ACTIVIDADES GENERALES
D. PREVISION DE NECESIDADES
6.4 PLAN DE CONTINGENCIA AMENAZA POR TERRORISMO
(CHAPTER 25) OVERVIEW OF GASTROINTESTINAL FUNCTION & REGULATION
1. Water is absorbed in the jejunum, ileum, and colon and excreted in the feces. Arrange these in order of the amount of water absorbed or excreted from greatest to smallest.
A. Colon, jejunum, ileum, feces B. Feces, colon, ileum, jejunum C. Jejunum, ileum, colon, feces D. Colon, ileum, jejunum, feces E. Feces, jejunum, ileum, colon
ANSWER: C
Ganong. Review of Medical Physiology 23rd ed. Chapter 26 , page .441
2. Following a natural disaster in Haiti, there is an outbreak of cholera among displaced persons living in a tent encampment. The affected individuals display severe diarrheal symptoms because of which of the following changes in intestinal transport? ’
A. Increased Na+–K+ cotransport in the small intestine B. Increased K+ secretion into the colon
C. Reduced K+ absorption in the crypts of Lieberk ühn D. Increased Na+ absorption in the small intestine E. Increased Cl− secretion into the intestinal lumen
ANSWER:
•Cholera toxin increase cAMP opens chloride channels chloride ions secretion activate a sodium pump secretion
of sodium ionsNaCl formed in the crypts extreme
osmosis of water from the blood into the intestinal lumen.
Guyton.Textbook of Medical Physiology 11th ed.Chapter 65, page 815
3. A 50-year-old man comes to see his clinician complaining of severe epigastric pain, frequent heartburn, and unexplained weight loss of 20 pounds over a 6-month period. He claims to have obtained no relief from over-the-counter H2 antihistamine drugs. He is referred to a gastroenterologist, and upper
endoscopy reveals erosions and ulcerations in the proximal duodenum and an increased output of gastric acid in the fasting state. The patient is most likely to have a tumor secreting which of the following hormones?
A. Secretin B. Somatostatin C. Motilin D. Gastrin E. Cholecystokinin ANSWER: D
•Zollinger–Ellison syndrome is a syndrome is seen in patients with gastrinomas.Gastrin causes prolonged hypersecretion of acid, and severe ulcers are produced.
Ganong. Review of Medical Physiology 23rd ed. Chapter 26, page 433 .
4. Which of the following has the highest pH? A. Gastric juice
B. Colonic luminal contents C. Pancreatic juice
D. Saliva
E. Contents of the intestinal crypts
ANSWER: C
•Gastric juice pH 1-3 MOST ACIDIC •Colonic luminal contents pH 5-7 •Pancreatic juice pH 8 MOST BASIC •Saliva pH 6.5-7
•Contents of the intestinal crypts pH 5-7
Ganong. Review of Medical Physiology 23rd ed. Chapter 26, page 438 .
5. A 60-year-old woman undergoes total pancreatectomy because of the presence of a tumor. Which of the following outcomes would not be expected after she recovers from the operation?
A. Steatorrhea B. Hyperglycemia C. Metabolic acidosis D. Weight gain
E. Decreased absorption of amino acids
ANSWER: D
•Pancreatectomy loss of pancreatic secretions steatorrhea and protein malabsorption.
•Pancreatectomy loss ofinsulin secretion high glucagon/insulin ratiohyperglycemia
•Pancreatectomy loss ofinsulin secretion decreased intracellularuptake of glucose and increase protein and fat catabolismweight loss.
Ganong. Review of Medical Physiology 23rd ed. Chapter 21, page 324.
6. A patient with a tumor secreting abnormal amounts of gastrin (gastrinoma) would be most likely to exhibit which of the ff?
A. decreased chief cell exocytosis B. duodenal ulceration
C. increased gastric pH in the period between meals D. a reduced incidence of gastroesophageal reflux disease E. protein malabsoprtion
ANSWER: C
•Zollinger–Ellison syndrome is a syndrome is seen in patients with gastrinomas.Gastrin causes prolonged hypersecretion of acid, and severe ulcers are produced.
