Part 7: Blood Vessels and Circulation (25 MCQs)

Q1. Which blood vessel carries blood away from the heart?

A. Veins
B. Arteries
C. Capillaries
D. Venules

Answer: B

Explanation:

A. Incorrect: Veins bring blood back to the heart.
B. Correct: Arteries carry blood away from the heart.
C. Incorrect: Capillaries connect arteries and veins.
D. Incorrect: Venules collect blood from capillaries.

Q2. Which of the following carries oxygenated blood?

A. Pulmonary artery
B. Pulmonary vein
C. Vena cava
D. Coronary sinus

Answer: B

Explanation:

A. Incorrect: Pulmonary artery carries deoxygenated blood.
B. Correct: Pulmonary vein carries oxygenated blood to left atrium.
C. Incorrect: Vena cava carries deoxygenated blood.
D. Incorrect: Coronary sinus carries deoxygenated blood from heart.

Q3. Which blood vessel has the thickest muscular walls?

A. Veins
B. Capillaries
C. Arteries
D. Venules

Answer: C

Explanation:

A. Incorrect: Veins have thinner walls.
B. Incorrect: Capillaries are single-cell thick.
C. Correct: Arteries have thick, muscular walls to withstand high pressure.
D. Incorrect: Venules are thin-walled.

Q4. Which blood vessel has valves to prevent backflow?

A. Arteries
B. Capillaries
C. Veins
D. Arterioles

Answer: C

Explanation:

A. Incorrect: Arteries have no valves (except aorta, pulmonary trunk).
B. Incorrect: Capillaries don’t need valves.
C. Correct: Veins have valves to prevent backflow.
D. Incorrect: Arterioles regulate flow but no valves.

Q5. Exchange of gases, nutrients, and waste occurs in:

A. Arteries
B. Capillaries
C. Veins
D. Aorta

Answer: B

Explanation:

A. Incorrect: Arteries transport blood under pressure.
B. Correct: Capillaries have thin walls for exchange.
C. Incorrect: Veins return blood, not for exchange.
D. Incorrect: Aorta is a large artery.

Q6. Which blood vessel has the lowest blood pressure?

A. Aorta
B. Arterioles
C. Capillaries
D. Veins

Answer: D

Explanation:

A. Incorrect: Aorta has the highest BP.
B. Incorrect: Arterioles lower, but not lowest.
C. Incorrect: Capillaries intermediate.
D. Correct: Veins have lowest BP.

Q7. Normal systolic/diastolic blood pressure in humans is:

A. 100/60 mmHg
B. 120/80 mmHg
C. 140/100 mmHg
D. 160/110 mmHg

Answer: B

Explanation:

A. Incorrect: Slightly low.
B. Correct: Normal BP = 120/80 mmHg.
C. Incorrect: Hypertension.
D. Incorrect: Severe hypertension.

Q8. Pulse is felt in:

A. Veins
B. Capillaries
C. Arteries
D. Venules

Answer: C

Explanation:

A. Incorrect: No pulse in veins.
B. Incorrect: Capillaries too small.
C. Correct: Pulse felt due to pressure waves in arteries.
D. Incorrect: Venules don’t show pulse.

Q9. Which artery supplies blood to the heart muscles?

A. Carotid artery
B. Coronary artery
C. Pulmonary artery
D. Subclavian artery

Answer: B

Explanation:

A. Incorrect: Carotid supplies brain.
B. Correct: Coronary arteries supply myocardium.
C. Incorrect: Pulmonary artery carries deoxygenated blood to lungs.
D. Incorrect: Subclavian supplies arms.

Q10. Which vein carries oxygenated blood?

A. Pulmonary vein
B. Vena cava
C. Jugular vein
D. Renal vein

Answer: A

Explanation:

A. Correct: Pulmonary vein carries oxygenated blood.
B. Incorrect: Vena cava = deoxygenated blood.
C. Incorrect: Jugular vein = deoxygenated blood.
D. Incorrect: Renal vein = deoxygenated blood from kidney.

Q11. The velocity of blood flow is slowest in:

A. Arteries
B. Veins
C. Capillaries
D. Arterioles

Answer: C

Explanation:

A. Incorrect: Fast in arteries.
B. Incorrect: Faster in veins than capillaries.
C. Correct: Slowest in capillaries for exchange.
D. Incorrect: Arterioles intermediate.

Q12. Which artery carries deoxygenated blood?

A. Pulmonary artery
B. Coronary artery
C. Aorta
D. Carotid artery

Answer: A

Explanation:

A. Correct: Pulmonary artery carries deoxygenated blood.
B. Incorrect: Coronary artery oxygenates heart muscle.
C. Incorrect: Aorta oxygenates body.
D. Incorrect: Carotid artery oxygenates brain.

Q13. Which blood vessel connects arteries and veins?

A. Arterioles
B. Venules
C. Capillaries
D. Coronary vessels

Answer: C

Explanation:

A. Incorrect: Arterioles branch from arteries.
B. Incorrect: Venules collect from capillaries.
C. Correct: Capillaries connect arteries and veins.
D. Incorrect: Coronary supply heart.

