Gastrointestinal physiology

Question 1

22944 – Which of the following occur(s) in the liver?
1: conversion of free fatty acids to ketones
2: conversion of ammonia to urea
3: synthesis of very low density lipoproteins
4: synthesis of somatomedin-C (IGF-I)

Answer 1

TTTT
Ganong 13th Ed. Chapter: 17 Page: 243, 248, 251 Ch. 22 P. 337

Question 2

23519 – Metabolic functions of the liver include
1: storage of glucose as glycogen
2: processing of chylomicron remnants from the blood
3: gluconeogenesis to maintain blood glucose concentration
4: chemical modification and excretion of thyroxine

Answer 2

TTTT
Guyton Page: 837

Question 3

23549 – The abnormally high blood ammonia levels commonly found in hepatic coma are due to
1: porto-systemic shunting of blood
2: reduced capacity for urea synthesis in the liver
3: bacterial production of ammonia in the gut
4: decreased hydrogen ion excretion by the kidney

Answer 3

TTTF
Guyton 7th Edition CHAPTER: 70 PAGE: 837

Question 4

21973 – Ammonia
1: may be formed from glutamine in the kidney
2: is taken up by glutamic acid in the brain
3: is converted to urea in the liver
4: is a substrate for urea production in the kidney

Answer 4

TTTF
Ganong 13th Ed. Ch. 32 P. 514 Ch. 38 P. 599

Question 5

10094 – With respect to bile pigments
1: about 85% of bilirubin is formed from haemoglobin released by destruction of mature red blood cells which normally have a life-span of 74 days
2: unconjugated bilirubin in plasma is filtered into the proximal convoluted tubules
3: about 20% of bilirubin in the small intestine recirculates to the liver in the enterohepatic circulation
4: unconjugated bilirubin rises in the plasma when there is excessive destruction of red blood cells

Answer 5

FFFT
Ganong, 19th ed, Ch 26
1: formed in reticuloendothelial system & bone marrow - RBC life span 120 days
3: 95%

Question 6

22409 – With respect to bile salts
1: they are absorbed largely from the ileum
2: the primary bile salts are cholate and chenodeoxycholate and are conjugated with glycine or taurine in the liver
3: they are synthesised from cholesterol and are concentrated in the gall bladder
4: about 90% of cholate and chenodeoxycholate which enter the small intestine are absorbed from the jejunum and recirculate to the liver

Answer 6

TTTF
Ganong CHAPTER: 26 PAGE: 403
1,4: 95% reabsorbed from small bowel, mainly TI
2: cholic acid 50%, chenodeoxycholic acid 30%

Question 7

12929 – Bilirubin is
1: normally transported in the blood bound to albumin
2: normally converted to urobilinogen in the small intestine
3: conjugated in the liver with glucuronic acid
4: formed in the reticuloendothelial system and bone marrow

Answer 7

TTTT
Haemoglobin is broken down in the reticuloendothelial system and bone marrow (D true). The ‘haem’ portion is subsequently transported to the liver bound to albumin (A true) where it is conjugated with glucuronic acid (C true). After secretion in the bile, it is converted in the small intestine to urobilinogen (B true) of which 10-20% is reabsorbed.

Question 8

0835 – S. The bile pigment in greatest quantity recycling in the enterohepatic circulation is bilirubin BECAUSE R. bilirubin glucuronide is deconjugated by bacteria in the intestine.

Answer 8

S is false and R is true
Guyton 7th Ed./Ganong 13th Ed./Walter & Israel 6th Ed. CHAPTER: 70/26/47 PAGE: 838-839/419/5

Question 9

21453 – Cholesterol solubility in bile depends on the relative
concentrations of
1: lecithin
2: calcium
3: bile salts
4: bilirubin

Answer 9

TFTF
Ganong 13th Edition CHAPTER: 26 PAGE: 420 (Fig.26-23)

Question 10

13313 – If bile is analysed chemically, which of the following would be found in highest concentration?
A. bile salts
B. cholesterol
C. fatty acids
D. fat
E. bile pigments

Answer 10

A
Hepatic bile is made up of bile salts (0.7%), bile pigments (0.2%), cholesterol (0.06%), and other substances (fatty acids 0.15%, fat 0.1%) dissolved in an alkaline electrolyte solution resembling pancreatic juice (A true).

Question 11

14651 – Concerning bile production and secretion
1: reabsorption of bile salts from the intestine leads to further secretion of bile
2: active transport of NaCl out of the gall bladder is the mechanism by which the bile is concentrated
3: a certain concentration of bile salt is required for the formation of micelles
4: bile salts are derived from waste products of haemoglobin breakdown

Answer 11

TTTF
Refer to Ganong, 19th Ed, Ch 26, page 479-482.
4: BILIRUBIN is the waste products of Hb breakdown

Question 12

853, 13397, 20649 – S. If there is complete obstruction of the common bile duct, retained bile salts may cause skin itch because R. the liver forms cholic acid from which 10-20gm of bile salts are formed daily.

Answer 12

S is true and R is false
Ganong 13th Edition CHAPTER: 26 PAGE: 418.
The liver secretes about 500ml of bile daily, containing 0.7% bile salts. These are sodium and potassium salts of conjugated bile acids synthesised from cholesterol. The two principal bile acids formed in the liver are cholic acid and chenodeoxycholic acids. The normal rate of bile salt synthesis is only 0.2 to 0.4 gram daily (R false). The total bile salt pool of approximately 3.5 gram recycles repeatedly via the enterohepatic circulation with minimal faecal loss. Obstructive jaundice associated with complete obstruction of the bile duct can cause intense skin itching mainly contributed to by bile salt retention (S true). Five hundred ml of bile are secreted daily. Bile salts are secreted into the bowel lumen. Ninety to ninety-five per cent of these are absorbed in the terminal ileum, and returned to the liver via the enterohepatic circulation, and then reexcreted. In complete obstruction of the common bile duct bile salts accumulate in the serum and itching occurs (S true). Cholic acid is formed in the liver. This represents 50% of total bile salt production which amounts to 0.2-0.4 gm/day (R false). This is recycled, so effectively that 3.5 gm are recycled daily as the bile salt pool

Question 13

25970 – The bile acids are converted in the colon to
1: chenodeoxycholic acid
2: deoxycholic acid
3: cholic acid
4: taurocholic acid

Answer 13

FTFF
Ganong 15th ed Chapter:26 Page:466
converted to deoxycholic acid (absorbed) and lithocholic acid (1% absorbed)

Question 14

14110 – S. About 90-95% of the cholate and chenodeoxycholate which enters the small intestine recycles in the enterohepatic because R. cholate and cheno-deoxycholate are passively reabsorbed in the jejunum circulation

Answer 14

C: S is true and R is false
Refer to Gangong, 19th Ed, Ch 26, page 480-481
R: 95% reabsorbed by Na-bile salt co-transport, powered by basolateral Na-K ATPase

Question 15

20091 – S. The patient who has obstructive jaundice due to gallstones may have an increased tendency to bleed because R. in obstructive jaundice decreased absorption of vitamin K occurs in the gut

Answer 15

S is true, R is true and a valid explanation of S
Kyle CHAPTER: 18 PAGE: 408

Question 16

19929 – The oesophagus is normally
A. relaxed, and open at both ends
B. closed at the stomach end only
C. closed at the oral end only
D. contracted throughout its length
E. closed at both ends

Answer 16

E
Ganong 13th Edition CHAPTER: 26 PAGE: 408

Question 17

15107 – Concerning the lower oesophageal sphincter
1: it has a resting pressure of 5mm of Hg above gastric pressure
2: exhibits tonic muscular activity unlike the body of the oesophagus
3: in achalasia absence of ganglion cells results in failure of adequate contraction in this region
4: reflex relaxation of the sphincter is integrated in the tractus solitarius and the nucleus ambiguous

Answer 17

FTFF
Refer to Ganong, 19th Ed, Ch 26, page 469.

