L3 QS BANK PDF

Okay, here is a 30-MCQ quiz based on the provided lecture notes, with a focus on the cardiac properties: Part One: Simple MCQs 1. Which node is known as the pacemaker of the heart? a) Atrioventricular node (AVN) b) Sinoatrial node (SAN) c) Bundle of His d) Purkinje fibers 2. What is the approxima...

Okay, here is a 30-MCQ quiz based on the provided lecture notes, with a focus on the cardiac properties: Part One: Simple MCQs 1. Which node is known as the pacemaker of the heart? a) Atrioventricular node (AVN) b) Sinoatrial node (SAN) c) Bundle of His d) Purkinje fibers 2. What is the approximate weight of the heart in females? a) 320 gm b) 250 gm c) 300 gm d) 200 gm 3. Which of the following is NOT a layer of the heart wall? a) Endocardium b) Myocardium c) Pericardium d) Epicardium 4. What is the function of the atrioventricular node (AVN)? a) Initiates the cardiac impulse b) Conducts the impulse to the atrioventricular bundle c) Causes the heart to beat regularly d) Contracts the ventricles 5. Which of the following is NOT a type of cardiac muscle fiber? a) Nodal fibers b) Contractile fibers c) Purkinje fibers d) Connective fibers 6. Which of the following is NOT a function of the atria? a) Blood reservoirs during ventricular systole b) Pumping blood into the aorta and pulmonary artery c) Contain receptors for many cardiac reflexes d) Secrete atrial natriuretic peptide (ANP) 7. What is the resting membrane potential of the sinoatrial node (SAN)? a) -70 mV b) -55 mV c) -40 mV d) +10 mV 8. Which of the following is responsible for the self-excitation of SAN fibers? a) High electric resistance of the membrane b) Natural leakiness of the membrane to Na+ c) Neurogenic stimulation d) Hormonal influence 9. What separates the atria from the ventricles? a) Intercalated discs b) Gap junctions c) Fibrous skeleton d) Myocardium 10. Which of the following is NOT a property of cardiac muscle? a) Rhythmicity b) Conductivity c) Elasticity d) Contractility Part Two: Complex MCQs 1. Which of the following statements about the structure of cardiac muscle is INCORRECT? a) Cardiac myocytes are short, branched, striated muscle cells. b) Gap junctions have high electric resistance. c) Cardiac muscle responds as one cell due to low resistance. d) The heart is composed of two separate functional syncytia: atria and ventricles. 2. What is the significance of the slow conductivity in the atrioventricular node (AVN)? a) Allows for immediate transmission of impulse in ventricles b) Protects the atria from high pathological ventricular rhythms c) Gives time for atria to empty blood into ventricles d) Enhances the pumping action of the atria 3. Which of the following is NOT a characteristic of Purkinje fibers? a) Large size of fibers b) More gap junctions c) Slow conduction velocity d) Immediate transmission of impulse in ventricles 4. What is the effect of sympathetic stimulation on the heart rate? a) Decreases heart rate b) Increases heart rate c) No effect on heart rate d) Stabilizes heart rate 5. Which of the following is NOT a function of the ventricles? a) Pump blood into the aorta and pulmonary artery b) Blood reservoirs during atrial systole c) Contain Purkinje fibers for impulse transmission d) Contract to propel blood out of the heart 6. What is the role of gap junctions in cardiac muscle? a) Separate the atria from the ventricles b) Transmit electrical currents for cell-to-cell conduction c) Initiate the cardiac impulse d) Regulate the heart rate 7. Which of the following is NOT a factor affecting rhythmicity? a) Autonomic nervous system b) Hormonal levels c) Body temperature d) Blood pressure 8. What is the mechanism of parasympathetic stimulation on the sinoatrial node (SAN) rhythm? a) Increases K+ efflux b) Decreases K+ efflux c) Increases Ca++ influx d) Decreases Ca++ influx 9. Which of the following is NOT a phase of the SAN action potential? a) Upstroke phase b) Repolarization phase c) Plateau phase d) Pacemaker potential phase 10. What is the threshold level for the membrane potential in the SAN action potential? a) -70 mV b) -55 mV c) -40 mV d) +10 mV 11. Which of the following is NOT a component of the action potential? a) Spike b) Threshold c) After-hyperpolarization d) Resting potential 12. What is the function of the Na-K pump in repolarization? a) Initiates depolarization b) Resumes the normal polarity and ionic distribution c) Increases the permeability of the membrane to Na+ d) Triggers