Digestion and absorption Flashcards
1
Q
The stimuli for the cephalic phase
A
Cognitive anticipation of food consumption, and sensory input (olfactory, visual, auditory)
2
Q
The response to cephalic stimulation is activation of what part of the brain?
A
Dorsal motor nucleus in the brainstem
3
Q
The salivary response is mediated via which nerve?
A
CN IX (glossopharyngeal)
4
Q
Gastric acid secretion, pancreatic enzyme secretion, gallbladder contraction, relaxation of the sphincter of Oddi are mediated via which CN?
A
CN X (vagus)
5
Q
The three major pairs of salivary glands
A
Parotid, sublingual, submandibular
6
Q
Type of secretion of parotid glands
A
Serous
7
Q
Type of secretion of sublingual glands
A
Mucous
8
Q
Type of secretion of submandibular glands
A
Mixed serous and mucous
9
Q
Salivary secretion is often isotonic. T/F
A
F
It is always hypotonic.
10
Q
Control of saliva secretion: neural, paracrine, endocrine
A
Neural
11
Q
Control of most GI secretion: neural, paracrine, endocrine
A
Endocrine
12
Q
Primary secretion of saliva: hypotonic, isotonic, hypertonic
A
Isotonic
13
Q
Protein ion transporters in acinar cells of salivary glands
A
Na,K-ATPase and NA-K-2Cl symporter
14
Q
Na,K-ATPase and NA-K-2Cl symporter are located in which part of the cell membrane of salivary glands?
A
Basolateral membrane
15
Q
In acinar cells of salivary glands, Cl and HCO3 leave the acinar cell via an anion channel in which part of the cell membrane?
A
Apical membrane
16
Q
The only gastric secretion required
A
Intrinsic factor
17
Q
K is higher in gastric juice or in plasma?
A
Gastric juice
18
Q
Why may prolonged vomiting lead to hypokalemia?
A
Because gastric juice is high in K.
19
Q
Which is the main anion of gastric juice?
A
Cl
20
Q
The basal rate of H production is highest and lowest which part of the day?
A
Higher at night, lowest in the morning
21
Q
The higher secretory rates of gastric juice, the higher the concentration of which ions?
A
H
22
Q
Lower secretory rates of gastric juice (increases/decreases) Na.
A
Increases
23
Q
At high secretory rates of gastric juice, H (increases/decreases)
A
Increases
24
Q
At high rates of gastric juice secretion, gastric juice resemble an (hypotonic/hypertonic/isotonic) solution of HCl
A
Isotonic
25
The predominant organic constituent of gastric juice
Pepsinogen
26
The lower the pH, the (faster/slower) the conversion of pepsinogen to pepsin
Faster
27
Pepsins also act proteolytically to activate more pepsinogen. T/F
T
28
Why are pepsins not require for digestion?
Because their function can be replaces by that of pancreatic proteases.
29
Intrinsic factor is important in absorption of which vitamin?
B12 (cobalamin)
30
Which of the following principal control mechanisms involved in GI function regulation is represented by serotonin (syn. 5-hydroxy-trptamine)?
a. Endocrine
b. Paracrine
c. Neural
d. Combination
D
31
Which of the following combination is incorrect?
a. Gastrin-endocrine
b. Histamine-paracrine
c. Acetylcholine-neural
d. Cholecystokinin-paracrine
D
32
Xerostamia, or dry mouth, is caused by impaired salivary secretion. Which of the following is not an expected complication of this clinical correlation?
a. Tooth decay
b. Esophageal erosions
c. Difficulty swallowing
d. Gastric ulceration
D
33
Which of the following neurotransmitters act mainly by elevating the Ca++ concentration in the cytosol?
a. Acetylcholine
b. Cholecystokinin
c. Substance P
d. Vasoactive intestinal polypeptide (VIP)
A
34
The following are true statements on the regulation of gastric secretion, except:
a. Parietal cell is regulated by a combination of pathways
b. Ach directly activates parietal cells
c. Enterochromaffin cells release histamine
d. Gastrin acts via the paracrine pathway to stimulate the parietal cell.