Question 18

13605, 22584 – Physiological properties of the stomach include
1: receptive relaxation
2: control of the rate of access of food to the small intestine
3: secretion of a lipase
4: secretion of a factor contributing to erythrocyte formation

Answer 18

TTTT
Guyton 7th Edition Chapter: 63 & 64 Page: 761, 774-775.
Receptive relaxation of the stomach takes place as oesophageal peristaltic waves pass towards the stomach, transmitted by myenteric inhibitory nerves (A true). The gastro-oesophageal sphincter relaxes ahead of time ready to receive food being propelled down the oesophagus during the act of swallowing. Stomach emptying is regulated by signs from both the stomach and duodenum. Signals from the stomach are twofold: (i) nervous signals, caused by distention by food; (ii) gastrin released by antral mucosa in response to certain types of food within the stomach (B true). The stomach secretes a number of minor enzymes, such as lipase (C true) amylase and gelatinase. These are of little quantitative significance in digestion. The stomach secretes intrinsic factor which is essential for vitamin B12 absorption (D true).

Question 19

7355 – S Removal of the part of the stomach nearst the pylorus would be expected to reduce gastric acid secretion Because R the part of the stomach nearest the pylorus secretes most of the hydrochloric acid

Answer 19

S is true and R is false
Removal of the part of the stomach nearest the pylorus would be expected to reduce gastric acid secretion; this operation would remove the antrum, and with it the hormonal stimulus to acid secretion. The response is incorrect. The antrum does not secrete most of the hydrochloric acid the body and fundus do this.

Question 20

20589 – S. The secretion of acid from the stomach is reduced when chyme enters the duodenum BECAUSE R. pancreatic polypeptide in the duodenum causes pancreatic exocrine secretion

Answer 20

S is true and R is false
Ganong 11th Edition CHAPTER: 19 PAGE: 284

Question 21

838 – With respect to gastric secretion
1: vagal stimulation increases the secretion of acid and pepsin.
2: resection of large segments of small intestine is associated with hypersecretion of acid.
3: vagotomy abolishes acid production.
4: vagotomy abolishes gastric motility.

Answer 21

TTFF
The cells of the gastric glands secrete 2.5 litres of gastric juice daily. Regulation is by neural and
humoral mechanisms. Vagal stimulation increases gastrin secretion by release of gastrin-releasing peptide and acetylcholine. It is convenient to break up the physiological regulation of gastric secretion into cephalic, gastric and intestinal influences. Cephalic influences are vagally-mediated responses induced by activity in the CNS. The gastric influences are primarily local reflex responses and responses to gastrin. The intestinal influences are the reflex and hormonal feedback effects on gastric secretion initiated from the small intestine. Resection of large segments of small intestine is associated with hypersecretion of acid (2 true). Vagal stimulation increases the secretion of acid and pepsin (1 true). Vagotomy affects only the cephalic phase of secretion, and diminishes (but does not
abolish) acid secretion. Gastrin is produced by G cells in the gastric antral mucosa and stimulates
gastric acid and pepsin secretion. Acid in the antrum inhibits gastric secretion by a feedback mechanism involving somatostatin. Gastric motility is also reduced (but not abolished) after vagotomy (3 & 4 false). Gastric drainage procedures are required if total truncal vagotomy is performed, but not with highly selective vagotomy. All these operations are now relatively rare for peptic ulcer disease due to the effectiveness of H2 receptor blockers and proton pump inhibitors; and by control of infection from the bacterium Helicobacter pylori which disrupts the mucus barrier (as does aspirin and other NSAIDs).

Question 22

23409 – With respect to gastric secretion
1: vagal stimulation increases the secretion of acid and pepsin but not mucus
2: after the operation of high gastro-jejunostomy (gastric bypass) for obesity the level of plasma gastrin may rise following a meal
3: vagotomy abolishes acid production
4: vagotomy abolishes gastric motility

Answer 22

FTFF
Ganong 13th Edition CHAPTER: 26 PAGE: 409-413, 403-404

Question 23

22544 – With respect to the vagal distribution to the stomach
1: the posterior vagus gives rise to hepatic branches which enter the liver via the lesser omentum and the porta hepatis
2: the main terminal branch of the anterior vagus nerve crosses the stomach distal to the incisura angularis about 5-6 cm from the pylorus
3: most of the fibres of the posterior vagus nerve terminate in the stomach
4: some vagal fibres travelling to the parietal cell mass may sink into the muscular wall at the oesophagus some distance above the cardia

Answer 23

FTFT
Last (8) PAGE: 336

Question 24

21258 – A decrease in gastric antral pH to 2.0
1: inhibits the release of gastrin
2: occurs due to the synergistic action of histamine, gastrin and acetyl choline
3: reflexly inhibits gastric secretion
4: promotes activity in inhibitory afferent fibres of the vagus

Answer 24

TTTF
Ganong 11th Ed. CHAPTER: 26 PAGE: 396-397

Question 25

20385 – S. The respiratory quotient of the stomach during secretion of gastric juice is less than one BECAUSE R. the stomach takes up more CO2 from the arterial blood than it puts into the venous blood

Answer 25

S is true, R is true and a valid explanation of S
Ganong 11th Edition CHAPTER: 26 PAGE: 397-398

Question 26

22404 – A patient with pyloric stenosis due to an active duodenal ulcer has been vomiting most of his meals during the past week. He is hypokalaemic.
The mechanisms causing this hypokalaemia include
1: intracellular protein breakdown
2: loss of potassium into gastric juice
3: decreased insulin production
4: increased renal loss of potassium

Answer 26

FTFT
Guyton 7th Edition CHAPTER: 64, 77 PAGE: 774-775, 911

Question 27

13625 – Prolonged vomiting from severe pyloric stenosis may be associated with
1: metabolic alkalosis
2: low pH of the urine
3: high serum sodium
4: low serum potassium

Answer 27

TTFT
2: The late aciduria is associated with hydrogen ion excretion by renal tubular cells in the face of severe depletion of the cations sodium and potassium.

Question 28

22078 – Following prolonged vomiting associated with complete pyloric
obstruction, a patient would be likely to develop
1: an increase in alveolar ventilation
2: a rise in plasma Cl-concentration
3: an increase in CSF pressure
4: a rise in plasma HCO-3 concentration

Answer 28

FFFT
Ganong 13th Edition Chapter: 39 Page: 608-611

Question 29

848 – Which of the following may be associated with prolonged vomiting from severe pyloric stenosis due to a duodenal ulcer?
1: Low serum potassium.
2: Low pH of the blood.
3: Low pH of the urine.
4: Extracellular metabolic acidosis.

Answer 29

TFTF
“Pyloric” stenosis occurs when the gastric outlet is obstructed by a benign duodenal or prepyloric ulcer or by a stomach cancer. Loss of gastric acid from prolonged vomiting can cause extracellular metabolic alkalosis (4 false), particularly when the cause of the obstruction is a peptic ulcer associated with hypersecretion of acid. Serum bicarbonate rises and serum chloride falls, with a rise in blood pH (2 false). The renal response of urinary bicarbonate excretion is initially associated with an alkaline urine containing sodium, potassium and bicarbonate. Subsequently the urine can become acid (“paradoxical aciduria”) (3 true) after prolonged vomiting with continuing combined gastrointestinal and urinary losses of water and electrolytes, associated with gross deficiencies in water, sodium, chloride and potassium with low serum potassium (1 true). The late aciduria is associated with hydrogen ion excretion by renal tubular cells in the face of severe depletion of the cations sodium and potassium.
KEY ISSUE
Correction requires intravenous administration of isotonic saline with added potassium, which almost always suffices to restore acid-base balance provided that continuing losses are avoided by correcting the obstruction.