the action potential 13. Which of the following is NOT a characteristic of the action potential? a) Transient change in resting membrane potential b) Occurs in excitable tissues c) Caused by an ineffective stimulus d) Leads to changes in membrane permeability to ions 14. What is the main function of the fibrous skeleton of the heart? a) Provides structural support and insulation b) Contracts the heart muscle c) Transmits electrical impulses d) Regulates blood flow 15. Which of the following is NOT a characteristic of contractile muscle fibers? a) Form the bulk of the heart muscle b) Responsible for the pumping action of the heart c) Initiate and propagate the heartbeat d) Found in both atria and ventricles 16. What is the main function of the intercalated discs in cardiac muscle? a) Generate electrical impulses b) Facilitate cell-to-cell conduction c) Separate the atria from the ventricles d) Regulate the heart rate 17. Which of the following is NOT a characteristic of nodal fibers? a) Specialized muscle fibers b) Generate and conduct electrical impulses c) Responsible for the contractile function of the heart d) Include the sinoatrial node (SAN) and atrioventricular node (AVN) 18. What is the main function of the conducting fibers in the heart? a) Contract the heart muscle b) Transmit electrical impulses throughout the heart c) Regulate the heart rate d) Separate the atria from the ventricles 19. Which of the following is NOT a component of the conducting system of the heart? a) Sinoatrial node (SAN) b) Atrioventricular node (AVN) c) Bundle of His d) Chordae tendineae 20. What is the significance of the vagus escape phenomena? a) Increases the heart rate during stress b) Prevents the heart from stopping completely under high vagal tone c) Enhances the effect of sympathetic stimulation d) Regulates the conduction velocity in the AV node 21. What is the function of the Na-K pump in repolarization? a) Initiates depolarization b) Resumes the normal polarity and ionic distribution c) Increases the permeability of the membrane to Na+ d) Triggers the action potential 22. Which of the following is NOT a characteristic of the action potential? a) Transient change in resting membrane potential b) Occurs in excitable tissues c) Caused by an ineffective stimulus d) Leads to changes in membrane permeability to ions 23. What is the main function of the fibrous skeleton of the heart? a) Provides structural support and insulation b) Contracts the heart muscle c) Transmits electrical impulses d) Regulates blood flow 24. Which of the following is NOT a characteristic of contractile muscle fibers? a) Form the bulk of the heart muscle b) Responsible for the pumping action of the heart c) Initiate and propagate the heartbeat d) Found in both atria and ventricles 25. What is the main function of the intercalated discs in cardiac muscle? a) Generate electrical impulses b) Facilitate cell-to-cell conduction c) Separate the atria from the ventricles d) Regulate the heart rate 26. Which of the following is NOT a characteristic of nodal fibers? a) Specialized muscle fibers b) Generate and conduct electrical impulses c) Responsible for the contractile function of the heart d) Include the sinoatrial node (SAN) and atrioventricular node (AVN) 27. What is the main function of the conducting fibers in the heart? a) Contract the heart muscle b) Transmit electrical impulses throughout the heart c) Regulate the heart rate d) Separate the atria from the ventricles 28. Which of the following is NOT a component of the conducting system of the heart? a) Sinoatrial node (SAN) b) Atrioventricular node (AVN) c) Bundle of His d) Chordae tendineae 29. What is the significance of the vagus escape phenomena? a) Increases the heart rate during stress b) Prevents the heart from stopping completely under high vagal tone c) Enhances the effect of sympathetic stimulation d) Regulates the conduction velocity in the AV node 30. In the sinoatrial (SA) node, phase 4 depolarization (pacemaker potential) is attributed to: a) An increase in K+ conductance b) An increase in Na+ conductance c) A decrease in Cl− conductance d) A decrease in Ca2+ conductance e) Simultaneous increases in K+ and Cl− Answer Guide Part One 1. b 2. b 3. c  4. b 5. d 6. b 7. b 8. b 9. c 10. c Part Two 1. b 2. c 3. c 4. b 5. b 6. b 7. d 8. a 9. c 10. c 11. d 12. b 13. c 14. a 15. c 16. b  17. c 18. b 19. d 20. b 21. b 22. c 23. a 24. c 25. b 26. c 27. b 28. d 29. b 30. b Done