D
35
Which of the following hormone is released to inhibit a meal-stimulated gastrin secretion?
a. Secretin
b. Gastrin
c. Gluco-insulinotropic peptide (GIP)
d. Somatostatin
D
36
Which of the following is responsible for our experiencing the “coolness of menthol” or the “sting of ammonia”
a. Olfactory cells
b. Gustatory cells
c. Common chemical sense
d. Mucus cells of the tongue
C
37
Which of the following is not a response in the cephalic phase of digestion?
a. Hypothermia (decreased temp)
b. Increased flow of saliva
c. Increased HR
d. Change in urine osmolarity
A
38
Which of the following hormones stimulates an enzyme-rich pancreatic secretion?
a. Secretin
b. CCK
c. Somatostatin
d. VIP
B
39
Which of the following hormones stimulates a HCO3-rich pancreatic secretion?
a. Secretin
b. CCK
c. Samatosatin
d. VIP
A
40
Which is the primary physiologic control for salivary secretion?
a. Sympathetic
b. Parasympathetic
c. Hormonal
d. Paracrine
B
41
Which of the following agonists of pancreatic acinar secretion is not mediated by an increased intracellular calcium?
a. Acetycholine
b. CCK
c. Gastrin
d. Secretin
D
42
Procarboxypeptidase is directly activated by
a. Chymotrypsin
b. Trypsin
c. Pepsin
d. Enterokinase
B
43
The digestion of the major foodstuff in the GIT is a process of:
a. Sulfation
b. Decarboxylation
c. Hydrolysis
d. Amidation
C
44
Phospholipids are digested into:
a. Monoglyceride and cholesterol
b. Cholesterol and lysolecithin
c. Fatty acids and lysolecithin
d. Lysilecithin and monoglyceride
C
45
Which of the following is responsible for apical transport of fructose in enterocytes?
a. SGLT1
b. GLUT 2
c. GLUT 4
d. GLUT 5
D
46
Reesterification of monoglyceride and fatty acids occur in the enterocyte:
a. Cytosol
b. Smooth ER
c. Golgi apparatus
d. nucleus
B
47
What digestive enzyme is necessary for the hydrolysis of phospholipids?
a. Cholesterol easter hydrolase
b. Phospholipiase A2
c. Pancreatic lipase
d. Lingual lipase
B
48
Extensive injury of the ileum will greatly affect the absorption of:
a. Vitamin C
b. Fructose
c. Cyanocobalamin
d. Amino acids
C
49
Which of the following monosaccharides will be absorbed first?
a. Pentose
b. Arabinose
c. Galactose
d. Glucose
C
50
Absorption of fat digestion products and fat soluble vitamins is by what transport mechanism?
a. Primary active
b. Secondary active
c. Facilitated diffusion
d. Passive diffusion
D
51
Dipeptides and tripeptides are absorbed by the intestines with which ion?
a. Sodium
b. Chloride
c. Hydrogen
d. potassium
C
52
The strongest stimulant of gastric H secretion
Parasympathetic innervation of the vagus nerve
53
Strongest agonist of H secretion
Histamine
54
The parietal cell is stimulated by the parasympathetic vagus pathway through which neurotransmitter?
Acetylcholine
55
Cholinergic receptors of the parietal cell: muscarinic or nicotinic?
Muscarinic
56
The effect of histamine to parietal cells
Stimulation of H secretion
57
Histamine receptors of the parietal cell
H2 receptors
58
Which G-cell secretion stimulates the parietal cell?
Gastrin
59
Gastrin stimulates the parietal cell via: neural, paracrine, endocrine mechanism
Endocrine
60
Parietal cell stimulation: neural, paracrine, endocrine mechanism
All
61
Gastrin's effect on ECL cells
Histamine secretion
62
Which neurotransmitter activates G-cells?
Gastrin-releasing peptide
63
Gastrin receptors on the parietal cell
CCK2
64
Stimulation of ECL cells via gastrin: neural, paracrine, endocrine mechanism
Endocrine
65
ECL cells are stimulated by parasympathetic innervation through which neurotransmitter?