Question 30

13307 – Which of the following results in an increase in the pH of duodenal contents?
A. gastrin-releasing peptide
B. secretin
C. intrinsic factor
D. cholecystokinin
E. gastrin

Answer 30

B
Secretin is released from the duodenum in response to duodenal acidification. It significantly increases pancreatic water and bicarbonate secretion and inhibits gastric acid output. Thus it leads to increased pH of duodenal contents (B true). Gastrin and gastrin-releasing peptide increase gastric acid output which would lower duodenal pH (A and E false). Cholecystokinin stimulates pancreatic enzyme secretion and contraction of the gallbladder (D false). Intrinsic factor is released from the oxyntic cells along with the secretion of acid and is essential for Vitamin B12 absorption in the ileum. It has no effect on duodenal pH (C false).

Question 31

22414 – In the small intestine
1: the most significant single factor that increases the luminal surface area is the presence of villi
2: mucosal cells are formed from undifferentiated cells in the crypts of Lieberkuhn
3: peristalsis is the only type of movement demonstrated
4: the frequency of slow waves decreases from the jejunum to the ileum

Answer 31

FTFT
Ganong 20th Ed, Chapter 26, p490.
1: It is the microvilli that make the greater contribution to increase in surface area.

Question 32

870 – With regard to the intestine
1: about 8-9 litres of water are absorbed by the small and large intestine daily.
2: potassium is absorbed by the small intestine and secreted by the large intestine.
3: the absorptive surface of the small intestine is increased 600 fold by the valvulae conniventes, villi and microvilli.
4: diarrhoea can cause hypokalaemia

Answer 32

TTTT
The endogenous secretions (salivary glands 1500ml, stomach 2500ml, bile 500ml, pancreas 1500ml and small intestine 1000ml) total around 7 litres; to which is added 2 litres of ingested water in food and fluid. Of this total intestinal input of 9 litres almost all is absorbed (1 true), leaving 100 to 200ml as output in the stool. Of the reabsorption, approximately 8 litres occurs in the small intestine (6 litres in the jejunum and 2 litres in the ileum); and one litre in the colon. The absorptive surface of the small intestine is increased about 600 fold by the valvulae conniventes and villi (3 true). Potassium is absorbed from the small intestine and can be actively secreted into the large intestine (2 true). There is normally a net secretion of potassium and bicarbonate into the colon. Active absorption of sodium from the colon is accompanied by water absorption. Diarrhoea can cause significant loss of electrolytes, including potassium (4 true).

Question 33

13599, 23539 – The intestinal mucosa below the duodenum produces
1: mucus
2: secretin
3: cholecystokinin
4: isotonic intestinal secretion

Answer 33

TTTT
Ganong 11th Edition CHAPTER: 26 PAGE: 390, 408.
The intestinal glands of the jejunum produce secretin, cholecystokinin and mucus (A, B and C true) in an isotonic secretion (D true) as do glands in
the duodenum.

Question 34

24014 – Substances maximally absorbed in the upper part of the small
intestine include
1: vitamin B12
2: iron
3: bile salts
4: calcium

Answer 34

FTFT
Ganong 13th Edition CHAPTER: 25 PAGE: 399-400

Question 35

20079 – S. Patients who undergo massive resection of the proximal small bowel are likely to develop peptic ulcer BECAUSE R. in such patients there is decreased secretion of secretin and gastric inhibitory polypeptide (G.I.P.)

Answer 35

S is true, R is true and a valid explanation of S
Ganong 13th Edition CHAPTER: 26 PAGE: 402-405

Question 36

13385 – S:Patients who undergo massive resection of the proximal small bowel are likely to develop peptic ulcer disease because R:patients who undergo massive resection of the proximal small bowel have hypersecretion of gastric acid

Answer 36

S is true, R is true and a valid explanation of S
Gastrin secreted by the stomach is inactivated primarily in the kidney and in the small intestine. Thus if this inhibitory effect is removed in part, (less secretin and GIP) more gastrin is present to stimulate gastric acid production (R true and is a valid explanation) and peptic ulcer may develop (S true).

Question 37

19557 – After massive resection of the small bowel all of the following are common, EXCEPT
A. intractable diarrhoea
B. increased likelihood of renal stone
C. hypergastrinaemia
D. increased serum calcium
E. lowered serum protein

Answer 37

D

Question 38

10179 – Resection of the ileum markedly reduces the absorption of
1: bile salts
2: vitamin B12
3: fat-soluble vitamins
4: ferrous iron

Answer 38

TTTF
Ganong, 19th ed, Ch 26

Question 39

20817 – S. Resection of the last metre of small bowel leaving the ileo-caecal valve intact might result in a macrocytic anaemia developing within three months BECAUSE R. the last metre of ileum is the major site of vitamin B12 absorption

Answer 39

S is false and R is true
Guyton 7th Edition, Ganong 13th Edition CHAPTER: 66 & 26 PAGE: 799 & 414

Question 40

20745 – S. Intestinal bacteria are largely responsible for the odour of the faeces BECAUSE R. the odour of the faeces is largely due to the presence of methane formed by bacterial action on ingested food

Answer 40

C: S is true and R is false
Ganong 13th Ed. CHAPTER: 26 PAGE: 425

Question 41

20787 – S. In the blind loop syndrome steatorrhea occurs BECAUSE R. the
proliferation of bacteria in a blind loop results in excessive oxidation of
conjugated bile salts

Answer 41

S is true and R is false
Ganong 13th Edition CHAPTER: 26 PAGE: 425-426

Question 42

23244 – In the blind loop syndrome
1: the harmful effects are caused by bacterial invasion of the small intestine
2: steatorrhoea is a clinical feature
3: bacterial overgrowth may contribute to the development of macrocytic anaemia
4: jaundice is a clinical feature

Answer 42

TTTF
Ganong 13th Edition CHAPTER: 26 PAGE: 425-426

Question 43

20187 – S. Steatorrhoea may follow resection of the terminal ileum BECAUSE R. 95% of the bile salts are absorbed in the terminal ileum and recycled by the enterohepatic circulation

Answer 43

S is true, R is true and a valid explanation of S
Ganong 13th ed. Chapter: 26 Page: 418

Question 44

22384 – Diarrhoea during enteral tube feeding may be due to
1: excess volume of feed
2: hyperosmolarity of feed
3: malabsorption
4: short bowel syndrome

Answer 44

TTTT
Burnett - C. S. S. CHAPTER: 18.22.4 PAGE: 347

Question 45

15478 – Features of colonic function include
1: constancy of faecal content despite variation in diet
2: active transport of Na+ out of the colonic mucosa
3: sterile contents at birth
4: secretion of K+ and HCO3
- into lumen

Answer 45

TTTT
Refer to Ganong, 19th Ed, Ch 26, page 486 and following

Question 46

13403 – S: A narrowed segment of the distal third of the colon is more likely to produce symptoms than a narrowed segment of the proximal third of the colon because R: faeces are more fluid in the proximal third of colon than they are in the distal third

Answer 46

S is true, R is true and a valid explanation of S
Approximately 1000-2000 ml of isotonic chyme enter the colon each day from the ileum. As it passes through the colon, 90% of the water is absorbed by the colon until 200-250 ml of semi-solid faeces are found at the distal colon. Semi-solid or fluid faeces passes more easily through a constriction than solid faeces. Thus a proximal tumour will not stop fluid and semi-solid colonic contents and will be quiescent.

