Digestive Effect of Saliva on Starch
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Questions and Answers

What is the final digestion product of starch in the mouth?

  • Amylodextrine
  • Maltose (correct)
  • Erythrodextrine
  • Acrodextrine

    • What color indicates the presence of amilodextrine upon the addition of Lugol solution?

  • Blue-violet (correct)
  • Colorless
  • Pink-violet
  • Dark brown

    • What effect does boiling saliva have on ptyalin activity?

  • Enhances the activity
  • Inactivates the activity (correct)
  • No effect on the activity
  • Produces amylodextrine

    • Which of the following conditions can influence salivary amylase activity?

    <p>Temperature and pH</p> Signup and view all the answers

    What happens to the solution after a complete digestion of starch to maltose?

    <p>It becomes colorless</p> Signup and view all the answers

    What is observed in test tube T6 after waiting 30 minutes with fresh saliva?

    <p>Colorless solution</p> Signup and view all the answers

    What is the main reagent used to identify maltose in the Trommer reaction?

    <p>CuSO4 solution</p> Signup and view all the answers

    What color indicates the presence of erythrodextrine upon the addition of Lugol solution?

    <p>Pink-violet</p> Signup and view all the answers

    What indicates the presence of calcium in saliva during the ammonium oxalate test?

    <p>White unsoluble precipitate</p> Signup and view all the answers

    What color precipitate is expected when testing for phosphorus in saliva with ammonium molybdate?

    <p>Yellow precipitate</p> Signup and view all the answers

    What is formed when CuSO4 is added to a maltose solution and boiled?

    <p>Red-copper precipitate</p> Signup and view all the answers

    Which ion in saliva increases in concentration in smokers, resulting in a darker color in the KSCN test?

    <p>Sulfocyanate ion</p> Signup and view all the answers

    What materials are needed to test for phosphorus in saliva?

    <p>HNO3 and ammonium molybdate</p> Signup and view all the answers

    What is a significant clinical method for collecting gastric juice?

    <p>Endoscopic sample collection</p> Signup and view all the answers

    What precipitate indicates the presence of ferric sulfocyanate when adding FeCl3 to saliva?

    <p>Brick-red precipitate</p> Signup and view all the answers

    Which component is primarily being detoxified by KSCN in saliva?

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

    What is the preferred mode of a thyroid scintigram?

    <p>Histogram mode</p> Signup and view all the answers

    Which isotope is noted for having the shortest half-life for thyroid imaging?

    <p>Iodine 123 (I123)</p> Signup and view all the answers

    How long after administration of Iodine 131 (I131) is the scanning typically performed?

    <p>24 to 72 hours</p> Signup and view all the answers

    What type of nodule is generally more aggressive in its management due to a higher incidence of malignancy?

    <p>Cold nodule</p> Signup and view all the answers

    What does the term 'hot' nodule indicate in a thyroid scintigram?

    <p>Nodule has more uptake than normal</p> Signup and view all the answers

    Which of the following is NOT a characteristic that can be assessed via a thyroid scintigram?

    <p>Presence of antibodies against TSH</p> Signup and view all the answers

    What percentage of solitary, hot nodules are generally benign?

    <p>90%</p> Signup and view all the answers

    Graves' disease results from the action of which class of immunoglobulin on the thyroid gland?

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

    What is the primary purpose of administering antihistaminic drugs before the histamin test?

    <p>To prevent adverse events during the test</p> Signup and view all the answers

    What effect does the intake of large amounts of iodide (>5 mg/day) have on RAIU values?

    <p>It suppresses RAIU values to nearly undetectable levels.</p> Signup and view all the answers

    At what dose was histamine administered in the augmented histamine test introduced by Kowalewski?

    <p>40 µg/kg</p> Signup and view all the answers

    What is a major advantage of the Histalog test compared to the standard histamin test?

    <p>It has fewer adverse events</p> Signup and view all the answers

    What does the RAIU test primarily measure?

    <p>Avidity of the thyroid gland for iodide.</p> Signup and view all the answers

    Which condition is most commonly associated with increased thyroidal RAIU?

    <p>Graves Disease.</p> Signup and view all the answers

    Which of the following conditions does histamine not stimulate HCl secretion in?

    <p>Atrophic gastritis</p> Signup and view all the answers

    Under which condition can prolonged uptake of radioiodide occur?

    <p>Renal disease.</p> Signup and view all the answers

    What is the role of insulin in the insulin test (Hollander) for gastric secretion?

    <p>To stimulate gastric secretion through hypoglycemia</p> Signup and view all the answers

    Which statement about dietary iodine intake is true regarding thyroidal RAIU?

    <p>Low dietary iodine intake can lead to decreased thyroidal RAIU.</p> Signup and view all the answers

    What protective treatment is necessary prior to the maximal stimulatory test using histamin?

    <p>Antihistaminic therapy</p> Signup and view all the answers

    What is the normal range for RAIU values?

