PNB 2265 HEART EXAM QUESTIONS
AND ANSWERS ALL CORRECT
Which ion primarily drives Phase 4 depolarization in pacemaker cells? A. Sodium via
HCN channels B. Potassium efflux C. Chloride influx D. SR calcium release - Answer-
Sodium via HCN channels — Produces the funny current.
Which event occurs immediately after ventricular depolarization? A. T wave B. AV valve
opening C. Ventricular contraction D. Atrial systole - Answer- Ventricular contraction —
Electrical events precede mechanical contraction.
Which layer is continuous with the endothelial lining of blood vessels? A. Epicardium B.
Myocardium C. Endocardium D. Fibrous pericardium - Answer- Endocardium — It lines
chambers and is continuous with vessels.
Which mechanical event produces S2? A. AV valve closure B. Semilunar valve closure
C. Ventricular filling D. Atrial contraction - Answer- Semilunar valve closure — Marks
beginning of diastole.
Which ion is responsible for rapid repolarization in contractile cells? A. Sodium B.
Calcium C. Potassium D. Chloride - Answer- Potassium — Efflux through delayed
rectifier channels.
Which structure separates left and right ventricles? A. Interatrial septum B.
Interventricular septum C. Coronary sulcus D. Auricle - Answer- Interventricular septum
— Divides ventricles structurally and electrically.
Which event increases cardiac output the most? A. Parasympathetic stimulation B.
Increased stroke volume C. Decreased preload D. Increased ESV - Answer- Increased
stroke volume — CO = HR × SV.
Which structure conducts impulses most rapidly? A. AV node B. SA node C. Purkinje
fibers D. Bundle of His - Answer- Purkinje fibers — Extensive gap junctions allow rapid
conduction.
Which ion movement initiates contraction strength changes? A. Sodium influx B.
Calcium release into cytoplasm C. Potassium efflux D. Chloride shift - Answer- Calcium
release into cytoplasm — Force proportional to cytosolic Ca²⁺.
During atrial systole, blood flows because: A. Ventricular pressure higher B. Atrial
pressure exceeds ventricular pressure C. Semilunar valves open D. Both valves closed
, - Answer- Atrial pressure exceeds ventricular pressure — Blood moves down pressure
gradient.
Which chamber forms the systemic pump? A. Right atrium & ventricle B. Left atrium &
ventricle C. Right ventricle only D. Left atrium only - Answer- Left atrium & ventricle —
They pump oxygenated blood to systemic circulation.
Which condition increases afterload? A. Low arterial pressure B. High diastolic pressure
C. Increased venous return D. Decreased EDV - Answer- High diastolic pressure —
Increases resistance against ejection.
Which layer is directly superficial to the myocardium? A. Parietal serous pericardium B.
Fibrous pericardium C. Visceral serous pericardium (epicardium) D. Endocardium -
Answer- Visceral serous pericardium (epicardium) — It is the outermost layer of the
heart wall and lies directly superficial to the myocardium.
Pericardial effusion refers to fluid buildup in which region? A. Right ventricle B. Left
ventricle C. Endocardium D. Serous pericardial cavity E. Apex - Answer- Serous
pericardial cavity — Fluid accumulates between the visceral and parietal serous
pericardium.
The cardiac skeleton primarily functions to: A. Conduct electrical signals B. Electrically
insulate atria from ventricles C. Generate force D. Anchor papillary muscles - Answer-
Electrically insulate atria from ventricles — It prevents direct electrical conduction
between chambers.
Which valve is located between the left atrium and left ventricle? A. Tricuspid B.
Pulmonary C. Aortic D. Mitral (bicuspid) - Answer- Mitral (bicuspid) valve — It separates
the left atrium and left ventricle.
Semilunar valves are located: A. Between atria and ventricles B. Between ventricles
and major arteries C. In the vena cava D. Between veins and atria - Answer- Between
ventricles and major arteries — The aortic and pulmonary valves prevent backflow into
ventricles.
The primary function of chordae tendinae is to: A. Open AV valves B. Open semilunar
valves C. Stabilize AV valves during ventricular contraction D. Stabilize semilunar
valves - Answer- Stabilize AV valves during ventricular contraction — They prevent
eversion into the atria.
The pulmonary artery carries: A. Oxygen-rich blood B. Oxygen-poor blood C. Mixed
blood D. Nutrient-rich blood - Answer- Oxygen-poor blood — It carries deoxygenated
blood from the right ventricle to the lungs.