Question 47

23419 – Of the gastrointestinal hormones
1: gastrin stimulates gastric mucosal growth
2: cholecystokinin secretion by cells of the upper small intestine is enhanced by amino acids and fatty acids
3: secretin augments the action of cholecystokinin in producing pancreatic secretion of digestive enzymes
4: gastric inhibitory peptide (GIP) increases the sensitivity of insulin response to raised blood glucose

Answer 47

TTTT
Ganong 16th Edition CHAPTER: 26 PAGE: 452-54 Guyton CHAPTER: 78 PAGE: 977-78

Question 48

23434 – Common features of the gastrointestinal hormones VIP, GIP, secretin and glucagon include
1: lipolytic activity
2: present in the nerves of the gastrointestinal tract
3: release by vagal stimulation
4: portions of similar amino acid sequence

Answer 48

FFFT
Ganong 13th Edition CHAPTER: 26 PAGE: 442-44

Question 49

9820 – The following are all gastrointestinal hormones EXCEPT
A. glucagon
B. GIP
C. enterokinase
D. gastrin-releasing peptide
E. cholecystokinin

Answer 49

C
Ganong 19th ed, Ch 26
Enterokinase is an enzyme

Question 50

13620, 23399 – Secretin
1: is a powerful stimulant of pancreatic enzyme
2: inhibits gastric motility
3: is produced in the upper small intestine
4: inhibits gastric acid secretion

Answer 50

FTTT
Secretin is produced by cells in the mucosal glands of the duodenum and jejunum (C true). Its main action is to stimulate the pancreas to secrete watery, alkaline pancreatic juice augmenting CCK (A false). Secretin decreases gastric acid secretion (D true) by a feedback loop via gastrin by increasing the pH of the duodenum. Secretin has a mild inhibitory effect on the motility of most of the gastrointestinal tract (B true).
Ganong 13th Edition & Guyton 7th Edition CHAPTER: 26/63 & 64 (Guyton) PAGE: 405/764 -778 (Guyton)

Question 51

9998 – Secretin is
1: released by acid in the duodenum
2: released by vagal stimulation
3: a stimulant of secretion from biliary and pancreatic duct cells
4: responsible for a high chloride ion concentration in external pancreatic secretion

Answer 51

TFTF
Ganong, 19th ed, Ch 26

Question 52

21733 – Secretin
1: is secreted by cells in the mucosa of the duodenum
2: increases HCO3- secretion from the exocrine pancreas
3: decreases gastric acid secretion
4: augments the action of CCK on the pancreas

Answer 52

TTTT
Ganong 13th ed. Chapter: 26 Page: 405

Question 53

14646 – Secretin
1: is secreted when protein breakdown products arrive in the upper small intestine
2: increases the secretion of bicarbonate from the biliary tract
3: is released in conjunction with Substance P
4: is structurally similar to glucagon

Answer 53

TTFT
Refer to Ganong, 19th Ed, Ch 26, page 465-466

Question 54

23414 – Somatostatin inhibits acid secretion because it
1: stimulates luminal gastrin release
2: stimulates gastric inhibitory peptide release
3: inhibits gastrin release into the blood stream
4: inhibits parietal cell function

Answer 54

FFTT
Ganong 11th Edition CHAPTER: 26 PAGE: 391

Question 55

25975 – Cholecystokinin
1: secretion is increased by fatty acids in the duodenum
2: has a more marked effect on the ducts than on the acini of the pancreas
3: exerts a trophic effect on the pancreas
4: inhibits the action of secretin in producing secretion of an alkaline pancreatic juice

Answer 55

TFTF
Ganong 16th Ed. Chapter 26 Page:442-443

Question 56

23249 – Serum gastrin
1: is decreased by products of protein digestion in the stomach
2: is increased by hypercalcaemia
3: is low in pernicious anaemia
4: is increased after massive small bowel resection

Answer 56

FTFT
Ganong 14th ed. Chapter: 26 Page: 411

Question 57

13295 – Gastrin
A. is produced in the gastric antrum, stimulates HC1 secretion and is inhibited by secretin
B. is produced in the gastric body, stimulates secretin production and is inhibited by HC1 secretion
C. is produced in the gastric fundus, stimulates HC1 production and stimulates secretin production
D. stimulates secretin production
E. is produced in the gastric antrum, suppresses HC1 secretion and stimulates secretin production

Answer 57

A
Gastrin is formed in the G cells principally in the gastric antrum (B and C false), and is present in the duodenum in one-tenth the concentration released into the blood stream. It has two principal actions - one of increased HC1 secretion (E false) by the parietal cells of the fundus, the other a trophic effect on gastric and intestinal mucosa. An acid pH in the antrum is the powerful shut-off mechanism for acid, acting mainly through inhibition of gastric release. This is complete at pH 1.2. Gastrin and cholecystokinin (CCK) are partial agonists, but gastrin and secretin are antagonists. Secretin inhibits gastrin release after a meal. Acidification of the duodenum is the principal stimulus for secretin release (D false). Thus gastrin is formed principally in the gastric antrum, stimulates HC1 secretion and is inhibited by secretin (A true).

Question 58

843, 13635 – Gastrin
1: is functionally and structurally related to cholecystokinin
2: is secreted by the antral mucosa
3: is liberated by distension of the antrum
4: stimulates the secretion of both acid and pepsin

Answer 58

TTTT
Gastrin, which is secreted by the antral mucosa under stimulus of antral distension is functionally and structurally related to cholecystokinin; and stimulates secretion of both acid and pepsin (1, 2, 3 and 4 true). The C-terminal pentapeptide of gastrin is identical to that of cholecystokinin (A true). Both peptides are released by a protein meal and both stimulate glucagon secretion. Gastrin is produced by G cells in the antral mucosa (B true). Receptors in the wall of the stomach and in the gastric mucosa respond to stretch (C true). Gastrin stimulates both the oxyntic and peptic cells to secrete acid and pepsin (D true).

Question 59

23424 – Circulating gastrin levels are high in
1: Zollinger-Ellison syndrome
2: pernicious anaemia
3: secretory tumours of the pancreatic delta cells
4: most patients with duodenal ulcer

Answer 59

TTFF
Ganong 13th Edition CHAPTER: 26 PAGE: 403-404, 413

Question 60

14661 – Gastrin secretion is increased by
1: glucagon
2: calcium
3: secretin
4: tryptophan

Answer 60

FTFT
Refer to Ganong, 19th Ed, Ch 26, page 462 and following

Question 61

15092 – Gastrin is present in the following tissues
1: gastric antrum
2: gastric fundus
3: first part of duodenum
4: renal parenchyma

Answer 61

TFTF
Refer to Ganong, 19th Ed, Ch 26, page 470 and following. To

Question 62

23664 – VIP (Vasoactive intestinal peptide)
1: potentiates action of acetylcholine in salivary glands
2: is formed from prepro-VIP
3: inhibits gastric acid secretion
4: causes vasoconstriction of peripheral blood vessels

Answer 62

TTTF
Guyton 13th Edition CHAPTER: 26 PAGE: 405

Question 63

576 – Cholecystokinin causes all the following EXCEPT
A. Stimulation of an enzyme-rich pancreatic juice.
B. Relaxation of the sphincter of Oddi.
C. Stimulation of hepatic flow of bile.
D. Contraction of the gallbladder.
E. Stimulation of pancreatic juice rich in bicarbonate

Answer 63

E
Secretin, not cholecystokinin, stimulates a pancreatic juice rich in bicarbonate. The response is false and E is accordingly the correct answer.

Question 64

570 – In the control of gastric acid secretion, the MAIN action of somatostatin is to
A. suppress the release of gastrin.
B. bind with the gastrin molecule to prevent its action.
C. stimulate the secretion of bicarbonate.
D. stimulate the parietal cell.
E. stimulate the release of gastrin.

