Biology 3U03 - Exam 1 Fall 2006

Student Name:Student #:BIOLOGY 3UO3DAY CLASSDURATION OF EXAMINATION: 2 hoursDr. C.M.WoodMcMaster University Final ExaminationDecember 2006THIS EXAMINATION PAPER INCLUDES 9 PAGES AND 34 QUESTIONS. YOU ARERESPONSBILE FOR ENSURING THAT YOUR COPY OF THE PAPER IS COMPLETE. BRING ANYDISCREPANCY TO THE ATTENTION OF YOUR INVIGILATOR.Special Instructions:Print your Name and Student # on page 1, 6, 7, 8 and 9 of this examination paper.This examination consists of three parts. Part I consists of twenty two (22) multiple choicequestions worth 1 mark each. These must be answered on the optical scan sheet provided.Part II has eight(8) short explanatory notes worth 3 marks each. Part III consists of + shortessays worth 6 marks each. Part II and III must be answered in the space provided on thisexamination.Standard Casio-FX 991 calculator allowed.OMR EXAMINATION - INSTRUCTIONSNOTE: IT IS YOUR RESPONSIBILITY TO ENSURE THAT THE ANSWER SHEET ISPROPERLY COMPLETED. YOUR EXAMINATION RESULT DEPENDS UPONPROPER ATTENTION TO THESE INSTRUCTIONS.The scanner, which reads the sheets, senses the bubbled shaded areas by their non-reflection of light. Aheavy mark must be made, completely filling the circular bubble, with an HB pencil. Marks made with apen or felt-tip marker will NOT be sensed. Erasures must be thorough or the scanner may still sense a mark.Do NOT use correction fluid on the sheets. Do NOT put any unnecessary marks or writing on the sheet.1. On side 1 print your student number, course name, section number, instructor name and the date in thespaces provided. Then the sheet MUST be signed in the space marked SIGNATURE.2. Mark your student number in the space provided on the sheet on Side 1 and fill in the correspondingbubble number underneath.3. Answers, mark only ONE choice from the alternatives (1,2,3,4,5 or A,B,C,D,E) provided for eachquestion. If there is a True/False question, enter response of 1 (or A) as True, and 2 (or B) as False. Thequestion number is to the left of the bubbles. Make sure that the number of the question on the scansheet is the same as the question number on the test paper.4. Pay particular attention to the Marking Directions on the form.5. Begin answering questions using the first set of bubbles, marked "1".McMastecontinued on next page. BIOLOGY 3UO3 (McMaster University Final Examination)Page 2 of 9Questions - 1-22 Multiple Choice: Choose the one fully correct answer no penalty for guessing1mark each.1. Pco2 gradients across the lungs (alveoli to pulmonary capillaries) are much lower than PO2 gradientsbecausea. the CO2 molecule is 1/30th the size of the O2 molecule.b. CO2 is 30 X more soluble than O2 so CO2 diffusion per torr of gradient is 30 X greater also.c. Only 1/30th as much CO2 is produced relative to the O2 consumed.d. O2 diffusion per torr of gradient is 30 X greater than CO2 diffusion per torr of gradient.e. the affinity of hemoglobin for CO2 is 30 X greater than the affinity of hemoglobin for O2.2. The single most important factor increasing the unloading of O2 from the blood to the systemic tissueduring exercise isa. the rise in cardiac output.b. the fall in pHv.c. the rise in blood temperature.d. the rise in PvCO2.e. the fall in PvO2.3. Which of the following is not true.a. Normally there is a lot more CO2 than O2 in the blood.b. Most of the CO2 in the blood is chemically combined with hemoglobin as carbamino - CO2.c. The Bohr effect, temperature effect and Haldane effect on blood O2 and CO2 transport occur to asmall extent even at rest..d. De-oxygenated hemoglobin binds H+ and carbamino-CO2 more easily than does oxygenatedhemoglobin.e. The "Band 3" protein in the red blood cell serves as an electro-neutral CI/HCO3 exchanger.4. The function(s) of the (intra) pleural space isa. to provide pneumothorax.b. to provide a flexible lubricated connection between the outer surface of the lungs and the wall of thethorax.c. to prevent pulmonary edemad. all of the