Clinical Aspects of Digestion
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Questions and Answers

Which biochemical test is often used to diagnose defective absorption of dietary fat?

  • Iron (Fe+2) and Ferritin
  • Serum albumin
  • Xylose absorption rate
  • Faecal fat estimation (correct)
  • What condition may bacterial growth in the small intestine cause?

  • Enhanced protein absorption
  • Increased plasma cholesterol levels
  • Functional deficiency of bile secretion (correct)
  • Decreased plasma glucose levels
  • In the case of biliary obstruction, what is the likely result for faecal fat estimation?

  • Not indicated
  • Normal
  • Decreased
  • Increased (correct)
  • Which of the following is NOT a common test used to diagnose defective intestinal absorption?

    <p>Electrocardiogram (ECG)</p> Signup and view all the answers

    Excessive losses into the intestinal lumen can cause a marked reduction in which protein?

    <p>Albumin</p> Signup and view all the answers

    What is the xylose absorption result in chronic pancreatitis?

    <p>Normal</p> Signup and view all the answers

    Which enzyme is responsible for hydrolyzing lactose in the small intestine?

    <p>Lactase</p> Signup and view all the answers

    What is the significance of a rise in blood glucose of less than 1.1 mmol/L in the lactose intolerance test?

    <p>Indicates lactose intolerance</p> Signup and view all the answers

    What measurement is indicative of excessive fermentation of undigested lactose in the large intestine?

    <p>High level of H2 in breath</p> Signup and view all the answers

    Which disease is associated with a defect in the transport mechanism for cystine?

    <p>Cystinuria</p> Signup and view all the answers

    What is a key symptom of protein-losing enteropathy?

    <p>Large amounts of nitrogen compounds being excreted</p> Signup and view all the answers

    Which amino acid absorption issue is specifically seen in Hartnup disease?

    <p>Reduced tryptophan absorption</p> Signup and view all the answers

    Which cells in the stomach secrete hydrochloric acid (HCl)?

    <p>Parietal cells</p> Signup and view all the answers

    Which hormone acts as a potent stimulator of gastric juice production?

    <p>Gastrin</p> Signup and view all the answers

    What is the main effect of the pentagastrin test?

    <p>To examine the level of HCl in the stomach</p> Signup and view all the answers

    Hyperacidity in the stomach is most commonly found in which condition?

    <p>Duodenal ulcer</p> Signup and view all the answers

    Which type of food acts as a physiological stimulant for the release of gastrin hormone?

    <p>Proteins</p> Signup and view all the answers

    What does an abnormally high level of gastric acid (HCl) above the normal range indicate?

    <p>Impaired gastric emptying due to pyloric stenosis</p> Signup and view all the answers

    Which condition is characterized by no response to administration of pentagastrin?

    <p>Pernicious anemia</p> Signup and view all the answers

    What volume of resting gastric juice is considered normal?

    <p>Less than 50 ml</p> Signup and view all the answers

    Which hormone is responsible for enhancing the secretion of bicarbonate (HCO3) from the pancreas?

    <p>Secretin</p> Signup and view all the answers

    In chronic pancreatitis, what would you expect the faecal fat estimation and xylose absorption rate to be?

    <p>↑ faecal fat, N xylose absorption</p> Signup and view all the answers

    Which hormone enhances the release of insulin and inhibits gastric secretion?

    <p>Gastrin inhibitory polypeptide (GIP)</p> Signup and view all the answers

    Which of the following conditions is characterized by an increase in faecal fat estimation and a normal xylose absorption rate, but vitamin B12 absorption is not indicated?

    <p>Biliary obstruction</p> Signup and view all the answers

    What is the role of motilin in gastrointestinal function?

    <p>Stimulates GI motility</p> Signup and view all the answers

    In which part of the gastrointestinal tract is cholecystokinin primarily active?

    <p>Duodenum and jejunum</p> Signup and view all the answers

    Which test can be used to evaluate the efficiency of the small intestine by monitoring fat excretion?

    <p>Faecal fat estimation</p> Signup and view all the answers

    What is the primary function evaluated by the Schilling test?

    <p>Absorption of vitamin B12</p> Signup and view all the answers

    Which of the following is NOT a typical cause of intestinal malabsorption?

    <p>Hydronephrosis</p> Signup and view all the answers

    Which test involves measuring plasma vitamin A levels before and after its administration?

    <p>Vitamin A absorption test</p> Signup and view all the answers

    What is a common effect of biliary disease on digestion?

    <p>Fat malabsorption</p> Signup and view all the answers

    In the context of malabsorption, which organ's dysfunction can lead to deficiencies in digestive enzymes for proteins, fats, and carbohydrates?

    <p>Pancreas</p> Signup and view all the answers

    Which part of the digestive system is NOT involved in the direct breakup and lubrication of food?

    <p>Esophagus</p> Signup and view all the answers

    What role does gastric HCl play in the stomach?

    <p>Inhibits salivary amylase</p> Signup and view all the answers

    Which organ is responsible for digesting polysaccharides in the mouth?