Answer 64

C

Question 65

22068 – With respect to fat absorption
1: it is greatest in the upper small intestine
2: it occurs through active absorption of micelles
3: 95% of dietary fat is normally absorbed in adults
4: only 75% of dietary fat is absorbed in infants

Answer 65

TFTF
Ganong 20th Edition, p459.
Active absorption does not occur. Ganong refers to some “carrier” transport which is not neccessarily “active” and does not refer to evidence for “active” transport.

Question 66

15097 – With respect to fat absorption
1: small amounts of medium and larger chain fatty acids are absorbed directly into the portal blood
2: chylomicra are small droplets of fat combined with apoproteins which aid diffusion through enterocyte membrane
3: without bile acids, less than 15% of fat is normally absorbed
4: between 80 - 90% of all fat absorbed from the gut is transported to the blood via the thoracic duct as chylomicrons

Answer 66

FFFT
Refer to Guyton, 9th Ed, Ch 65, page 842-843; Ganong, 19th Ed, Ch 25, page 452 and following
1, 2, 4: FAs containing >10-12 carbon atoms are re-esterified into triglycerides in mucosal cells –> coated with protein, cholesterol and phospholipid to form chylomicrons which leave the mucosal cells and pass into the lymphatics as emulsified particles, accounting for most of the fat transport. Only fatty acids containing less
than 10 to 12 carbon atoms pass from mucosal cells directly into the portal blood.

Question 67

24339 – During fat digestion/absorption
1: bile salts combine with fatty acids and monoglycerides to form micelles
2: in the absence of bile salts fatty acids are not absorbed
3: fatty acids containing more than 10-12 carbon atoms are re-esterified to triglycerides in the mucosal cells
4: pancreatic lipase produces fatty acids and monoglycerides from dietary triglycerides

Answer 67

TFTT
Ganong 19 Edition CHAPTER: 25 PAGE: 452-453 (also fig. 25.4)

Question 68

82, 10404 – With regard to the parenteral administration of fat:
A. Can constitute up to 70% of the total energy administered per day.
B. There is a specific requirement for short-chain fatty acids in order to generate ketone bodies for metabolism by colonocytes.
C. Omega-6 polyunsaturated fatty acid triglycerides should be provided in doses adequate to prevent essential fatty acid deficiency.
D. There is a specific requirement for medium-chain triglycerides to maintain the fluidity of
membranes.
E. Omega-3 polyunsaturated fatty acids may modulate the immune response by inhibiting the induction of free-radical lipid peroxides.

Answer 68

C
Between 15% to 30% of the total calories administered per day can be provided as fat. There is no specific requirement for short-chain fatty acids. Medium-chain triglycerides can be used as a source of calories. Omega-6 polyunsaturated fatty acid triglycerides should be provided in doses adequate to prevent essential fatty acid deficiency ie. at least 7.0% of total calories. Omega-3 polyunsaturated
fatty acids are sometimes referred to as ‘Fish Oils’. Whilst they have no established requirement in critically ill patients, they are under clinical investigation as immune - modulating and antiinflammatory agents. They may regulate the immune response in at least three ways: (1) by increasing membrane fluidity, (2) inducing free-radical lipid peroxides, and (3) by providing precursors for eicosanoid metabolism.

Question 69

18856 – Which of the following (after fat) is the largest energy store?
A. muscle protein
B. visceral protein
C. extracellular protein
D. liver glycogen
E. muscle glycogen

Answer 69

A
BURNETT. C.S.S. CHAPTER: 14.2.2 PAGE: 208

Question 70

864, 3980 – After a fatty meal, most of the fat will be transported away from the intestine
A. as free fatty acids in the portal vein blood.
B. as emulsified particles in the lymph.
C. as monoglycerides in the portal vein blood.
D. as triglyceride in the portal vein blood.
E. attached to plasma albumin carrier molecules.

Answer 70

B
Refer to Ganong, 19th Ed, Ch 25, page 453-454, Figure 25.5.
Fats are emulsified in the small intestine by the detergent action of bile salts, lecithin, and mono-glycerides. After a fatty meal 95% or more of the ingested fat is absorbed. Fatty acids containing more than 10 to 12 carbon atoms are reesterified to triglycerides in the mucosal cells; and are coated with protein, cholesterol and phospholipid to form chylomicrons which leave the mucosal cells and pass into the lymphatics as emulsified particles, accounting for most of the fat transport (B true). Only fatty acids containing less than 10 to 12 carbon atoms pass from mucosal cells directly into the portal blood. Absorption of long chain fatty acid begins in the duodenum and is greatest in the upper parts of the small intestine, although appreciable amounts are also absorbed from the ileum. Short chain fatty acids are produced by bacterial action on undigested complex carbohydrates from fruits and vegetables in the colon, and are probably trophic to colonic mucosa.

Question 71

14104 – S: Fat in the duodenum delays stomach emptying because R: fat in the duodenum releases CCK, secretin and gastric inhibitory peptide (GIP)

Answer 71

S is true, R is true and a valid explanation of S
Refer to Ganong, 19th Ed, Ch 26, page 474-475

Question 72

22704 – Plasma cholesterol levels are decreased by
1: thyroxine
2: androgens
3: oestrogens
4: growth hormone

Answer 72

TFTF
Ganong 16th ed. CHAPTER: 17 PAGE: 279.

Question 73

21213 – Endogenously-derived triglyceride circulating in the plasma is
1: transported primarily as very low density lipoprotein
2: increased by carbohydrate excess in the diet
3: removed from the circulation by both muscle and adipose tissue
4: increased when plasma cholesterol levels rise

Answer 73

TTTF
Ganong 13th ed. Chapter 17 Page: 251-254

Question 74

19647 – With respect to lipoproteins, which of the following statements is FALSE?
A. low density lipoproteins (LDL) contain more cholesterol than high density lipoproteins (HDL)
B. low density lipoproteins (LDL) contain more triglyceride than high density lipoproteins (HDL)
C. individuals with elevated LDL have a higher than normal incidence of atherosclerosis
D. individuals with elevated HDL have a higher than normal incidence of atherosclerosis
E. the primary function of HDL is in cholesterol exchange and esterification

Answer 74

D
Ganong 11th ed. CHAPTER: 17 PAGE: 243-245

Question 75

15102 – Iron absorption is
1: facilitated by pancreatic juice
2: inhibited by cereal products
3: increased by adding ascorbic acid to the diet
4: predominantly in the duodenum

Answer 75

FTTT
Refer to Ganong, 19th Ed, Ch 25, page 456 and following
2: due to presence of phytates in cereal
3: Ascorbic acid forms a highly soluble iron chelate which facilitates intestinal mucosal attachment. Ascorbate also acts as a reducing agent to maintain iron in the ferrous form which is more soluble than ferric iron in alkaline conditions and thereby more readily absorbed

Question 76

14681 – Iron absorption
1: is increased by low pH of gastric secretions
2: is increased in states of iron overload
3: requires the presence of transferrin
4: occurs in terminal ileum

Answer 76

TFTF
Refer to Ganong, 19th Ed, Ch 25, page 456-458

Question 77

12934 – Iron absorption is inhibited by
1: pH of pancreatic juice
2: phytic acid
3: ascorbic acid
4: phosphates

Answer 77

TTFT
The absorption of non-haem iron is inhibited by its binding to dietary phytates in cereals (B true) and phosphates (D true). Alkaline conditions reduce iron absorption (A true). Ascorbic acid forms a highly soluble iron chelate which facilitates intestinal mucosal attachment. Ascorbate also acts as a reducing agent to maintain iron in the ferrous form which is more soluble than ferric iron in alkaline conditions and thereby more readily absorbed (C false).

