate needed for DNA synthesis
5,10 - Methylene THF
206
Cell converts THF to
5,10 - Methylene THF
* which is the form of folate needed for DNA Synthesis
207
Cell transform 5,10 - methylene THF to
N5 - methyl THF
208
Acts as methyl donor in synthesis of METHIONINE
N5 - methyl THF
209
TRUE or FALSE
Cobalamin (Vitamin B12) is synthesized only by microorganisms not by mammalian cells
TRUE
210
Primary source of COBALAMIN in humans:
Ingestion of Animal Products
* not present in vegetables or fruit
211
Strict vegetarians have
Cobalamin deficiency
212
Cobalamin primary function
COENZYME for Homocysteine: Methionine Methyltransferase
213
Steps 1-8 show:
Steps 4-8 show:
Fate of Dietary Cobalamim (CBL)
Role of IF
214
Carries Cobalamin into the duodenum
Bile
215
Absorption of Cobalamin
(1) Cobalamin is bound to proteins in food
(2) Acid pH & Pepsin release cobalamin from dietary protein
(3) Gastric glands secrete HAPTOCORIN, which binds to cobalamin
(4) Gastric parietal cells secrete IF
(5) Pancreas secretes proteases & HCO3-
(6) CBL is released after proteolytic degradation of haptocorrin
(7) IF-CBL complex forms
(8) Ileal enterocyte absorbs IF-CBL complex
216
IF/cobalamin compolex is through
Endocytosis
217
Cobalamin binds to _________: required for cobalamins exit from entercoyte
Transcobalamin II (TCII)
218
Comprises dietary sources & digestive secretions
Ca2+ load presented to SI
219
Ca2+ absorption is regulated primarily by
Vitamin D
220
Ca2+ occurs by _________ in DUODENUM
Active Transport
221
Ca2+ absorption is by ________ throughout SMALL INTESINE
Diffusion
222
SI absorbs calcium by 2 mechanisms
(1) PASSIVE (Paracellular Absorption) of calcium
| (2) ACTIVE (Transcellular Absorption) of calcium
223
Pathway predominates but not under control of Vitamin D
Passive (Paracellular) Absorption of Calcium
224
Absorption of Calcium that occurs throughout the SI
Passive (Paracellular) Absorption of calcium
225
Absorption of Calcium that occurs only in the duodenum
Active (Transcellular) Absorption of calcium
226
TRANSCELLULAR Calcium Absorption involves 3 Steps:
(1) Calcium enters cell across APICAL MEMBRANE through channel
(2) Inside cell -> Calcium buffered by binding proteins - CALBINDIN -> Taken up into endoplasmic reticulum
(3) Enterocyte extrudes calcium across BASOLATERAL MEMBRANE through CALCIUM PUMP & Na-Ca EXCHANGER -> Calcium Absorption
227
Calcium buffered by binding proteins called
Calbindin
228
Enterocyte extrudes calcium across BASOLATERAL MEMBRANE through
Calcium pump & Na-Ca exchanger
229
MAGNESIUM
Load to __________
SI; dietary sources & digestive secretions (green vegetables, cereals, meats)
230
Important for proper secretion of PTH hormone
Magnesium
231
Depletion of this vitamin is associated with Hypocalcemia
Magnesium
232
Depletion of Magnesium is associated with
Hypocalcemia
233
Systems affected by Mg deficiency
- GI
- Cardiovascular
- Neuromuscular
234
Magnesium absorption occurs by
ACTIVE PROCESS in ILEUM
235
An important intracellular ion required as ENZYME COFACTOR
Magnesium
236
Many enzymes using ATP require that ATP be complexed with _________
Magnesium
237
This does not consistently increase Mg absorption
1,25 - dihydroxyvitamin D
238
The rest of SI absorbs Mg _________
passively
239
TRUE or FALSE
Patients with decreased intestinal Calcium absorption have normal Mg absorption
FALSE
* Patients with INCREASED intestinal Calcium absorption have normal Mg absorption
240
Heme & nonheme iron is absorbed by
DUODENUM by Distinct Cellular Mechanisms
241
Iron overload
Hemochromatosis
242
Most anemia complication of iron depletion
Anemia
243
Iron plays important roles in:
(1) HEME GROUPS of cytochromes
| (2) Key component of OXYGEN-CARRYING HEME MOIETIES OF HGB & MYOGLOBIN
244
Heme Iron is derived from
Myoglobin & Hemoglobin
245
Heme Iron is absorbed by
Duodenal Epithelial Cells
246
Two types of Nonheme Iron
- Ferric Iron (Fe3+)
| - Ferrous Iron (Fe2+)
247
Nonheme iron that form salt complexes with anions easily
Ferric Iron (Fe3+)
248
Nonheme Iron that is not readily absorbed
Ferric Iron (Fe3+)
249
Ferric Iron (Fe3+) is not soluble in what pH
pH values > 3
250
Nonheme Iron that does not complex easily
Ferrous Iron (Fe2+)
251
Ferrous Iron (Fe2+) is soluble in which pH
Soluble at pH as high as 8
252
________ reduces non-heme Fe3+ to Fe2+ iron
Dcytb
253
The absorption of nonheme iron occurs almost exclusively as ________
Fe2+
254
How is Nonheme Fe2+ Absorption
DMT cotransports Fe2+ iron with H+
255
TRUE or FALSE
No absolute daily requirement for carbohydrate or fat intake exists
TRUE
256
TRUE OR FALSE
Nutritionists recommend: daily intake of carbohydrate vs fat should differ with age, gender or activity level
Nutritionists recommend: daily intake of carbohydrate vs fat should not differ with age, gender or activity level
257
Requirement for total caloric intake vary & depend
Person's ability to use & store energy
Daily activity level
258
What is the daily protein requirmeent for adult humans
0.8 g/kg body weight
259
TRUE or FALSE
Daily protein requirement is higher in pregnant women, postsurgical patients & athletes
TRUE
260
Diet must contain the 9 essential AA because
the body cannot synthesize tyem
261
Amino acids
(1) Arginine
(2) Glutamate
(3) Glycine
(4) Glutamine
262
Amino Acid that is PRECURSOR TO NITRIC OXIDE
Arginine
263
Amino Acid that is a MAJOR EXCITATORY NEUROTRANSMITTER IN THE BRAIN
Glutamate
264
Amino Acid that is a MAJOR INHIBITORY NEUROTRANSMITTER
Glycine
265
Amino Acid that is the MAJOR SOURCE OF NH3 PRODUCTION IN THE KIDNEY & REGULATES PROTEIN TURNOVER IN THE MUSCLE
Glutamine
266
TRUE or FALSE
Minerals & Vitamins are energy sources
FALSE
* not energy sources
267
Minerals & Vitamins are essential for
(1) Enzymatic reactions
(2) Protein complexes
(3) Pecursors for biomolecules
(4) Metabolism
(5) Immune competence
(6) Muscle force production
(7) Blood clotting
