Free Circulation MCQs with Answers

• A. SA node > AV node > Purkinje fibres > ventricles
• B. SA node > Purkinje fibres > AV node > ventricles
• C. AV node > SA node > Purkinje fibres > ventricles
• D. AV node > Purkinje fibres > SA node > ventricles

Explanation: The correct pathway of nerve impulse during the excitation and contraction of the human heart is: SA node > AV node > Purkinje fibres >…

• A. Option A
• B. Option B
• C. Option C
• D. Option D

Explanation: During ventricular systole, ventricular pressure exceeds atrial pressure to pump blood into aorta, AV valves closes to prevent backflow of…

• A. Option A
• B. Option B
• C. Option C
• D. Option D

Explanation: When pressure is highest in aorta both AV valves and semilunar are closed because ventricular contraction has just completed.So C is…

• A. Aortic pressure exceeds ventricular pressure
• B. Left atrial pressure exceeds left ventricular pressure
• C. Right ventricular pressure exceeds right atrial pressure
• D. Pulmonary trunk pressure exceeds ventricular pressure

Explanation: The tricuspid valve is located between the right atrium and the right ventricle of the heart.

• A. A
• B. B
• C. C
• D. D

Explanation: During atrial systole, the atria contract to push blood into the ventricles. Therefore, the ventricles are relaxed at this stage.

• A. Ventricular repolarization
• B. Ventricular depolarization
• C. Atrial repolarization
• D. Atrial depolarization

Explanation: The T wave in an ECG (electrocardiogram) represents ventricular repolarization, indicating the recovery of the ventricles before the next…

• A. P wave
• B. QRS Complex
• C. T wave
• D. PQRS

Explanation: The P wave on an electrocardiogram (ECG) represents atrial depolarization, which is the electrical activation that initiates the…

• A. Brain
• B. Heart
• C. Kidney
• D. Pancreas

Explanation: The Bundle of His conducts impulses from the AV node to ventricles, ensuring synchronized contraction of the heart.

• A. Femoral
• B. Pulmonary
• C. Renal
• D. Iliac

Explanation: Pulmonary veins carry oxygen-rich blood from lungs to the left atrium. They are veins because they carry blood toward the heart.

• A. 6
• B. 1
• C. 3
• D. 4

Explanation: The left ventricle of the heart is located at position 6 in the figure.

• A. Return the interstitial fluid to the blood
• B. Return the WBCs and RBCs to the lymph nodes
• C. Transport CO2 to the lungs
• D. Transport O2 to the brain

Explanation: Lymph collects excess interstitial fluid, containing water, proteins, and wastes, and returns it to the blood, maintaining fluid balance…

• A. Heart
• B. Brain
• C. Skin
• D. Nephron

Explanation: The correct answer is Option A: Heart. Purkinje fibers are a critical component of the heart's impulse conducting system.

• A. AV Node
• B. SV Node
• C. SA Node
• D. PQ Node

Explanation: SA Node: This option is the correct answer. The SA (sinoatrial) node, also known as the natural pacemaker of the heart, is the initial…

• A. AV node receives a signal from SA node
• B. AV valves open up
• C. Ventricular walls vibrate due to gushing in of blood from atria
• D. Semilunar valves close down after the blood flows into vessels from ventricles

Explanation: The second heart sound (S2) is produced by the closure of the semilunar valves (aortic and pulmonary valves) after the ventricles have…

• A. Outlet valves
• B. Atrioventricular valves
• C. Semilunar valves
• D. Inter ventricular valves

Explanation: "Lubb" sound is produced when inlet valves or atrioventricular valves close and their flaps strike with each other.

• A. Hepatic portal vein
• B. Iliac vein
• C. Hepatic vein
• D. Renal vein

Explanation: The hepatic portal vein collects blood from the entire alimentary canal and carries it to the inferior vena cava.

• A. Right atrium
• B. Left atrium
• C. Right ventricle
• D. Left ventricle

Explanation: Both superior and inferior venae cavae open into right atrium which carry the deoxygeated blood of the whole body.

• A. Two upper thick-walled atria
• B. Two lower thin-walled ventricles
• C. Two upper thin-walled atria and two lower thick-walled ventricles
• D. Two upper thin-walled ventricles and two lower thick-walled atria

Explanation: Two upper chambers containing thin walls are called atria whereas two lower chambers containing thick wall are called ventricles.

• A. Overextension
• B. Abrasion
• C. Physical trauma
• D. Contraction

Explanation: Pericardium prevents the heart from over extension; Pericardial fluid prevents the heart from abrasion and ribcage prevents it from…

• A. Papillary muscles
• B. Papillary muscles and wall of tricuspid valve
• C. Flaps of tricuspid valve
• D. Walls of the right ventricle

Explanation: The flaps of bicuspid and tricuspid valves are similarly attached through chordae tendinae to papillary muscles of the walls of ventricles.