Acetylcholine
66
Cholinergic receptors on the ECL cells: muscarinic or nicotinic?
Muscarinic
67
Elevation of gastrin levels causes ECL cells to increase in size and number. T/F
T
68
Which hormone decrease the release of gastrin?
Somatostatin
69
Somatostatin inhibition of gastrin: neural, paracrine, endocrine mechanism
Paracrine
70
When do D-cells secrete somatostatin?
When acidity drops below threshold of pH 3
71
Pancreatic enzymes function optimally at low pH. T/F
F
They are deactivated by high levels of acidity.
72
Which organ is the largest quantitative contributor to the supply of bicarbonate ions needed to neutralize the gastric acid load?
Pancreas
73
What stimulates the intercalated ducts of the pancreas to secrete HCO3?
Secretin
74
What stimulates the acinar cells of the pancreas to secrete proenzymes?
CCK
75
Somatostatin inhibit insulin and glucagon. T/F
T
76
The pH-sensing cell in the small intestines
S cells
77
What happens when S cells sense the fall in pH when gastric contents enter the duodenum?
S cells secrete secretin
78
How does secretin reach the pancreas?
Through the blood stream
79
Which cells secrete CCK?
I cells of the duodenum
80
Which food components particularly trigger the secretion of CCK?
Free fatty acids and amino acids
81
Regulation of CCK release involves which mechanisms?
Interaction of FFA and AA with I cells
CCK-releasing factor (or peptide) from paracrine cells in duodenum
Monitor peptide from pancreatic acinar cells
82
What is the most common cause of GERD
Transient LES Relaxation
83
Which part of the colon acts as a volitional reservoir?
A. Ascending
B. Transverse
C. Descending
D. Rectosigmoid
D
84
Which of the ff monosaccharides would be absorbed 2nd
a. glucose
b. galactose
c. fructose
d. mannose
a
85
Pepsin will degrade ingested proteins into which of the following except.
A. Peptone
B. Dipeptides
C. Amino Acids
D. Tripeptides (I forgot the choices )
C
86
Absorption usually occurs in the
A. Esophagus
B. Stomach
C. Proximal small bowel
D. Transverse colon
C
87
Approx how much saliva produced daily
1.5 liters
88
The process where food is broken down into simple substances absorbed in the blood.
A. Ingestion
B. Digestion
C. Processing
D. Divertion
B
89
Vagal stimulation releases acetylcholine on all of the following cells, EXCEPT:
A. Chief cell
B. G cell
C. Parietal cell
D. ECL cell
A
90
Which phase has the least acid secretion?
A. Cephalic
B. Gastric
C. Intestinal
D. Hepatic
C
91
Brunner's glands secrete this substance that activates trypsin
A. Mucus
B. Glucagon
C. Neurotensin
D. Enterokinase
D
92
The small intestinal modifications increase surface area by how many times?
A. 200
B. 400
C. 600
D. 800
C
93
Formation of macromolecules from small molecules occurs through?
A. Hydrolysis
B. Condensation
C. Sulfation
D. Amination
B
94
Water absorption occurs through what process?
A. Primary active transport
B. Secondary active transport
C. Facilitated diffusion
D. Diffusion
D
95
Which is TRUE about protein digestion and absorption?
A. The main product of digestion is amino acids
B. Amino acids have only 1 transport protein
C. Some dipeptides can be absorbed directly
by enterocytes
D. Amino acids are more efficiently absorbed from a mixture of amino acids than a mixture of dipeptides
C
96
Glucose absorption through the apical membrane of enterocytes is through what transport mechanism?
A. Facilitated diffusion
B. Diffusion
C. Primary active transport
D. Secondary active transport
D
97
Which of the following monosaccharides will be absorbed last by enterocytes?
A. Xylose
B. Fructose
C. Glucose
D. Galactose
A
98
Fat is primarily absorbed in:
A. Rectum
B. Colon
C. Ileum
D. Proximal intestines
D
99
Iron absorption is inhibited by:
A. High gastric acidity
B. High protein meal
C. Ascorbic acid
D. Tea
D
100
Which of the following isocaloric meals will be emptied first by the stomach?