AND ANSWERS ALL CORRECT
Which ion primarily drives Phase 4 depolarization in pacemaker cells? A. Sodium via
HCN channels B. Potassium efflux C. Chloride influx D. SR calcium release - Answer-
Sodium via HCN channels — Produces the funny current.
Which event occurs immediately after ventricular depolarization? A. T wave B. AV valve
opening C. Ventricular contraction D. Atrial systole - Answer- Ventricular contraction —
Electrical events precede mechanical contraction.
Which layer is continuous with the endothelial lining of blood vessels? A. Epicardium B.
Myocardium C. Endocardium D. Fibrous pericardium - Answer- Endocardium — It lines
chambers and is continuous with vessels.
Which mechanical event produces S2? A. AV valve closure B. Semilunar valve closure
C. Ventricular filling D. Atrial contraction - Answer- Semilunar valve closure — Marks
beginning of diastole.
Which ion is responsible for rapid repolarization in contractile cells? A. Sodium B.
Calcium C. Potassium D. Chloride - Answer- Potassium — Efflux through delayed
rectifier channels.
Which structure separates left and right ventricles? A. Interatrial septum B.
Interventricular septum C. Coronary sulcus D. Auricle - Answer- Interventricular septum
— Divides ventricles structurally and electrically.
Which event increases cardiac output the most? A. Parasympathetic stimulation B.
Increased stroke volume C. Decreased preload D. Increased ESV - Answer- Increased
stroke volume — CO = HR × SV.
Which structure conducts impulses most rapidly? A. AV node B. SA node C. Purkinje
fibers D. Bundle of His - Answer- Purkinje fibers — Extensive gap junctions allow rapid
conduction.
Which ion movement initiates contraction strength changes? A. Sodium influx B.
Calcium release into cytoplasm C. Potassium efflux D. Chloride shift - Answer- Calcium
release into cytoplasm — Force proportional to cytosolic Ca²⁺.
During atrial systole, blood flows because: A. Ventricular pressure higher B. Atrial
pressure exceeds ventricular pressure C. Semilunar valves open D. Both valves closed
, - Answer- Atrial pressure exceeds ventricular pressure — Blood moves down pressure
gradient.
Which chamber forms the systemic pump? A. Right atrium & ventricle B. Left atrium &
ventricle C. Right ventricle only D. Left atrium only - Answer- Left atrium & ventricle —
They pump oxygenated blood to systemic circulation.
Which condition increases afterload? A. Low arterial pressure B. High diastolic pressure
C. Increased venous return D. Decreased EDV - Answer- High diastolic pressure —
Increases resistance against ejection.
Which layer is directly superficial to the myocardium? A. Parietal serous pericardium B.
Fibrous pericardium C. Visceral serous pericardium (epicardium) D. Endocardium -
Answer- Visceral serous pericardium (epicardium) — It is the outermost layer of the
heart wall and lies directly superficial to the myocardium.
Pericardial effusion refers to fluid buildup in which region? A. Right ventricle B. Left
ventricle C. Endocardium D. Serous pericardial cavity E. Apex - Answer- Serous
pericardial cavity — Fluid accumulates between the visceral and parietal serous
pericardium.
The cardiac skeleton primarily functions to: A. Conduct electrical signals B. Electrically
insulate atria from ventricles C. Generate force D. Anchor papillary muscles - Answer-
Electrically insulate atria from ventricles — It prevents direct electrical conduction
between chambers.
Which valve is located between the left atrium and left ventricle? A. Tricuspid B.
Pulmonary C. Aortic D. Mitral (bicuspid) - Answer- Mitral (bicuspid) valve — It separates
the left atrium and left ventricle.
Semilunar valves are located: A. Between atria and ventricles B. Between ventricles
and major arteries C. In the vena cava D. Between veins and atria - Answer- Between
ventricles and major arteries — The aortic and pulmonary valves prevent backflow into
ventricles.
The primary function of chordae tendinae is to: A. Open AV valves B. Open semilunar
valves C. Stabilize AV valves during ventricular contraction D. Stabilize semilunar
valves - Answer- Stabilize AV valves during ventricular contraction — They prevent
eversion into the atria.
The pulmonary artery carries: A. Oxygen-rich blood B. Oxygen-poor blood C. Mixed
blood D. Nutrient-rich blood - Answer- Oxygen-poor blood — It carries deoxygenated
blood from the right ventricle to the lungs.