    <p>Salivary glands</p> Signup and view all the answers

    What is one of the functions of mucin protein in the mouth?

    <p>Protecting mouth from abrasion</p> Signup and view all the answers

    Which part of the small intestine is the first to receive chyme from the stomach?

    <p>Duodenum</p> Signup and view all the answers

    Which enzyme is inhibited by gastric HCl in the stomach?

    <p>Salivary amylase</p> Signup and view all the answers

    What is indicated by the plasma gastrin level?

    <p>The rate of gastrin secretion by the pyloric antrum</p> Signup and view all the answers

    In which condition is the plasma gastrin level significantly reduced?

    <p>Gastritis</p> Signup and view all the answers

    Which syndrome is characterized by severe peptic ulceration and excessive HCl production?

    <p>Zollinger-Ellison syndrome</p> Signup and view all the answers

    What induces the secretion of pancreatic juice?

    <p>Presence of acid in the duodenum</p> Signup and view all the answers

    Which of the following hormones stimulate the secretion of bicarbonate (HCO3) from the pancreas?

    <p>Secretin</p> Signup and view all the answers

    Which enzyme is NOT found in pancreatic juice?

    <p>Pepsin</p> Signup and view all the answers

    What are the primary components of pancreatic juice?

    <p>Electrolytes and digestive enzymes</p> Signup and view all the answers

    What is a common symptom of Zollinger-Ellison syndrome due to excessive HCl production?

    <p>Malabsorption</p> Signup and view all the answers

    What is a primary cause of chronic pancreatitis?

    <p>Alcohol intake</p> Signup and view all the answers

    Which enzyme's stool test has shown promise as a diagnostic tool for chronic pancreatitis?

    <p>Elastase</p> Signup and view all the answers

    Carcinoma of the pancreas often results in which of the following?

    <p>Obstruction in the bile duct</p> Signup and view all the answers

    Which tumor marker is most sensitive for the detection of pancreatic carcinoma?

    <p>CA-19-9</p> Signup and view all the answers

    Which part of the digestive system is most involved in absorption?

    <p>Small intestine</p> Signup and view all the answers

    The xylose absorption test measures the ability of the small intestine to absorb which type of molecules?

    <p>Monosaccharides</p> Signup and view all the answers

    In a healthy subject, what percentage of the standard dose of xylose is excreted in urine over 5 hours?

    <p>40%</p> Signup and view all the answers

    Which of the following can lead to low xylose excretion?

    <p>Bacterial growth in the small intestine</p> Signup and view all the answers

    What is a major clinical risk associated with acute pancreatitis?

    <p>Adult respiratory distress syndrome (ARDS)</p> Signup and view all the answers

    Which enzyme's activity is usually increased more than five times in acute pancreatitis?

    <p>α-amylase</p> Signup and view all the answers

    What is a specific confirmatory test for the occurrence of acute pancreatitis?

    <p>Increased urinary α-amylase activity</p> Signup and view all the answers

    Which of the following increased enzymes can indicate the presence of gall stones causing acute pancreatitis?

    <p>ALT and AST</p> Signup and view all the answers

    Which of the following measures is essential in managing acute pancreatitis?

    <p>Maintaining fluid electrolytes balance</p> Signup and view all the answers

    What is the role of C-reactive protein measurement in the management of acute pancreatitis?

    <p>To monitor the progression of the case</p> Signup and view all the answers

    In acute pancreatitis, what is the probable cause of methaemalalbumunemia?

    <p>Oxidation of hemoglobin heme groups</p> Signup and view all the answers

    What is a recommended method to ensure nutrition in a patient with acute pancreatitis?

    <p>Intravenous feeding</p> Signup and view all the answers

    Study Notes

    Clinical Aspects of Digestion

    Diseases of the Intestinal Mucosa

    • May affect digestion or transport of dietary constituents
    • Can cause functional deficiency of bile secretion, interfering with vitamin B12 and fat absorption

    Bacterial Growth in Small Intestine

    • Causes functional deficiency of bile secretion and interferes with vitamin B12 and fat absorption

    Excessive Losses into the Intestinal Lumen

    • Includes gastrointestinal diseases causing water, electrolyte, and protein loss, leading to a marked reduction in plasma albumin

    Clinical Tests for Intestinal Malabsorption

    • Serum albumin, alkaline phosphatase, cell blood count (RBC, WBC, MCV), iron (Fe+2) and ferritin, vitamin B12, faecal fat estimation, xylose absorption rate, calcium, phosphate, folic acid, and prothrombin time (PT)

    Results of Biochemical Investigation for Causes of Defective Intestinal Malabsorption

    • Chronic pancreatitis: increased faecal fat estimation, normal xylose absorption rate
    • Pancreatic carcinoma: increased faecal fat estimation, normal xylose absorption rate
    • Biliary obstruction: increased faecal fat estimation, not indicated for xylose absorption rate