A. High fat solid diet
B. High fat liquid diet
C. High protein solid diet
D. High protein liquid diet
D
101
Which region of the stomach has HCl and pepsinogen as its main luminal secretion?
A. Cardia
B. Fundus
C. Antrum
D. Pylorus
B
102
Which of the following gastric cells elaborates a secretion that inhibits acid secretion?
A. D cells
B. G cells
C. Chief cells
D. Parietal cells
A
103
Which of the following gastric cell secretion denatures proteins and is involved in the 1st line of defense against microbes?
A. Pepsinogen
B. HCl
C. Intrinsic factor
D. Gastrin
B
104
Rate of basal secretion of gastric acid:
A. 5-40 mEq/hr
B. 4-30 mEq/hr
C. 1-5 mEq/hr
D. 10-20 mEq/hr
C
105
Which is active in gastric acid secretion?
A. H-K ATPase
B. Na-Cl ATPase
C. Carbonic acid symport
D. Cl symport
A
106
Blockage of what membrane protein causes the greatest acid reduction?
A. Muscarinic receptor
B. H2 receptor
C. CCK-B receptor
D. H-K ATPase
D
107
Which of the following is responsible for the trophic effect of ECL cells?
A. Histamine
B. Acetylcholine
C. Gastrin
D. Intrinsic factor
C
108
Primary driving force for ionic transport in salivary acinar cells?
A. K channels
B. Na/K/2Cl symport
C. HCO3/Cl exchanger
D. Na-K ATPase
D
109
Which of the following is a common luminal secretion of the cardia, antrum and pylorus?
A. HCl
B. Intrinsic factor
C. Mucus
D. Pepsinogen
C
110
What is the function of mastication?
A. Purely voluntary
B. Increase pleasure of eating
C. Required for carbohydrate digestion
D. Involves CN V and CN X
B
111
Which of the following is true about pepsin secretion?
A. Secreted in active form
B. 50% of protein digestion of meal
C. Activated at low pH
D. From parietal cell
C
112
Which of the following can cause an increase in mucus secretions?
A. Acetylcholine
B. Food
C. Acid
D. Somatostatins
A
113
What is the primary innervation of salivation?
A. Sympathetic
B. Parasympathetic
C. Hormonal
D. A and B
B
114
What is the characteristic of primary salivary secretion?
A. Lower K+ than plasma
B. Lower bicarbonate than plasma
C. Isotonic to plasma
D. Hypotonic to plasma
C
115
Which of the following statements describe the esophageal phase of swallowing?
A. It is voluntary
B. Food is aided by gravity
C. It is inhibited by anti-cholinergic drugs
D. It lasts for about 20 seconds
C
116
Which factor prevents trypsin activation in the pancreas?
A. Synthesis of protease inhibitor serine protease inhibitor kazal type 1 (SPINK 1)
B. Packaging of proteases as active enzymes
C. High Ca2+ concentration in the pancreas
D. Activation of trypsinogen in the stomach
A
117
Pancreatic secretions produce enzymes that digest
A. Neutral fat
B. Cellulose
C. Tripeptides
D. Toxins
C
118
Which of the following statements accurately describes carbohydrate digestion and absorption?
A. Monosaccharides and disaccharides are absorbed readily.
B. Luminal digestion is performed by lactase.
C. Glucose is absorbed via secondary transport.
D. Membrane digestion is performed by pancreatic lipase.
C
119
What is the common monosaccharide that can be derived from maltose, sucrose, lactose and maltotriose?
A. Galactose
B. Fructose
C. maltotriose
D. glucose
D
120
Which of the following pancreatic enzymes is secreted in active form?