Q14. Blood pressure is measured with:

A. Spirometer
B. Sphygmomanometer
C. ECG
D. EEG

Answer: B

Explanation:

A. Incorrect: Spirometer measures lung volume.
B. Correct: BP measured with sphygmomanometer.
C. Incorrect: ECG measures electrical activity.
D. Incorrect: EEG measures brain activity.

Q15. Diastolic pressure is due to:

A. Ventricular contraction
B. Ventricular relaxation
C. Atrial contraction
D. Atrial relaxation

Answer: B

Explanation:

A. Incorrect: Ventricular contraction = systolic pressure.
B. Correct: Diastolic pressure = during relaxation.
C. Incorrect: Atria contraction not main cause.
D. Incorrect: Atrial relaxation not relevant.

Q16. Which factor increases blood pressure?

A. Increased blood volume
B. Decreased heart rate
C. Dehydration
D. Vasodilation

Answer: A

Explanation:

A. Correct: More blood volume → ↑ BP.
B. Incorrect: Decreased HR lowers BP.
C. Incorrect: Dehydration reduces BP.
D. Incorrect: Vasodilation reduces BP.

Q17. Baroreceptors regulate blood pressure and are located in:

A. Aorta and carotid sinus
B. Pulmonary artery
C. Left ventricle
D. Right atrium

Answer: A

Explanation:

A. Correct: Baroreceptors in aortic arch + carotid sinus.
B. Incorrect: Pulmonary artery lacks baroreceptors.
C. Incorrect: Left ventricle = pumping chamber.
D. Incorrect: Right atrium lacks baroreceptors.

Q18. Which hormone increases blood pressure?

A. ADH (Vasopressin)
B. Atrial natriuretic peptide
C. Insulin
D. Calcitonin

Answer: A

Explanation:

A. Correct: ADH increases water reabsorption → ↑ BP.
B. Incorrect: ANP lowers BP.
C. Incorrect: Insulin regulates glucose.
D. Incorrect: Calcitonin regulates calcium.

Q19. Which hormone decreases blood pressure?

A. ADH
B. Aldosterone
C. Atrial natriuretic peptide (ANP)
D. Adrenaline

Answer: C

Explanation:

A. Incorrect: ADH increases BP.
B. Incorrect: Aldosterone increases BP.
C. Correct: ANP reduces BP by increasing sodium excretion.
D. Incorrect: Adrenaline increases BP.

Q20. Which vessels act as blood reservoirs?

A. Arteries
B. Veins
C. Capillaries
D. Arterioles

Answer: B

Explanation:

A. Incorrect: Arteries carry under pressure.
B. Correct: Veins store majority of blood volume.
C. Incorrect: Capillaries small.
D. Incorrect: Arterioles regulate flow.

Q21. Which factor primarily determines diastolic pressure?

A. Stroke volume
B. Arteriolar resistance
C. Venous return
D. Heart rate

Answer: B

Explanation:

A. Incorrect: Stroke volume affects systolic, not diastolic.
B. Correct: Arteriolar resistance determines diastolic pressure.
C. Incorrect: Venous return influences stroke volume.
D. Incorrect: Heart rate affects pulse pressure.

Q22. Which law relates blood flow to pressure and resistance?

A. Boyle’s law
B. Ohm’s law analogy
C. Dalton’s law
D. Henry’s law

Answer: B

Explanation:

A. Incorrect: Boyle’s law = gases.
B. Correct: Blood flow ∝ Pressure / Resistance (Ohm’s analogy).
C. Incorrect: Dalton’s law = gases.
D. Incorrect: Henry’s law = solubility.

Q23. Which of the following blood vessels has the largest cross-sectional area?

A. Aorta
B. Capillaries
C. Veins
D. Arterioles

Answer: B

Explanation:

A. Incorrect: Aorta is single vessel.
B. Correct: Capillaries collectively have largest area → slow flow.
C. Incorrect: Veins are fewer.
D. Incorrect: Arterioles smaller total area.

Q24. Hypertension is defined as persistent BP above:

A. 100/70 mmHg
B. 120/80 mmHg
C. 140/90 mmHg
D. 160/100 mmHg

Answer: C

Explanation:

A. Incorrect: Normal.
B. Incorrect: Normal adult BP.
C. Correct: Hypertension = ≥140/90.
D. Incorrect: Severe hypertension.

Q25. The “muscular pump” that helps venous return is due to:

A. Arterial walls
B. Skeletal muscle contractions
C. Capillary exchange
D. Heart valves

Answer: B

Explanation:

A. Incorrect: Arteries pump blood away, not assist veins.
B. Correct: Skeletal muscles contract → compress veins → push blood upward.
C. Incorrect: Capillary exchange unrelated.
D. Incorrect: Valves prevent backflow, not pump.

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Part 7: Blood Vessels and Circulation (25 MCQs)