Question 78

23164 – Concerning iron
1: absorption is mainly in the ferrous form
2: adult males require absorption of 0.5-1.0 mg. per day
3: absorption occurs mainly in the upper small intestine
4: haemosiderin is the principal storage form of iron in the tissues

Answer 78

TTTF
Ganong 19th Edition CHAPTER: 25 PAGE: 456-458

Question 79

12939 – A 50-year-old man has a past history of a duodenal ulcer and has been taking aspirin 4-hourly for painful rheumatoid arthritis for a period of two months. This has caused a loss of 30 ml of blood daily in his stools. It is likely that
1: his blood will show an iron deficiency anaemia
2: his absorption of iron from a full normal diet will be affected by arthritis
3: his plasma iron binding capacity will be decreased
4: there will be no suspicion of melaena on macroscopic examination of his stools

Answer 79

TTFT
This man has lost 900 mg of iron which, under normal conditions, would have been his reserve iron store. As he has a past history of duodenal ulcer with probable iron loss and a history of active rheumatoid arthritis which will affect iron absorption and mobilisation, he is most likely to have iron deficiency anaemia (1 true). Consequent to this iron deficiency, his plasma iron binding capacity may be increased (3 false) although chronic inflammation may reduce the expected rise (2 true). His iron absorption will thus tend to increase. Melaena will not be seen on macroscopic examination until more than 100 ml of blood are lost daily into the large intestine (4 true).

Question 80

13409 – S: Iron deficiency anaemia may occur in patients who have had radical gastrectomy because R: following radical gastrectomy, iron in the ferric (Fe3+) state is the main form present for absorption in the small intestine.

Answer 80

S is true, R is true and a valid explanation of S
Iron is readily absorbed as ferrous (Fe++) iron. Most dietary iron, however is in the ferric (Fe+++) form. Gastric secretions are necessary to convert Fe+++ to Fe++ forms. Absorption takes place mainly in the duodenum and upper jejunum. Following radical gastrectomy iron deficiency anaemia is a relatively frequent complication (S true, R true and is a valid explanation of S).

Question 81

9892 – S: Iron deficiency anaemia is a recognised complication of partial gastrectomy because R: acid is required for iron absorption within the stomach

Answer 81

S is true and R is false
Ganong, 19th ed, Ch 35

Question 82

20529 – S. Following total removal of the stomach, microcytic anaemia is likely to develop BECAUSE R. a secretion from the stomach is essential for normal erythropoiesis

Answer 82

S is true, R is true but NOT a valid explanation of S
Ganong 15th Edition CHAPTER: 25, 26 PAGE: 446-47; 461-62.
The stomach secretes intrinsic factor which is essential for vitamin B12 absorption

Question 83

20139 – S. Anaemia may be a consequence of peptic ulcer surgery BECAUSE R. there are less gastric secretions to convert dietary Fe3+ to its more easily absorbable form Fe2+ after peptic ulcer surgery

Answer 83

S is true, R is true and a valid explanation of S
Ganong CHAPTER:25 PAGE: 399

Question 84

662 – Which of the following statements, concerning iron metabolism, is/are true?
1: gastric acidity is required for absorption of haem-iron
2: achlorhydria leads to a significant reduction in absorption of non-haem-iron
3: iron absorption does not increase after haemolysis
4: iron absorption is increased after haemorrhage

Answer 84

FTFT
Ganong, 19th ed, Ch 26; Guyton, 9th ed, Ch 32; Robbins, 6th ed, Ch 14.
Gastric acidity and secretions enhance iron absorption and patients without a stomach can become iron deficient but may still absorb some iron. (Hence can be treated with iron tablets.) Thus gastric acidity is not required.

Question 85

20955 – S. In patients suffering from pernicious anaemia the serum gastrin levels are normal BECAUSE R. there is no increase in gastric intra-luminal acid in pernicious anaemia

Answer 85

S is false and R is true
Ganong 11th Edition & W & I 5th Edition CHAPTER: 26 PAGE: 390 609

Question 86

13072 – Pernicious anaemia is typically associated with
1: a reduced packed cell volume
2: megaloblastic marrow
3: gastric atrophy
4: thrombocytopenia

Answer 86

TTTT
Anaemia is typically associated with a reduced packed cell volume (A true). Even though the red cells are larger than normal in pernicious anaemia, their numbers are considerably reduced, and the PCV is, therefore, low. Gastric atrophy is the most important cause of pernicious anaemia and results from an auto-immune reaction (C true). The megaloblastic marrow reflects a deficiency of Vitamin B12 and folate (B true). Pernicious anaemia is typically associated with a thrombocytopenia (D true).

Question 87

10089 – The pancreas secretes
1: insulin, in increased quantity following a-adrenergic stimulation
2: proelastase
3: glucagon, in decreased quantity following administration of somatostatin
4: inactive precursors of trypsin and lipase

Answer 87

FTTT
Ganong, 19th ed, Ch 19 and 26

Question 88

5977, 13630 – The exocrine secretion of the pancreas contains
1: phospholipase A
2: ribonuclease and deoxyribonuclease which split nucleotides from nucleic acids
3: chloride at about 130 mmol/l concentration
4: prolipase from nucleic acids

Answer 88

TTFT
Pancreatic juice is alkaline and about 2 litres are secreted daily. Pancreatic juice contains phospholipase A, ribonuclease and deoxyribonuclease and prolipase (1,2,4 true). The main anions are HCO3- and chloride. The concentration of bicarbonate is about 80 mmol/l rising to 150 mmol/l on stimulation by secretin. The concentration of chloride, by contrast, is about 55 mmol/l and falls when the pancreas is stimulated by secretin (3 false).

Question 89

10174 – The external secretion of the pancreas contains
1: phospholipase A
2: chloride at about 130 mmol/l concentration
3: ribonuclease and deoxyribonuclease which split nucleotides from nucleic acids
4: a bile salt activated lipase capable of hydrolysing cholesterol esters

Answer 89

TFTT
Ganong, 20th ed, Ch 26 Pages 483, 458.
Pancreatic juice is alkaline and about 2 litres are secreted daily. Pancreatic juice contains phospholipase A, ribonuclease and deoxyribonuclease and prolipase. The main anions are HCO3- and chloride. The concentration of bicarbonate is about 80 mmol/l rising to 150 mmol/l on stimulation by secretin. The concentration of chloride, by contrast, is about 55 mmol/l and falls when the pancreas is stimulated by secretin.

Question 90

23429 – HCO3- rich pancreatic juice is secreted by the pancreas in response to
1: secretin
2: vagal stimulation
3: CCK
4: gastrin

Answer 90

TFFF
Ganong 13th Edition CHAPTER: 26 PAGE: 452-454.
2: Stimulation of the vagi with release of acetylcholine causes discharge of zymogen granules and secretion of a small amount of juice rich in enzymes
3: CCK stimilates pancreas to produce ENZYME-rich juice

Question 91

859, 13610, 233404 – Enzyme-rich pancreatic juice is secreted when
1: secretin acts on the pancreas.
2: cholecystokinin (CCK) acts on the pancreas.
3: the vagus stimulates the pancreas.
4: the sympathetic nerves stimulate the pancreas.

