10th class Biology, Chapter 3: Human Blood Circulatory System MCQs

1. Which component of blood is mainly responsible for carrying oxygen?

1. (A) White blood cells
2. (B) Platelets
3. (C) Red blood cells ✓
4. (D) Plasma

2. A person with low platelet count is likely to face difficulty in:

1. (A) Fighting infections
2. (B) Breathing
3. (C) Clotting blood ✓
4. (D) Transporting oxygen

3. Which of the following layer is found in all blood vessels?

1. (A) Smooth muscle
2. (B) Endothelium ✓
3. (C) Skeletal muscle
4. (D) Connective tissue

4. Which of the following contains deoxygenated blood in an adult human?

1. (A) Left atrium
2. (B) Pulmonary artery ✓
3. (C) Pulmonary vein
4. (D) Aorta

5. When fibrinogen makes blood clot it separates from blood and the rest is:

1. (A) Plasma
2. (B) Lymph
3. (C) Serum ✓
4. (D) Pus

6. Which heart chamber has the thickest walls?

1. (A) Right atrium
2. (B) Left atrium
3. (C) Left ventricle ✓
4. (D) Right ventricle

7. The exchange of materials between the blood and tissues occurs in:

1. (A) Arteries
2. (B) Veins
3. (C) Capillaries ✓
4. (D) Arteries and veins

8. All veins carry deoxygenated blood except the ______ vein.

1. (A) Vena cava
2. (B) Hepatic portal
3. (C) Pulmonary ✓
4. (D) Renal

9. Myocardial infarction is due to blockage of blood flow in:

1. (A) Aorta
2. (B) Pulmonary artery
3. (C) Coronary artery ✓
4. (D) Hepatic artery

10. If the bicuspid valve is damaged, which flow of blood will be affected?

1. (A) From left atrium to left ventricle ✓
2. (B) From right atrium to right ventricle
3. (C) From left ventricle to aorta
4. (D) From lungs to left atrium

11. Trace the correct pathway for deoxygenated blood from legs back to the heart:

1. (A) Femoral veins → Superior vena cava → Right atrium
2. (B) Femoral arteries → Superior vena cava → Right atrium
3. (C) Femoral veins → Inferior vena cava → Right atrium ✓
4. (D) Femoral arteries → Inferior vena cava → Right atrium

12. Plasma makes up about what percentage of blood?

1. (A) 91%
2. (B) 8%
3. (C) 55% ✓
4. (D) 45%

13. An adult human has about:

1. (A) 5 litres of blood ✓
2. (B) 2 litres of blood
3. (C) 10 litres of blood
4. (D) 1 litre of blood

14. The plasma protein that maintains the osmotic pressure of blood is:

1. (A) haemoglobin
2. (B) albumin ✓
3. (C) fibrinogen
4. (D) antibody

15. Most of the carbon dioxide dissolved in plasma is in the form of:

1. (A) carbon monoxide
2. (B) oxyhaemoglobin
3. (C) bicarbonate ions ✓
4. (D) carbonic acid gas

16. The number of RBCs per mm3 of blood is:

1. (A) 7000
2. (B) 250,000
3. (C) 30 trillion
4. (D) 4 to 5.5 million ✓

17. In adults, RBCs are formed in the:

1. (A) lymph nodes
2. (B) kidneys
3. (C) red bone marrow ✓
4. (D) liver and spleen

18. The average life span of an RBC is about:

1. (A) 7 to 12 days
2. (B) 30 days
3. (C) 1 year
4. (D) 120 days ✓

19. The WBCs that release histamine are:

1. (A) basophils ✓
2. (B) neutrophils
3. (C) eosinophils
4. (D) monocytes

20. The WBCs that fight parasites are:

1. (A) eosinophils ✓
2. (B) basophils
3. (C) lymphocytes
4. (D) monocytes