Human Heart Practice Questions
20 free Human Heart practice questions for the NCERT Biology. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
The double-walled membranous bag that encloses the heart and contains a fluid to reduce friction is called:
- A Epicardium
- B Pericardium
- C Endocardium
- D Myocardium
Correct answer: Pericardium
The heart is protected by a double-walled membranous bag called the pericardium. It encloses the pericardial fluid which provides lubrication and protects the heart from mechanical shocks.
Which of the following valves prevents the backflow of blood from the right ventricle into the right atrium?
- A Bicuspid valve
- B Mitral valve
- C Tricuspid valve
- D Semilunar valve
Correct answer: Tricuspid valve
The tricuspid valve consists of three muscular flaps or cusps. It is located between the right atrium and the right ventricle to ensure one-way blood flow.
The 'Pacemaker' of the human heart is located in which chamber?
- A Left atrium
- B Left ventricle
- C Right ventricle
- D Right atrium
Correct answer: Right atrium
The Sino-atrial node (SAN) is called the pacemaker because it initiates and maintains the rhythmic contractile activity of the heart. it is located in the upper right corner of the right atrium.
Which nodal tissue is responsible for receiving impulses from the SAN and delaying them slightly before passing them to the ventricles?
- A Atrio-ventricular node
- B Bundle of His
- C Purkinje fibres
- D Chordae tendineae
Correct answer: Atrio-ventricular node
The atrio-ventricular node (AVN) is located in the lower-left corner of the right atrium close to the atrio-ventricular septum. It picks up the impulse from the SAN, delays it briefly to allow the atria to fully contract, and then transmits it to the AV bundle (Bundle of His).
During a cardiac cycle, the volume of blood pumped out by each ventricle per minute is called:
- A Stroke volume
- B Cardiac output
- C End-diastolic volume
- D Vital capacity
Correct answer: Cardiac output
Cardiac output is defined as the volume of blood pumped out by each ventricle per minute. It is calculated by multiplying the stroke volume (approx. 70mL) by the heart rate (approx. 72 beats/min).
The duration of a standard cardiac cycle in a healthy human heart is approximately:
- A 0.1 seconds
- B 0.5 seconds
- C 0.8 seconds
- D 1.2 seconds
Correct answer: 0.8 seconds
A cardiac cycle corresponds to one heartbeat. Given an average heart rate of 72 beats per minute, the duration of one cycle is 60 divided by 72, which is approximately 0.8 seconds.
Which of the following events occurs during 'Joint Diastole'?
- A All four chambers are simultaneously relaxed
- B Atria are contracting while ventricles relax
- C Ventricles are contracting while atria relax
- D Semilunar valves are wide open
Correct answer: All four chambers are simultaneously relaxed
During joint diastole, all four chambers of the heart are in a relaxed state. The tricuspid and bicuspid valves are open, allowing blood to flow from the pulmonary veins and vena cava into the ventricles.
The first heart sound 'Lubb' is associated with:
- A Closure of the semilunar valves at start of diastole
- B Opening of the atrio-ventricular valves during filling
- C Closure of the tricuspid and bicuspid valves
- D Opening of the semilunar valves during systole
Correct answer: Closure of the tricuspid and bicuspid valves
The first heart sound (Lubb) is produced during ventricular systole. It is caused by the sudden closure of the tricuspid and bicuspid (AV) valves to prevent backflow of blood into the atria.
The thick muscular wall that separates the right and left ventricles is known as the:
- A Inter-atrial septum
- B Atrio-ventricular septum
- C Inter-ventricular septum
- D Coronary sulcus
Correct answer: Inter-ventricular septum
The left and right ventricles are separated by a thick-walled inter-ventricular septum. This prevents the mixing of oxygenated and deoxygenated blood.
Which of the following represents the correct sequence of impulse conduction in the heart?
- A AVN -> SAN -> Bundle of His -> Purkinje fibres
- B SAN -> AVN -> Bundle of His -> Purkinje fibres
- C SAN -> Bundle of His -> AVN -> Purkinje fibres
- D Purkinje fibres -> AVN -> SAN -> Bundle of His
Correct answer: SAN -> AVN -> Bundle of His -> Purkinje fibres
The impulse starts at the SAN (pacemaker), travels to the AVN, then through the Atrio-ventricular bundle (Bundle of His), and finally spreads through the ventricular musculature via Purkinje fibres.
