MC questions

Which of the following is NOT a function of the pericardium?
A) Protect the heart
B) Anchor the heart
C) Prevent overfilling of the heart
D) Produce blood cells

D) Produce blood cells

The epicardium is also called:
A) Myocardium
B) Visceral layer of serous pericardium
C) Fibrous pericardium
D) Endocardium

B) Visceral layer of serous pericardium

The intrinsic conduction system of the heart:
A) Requires parasympathetic input to function
B) Generates action potentials without nervous input
C) Cannot function if SA node is intact
D) Is controlled solely by the medulla oblongata

B) Generates action potentials without nervous input

Which structure directly connects the atria to the ventricles in electrical conduction?
A) SA node
B) AV node
C) Purkinje fibers
D) Bundle branches

B) AV node

Which of the following is NOT part of the cardiac conduction pathway?
A) SA node
B) AV node
C) Bundle branches
D) Mitral valve

D) Mitral valve

Which of the following statements about the SA node is correct?
A) It is located in the right atrium
B) It is located in the left atrium
C) It delays conduction to allow ventricular filling
D) It connects directly to Purkinje fibers

A) It is located in the right atrium

What is the function of the AV node?
A) Initiates heart contraction
B) Delays conduction so atria finish contracting
C) Rapidly spreads signal to ventricles
D) Connects directly to SA node

B) Delays conduction so atria finish contracting

Which type of heart cells are autorhythmic?
A) Contractile cardiomyocytes
B) Pacemaker cells
C) Endothelial cells
D) Purkinje fibers

B) Pacemaker cells

Parasympathetic stimulation of the heart:
A) Increases heart rate
B) Decreases heart rate
C) Increases stroke volume
D) Increases cardiac output

B) Decreases heart rate

Sympathetic stimulation of the heart:
A) Decreases contraction force
B) Increases both heart rate and force of contraction
C) Only increases heart rate
D) Only decreases stroke volume

B) Increases both heart rate and force of contraction

The P wave on an ECG represents:
A) Ventricular depolarization
B) Atrial depolarization
C) Ventricular repolarization
D) Atrial repolarization

B) Atrial depolarization

The QRS complex represents:
A) Ventricular depolarization
B) Atrial depolarization
C) Ventricular repolarization
D) AV node delay

A) Ventricular depolarization

The T wave on an ECG represents:
A) Ventricular repolarization
B) Atrial depolarization
C) AV node delay
D) Atrial repolarization

A) Ventricular repolarization

Which heart sound corresponds to closure of the AV valves?
A) S1
B) S2
C) S3
D) S4

A) S1

Which heart sound corresponds to closure of semilunar valves?
A) S1
B) S2
C) S3
D) S4

B) S2

Stroke volume is calculated as:
A) EDV + ESV
B) EDV − ESV
C) HR × SV
D) CO ÷ HR

B) EDV − ESV

Cardiac output is calculated as:
A) HR + SV
B) HR × SV
C) EDV − ESV
D) SV ÷ HR

B) HR × SV

What does preload refer to?
A) Resistance against ventricular ejection
B) Stretch of ventricular muscle due to filling
C) Force of contraction
D) Heart rate

B) Stretch of ventricular muscle due to filling

What does afterload refer to?
A) Stretch of ventricular muscle
B) Pressure ventricles must overcome to eject blood
C) End-diastolic volume
D) Sympathetic stimulation

B) Pressure ventricles must overcome to eject blood

Which layer of the heart is primarily responsible for contraction?
A) Epicardium
B) Myocardium
C) Endocardium
D) Fibrous pericardium

B) Myocardium

Which of the following best demonstrates complementarity of structure and function?
A) The heart contracts to pump blood through vessels
B) Bones store calcium
C) Lungs are filled with alveoli
D) Kidneys filter waste

A) The heart contracts to pump blood through vessels

The SA node fires at 100 bpm. Why is resting heart rate lower (~75 bpm)?
A) Sympathetic inhibition
B) Parasympathetic vagal tone
C) AV node suppression
D) Purkinje fiber activity

B) Parasympathetic vagal tone

If the AV node fails, which structure takes over as pacemaker?
A) SA node
B) Purkinje fibers
C) AV bundle
D) AV node (ventricular pacemaker)

D) AV node (ventricular pacemaker)

Which structure spreads the action potential rapidly through the ventricles?
A) SA node
B) AV node
C) Purkinje fibers
D) Bundle of His

C) Purkinje fibers

Isovolumetric contraction occurs when:
A) All valves are open
B) AV valves are closed but semilunar valves are open
C) All valves are closed
D) Semilunar valves are open