A. elastase
B. lipase
C. pepsin
D. trypsin
B
121
Divalent cations, like Ca2+ and Fe3+ are best absorbed in the:
A. duodenum
B. jejunum
C. ileum
D. colon
B
122
Milk sugar is broken down into:
A. Glucose and Fructose
B. Glucose and Glucose
C. Maltose and Galactose
D. Glucose and Galactose
D
123
Chymotrypsinogen is activated by
A. enterokinase
B. trypsin
C. pepsin
D. HCl
B
124
Absorption of these vitamins is dependent on lipid absorption EXCEPT:
A. vitamin A
B. vitamin B
C. vitamin D
D. vitamin E
B
125
What is the characteristic of the salivary ductular system?
A. Absolutely permeable to H2O
B. Na is absorbed
C. HCO3 is absorbed
D. Final solution is isotonic
B
126
Digestive enzymes responsible for protein digestion
A. Lactase, α-dextriase, pepsin
B. α-dextriase, pepsin, carboxypeptidase
C. Pepsin, carboxypeptidase, trypsin
D. Carboxypeptidase, trypsin, lactase
C
127
Which of the following is most absorbable in the proximal small intestine?
A. galactose and fatty acids
B. bile acids and fatty acids
C. vitamin B12 and bile acids
D. fatty acids and vitamin B12
A
128
Galactose molecule is absorbed through apical membrane of enterocytes by:
A. passive diffusion
B. facilitated diffusion
C. secondary active transport
D. primary active transport
C
129
Carbohydrate digestion begins in the:
A. mouth
B. esophagus
C. stomach
D. small intestine
A
130
What substance increases the rate of iron absorption?
A. cereals
B. citrate
C. non-herbal teas
D. phytate
B
131
Which of the following is absorbed through a H+ dependent mechanism?
A. Galactose
B. Fatty Acids
C. Tripeptide
D. Amino Acids
C
132
What is the common luminal secretion in the cardia, antrum and pylorus of the stomach?
A. H+
B. IF
C. Pepsinogen
D. Mucus
D
133
Which of the following is true about gastric secretion?
A. Higher flow rate, Higher [H+]
B. Higher flow rate, Higher [Na+]
C. [K+] is lower in plasma
D. HCO3- is the major anion
A
134
What is true about pancreatic secretions?
A. It is isotonic to plasma at all secretion rates
B. [Na+] and [K+] are similar to plasma
C. HCO3- is less than in plasma
D. [Cl-] is greater in plasma
B
135
Which is an endopeptidase?
A. trypsin
B. carboxypeptidase
C. aminopeptidase
D. nuclease
A
136
Which of the following would most likely occur in a patient with diarrhea that is not treated properly?
A. alkalosis
B. hyperkalemia
C. acidosis
D. hypernatremia
C
137
Which transporter in the small intestines takes up glucose and galactose against their concentration gradient by coupling its transport to that of Na?
SGLT1
138
Through which transporter in the small intestines do glucose and galactose exit the basolateral membrane?
GLUT2
139
Fructose transporter in the apical membrane of enterocytes
GLUT5
140
Enzyme that activates trypsinogen once it is in the small intestine
Enterokinase
141
Digestion of lipids begin in which organ?
Stomach
142
Which enzyme begins digestion of lipids in the stomach?
Gastric lipase
143
Which cells secrete gastric lipase?
Chief cells
144
Three important lipolytic enzymes in pancreatic juice
Pancreatic lipase, phosopholipase A2 and cholesterol esterase
145
Which pancreatic lipolytic enzyme is inhibited by bile acids?
Pancreatic lipase
146
The cofactor that both binds to bile acids and to pancreatic lipase
Colipase
147
Pancreatic enzyme that hydrolyzes phopholipids
Phosopholipase A2
148
Phospholipase A2 is secreted inactive, and activated only when it reaches the stomach. T/F
F
It is activated only when it reaches the small intestines.
149
Cholosterol esterase breaks down only cholesterol. T/F
F
It is a relatively non-specific enzyme that can also breakdown esters of fat-soluble vitamins and TAG.
150
Which pancreatic enzyme requires bile acids for activity?
Cholesterol esterase
151
Complete obstruction of the common bile duct will maximally affect the digestion of which of the following?
a. Proteins
b. Carbohydrates
c. Fats
d. All of the above
C
152
Absorption of water is achieved by:
A. endocytosis
B. exocytosis
C. secondary active transport
D. osmosis
D
153
Complete resection of the stomach will have the most deleterious effect on the absorption which vitamin?