    <p>5-30%</p> Signup and view all the answers

    What is the equivalent stimulant to histamine that was approved in 1967?

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

    What is represented by the basal metabolic rate (BMR)?

    <p>Minimal energy necessary for basic vital processes.</p> Signup and view all the answers

    What adverse effects can occur despite preventive treatment in the histamin test?

    <p>Headache and tachycardia</p> Signup and view all the answers

    Which factor is crucial for accurately determining BMR?

    <p>Consistent environmental temperatures.</p> Signup and view all the answers

    What is the optimal pH range for gastric rennin activity?

    <p>4.5 - 5.5</p> Signup and view all the answers

    What role does calcium chloride play in the coagulation of casein?

    <p>It aids in the conversion of paracaseinate to curd.</p> Signup and view all the answers

    Which statement about phase I of casein coagulation is correct?

    <p>It is catalyzed by gastric rennin.</p> Signup and view all the answers

    What happens when gastric rennin is inactivated by boiling?

    <p>Coagulation of casein is inhibited.</p> Signup and view all the answers

    During the experiment, what was the effect of adding potassium oxalate before gastric rennin?

    <p>It blocked calcium ions, preventing coagulation.</p> Signup and view all the answers

    What is the main function of gastric lipase in newborns?

    <p>To hydrolyze fats into fatty acids and glycerol.</p> Signup and view all the answers

    What observation would indicate successful coagulation of casein in an experiment?

    <p>Formation of curd.</p> Signup and view all the answers

    How does bile salts aid in the emulsification of fats?

    <p>By reducing the surface tension between water and fats.</p> Signup and view all the answers

    Study Notes

    Digestive Effect of Saliva on Starch

    • Starch digestion starts in the mouth, mixed with saliva containing ptyalin.
    • Starch is broken down into shorter polysaccharides (amylodextrines, erythrodextrines, etc.) and finally maltose, a disaccharide.
    • Lugol's solution identifies different intermediate starch digestion products.
    • Trommer's reaction identifies the final product, maltose.

    Objective

    • Understand salivary amylase's action on starch.
    • Explore how to demonstrate salivary amylase's action.
    • Understand limits on salivary amylase action on starch.
    • Explain factors influencing amylase activity (e.g., temperature and pH).

    Materials

    • 1% Starch solution
    • 1% Iodine (Lugol's reagent)
    • Test tubes
    • Graduated cylinders
    • Saliva
    • NaOH solution
    • CuSO4 10% solution
    • Filter paper

    Procedure for Starch Digestion Test

    • Prepare 6 test tubes.
    • Add 5ml of starch solution to each.
    • Add 2-3 drops of Lugol's solution to each and observe the color (control).
    • T2: Add 0.5ml of boiled saliva, observe no color change (inactivation of ptyalin).
    • T3: Add 3ml fresh saliva, wait 2-3 minutes, then heat to stop the reaction.
    • T4: Add 3ml fresh saliva, wait 5-7 minutes, then heat.
    • T5: Add 3ml fresh saliva, wait 15-20 minutes, then heat.
    • T6: Add 3ml fresh saliva, wait 30 minutes, then heat.
    • Observe the color changes associated with different stages of starch digestion to maltose:
      • Amilodextrines: blue-violet
      • Erythrodextrines: pink-violet
      • Acrodextrines are colorless.
    • The final tube (T6) with complete digestion shows a colorless solution.

    Trommer's Reaction

    • Principle: Maltose reduces CuSO4 (in an alkaline medium) to cuprous oxide.
    • Materials: test tubes, gas burner, NaOH 20%, CuSO4 10%, starch solution, saliva.
    • Procedure: Mix maltose solution and NaOH, then add CuSO4 solution for a blue precipitate. Boil, a red-copper precipitate appears at bottom of tube.

    Calcium Evidence in Saliva

    • Materials: test tube, ammonium oxalate 10%, saliva, microscope.
    • Procedure: Add ammonium oxalate to saliva. A white precipitate indicates calcium. Examine under microscope for octahedral crystals (calcium oxalate).

    Phosphorus Evidence in Saliva

    • Materials: test tubes, gas burner, saliva, nitric acid (HNO3), ammonium molybdate.
    • Procedure: Add HNO3 and ammonium molybdate to saliva. A yellow precipitate (phosphomolybdate) indicates the presence of phosphorus.

    KSCN (Potassium Sulfocyanate) Evidence in Saliva

    • Materials: test tube, ferric chloride (FeCl3) 3%, hydrochloric acid (HCl) 10%, saliva.
    • Procedure: Add HCl and FeCl3 to saliva. A brick-red precipitate indicates the presence of SCN ions.

    Gastric Juice Collecting

    • Common method: aspiration using an Einthorn tube or endoscope.
    • Stimulation: Histamine, histalog, pentagastrin, insulin.