In a standard ECG, the P-wave represents:
- A Depolarisation of the atria
- B Depolarisation of the ventricles
- C Repolarisation of the atria
- D Repolarisation of the ventricles
Correct answer: Depolarisation of the atria
The P-wave is the first small upward wave in an ECG. It represents the electrical excitation (depolarisation) of the atria, which leads to atrial contraction.
A person with a heart rate of 100 beats per minute and a stroke volume of 50 mL has a cardiac output of:
- A Bicuspid and Tricuspid valves
- B Mitral and Pulmonary valves
- C Aortic and Pulmonary semilunar valves
- D Eustachian valves
Correct answer: Aortic and Pulmonary semilunar valves
As ventricular pressure rises during systole, the AV valves close and the semilunar valves — the aortic and pulmonary — are forced open, allowing blood to enter the systemic and pulmonary circulation respectively.
The hepatic portal system carries blood from the ______ to the ______ before it reaches the systemic circulation.
- A Kidney; Liver
- B Intestine; Liver
- C Liver; Heart
- D Intestine; Kidney
Correct answer: Intestine; Liver
The hepatic portal system is a unique vascular connection. It collects deoxygenated blood from the digestive tract (intestines) and carries it to the liver for processing before returning it to the heart.
During ventricular systole, which valves are forced open by the increasing pressure?
- A Bicuspid and Tricuspid valves
- B Mitral and Semilunar valves
- C Semilunar valves
- D Eustachian valves
Correct answer: Semilunar valves
As ventricular pressure rises during systole, the AV valves close and the semilunar valves (guarding the pulmonary artery and aorta) are forced open, allowing blood to enter the circulatory pathways.
The systemic circulation is responsible for carrying:
- A Deoxygenated blood to the lungs for oxygenation
- B Oxygenated blood to all body tissues
- C Blood from the heart to the brain only
- D Blood from the lungs back to the heart
Correct answer: Oxygenated blood to all body tissues
Systemic circulation begins in the left ventricle, which pumps oxygenated blood into the aorta. This blood is distributed to all body tissues and returns to the right atrium as deoxygenated blood via the venae cavae.
What is the function of chordae tendineae?
- A Initiating the heart beat
- B Regulating the cardiac output
- C Preventing AV valve cusps from everting into the atria
- D Opening the semilunar valves
Correct answer: Preventing AV valve cusps from everting into the atria
Chordae tendineae are 'heart strings' attached to the cusps of the bicuspid and tricuspid valves and anchored to papillary muscles. They prevent the AV valve cusps from being pushed back (everted) into the atria during powerful ventricular contractions.
The QRS complex in a standard ECG indicates:
- A The beginning of atrial systole
- B The end of ventricular systole
- C Ventricular depolarisation
- D Joint diastole
Correct answer: Ventricular depolarisation
The QRS complex represents the depolarisation of the ventricles, which initiates ventricular contraction. The contraction starts shortly after Q and marks the beginning of systole.
A special vascular system of blood vessels present in our body exclusively for the circulation of blood to and from the cardiac musculature is:
- A Renal circulation
- B Hepatic circulation
- C Coronary circulation
- D Pulmonary circulation
Correct answer: Coronary circulation
Coronary circulation is the functional blood supply of the heart itself. The coronary arteries and veins supply oxygenated blood to the myocardium and carry deoxygenated blood back to the right atrium.
The T-wave in an ECG represents the return of the ventricles from excited to normal state. This process is called:
- A Depolarisation of muscle cells
- B Repolarisation
- C Generation of action potential
- D Double circulation
Correct answer: Repolarisation
Repolarisation is the process where the electrical state of ventricular muscle cells returns to the resting phase after contraction. The T-wave in an ECG specifically marks the repolarisation of the ventricles.
Which chamber of the heart has the thickest muscular wall?
- A Right Atrium
- B Left Atrium
- C Right Ventricle
- D Left Ventricle
Correct answer: Left Ventricle
The left ventricle has the thickest walls because it must generate enough pressure to pump blood throughout the entire systemic circulation, whereas the right ventricle only pumps blood to the nearby lungs.