Answer 91

FTTF
Ganong 13th Edition Chapter: 26 Page: 415-416.
The pancreatic juice of the exocrine pancreas contains enzymes of major importance in digestion. Their secretion is controlled by the gastrointestinal hormones secretin and CCK, and by reflex mechanisms. The active enzymes secreted include pancreatic amylase, trypsin and chymotrypsins, pancreatic lipase and carboxypeptidases. The juice is alkaline with a high bicarbonate content. About 1.5L is secreted daily. Secretion is primarily under hormonal control. Secretin acts on the pancreatic ducts to cause a copious secretion of a very alkaline pancreatic juice which is rich in bicarbonate and poor in enzymes (1 false). CCK acts on the acinar cells to cause production of pancreatic juice rich in enzymes (2 true). Stimulation of the vagi with release of acetylcholine causes discharge of zymogen granules and secretion of a small amount of juice rich in enzymes (3 true). A vagally-mediated conditioned reflex secretion of pancreatic juice occurs in response the sight or smell of food. The sympathetic nerve supply of the pancreas is vasoconstrictive, and has minimal effect on exocrine secretion (4 false). Secretin stimulates pancreatic secretion, but this is poor in enzymes. Stimulation of the vagus causes secretion of a small amount of pancreatic juice rich in enzymes. This effect is blocked by atropine and by denervation of the pancreas, whereas the effects of cholecystokinin-pancreozymin are not. There
is evidence for a vagally mediated conditioned reflex secretion of pancreatic juice. Sympathetic stimulation in the gastro-intestinal tract can inhibit peristalsis and increase the tone of the sphincters but does not affect pancreatic secretion. Cholecystokinin-pancreozymin causes contraction of the gall bladder and stimulates the pancreas to secrete pancreatic juice rich in enzymes. Furthermore, CCK augments the action of secretin in producing an alkaline-rich pancreatic juice.

Question 92

23254 – The serum amylase may be elevated during
1: acute renal insufficiency
2: administration of morphine
3: acute perforation of a duodenal ulcer
4: mumps

Answer 92

TTTT
Canadian Exam

Question 93

9838 – In the absence of pancreatic enzymes the faeces contain more fat MAINLY because
A. there is little enteric lipase in the epithelial cells of the small intestine
B. pancreatic enzymes are necessary for adequate emulsification of fat
C. lack of pancreatic bicarbonate reduces the efficiency of succus entericus enzymes
D. proteolytic enzymes in pancreatic secretion are essential for the release of fat from the forms in which it is ingested
E. pancreatic secretion is necessary to stimulate bile production

Answer 93

A
Ganong 19th ed, Ch 26

Question 94

20865 – S. If a carcinoma of the head of the pancreas obstructs the common bile duct, there a high level of urobilinogen in the urine BECAUSE R. urobilinogen entering the circulation is excreted in the urine

Answer 94

S is false and R is true
Ganong 13th. ed. Chapter: 26 Page: 419

Question 95

20331 – S. Although protein has a theoretically higher caloric content than carbohydrate, in the body similar values are obtained from protein and carbohydrate BECAUSE R. the oxidation of protein is incomplete

Answer 95

S is true, R is true and a valid explanation of S
Ganong 15th ed. Page: 262

Question 96

13301, 19875 – Which of the following could NOT be considered evidence that intestinal absorption of carbohydrate is an active process?
A. absorption is inhibited by metabolic poisons
B. glucose in the lumen strongly reduces fructose absorption from the lumen
C. there is a maximum rate of absorption for glucose from the intestinal lumen
D. absorption rate can be different for sugars of similar molecular weight
E. carbohydrates must be broken down to disaccharides or monosaccharides before they can be absorbed in any quantity

Answer 96

E
Guyton 7th Edition Chapter: 65 PAGE: 787-788.
Transport of most monosaccharides is an active
process. This is demonstrated by the following: (i) Transport of most monosaccharides can be
blocked by metabolic inhibitors such as iodoacetic acid, cyanides and phlorizin (A false). (ii) Transport is selective for the different monosaccharides (D false). (iii) There is a maximum rate of transport for each monosaccharide the most rapid being for galactose (C false). (iv) There is competition between certain sugars for respective carrier systems (B false).

Question 97

976, 10398 – With regard to the parenteral administration of carbohydrates:
A. Patients require 15 kcal/kg/day.
B. Patients require 25 kcal/kg/day.
C. Patients require 35 - 40 kcal/kg/day.
D. Patients require 50 kcal/kg/day and the blood glucose levels should be maintained less than 225 mg/dL (12.5 mmol/L).
E. Patients require 50 kcal/kg/day and the blood glucose level should be maintained more than 225 mg/dL (12.5 mmol/L).

Answer 97

B
Administering 25 kcal/kg usual body weight/day appears to be adequate for most patients. From 30% to 70% of the total calories administered per day can be given as glucose. The dose should be adjusted to maintain a blood glucose level <225 mg/dL (12.5 mmol/L) - it may be desirable to administer insulin in patients with higher levels of glucose in the blood. The calorie-to-nitrogen ratio should be 150 kcal per gm of nitrogen (about 6.25 gm of protein contains 1 gm of nitrogen). In trying to adapt nutritional supply to needs, most dieticians and nutritionists will estimate energy expenditure from standard formulas like those of Harris and Benedict, which are derived from sex, weight, height, and age.

Question 98

1012, 10434 – With regard to the inclusion of fibre in solutions of enteral nutrients:
A. Butyrate, an endogenous product of fibre fermentation, is an important fuel for colonocytes.
B. It is desirable to consume > 250 gm of fibre each day.
C. A deficient fibre intake can lead to secretory diarrhoea.
D. The long-term consumption of a diet that is low in fibre increases the risk of bacterial translocation across the wall of the proximal colon.
E. An inadequate fibre intake can impair the entero-hepatic circulation of bile salts and thereby lead to the diminished absorption of fat soluble vitamins.

Answer 98

A
Endogenous products of fibre fermentation are important for colonocyte integrity and function. However, the provision of fibre has not been clearly demonstrated to be of any clinical advantage.

Question 99

13391, 20073 – S: Ingestion of protein foods such as eggs can sometimes provoke antibody formation in infants because R: in infants there is absorption of whole protein from the alimentary canal

Answer 99

S is true, R is true and a valid explanation of S
Ganong 13th Edition CHAPTER: 25 PAGE: 395.
In infants, moderate amounts of undigested protein are absorbed (R true and is a valid explanation of S). Maternal protein from colostrum is absorbed, affording passive immunity against infection. Absorption is via the small intestine by endocytosis and subsequent exocytosis. Foreign proteins entering the circulation, provoke the formation of antibodies
(S true) leading to possible allergic symptoms.

Question 100

10410 – With regard to the parenteral administration of protein:
A. Glycine should constitute at least 50% of the amino acids.
B. Dosing should ensure that the blood urea nitrogen level remains > 200 mg/dL.
C. Hepatic encephalopathy is not influenced by the amount of protein that is administered parenterally.
D. Solutions should contain > 0.25 g/kg/day of nucleotides to maintain the proliferative ability of bone marrow.
E. The protein requirement is about 1.2 to 1.5 g/kg/day.

Answer 100

E
The protein requirement is about 1.2 to 1.5 g/kg/day. Considerations for a decrease in dosing include a rising blood urea nitrogen level that exceeds 100 mg/dL or a rising blood ammonia level that is associated with clinical encephalopathy. A nutritional requirement for nucleic acids has not been established, but they are being investigated as beneficial nutrients for proliferation of intestinal crypt cells, lymphocyte proliferation, and cellular DNA and RNA synthesis. Glycine is the simplest of the amino acids as it is based only one carbon molecule. Its administration has no defined biological or clinical advantages, but it is often included in commercial solutions as a ‘stuffer’ amino acid ie. a convenient source of nitrogen. Incidentally, as opposed to chronic renal failure, there is no need to alter the amount of protein administered to patients with acute renal insufficiency. There is also no demonstrable advantage to be gained by administering just essential amino acids. Haemodialysis and haemofiltration remove amino acids in the range of 3 to 5 g/h. These losses need consideration when adjusting the amount of protein to be administered.