(CHAPTER 26) DIGESTION, ABSORPTION, & NUTRITIONAL PRINCIPLES
1. Maximum absorption of short-chain fatty acids produced by bacteria occurs in the
A. stomach. B. duodenum. C. jejunum. D. ileum. E. colon. ANSWER:
• Short-chain fatty acids are absorbed by specific transporters present in colonic epithelial cells. SCFAs make a significant contribution to the total caloric intake and exert a trophic effect on the colonic epithelial cells, combat inflammation, and maintain acid–base equilibrium.
Ganong. Review of Medical Physiology 23rd ed. Chapter 27 , page 458
2. A premenopausal woman who is physically active seeks advice from her primary care clinician regarding measures she can take to ensure adequate availability of dietary calcium to ensure bone health later in life. Which of the following dietary components should enhance calcium uptake?
A. Protein B. Oxalates C. Iron D. Vitamin D E. Sodium ANSWER: D
•Role ofvitamin D derivative: Ca2+ absorption is adjusted to body needs; absorption is increased in the presence of Ca2+ deficiency and decreased in the presence of Ca2+ excess.
Ganong. Review of Medical Physiology 23rd ed. Chapter 27 , page 458 .
3. A decrease in which of the following would be expected in a child exhibiting a congenital absence of enterokinase?
A. Incidence of pancreatitis B. Glucose absorption C. Bile acid reabsorption D. Gastric pH
E. Protein assimilation
ANSWER: E
•The protein assimilation machinery, which rests heavily on the proteases in pancreatic juice, is arranged such that these enzymes are not activated until they reach their substrates in the small intestinal lumen. This is accomplished by the
restricted localization of an activating enzyme,enterokinase.
Ganong. Review of Medical Physiology 23rd ed. Chapter 27 , page 466.
4. In Hartnup disease (a defect in the transport of neutral amino acids), patients do not become deficient in these amino acids due to the activity of:
A. PepT1.
B. brush border peptidases. C. Na+, K+ ATPase.
D. cystic fibrosis transmembrane conductance regulator (CFTR). E. trypsin.
ANSWER: A
•Hartnup disease is a congenital defect in the transport of neutral amino acids does not lead to nutritional deficiencies of these amino acids because peptide transport ( PepT1)
compensates.
Ganong. Review of Medical Physiology 23rd ed. Chapter 27 , page 456..
5. A newborn baby is brought to the pediatrician suffering from severe diarrhea that worsens with meals. The symptoms diminish when nutrients are delivered intravenously. The child most likely has a mutation in which of the following intestinal transporters?
A. Na+, K+ ATPase B. NHE3 C. SGLT-1 D. H+, K+ ATPase E. NKCC1 ANSWER: C
•“When the sodium-dependent glucose transporter (SGLT-1) is congenitally defective, the resulting glucose/galactose malabsorption causes severe diarrhea that is often fatal if glucose and galactose are not promptly removed from the diet.”
Ganong. Review of Medical Physiology 23rd ed. Chapter 27 , page 453 .
6. Calcium absorption is increased by: A. hypercalcemia
B. oxalates in the diet C. iron overload
D. 1,25- dihydroxycholecalciferol E. increased Na+ absorption
ANSWER: D
•Role of1,25- dihydroxycholecalciferol : Ca2+ absorption is adjusted to body needs; absorption is increased in the presence of Ca2+ deficiency and decreased in the presence of Ca2+ excess.
Ganong. Review of Medical Physiology 23rd ed. Chapter 27 , page 458 .
(CHAPTER 27) GASTROINTESTINAL MOTILITY
1. In infants, defecation often follows a meal. The cause of colonic contractions in this situation is
A. histamine.
B. increased circulating levels of CCK. C. the gastrocolic reflex.
D. increased circulating levels of somatostatin. E. the enterogastric reflex.
ANSWER: C
•Distention of the stomach by food initiates contractions of the rectum and, frequently, a desire to defecate. The response is called the gastrocolic reflex and may be amplified by an action of gastrin on the colon. Because of the response, defecation after meals is the rule in children.
