PHYSIOLOGY 452/552Cardiovascular ExamTuesday, February 26, 2019Version AINSTRUCTIONSThis examination consists of 35 questions, 8 pages (including this cover page). Please check that your copy has all pages.Print your name and 8-digit UB person number on the answer sheet. Please use a pen with blue or black ink to fill in your answers. Be sure to indicate the Version on the answer sheet. (You do not have to fill in “course section”)You may keep the examination. Results and answer keys will be posted as soon as possible on UBLearns.WE NEED TO SEE YOUR UB ID CARD WHEN YOU HAND IN THE ANSWER SHEET(NOT a Driver’s License, NOT a Passport)If you have forgotten your card, please bring it to Dr. Baizer in 123 Sherman Hall within 48 hours.WE DO NOT ANSWER QUESTIONS DURING THE EXAMINATIONPLEASE SIT IN YOUR ASSIGNED SEATTURN OFF YOUR CELL PHONEBE ON TIMENo one will be allowed to start the exam after 9:50 am. 1This study source was downloaded by 100000807760000 from CourseHero.com on 03-30-2021 16:42:23 GMT -05:00https://www.coursehero.com/file/68729928/PGY-452-Exam-1-2019docx/This study resource wasshared via CourseHero.com1. A Sarcomere is A. Equivalent to the cell membrane which covers the entire fiber. B. A Large multi-nucleated array of myofibrils, essentially one large fused cell. C. Facilitates mechanical and electrical communication between cells. D. A specialized form of the endoplasmic reticulum adapted for calcium uptake and release. E. None of the above. 2. The Junctional Sarcoplasmic Reticulum is A. The basic contractile unit in skeletal muscle. B. Equivalent to the cell membrane which covers the entire fiber. C. A highly organized array of contractile units. D. A specialized hexomeric protein that forms the electrical junction between adjacent sarcomeres. E. None of the above. 3. Thick Filaments contain A. Actin B. Troponin C. Tropomyosin D. Myosin E. All of the above 4. Thin Fillaments do not contain A. Actin B. Troponin C. Tropomyosin D. Calsequestrin E. None of the above 5. Which of the following is not true about the inward rectifier? A. The inward rectifier current is carried by potassium. B. The inward rectifier rectifies the potassium current so that it is inward during the plateau of the action potential. C. The inward rectifier current does not obey Ohm’s law. D. The inward rectifier is absent in the sino-atrial node. E. All of the above are true. 2This study source was downloaded by 100000807760000 from CourseHero.com on 03-30-2021 16:42:23 GMT -05:00https://www.coursehero.com/file/68729928/PGY-452-Exam-1-2019docx/This study resource wasshared via CourseHero.com6. Skeletal Muscle Contraction is influenced by A. Frequency of stimulation. B. Calcium Release from the Sarcoplasmic Reticulum. C. Dihydropyridine Receptors. D. Ryanodine Receptors. E. All of the above. 7. Smooth muscle contraction involves A. T-tubules B. Sarcomeres C. Myosin Kinase D. All of the above E. None of the above 8. Which of the following is not true about the resting Cardiac membrane potential? A. The membrane resting potential is equal to the Nernst potential for potassium. B. The membrane resting potential has a low sodium conductance. C. Balanced current flow gives rise to the resting membrane potential. D. Pumps and exchangers maintain the background electrical gradients. E. The Nernst potential for sodium is positive to the resting membrane potential. 9. Which of the following is not true about Ventricular cardiac action potentials? A. Action potentials arise from current flow across membranes. B. Current is carried by charged ions. C. Action potentials fire in an all-or-none fashion. D. A stimulus usually initiates the action potential in healthy cells. E. Chloride is the dominant current during the diastolic interval. 10. During the late phases (plateau) of the action potential of fast myocardium (e.g. ventricle), which is not true of the sodium channel? A. Its Nernst potential reverses to a repolarizing current. B. It is refractory. C. A slower inactivation gate keeps the channel shut in response to sustained depolarization. D. It fires transiently early on in the action potential and is not active during the late plateau. E. All are true. 3This study source was downloaded by 100000807760000 from CourseHero.com on 03-30-2021 16:42:23 GMT -05:00https://www.coursehero.com/file/68729928/PGY-452-Exam-1-2019docx/This study resource wasshared via CourseHero.com11. What is not true of most Potassium channel alpha subunits? A. Is formed from four linked domains. B. Tetramer forms a functional channel. C. Is selective for potassium over other cations. D. Is selective for potassium over other ions. E. Open and closes randomly. 12. The gap junction channel formed by connexin 43 in cardiac muscle has which of the following properties? A. Is highly selective for sodium ions. B. Is opened and closed by a gate on the intracellular side of S4. C. Is highly selective for potassium ions. D. Is opened and closed by positive charges on S4. E. None of the above. 13. Which properties of the electrocardiogram are not true? A. The P-Wave corresponds to excitation of the Sino Atrial Node. B. The QRS complex corresponds the depolarization of the ventricle. C. The T wave corresponds to the repolarization of the ventricle. D. The electrocardiogram gives a measure of the timing of events in the heart. E. All are true. 14. Voltage Clamp is A. A method for measuring ionic currents in cells. B. A method for resuscitating victims of an arrhythmia. C. A method for measuring the electrocardiogram. D. A method for measuring contractility. E. None of the above. 15. In the Sino-Atrial Node which is not true? A. Shows spontaneous (oscillatory) electrical behavior. B. Has a calcium mediated action potential upstroke. C. Has no stable resting membrane potential. D. Has a stabilizing inward rectifier potassium current. E. Has an additional inward current that turns on during diastolic depolarization. 4This study source was downloaded by 100000807760000 from CourseHero.com on 03-30-2021 16:42:23 GMT -05:00https://www.coursehero.com/file/68729928/PGY-452-Exam-1-2019docx/This study resource wasshared via CourseHero.com16. Which of the following is not true for conduction of the cardiac impulse? A. Action potentials propagate by current flow through gap junctions. B. Slow propagation occurs as a result of low intercellular conductance. C. Slow propagation requires a slower (sustained)