    Gastrointestinal Hormones

    • Gastrin: stimulates gastric secretion, produced in the stomach
    • Cholecystokinin: stimulates pancreatic secretion, produced in the duodenum and jejunum
    • Secretin: stimulates HCO3 secretion from the pancreas, produced in the duodenum and jejunum
    • Pancreatic polypeptide: inhibits pancreatic secretion, produced in the duodenum and jejunum
    • Gastrin inhibitory polypeptide (GIP): enhances insulin release and inhibits gastric secretion, produced in the duodenum and jejunum
    • Vasoactive intestinal poly peptide (VIP): acts as a neurotransmitter, regulates GI motility and secretion, produced in the GI tract
    • Motilin: stimulates GI motility, produced in the duodenum and jejunum

    Disaccharide Absorption Test (Lactose Intolerance Test)

    • Used to investigate impaired disaccharide absorption
    • Measures blood glucose levels after lactose ingestion
    • Normal result: blood glucose level increases by at least 1.1 mmol/L
    • Lactose intolerance: blood glucose level increase is less than 1.1 mmol/L

    Test of H2 Breath

    • Measures H2 levels in breath to diagnose lactose deficiency
    • Undigested lactose is fermented by bacteria in the colon, producing high H2 levels

    The Stomach

    • Gastric juice contains HCl, intrinsic factor, pepsin, and mucus
    • HCl and intrinsic factor are secreted by parietal cells
    • Pepsin is secreted by zymogen cells
    • Mucus is secreted by cells of the pyloric antrum
    • Gastric juice production is stimulated by gastrin and food

    The Gastric Function Tests

    • Pentagastrin test: measures HCl response to pentagastrin injection
    • Used to examine gastric acid secretion
    • Resting gastric juice is normally small in volume and low in acid content
    • Increased gastric acid secretion can indicate impaired gastric emptying due to pyloric stenosis
    • Achlorhydria: low volume of secreted HCl, no response to pentagastrin
    • Hyperacidity: increased output of HCl, found in cases of duodenal ulcer

    Tests of Fat Absorption

    • Faecal fat estimation: measures fat excretion in feces
    • Used to diagnose malabsorption due to small intestine defects
    • Vitamin A absorption test: measures plasma vitamin A levels after vitamin A administration
    • Not commonly used as a general test for small intestine function

    Test of Ileum Function (Schilling Test)

    • Measures vitamin B12 absorption
    • Used to diagnose pernicious anemia and ileum function defects
    • Defect in ileum absorption function leads to low vitamin B12 excretion in urine

    Causes of Intestinal Malabsorption

    • Pancreatic diseases: lead to malabsorption of large molecules due to pancreatic enzyme deficiencies
    • Biliary disease: deficiency of bile secretion can result in fat malabsorption

    Plasma Gastrin

    • Indicates rate of gastrin secretion by pyloric antrum
    • Normally reduced in fasting state and increased in presence of food
    • Hyperacidity: reduced plasma gastrin, found in duodenal ulcer cases
    • Zollinger-Ellison syndrome: high plasma gastrin levels due to hyperplasia or neoplasia of gastrin-producing cells
    • Gastritis: reduced plasma gastrin due to destruction of gastrin-producing cells

    Zollinger-Ellison Syndrome

    • Characterized by severe peptic ulceration and excessive HCl production
    • High secretion of gastric juice, containing more than 100mmol/L HCl
    • Plasma gastrin levels are significantly high
    • Malabsorption and diarrhea are also present

    The Pancreas

    • Secreting pancreatic juice containing electrolytes and digestive enzymes
    • Secretion induced by nervous stimuli and hormones secretin and cholecystokinin
    • Chronic pancreatitis: characterized by inability to secrete digestive enzymes, leading to malabsorption
    • Testing elastase enzyme in stool is a promising diagnostic test for chronic pancreatitis

    Carcinoma of the Pancreas

    • Difficult to diagnose, often results from metastasis, causing bile duct obstruction
    • Detection of tumor marker CA-19-9 is very sensitive in this case

    The Small Intestine

    • Site of digestion and absorption, including duodenum, jejunum, and ileum
    • Important for absorption process

    Tests of Carbohydrate Absorption

    • Measurement of carbohydrate metabolites (glucose): assesses intestinal absorption efficiency
    • Xylose absorption test: measures xylose excretion in urine to test small intestine absorption
    • Normal result: more than 2mg xylose excretion in 5-hour urine collection
    • Impaired absorption: reduced xylose excretion, often observed in small intestine diseases

    Pancreatic Disorders

    • Acute pancreatitis: characterized by tissue necrosis, high risk of adult respiratory distress syndrome (ARDS) and renal failure
    • Diagnosis: increased α-amylase, lipase, and trypsin levels, presence of methaemalalbumunemia
    • Management: intravenous feeding, fluid and electrolyte balance, prophylactic antibiotics, and monitoring C-reactive protein levels

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    Description

    Quiz on diseases affecting digestion, including those of the intestinal mucosa, bacterial growth in the small intestine, and excessive losses into the intestinal lumen.

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