•In adults, habit and cultural factors play a large role in determining when defecation occurs.
Ganong. Review of Medical Physiology 23rd ed. Chapter , page .
2. The symptoms of the dumping syndrome (discomfort after meals in patients with intestinal short circuits such as anastomosis of the jejunum to the stomach) are caused in part by
A. increased blood pressure. B. increased secretion of glucagon. C. increased secretion of CCK. D. hypoglycemia.
E. hyperglycemia.
ANSWER: D
•“Dumping syndrome,” is a distressing syndrome that develops in patients in whom portions of the stomach have been
removed or the jejunum has been anastomosed. Symptoms of weakness, dizziness, and sweating after meals is due to the hypoglycemia about2 h after meals.
3. Gastric pressures seldom rise above the levels that breach the lower esophageal sphincter, even when the stomach is filled with a meal, due to which of the following processes?
A. Peristalsis B. Gastroileal reflex C. Segmentation
D. Stimulation of the vomiting center E. Receptive relaxation
ANSWER:
•The stomach accommodates the meal by a process of receptive relaxation. When food enters the stomach, the fundus and upper portion of thebody relax, this permits an increase in volume without a significant increase in pressure.
Ganong. Review of Medical Physiology 23rd ed. Chapter 28 , page 473
4. The migrating motor complex is triggered by which of the following? A. Motilin B. NO C. CCK D. Somatostatin E. Secretin ANSWER: A
•Motilin released cyclically and stimulates interdigestive myoelectric complexes from stomach and small intestine every 90 minutes in a fasted person.
•NO intestinal smooth muscle relxation.
•CCK strongly contracts the gallbladder, expelling bile into the small intestine where the bile in turn plays important roles in emulsifying fatty substances.
• Somatostatin inhibits intestinal secretions.
• Secretin promote pancreatic secretion of bicarbonate which in turn helps to neutralize the acid in the small intestine.
Guyton.Textbook of Medical Physiology 11th ed.Chap62 , page 776
5. A patient is referred to a gastroenterologist because of
persistent difficulties with swallowing. Endoscopic examination reveals that the lower esophageal sphincter fails to fully open as the bolus reaches it, and a diagnosis of achalasia is made. During the examination, or in biopsies taken from the sphincter region, a decrease would be expected in which of the following?
A. Esophageal peristalsis
B. Expression of neuronal NO synthase C. Acetylcholine receptors
D. Substance P release
E. Contraction of the crural diaphragm
ANSWER: B
•Inachalasia, the myenteric plexus of the esophagus is deficient at the LES in this condition and the release of NO and VIP is defective, therefore there will be no anterograde relaxation or relaxation ahead of the stimulus.
Ganong. Review of Medical Physiology 23rd ed. Chapter 28, page 470, 473.
(CHAPTER 28) TRANSPORT & METABOLIC FUNCTIONS OF THE LIVER 1. A patient suffering from severe ulcerative colitis undergoes a
total colectomy with formation of a stoma. After a full recovery from surgery, and compared to his condition prior to surgery, which of the following would be expected to be decreased?
A. Ability to absorb lipids B. Ability to clot the blood
C. Circulating levels of conjugated bile acids D. Urinary urea
E. Urinary urobilinogen
ANSWER: E
•Colectomyantibiotic bowel preparation + resection of the entire colon eradicate intestinal bacteria and colonic
bacteria deconjugation of bilirubin absorption of
uribilinogen urobilinogen excretion in the kidneys.
•Lipids, fat soluble vitamin(vitamin K) reabsorption is not altered since the patient had intact intestinal mucosa
Ganong. Review of Medical Physiology 23rd ed. Chapter 29, page . 483.