A. C
B. D
C. B12
D. B6
C
154
Which of the following statements best describe fat digestion and absorption?
a. Lingual lipase is responsible for the majority of fat luminal digestion
b. Triglycerides and cholesterol estersdiffuse across the luminal membrane of the enterocyte
c. Bile acids emulsify lipids and increase the surface area for digestion
d. Chylomicrons are transported directly to the portal vein
C
155
Which of the following statements most accurately describe protein digestion and absorption?
a. Chymotrypsinogen is activated to chymotripsin by enterokinase
b. Dipeptides, tripeptides and amino acids are absorbable forms of protein digestion
c. The optimum pH for pepsinogen activation is between 7 and 9
d. Amino acids are transported from the enterocytes into the bloodstream via secondary active transport
b
156
Resection of the ileum results to malabsorption of which of the following?
a. proteins
b. fats
c. carbohydrates
d. vitamin B6
b
157
Lactose intolerance represents inadequate _________ digestion of carbohydrates?
a. luminal
b. membrane
c. both a and b
d. none of the above
b
158
Which of the following statements most accurately describes carbohydrate digestion and absorption?
a. Luminal digestion is performed by lactase.
b. Membrane digestion is performed by pancreatic amylase.
c. Monosaccharides and disaccharides can be absorbed.
d. Glucose is absorbed via secondary active transport.
d
159
Which of the following is TRUE regarding lipid
digestion and absorption?
a. Complete digestion by lingual and gastric lipase.
b. Emulsification of large lipids into small droplets by bile salts.
c. Bile salts in micelles carrying fatty acids across the intestinal membrane.
d. Absorbed short chain fatty acids enter the portal vein.
b
160
Which of the following substances are primarily absorbed in the proximal small intestines?
A. Fatty acids and bile acids
B. Bile acids and Vitamin B12
C. Vitamin B12 and Galactose
D. Galactose and Fatty acids
D
161
Maltose is digested into:
A. Glucose + Arabinose
B. Glucose + Galactose
C. Glucose + Fructose
D. Glucose + Glucose
d
162
Which of the following pancreatic enzymes for digestion is secreted in its active form ?
A. Trypsinogen
B. Pepsinogen
C. Lipase
D. Elastase
c
163
Which form of carbohydrate serves as the
substrate for carbohydrate membrane digestion?
a. monosaccharides
b. disaccharides
c. polysaccharides
d. AOTA
B
164
Which of the following statements is/are true regarding the absorption of monosaccharides?
a. it requires ATP/energy
b. glucose absorption depends on endocytosis
c. glucose absorption depends on diffusion
d. does not require transport proteins
a
165
Which of the following statements are true regarding the digestion of disaccharides?
A. Sucrose is broken down into fructose and galactose
B. Lactose is broken down into 2 molecules of galactose
C. Maltose is broken down into two molecules of glucose
D. Alpha-dextrinase acts upon sucrose oligomers
C
166
Which of the following statements is/are true regarding the absorption of monosaccharides?
A. SGLT1 transporter moves glucose across the basolateral membrane
B. SGLT 1 transporter moves galactose across the basolateral memebrane
C. GLUT5 transporter moves fructose across the luminal membrane
D. GLUT2 tarnsporter moves glucose across the luminal membrane
C
167
This enzyme is responsible for membrane digestion of proteins
a. peptidase
b. pepsin
c. trypsin
d. chymotrypsin
a
168
Which monosaccharide is absorbed across the luminal membrane using facilitated diffusion?
A. Glucose
B. Galactose
C. Fructose
D. Sucrose
C
169
Which of the following statements is/are true regarding fat digestion and absorption?
