Free Cardiovascular System MCQs with Answers

• A. Tricuspid valve
• B. Pulmonary valve
• C. Mitral valve
• D. Aortic valve

Explanation: The tricuspid valve is the right atrioventricular valve and allows blood to move from the right atrium to the right ventricle.

• A. Atrioventricular valves
• B. Aortic and pulmonary valves
• C. Superior and inferior venae cavae
• D. Coronary artery openings

Explanation: S1 occurs when the tricuspid and mitral valves close at the beginning of ventricular systole.

• A. All four valves are closed
• B. The ventricles rapidly fill with blood
• C. The semilunar valves are fully open
• D. The atria actively eject blood into arteries

Explanation: During isovolumetric contraction, ventricular pressure rises while all valves remain closed, so ventricular volume does not change.

• A. The first clear Korotkoff sound
• B. The disappearance of Korotkoff sounds
• C. The strongest sound during deflation
• D. The return of sounds after a pause

Explanation: The first clear Korotkoff sound heard as the cuff deflates represents systolic pressure.

• A. Left ventricle, aorta, body tissues, venae cavae, right atrium
• B. Right ventricle, pulmonary artery, lungs, pulmonary veins, left atrium
• C. Left atrium, pulmonary veins, lungs, pulmonary artery, right ventricle
• D. Right atrium, aorta, body tissues, pulmonary veins, left ventricle

Explanation: Systemic circulation begins at the left ventricle and sends oxygenated blood through the aorta to body tissues.

• A. Arteries receive blood under higher pressure
• B. Arteries contain valves throughout their length
• C. Arteries always carry oxygenated blood
• D. Arteries have wider internal lumens

Explanation: Arteries have thick, elastic and muscular walls to tolerate and regulate the higher pressure produced by ventricular contraction.

• A. One-way valves prevent backward flow
• B. Thick elastic walls maintain high pressure
• C. A thick myocardium creates the pressure
• D. Small pores allow direct tissue drainage

Explanation: Venous valves keep blood moving toward the heart, while skeletal muscle contraction compresses veins and assists venous return.

• A. Diffusion down a concentration gradient
• B. Active transport against a concentration gradient
• C. Filtration caused by arterial pressure
• D. Pinocytosis through the cell membrane

Explanation: Oxygen crosses the thin capillary wall and cell membrane by diffusion, moving from higher concentration in the blood to lower…

• A. Increased heart rate and peripheral vasoconstriction
• B. Decreased heart rate and peripheral vasodilation
• C. Reduced sympathetic activity and venous pooling
• D. Lower contractility and increased capillary filtration

Explanation: Standing causes temporary venous pooling in the lower limbs, reducing venous return.

• A. Tunica intima
• B. Tunica media
• C. Tunica externa
• D. Endocardium

Explanation: The tunica media contains smooth muscle and elastic fibres, allowing arteries and arterioles to constrict or dilate.

• A. Atrioventricular node
• B. Sinoatrial node
• C. Bundle of His
• D. Purkinje fibres

Explanation: The sinoatrial node normally generates the fastest regular electrical impulses, so it sets the heart rate.

• A. Atrial depolarisation
• B. Atrial repolarisation
• C. Ventricular depolarisation
• D. Ventricular repolarisation

Explanation: The P wave represents depolarisation of the atria, which is followed by atrial contraction.

• A. Atrial systole
• B. Isovolumetric relaxation
• C. Ventricular ejection
• D. Passive ventricular filling

Explanation: The aortic and pulmonary valves open when ventricular pressure rises above the pressure in the aorta and pulmonary artery.

• A. Increased sympathetic activity
• B. Increased heart rate
• C. Reduced parasympathetic activity
• D. Reduced sympathetic activity

Explanation: High arterial pressure stretches the carotid and aortic baroreceptors, increasing signals to the cardiovascular centre.

• A. Reduced renin release
• B. Reduced aldosterone secretion
• C. Increased sodium and water retention
• D. Increased urinary water loss

Explanation: Reduced renal perfusion activates the renin-angiotensin-aldosterone system, which promotes sodium and water retention and supports…

• A. Capillary hydrostatic pressure
• B. Plasma colloid osmotic pressure
• C. Interstitial hydrostatic pressure
• D. Lymphatic valve pressure

Explanation: Plasma proteins, especially albumin, create colloid osmotic pressure that draws water into the capillary at the venous end.

• A. Encourage the patient to walk
• B. Administer oral fluids
• C. Assess airway and breathing
• D. Apply a warm pack to the calf

Explanation: The symptoms may indicate a pulmonary embolism, which can rapidly impair breathing and oxygenation.

• A. A thick muscular wall
• B. A single endothelial cell layer
• C. Multiple elastic lamellae
• D. A wide lumen with valves

Explanation: Most capillaries have a wall only one endothelial cell thick, providing a short diffusion distance.

• A. Atrial filling
• B. Ventricular ejection into an artery
• C. Venous return to the atrium
• D. Closure of the atrioventricular valves

Explanation: The pulse wave is produced when ventricular ejection stretches the elastic arterial wall and the pressure wave travels along the artery.

• A. Aortic and pulmonary valves
• B. Mitral and tricuspid valves
• C. Aortic and mitral valves
• D. Pulmonary and tricuspid valves

Explanation: S2 occurs at the beginning of ventricular diastole when the aortic and pulmonary semilunar valves close.