2. A surgeon is studying new methods of liver transplantation. She performs a complete hepatectomy in an experimental animal. Before the donor liver is grafted, a rise in the blood level of which of the following would be expected?
A. Glucose B. Fibrinogen C. 25-Hydroxycholecalciferol D. Conjugated bilirubin E. Estrogens ANSWER: E
•Estrogen levels are expected to rise since estrogen is converted to
glucuronide and sulfate conjugates. All these compounds, along with other metabolites, are excreted in the urine.
•The other choices are expected to fall because:
oGlucose: no liver glycogen source oFibrinogen: no synthesis
o25-Hydroxycholecalciferol : absence of liver enzyme 24hydroxylase. oConjugated bilirubin: absence of liver UDP-glucoronidase
Ganong. Review of Medical Physiology 23rd ed. Chapter 25 , page 412..
3. Which of the following cell types protects against sepsis secondary to translocation of intestinal bacteria?
A. Hepatic stellate cell B. Cholangiocyte C. Kupffer cell D. Hepatocyte
E. Gallbladder epithelial cell
ANSWER: C
•Hepatic stellate cell : formation of fibrosis
•Cholangiocyte: absorptive and secretory function.
•Kupffer cell : prevents bacterial translocation by its phagocytic activity
•Hepatocyte: synthesis of various compounds, & detoxification. •Gallbladder epithelial cell: concentrates bile
Ganong. Review of Medical Physiology 23rd ed. Chapter 29 , page . 486.
4. P450s (CYPs) are highly expressed in hepatocytes. In which of the following do they not play an important role?
A. Bile acid formation B. Carcinogenesis
C. Steroid hormone formation D. Detoxification of drugs E. Glycogen synthesis
ANSWER: E
•Glycogen synthesis is the function of glycogen synthase and not the CYP450.
Ganong. Review of Medical Physiology 23rd ed. Chapter 1 , page 21..
5. A 40-year-old woman comes to her primary care clinician
complaining of severe, episodic abdominal pain that is particularly intense after she ingests a fatty meal. An imaging procedure reveals that her gallbladder is acutely dilated, and a diagnosis of
cholelithiasis is made. A gallstone lodged in which location will also increase her risk of pancreatitis?
A. Left hepatic duct B. Right hepatic duct C. Cystic duct
D. Common bile duct E. Sphincter of Oddi
ANSWER: E
•The most common cause of pancreatitis is drinking excess alcohol, and the second most common cause is blockage of the papilla of Vater by a gallstone; the two together account for
more than 90 per cent of all cases.
6. Compared to hepatic bile, gallbladder bile contains a reduced concentration of which of the following?
A. Bile acids B. Chloride ions C. Protons D. Glucose E. Calcium ions ANSWER: B
•The concentration of sodium ions rises with a concomitant loss ofchloride and bicarbonate as the bile is concentrated in the gallbladder.
•Other substances which arehighly concentrated in the gallbladder bile:
oCalcium ions oBile salts oCholesterol oLecithin
Ganong. Review of Medical Physiology 23rd ed., Chapter 29 page .486 Guyton.Textbook of Medical Physiology 11th ed.Chapter 64, page 587, 803.
7. Removal of the entire colon would be expected to cause: A. death
B. megaloblastic anemia C. severe malnutrition
D. a decrease in the blood level of ammonia in patients with cirrhosis of the liver
E. decreased urinary urobilinogen
ANSWER: E
•Colectomyantibiotic bowel preparation + resection of the entire colon eradicate intestinal bacteria and colonic
bacteriadecreased deconjugation of bilirubindecreased
absorption of uribilinogen decreased urobilinogen excretion
in the kidneys.
• Anemia due to decreased B12 and malnutrition because of protein malabsorption is nota consequence because both are reabsorb in the small intestines.
• Ammonia is handled by the liver, and levels will increase in cirrhosis.
Ganong. Review of Medical Physiology 23rd ed. Chapter 29, page . 483