above are correct.e. none of the above are correct.5. If breathing rate is 15 breaths /min., tidal volume is 500 ml/ breath and anatomic deadspace is 160 ml,the alveolar ventilation is :a. 7.5 L/ min.b.2.4 L/ min.c. 5.1L/ min.d. less than it would be if anatomic deadspace were reduced to 140 ml.e. greater than it would be if tidal volume were increased to 600 ml/breath.continued on next page... BIOLOGY 3UO3 (McMaster University Final Examination)Page 3 of 96.The segment of the respiratory control centre which terminates inhalation isa. the aortic and carotid bodies.b. the dorsal respiratory group neurons ("I" neurons).c. the apneustic centre.d. the pneumotaxic centre.e. the supra-optic nucleus.7. Glomus cellsa. are an important component (likely the detector system) of the peripheral arterial chemoreceptors.b.are innervated by branches of cranial nerves IX and X.c. may be evolutionarily derived from the neuroepithelial cells (" NEC's") on the efferent branchialarteries of fish gills.d.all of the above are correct.e. none of the above are correct.8.During sustained aerobic exercise at a high levela. the relative increase in cardiac output is greater than that in total ventilation.b. the increase in ventilation is mainly due to increases in breathing frequency in trained athletes.c. the size of the venous reserve increases almost 3-fold.d.all of the above are correct.e. none of the above are correct.9. The two major buffer systems in the blood area. the phosphate and ammonia systems.b. the phosphate and CO2 systems.C. the protein and phosphate systems.d. the CO2 and protein systems.e. the ammonia and CO2 systems.10. A patient with much lower than normal PaCO, much higher than normal pHa, and slightly lowerthan normal plasma [ HCO3] would likely be in a state ofa. metabolic alkalosis.b. metabolic acidosis.c. respiratory alkalosis.d. respiratory acidosis.e. metabolic alkalosis with respiratory compensation11. Under normal circumstances, as blood plasma passes through the glomerular capillaries, the filtrationfraction isa. above 99%.b. less than 1%.c. between 40 and 60%d. 2-3%.e. about 20%continued on next page BIOLOGY 3UO3 (McMaster University Final Examination)Page 4 of 912. Which of the following substance is a naturally occurring GFR marker in humans,a. para amino hippuric acid.b. inulin.c. insulin.d. creatinine.e. glucose.13. In the mechanism of glomeular filtration :a. constriction of the afferent arteriole will increase filtration rate.b. constriction of the efferent arteriole may either increase or decrease filtration rate depending on thedegree to which blood flow rate through the glomerulus is changed.c. the large amount of protein normally present in Bowman's capsule is a critical determinant offiltration rate.d. filtration rate normally falls as mean arterial blood pressure increases and vice versa.e. none of the above are correct.14. Renina. acts on angiotensin I to create angiotensin II.b. is released by the macula densa cells of the juxtaglomerular apparatus.c. acts eventually to lower mean arterial blood pressure.d. is an enzyme not a hormone.e. none of the above are correct.15. The insertion of aquaporins into the membranes of the distal convoluted tubule and the commoncollecting duct is under the control ofa. the sympathetic nervous system.b. aldosterone.c. angiotensin II.d. cortisol.e. antidiuretic hormone.16. The cells in the late distal convoluted tubule and common collecting duct which are capable ofpowerful acidification of the urinea. are the principal cells.b. use a Na*/H exchange mechanism.c. actively secrete NH4 to achieve very low urine pH.d. contain no carbonic anhydrase.e. none of the above are correct.continued on next page BIOLOGY 3UO3 (McMaster University Final Examination)Page 5 of 917. Which of the following terms correctly describes the net renal acid excretion rate by the kidneya UFR X [Titratable Acidity + HCO3 - Ammonia].UFR X [ Titratable Acidity + Ammonia]HCO3c. UFR X [Titratable acidity + Ammonia- HCO3]d. UFR X [Ammonia - Titratable acidity] + HCO3e. UFR X Titratable acidity.18. Changes in myocardial contractility usually reflecta. changes in the fuel supply to the Purkinje fibres.b. changes in the intracellular pH of the sarcoplasm.c changes in the amount of Ca24 mobilized per action potential into the ventricular muscle cells.d. changes in degree of overlap of the thick and thin filaments in the sarcomeres at the start ofcontraction.e. changes in end diastolic volume.19. A useful emergency treatment for someone suffering from chronic mountain sickness isa. making him breathe air which is enriched in CO2b. bleeding him.c. making him exercise.d. making him breathe air which has a lower concentration of O2e. severely restricting his intake of fluid.20. In Heymans classic "cross-perfused" dog experimentsa. the circulatory system of the "donor" dog was essentially intact.b. the head of the "recipient" dog received the same mean arterial pressure as in the "donor" dog.c. a rise in mean arterial pressure elicited by injection of adrenaline into the circulation of the "donor"dog caused a decrease in heart rate in both dogs.d. all of the above are correct.e. none of the above are correct.21. In the Starling-Landis theory of fluid exchange in capillary beds:a. hydrostatic pressure is normally greater in the capillaries than in the interstitial fluidb. oncotic pressure (on an absolute basis) is normally greater in the capillaries than in the interstitialfluid because protein concentration is greater in blood plasma than interstitial fluid.C. net fluid filtration normally exceeds net fluid reabsorption in systemic capillary beds, with thedifference becoming the lymph.d. all of the above are correct.e. none of the above are correct.22. Endothelin, histamine, nitric oxide, and bradykinin are:a. nicotinic cholinergic blocking agents.b. agonists of alpha-adrenergic receptors.c. hormones released by the adrenal cortex.d. paracrine agents with local effects on blood vessels.e. none of the above are correct.continued on next page Student Name:Student #:BIOLOGY 3UO3 (McMaster University Final Examination)Page 6 of 9Questions 23-30: Write short explanatory notes on the following (3-4 sentences suggested)- 3 marks each23. The measurement of anatomic deadspace.24. The Henderson - Hasselbalch equation and its role in describing acid-base status.25. The difference between clearance rate and clearance ratio. What does each indicate?26. The measurement of the net secretion rate of a particular substance by the kidney.continued on next page Student Name:Student #:BIOLOGY 3UO3 (McMaster University Final Examination)Page 7 of 927. Peritubular reabsorption mechanisms.28. Starling's Law ( Frank-Starling's Law of the Heart)29. Starling-Landis mechanism of fluid exchange in capillary beds.30. LaPlace's law and its relationship to critical closure of blood vessels.continued on the next page Student Name:Student #:BIOLOGY 3UO3 (McMaster University Final Examination)Page 8 of 9Questions 31-34: Please answer in the space provided in essay format , 6 marks each.31. Draw and label A) blood O2 dissociation curves and (B) blood CO2 dissociation curves to illustrate thechanges which occur in blood O2 and CO2 transport between rest and severe exercise. Write textexplaining the changes which occur.32. Explain as fully as possible the relationships in the Figure below.900800700Fitteredload600Excretion500400300TransportmaximumReabsorptionNormal200100Thresholdo0100 200 300 400 500 600 700 800Plasma glucose concentrationcontinued on the next page Student Name:Student #:BIOLOGY 3UO3 (McMaster University Final Examination)Page 9 of 933. Write a short essay describing the changes which will occur in ventilation over time when an individualliving at high altitude (~ 4000 m ) is suddenly transported to sea level.34. Write a short essay describing the mechanisms of homeostasis for systemic arterial blood pressure.THE END