C) All valves are closed

Isovolumetric relaxation occurs when:
A) All valves are closed
B) AV valves are open
C) Semilunar valves are open
D) Ventricles are contracting

A) All valves are closed

Which autonomic center increases heart rate via sympathetic fibers?
A) Cardioinhibitory center
B) Cardioacceleratory center
C) Medullary inhibitory center
D) SA node

B) Cardioacceleratory center

Which autonomic center decreases heart rate via the vagus nerve?
A) Cardioinhibitory center
B) Cardioacceleratory center
C) Medullary sympathetic center
D) AV node

A) Cardioinhibitory center

Which artery supplies oxygen-rich blood to the myocardium?
A) Pulmonary artery
B) Coronary arteries
C) Aorta
D) Venae cavae

B) Coronary arteries

Which of the following best describes the fibrous pericardium?
A) Thin serous layer
B) Thick, protective sac
C) Myocardial muscle layer
D) Endothelial lining

B) Thick, protective sac

The parietal layer of the serous pericardium:
A) Lines the fibrous pericardium
B) Covers the myocardium
C) Contains Purkinje fibers
D) Is part of the epicardium

A) Lines the fibrous pericardium

Cardiac muscle cells require many mitochondria because:
A) They need continuous ATP production for lifelong contraction
B) They store calcium
C) They produce hormones
D) They contract infrequently

A) They need continuous ATP production for lifelong contraction

The plateau phase in ventricular action potentials is caused by:
A) Sodium influx
B) Calcium influx
C) Potassium efflux
D) Chloride influx

B) Calcium influx

During ventricular filling, which valves are open?
A) AV valves
B) Semilunar valves
C) All valves
D) None

A) AV valves

During ventricular ejection, which valves are open?
A) AV valves
B) Semilunar valves
C) All valves
D) None

B) Semilunar valves

The SA node is located:
A) Left atrium
B) Right atrium near superior vena cava
C) AV node
D) Ventricular septum

B) Right atrium near superior vena cava

Which structure delays action potentials to allow atrial contraction?
A) SA node
B) AV node
C) Purkinje fibers
D) Bundle branches

B) AV node

If the heart is removed from the body, what is the approximate heart rate?
A) 50 bpm
B) 100 bpm
C) 150 bpm
D) 75 bpm

B) 100 bpm

Which of the following is TRUE regarding cardiac autorhythmic cells?
A) They require nervous input to fire
B) They depolarize spontaneously
C) They have stable resting potentials
D) They are contractile

B) They depolarize spontaneously

The absolute refractory period in cardiac muscle ensures:
A) Heart can beat backwards
B) Maximum action potential frequency
C) Contraction as a unit
D) After hyperpolarization

C) Contraction as a unit

Which is NOT a function of the endocardium?
A) Smooth lining of chambers
B) Reduces friction for blood flow
C) Generates contractile force
D) Lines valves

C) Generates contractile force

Which of the following is a direct effect of sympathetic stimulation?
A) Heart rate decreases
B) Contractility increases
C) AV node delay increases
D) Coronary artery constriction

B) Contractility increases

Which vessel receives blood from the right ventricle?
A) Pulmonary trunk
B) Aorta
C) Venae cavae
D) Coronary sinus

A) Pulmonary trunk

Which chamber is the receiving chamber of the heart?
A) Ventricles
B) Atria
C) Left ventricle
D) Right ventricle

B) Atria

Which of the following statements about cardiac output is TRUE?
A) CO = SV ÷ HR
B) CO = HR × SV
C) CO = EDV + ESV
D) CO = HR − SV

B) CO = HR × SV

Which of the following describes the fossa ovalis?
A) Remnant of ductus arteriosus
B) Remnant of foramen ovale
C) AV valve
D) Coronary vessel

B) Remnant of foramen ovale

Which of the following statements about the mitral valve is correct?
A) Separates right atrium from right ventricle
B) Prevents backflow into left atrium
C) Controls flow into pulmonary trunk
D) Separates left ventricle from aorta

B) Prevents backflow into left atrium

What is the typical resting stroke volume of an adult heart?
A) 70 mL
B) 50 mL
C) 100 mL
D) 200 mL

A) 70 mL

What does vagal tone refer to?
A) Sympathetic inhibition of the heart
B) Parasympathetic inhibition of the heart
C) Mechanical stretching of ventricles
D) Conduction delay in Purkinje fibers

B) Parasympathetic inhibition of the heart

Which of the following best describes the role of the coronary sinus?
A) Carries oxygenated blood to myocardium
B) Carries deoxygenated blood from myocardium to right atrium
C) Supplies coronary arteries
D) Drains pulmonary veins

B) Carries deoxygenated blood from myocardium to right atrium