    HCl Acid Dosage in Gastric Juice

    • Principle: Titration of HCl with NaOH in presence of fenolftalein and Topffer reactive indicators.
    • Materials: NaOH solution, fenolftalein 1% in alchohol, Topffer reactive, pipets, Erlenmeyer flasks, test tubes, burette.
    • Procedure: -Measure 10ml of gastric juice, add Topffer reactive, and add NaOH until the solution becomes yellow-orange.
    • Measure NaOH used (N1) to neutralize free HCL. Add fenolphthalein and titrate until pink. Measure NaOH used (N2) for combined HCL.
    • Calculate total acidity in clinical units or grams HCl per 1000 ml.

    Lactic Acid Evidence in Gastric Juice (Berg Reaction)

    • Principle: Lactic acid reacts with ferric salts to produce a yellow color.
    • Materials: Berg reagent (FeCl3), test tubes, gastric juice.
    • Procedure: Add Berg reagent to gastric juice. A yellow color indicates lactic acid.

    Lactic Acid Evidence in Gastric Juice (Uffalman Reaction)

    • Principle: Lactic acid turns Uffalman reagent (FeCl3 in phenol) from violet to yellow.
    • Materials: Uffalman reagent, test tubes, gastric juice.
    • Procedure: Add Uffalman reagent to gastric juice. A yellow color indicates lactic acid.

    Evidence of Free HCl in Gastric Juice

    • Principle: Free HCl reacts with the Gunsburg reagent to produce a red colour.
    • Materials: porcelain capsula, filtered gastric juice, gas burner, Gunsburg reagent (alcoholic solution of vanilin and fluroglucin).
    • Procedure: Place a few drops of gastric juice on a porcelain capsula, add the Gunsburg reagent, and heat gently to observe a red colour if free HCL is present.

    Hay Reaction

    • Principle: Bile salts reduce surface tension between water and fats.
    • Materials: test tubes, oil, bile salts solution, sulfur powder.
    • Procedure: Add bile salts solution to a test tube, add water and sulfur, observe if the sulfur sinks in the bile salts solution.

    Rosenbach's Reaction (Bile Pigments Identification)

    • Materials: Filter paper, bile pigments solution, concentrated nitric acid (HNO3), sodium nitrite crystals (NaNO2).
    • Procedure: Drop bile solution onto filter paper, then a drop of nitric acid, and observe concentric rings. The presence of yellow, red, viole, blue and green rings indicates bilirubin.

    Urinary Amylase Determination

    • Principle: Filtering of amylase by kidney and elimination in urine. Elevated amylase in acute pancreatitis.
    • Materials: 10 test tubes, urine, starch solution 1%, Lugol's solution.
    • Procedure: Create urine dilutions. Add starch solution to each. Add Lugol's solution. Observe the blue-color disappearance (indicating digestion) and determine the dilution where digestion is complete. Express results as Wohlgemuth units.
    • Normal values: 32-64 UW in urine, 16-32 UW in plasma

    Thyroid Scintigram

    • Different types of nuclear medicine investigations(histogram, list, synchronized measurements and three-dimensional reconstruction).
    • Principle: Injections of radioactive material (e.g., I123, Tc9m, Tl201) allow detection by gamma camera; provides information about thyroid size, shape, distribution of activity.
    • Useful information: approximate size and weight, distribution of activity, nodules.

    Thyroid Iodine Uptake (RAIU) Test

    • Principle: Measures thyroid's iodine uptake from the blood as an indicator of thyroid function.
    • Use: Identify thyroid abnormalities in various conditions.
    • Conditions: Fasting, no antithyroid meds for several days, use a radioactive tracer.
    • Measures: Iodine uptake (percentages in 4 and 24 hours of the isotope).
    • Normal Values: 5%-30% for 24 hours.

    Basal Metabolic Rate (BMR)

    • Principle: Measures the minimal energy expenditure for basic life functions (breathing, circulation).
    • Steps: Rest for 12 hours, avoid protein, control temperature (20-22°C).
    • Materials: Benedict spirometer, pure oxygen, calibration tools.
    • Procedure: Subject inhales pure oxygen for 6 minutes. Measure the oxygen consumed. Calculate BMR using a table or formula.
    • Abnormal BMR: indicates issues with hyperthyroidism (high BMR), hypothyroidism (low BMR).

    Oral Glucose Tolerance Test (OGTT)

    • Measures how the body processes glucose after consuming a glucose solution.
    • Procedure: Fasting, drink glucose solution, blood sample drawn at intervals. Assess blood glucose and insulin after ingestion.
    • Results: Examine 2 hour sample and graph changes. Abnormal results may indicate diabetes or other glucose regulation problems.

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    Description

    Explore the role of salivary amylase in starch digestion through various tests. This quiz will cover key concepts such as the breakdown of starch into maltose and how to identify digestion products using Lugol's solution and Trommer's reaction. Understand the factors influencing amylase activity and the practical procedures involved.

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