A. Most of its luminal digestion happens in the stomach
B. Most of its luminal digestion happens in the small intestine
C. Pancreatic secretory products act to emulsify large fat droplets
D. Glycerol and fatty acids cross the luminal membrane via endocytosis.
B
170
Which of the following statements is/are true regarding the absorption of iron?
a. Absorption occurs at the stomach.
b. Ferric form of ionis most readily absorb.
c. Absorption is increased by ascorbic acid.
d. Absorption is increased by wheat and cereals.
c
171
Procarboxypeptidase and trypsinogen are both activated by:
a. pepsin
b. trypsin
c. ribonuclease
d. enterokinase
b
172
Which of the following secretions is almost exclusively under neural control?
a. Gastric secretions
b. Intestinal secretions
c. Pancreatic secretions
d. Salivary secretions
d
173
Which of the following do gastric parietal cells secrete?
a. intrinsic factor
b. gastrin
c. somatostatin
d. Cholecystokinin (CCK)
a
174
Which of the following ions is bile acid uptake by hepatocytes dependent on?
A. Calcium
B. Sodium
C. Potassium
D. Iron
B
175
The enzyme responsible for active secretion of hydrogen ions by the parietal cell
A. Na+-K+ ATPase
B. H+-K+ ATPase
C. Adenylate cyclase
D. Carbonic anhydrase
B
176
Which of the following proteins is absent in saliva?
A. Lingual lipase
B. Amylase
C. Mucin
D. Intrinsic factor
D
177
Which of the following is the primary active process involved in the concentration of bile in the gallbladder?
A. Active transport of Na+
B. Active transport of Cl-
C. Active transport of HCO3-
D. Increased hydrostatic pressure in the cell
A
178
Which of the following would account for the hypotonic content of saliva in the main ducts?
A. Absorption of Na+
B. Secretion of Na+
C. Secretion of Cl-
D. Absorption of HCO3-
A
179
Which of the following statements about intrinsic factor is TRUE?
A. It is the only gastric secretion that is essential for health
B. It is secreted by chief cells
C. It forms a complex with albumin
D. Lack of it causes megaloblastic anemia
A
180
The interaction of histamine with its receptor in the parietal cell results in:
E. an increase in intracellular sodium concentration
F. an increase in intracellular cAMP production
G. an increase in intracellular cGMP production
H. an increase in intracellular Calcium concentration
F
181
Vagal stimulation could affect gastric acid secretion by
A. directly exciting the parietal cells
B. increading the release of gastrin from the G cells
C. both mechanisms
D. neither
C
182
Trypsinogen is activated by:
A. Hydrogen ions and pepsin
B. Enterokinase and trypsin
C. Chymotrypsin and amylase
D. Alkaline medium partly regulates it
B
183
Which of the following statements is true statements regarding regulation of gastrin release?
A. Increase in pH inhibits G cells
B. Fats in a meal buffers the proton
C. Proteins in a meal buffers the proton
D. Alkaline medium partly regulates it
B
184
Loss of bile from a draining cutaneous fistula (an abnormal connection between two areas, in this case, between the common bile duct and the skin) would results in all of the following except:
A. an increased rate of bile acid synthesis
B. maldigestion and malabsorption of fats
C. jaundice (yellow discoloration of skin due to bilirubin)
D. decreased body bile acid pool
C
185
When chyme enters the duodenum, it may cause:
A. decreased gastric juice secretion
B. increased pancreatic juice secretion
C. increased bile secretion
D. all of the above
D
186
Which of the following phases of pancreatic secretion is not significant in humans?
A. Cephalic phase
B. Gastric phase
C. Intestinal phase
D. All are important
B
187
The finding that there is more Na+ and Cl- in the beginning of the intercalated ducts than the excretory ducts of a salivary gland suggests:
A. Secretory function of the tubular system
B. Reabsorptive function of the tubular system
C. Secretory function of the acinar cells
D. Reabsorptive function of the acinar cells
B
188
What is the difference between luminal and membrane digestion?
Luminal digestion: by enzymes in gastric, salivary and pancreatic secretions
Membrane digestion: by enzymes synthesized by enterocytes the small intestines brush border
189
At which time of the day is the basal rate of gastric acid secretion the highest?
a. Night
b. Morning
c. Afternoon
d. Noon
A