Question 101

24194 – With regard to trace elements
1: iron deficiency may cause anaemia
2: cobalt deficiency may cause megaloblastic anaemia
3: iodine deficiency may cause goitre formation
4: chromium deficiency may cause insulin resistance

Answer 101

TTTT
Ganong 18th ed. Page: 293

Question 102

19270 – Which of the following is NOT an essential trace element
A. zinc
B. copper
C. beryllium
D. molybdenum
E. selenium

Answer 102

C
BURNETT. C.S.S. CHAPTER: 14.7 PAGE: 213

Question 103

18904 – Regarding the digestion and absorption of amino acids from the intestine
A. less than 5% of the protein in the small intestine escapes digestion and absorption
B. absorption of amino acids is rapid throughout the whole of the small intestine
C. over 90% of the digested protein is dietary
D. the protein in the stools is largely undigested dietary protein
E. amino acids are actively transported from the mucosal cells into the blood stream

Answer 103

A
Ganong 13th Ed. CHAPTER: 25/26 PAGE: 394-395/424-425.

Question 104

10416 – With regard to the parenteral administration of branched chain amino acids (BCAA):
A. BCAA administration to catabolic surgical patients enhances the quality and number of polyribosomes in skeletal muscle.
B. BCAA administration improves patient outcome after major hepatic surgery.
C. BCAA are mainly metabolised in the liver.
D. There is no role for parenteral BCAA therapy in patients with hepatic encephalopathy.
E. When used clinically, BCAA should be administered at a dose of 0.1 to 0.3 g/kg/d.

Answer 104

A
The BCAA - leucine, isoleucine, and valine - are essential amino acids required for protein synthetic functions. BCAA are primarily metabolised by skeletal muscle, rather than the liver. When given in a balanced amino acid formulation at a dose of 0.5 to 1.2 g/kg/d BCAA can improve nitrogen retention and increase protein synthetic functions relative to standard amino acids formulations e.g. the number and quality of polyribosomes in skeletal muscle. As illustrated, BCAA can be consumed in muscle to generate glutamine. Nevertheless, their exact role in promoting improved patient outcomes in surgical patients remains to be defined. But it is clear that, in patients who are protein-intolerant because of chronic or latent hepatic encephalopathy, BCAA-enriched parenteral nutrition permit greater protein intake without inducing encephalopathy than do standard protein formulas.

Question 105

21728 – The amino acid glycine
1: is probably the mediator responsible for direct inhibition in the spinal cord
2: when directly applied to the membranes of neurones causes hyperpolarization
3: with arginine and methionine is responsible for the synthesis of creatine in muscle
4: has an inhibitory function in the cord antagonized by atropine

Answer 105

TTTF
Ganong 7th Ed. Ch. 4 P. 74 126 243. Pending review. May 2003

Question 106

1000, 10422 – With regard to arginine:
A. When administered in pharmacological doses arginine may act as a neuotransmitter.
B. Alanine is the main precursor of arginine.
C. Critically ill patients require 30 g/day of arginine.
D. Arginine is a unique substrate for the production of nitric oxide.
E. Arginine is the preferred nutrient for immunocytes.

Answer 106

D
Arginine is now considered to be a conditionally essential amino acid. Arginine is synthesised endogenously in the kidney from gut-derived citrulline (the small intestine converts dietary amino acids, including glutamine, to citrulline). Arginine participates in a variety of metabolic functions, including urea synthesis, lymphocyte proliferation, and wound healing. In addition, arginine is a unique substrate for the production of the biologic effector molecule, nitric oxide. This important pathway has been shown to be present in many tissues and cells including endothelium and inflammatory cells. The role of arginine in critically ill patients remain to be defined but doses of up to 30 g/day have been used in evaluative studies. Combinations of nutrients with immune function activity - arginine, fish oil, and nucleic acids - are being evaluated as enteral nutrients in critically ill patients: although they are sometimes referred to as ‘immunonutrients’, their clinical efficacy has yet to be confirmed by independent clinical trials.

Question 107

1006, 10428 – With regard to glutamine:
A. Glutamine is the only amino acid that contains three nitrogen molecules.
B. Glutamine constitutes about 25% of the amino acid content of standard solutions of parenteral nutrients.
C. Critically ill patients require 20 g/day of glutamine.
D. Glutamine is the principal fuel used by rapidly proliferating cells.
E. The kidney consumes glutamine during periods of metabolic alkalosis.

Answer 107

D
We discussed the metabolism of glutamine in Topic 1. It is the main fuel consumed by rapidly dividing cells such as the gut mucosa, immunocytes, and some tumours. Glutamine is not included in standard solutions of parenteral nutrients because it is unstable in solution and breaks down to form toxic amounts of pyroglutamate and ammonia. It remains to be determined whether administering glutamine to catabolic patients results in an improved outcome. As mentioned in Topic 1, the kidney
consumes glutamine during periods of metabolic acidosis.

Question 108

23544 – Absorption of vitamin B12 requires
1: intrinsic factor binding with vitamin B12 in the small intestine
2: pepsin
3: trypsin which facilitates efficient absorption
4: a high oral intake of vitamin B12

Answer 108

TFTF
Ganong 13th ed. PAGE: 414

Question 109

20097 – S. Arctic explorers developed headache, diarrhoea and dizziness eating polar bear liver BECAUSE R. liver is a rich source of vitamin A

Answer 109

S is true, R is true and a valid explanation of S
Ganong 13th Ed. CHAPTER: 17 PAGE: 259

Question 110

15433 – Sources of carbohydrates which may be used in parenteral nutrition solutions include
1: glycerol
2: maltodextrins
3: sorbitol
4: starch

Answer 110

TFTF
Refer to Burnett, 2nd Ed, Ch 6, page 104; STEM Module: Metabolism/Nutrition

Question 111

23439 – Transport of glucose across intestinal cell membranes is thought to require
1: Na+ transport across enterocyte membrane
2: glucagon
3: carrier molecules
4: brush border disaccharidases

Answer 111

TFTF
Ganong 16th Edition CHAPTER: 25 PAGE: 430

Question 112

8651 – If conscious, pain would be experienced in response to which of the following stimuli applied to bowel?
1: visceral distension
2: surgical diathermy
3: visceral ischaemia
4: cutting with a sharp instrument

Answer 112

TFTF
Guyton, 9th ed, Ch 48; Ganong, 19th ed, Ch 17

Question 113

23169 – Uric acid
1: is formed from breakdown of purines
2: reabsorption in renal tubules can be inhibited by probenecid (Benemid)
3: level in plasma is normally 0.2 - 0.4 mmol/l
4: urinary excretion is increased by allopurinol

Answer 113

TTTF
Ganong 13th ed. Chapter 17 Page: 246

Question 114

964 – With regard to albumin:
A. Serum concentrations < 30 g/L strongly correlate with a poor clinical outcome.
B. It is a useful marker of nutritional status because it has a relatively short half-life.
C. Synthesis is markedly inhibited during the early stages of undernutrition.
D. It has a low exchange rate between the intra- and extra-vascular compartments.
E. Serum concentrations are increased during sepsis.

Answer 114

Hepatic secretory proteins such as albumin, transferrin, retinol binding protein, and prealbumin are markers of visceral protein stores and are used as indicators of nutritional status. Numerous studies have demonstrated that a low serum albumin concentration ( < 30 g/L) strongly correlates with a high incidence of mortality and morbidity. However, albumin has a half-life of about 28 days and acute changes in serum albumin concentration cannot be ascribed to poor nutrition. For example, serum albumin concentrations are usually not affected by nutritional intake during starvation until starvation has reached an advanced stage and there is a marked reduction in body weight accompanied by overt muscle wasting. On the other hand, the low serum albumin concentrations that are observed in stressed patients persist until the parts start to recover and there is an absence of inflammatory foci. The exchange rate between intravascular and extravascular albumin is large and even small variations in the percentage of exchange can cause significant changes in serum albumin concentration. Levels of regulatory hormones, acute-phase reactants, and the measurement of the circulating levels of a number of cytokines have also been proposed as ‘nutritional markers’. For example, C-reactive protein has the attraction of being present in very low concentrations in the serum of normal subjects, but rising exponentially within four hours of the onset of infection. However, such measurements reflect metabolic stress rather than nutritional status.