Chapter 18: Body Fluids and Circulation – Very Short Answer Type Questions
CBSE Class 11 Biology Very Short Answer Questions – Body Fluids and Circulation (NCERT)
Course & Examination Details
- Course: CBSE Class 11 Biology
- Prescribed By: Central Board of Secondary Education
- Based On: NCERT
- Unit: Unit V – Human Physiology
- Chapter: Chapter 18 – Body Fluids and Circulation
- Question Type: Very Short Answer Questions (VSA)
- Answer Length: 20–30 words
- Exam Utility: CBSE Class 11 Annual Exam, Unit Tests, School Assessments
Section A: Blood (Q1–Q18)
Q1. What is blood?
Answer:
Blood is a fluid connective tissue that circulates in the body, transporting gases, nutrients, hormones, and waste materials while maintaining homeostasis.
Q2. Name the two main components of blood.
Answer:
Blood consists of plasma as the liquid component and formed elements including red blood cells, white blood cells, and platelets.
Q3. What percentage of blood is plasma?
Answer:
Plasma constitutes about 55 percent of the total blood volume and serves as the medium for transport of substances.
Q4. Name the major plasma proteins.
Answer:
The major plasma proteins are albumins, globulins, and fibrinogen, each having specific roles in osmotic balance, immunity, and blood clotting.
Q5. State one function of albumins.
Answer:
Albumins help maintain osmotic pressure of blood and regulate the exchange of fluids between blood and tissues.
Q6. What is the role of globulins?
Answer:
Globulins play an important role in body defense by functioning as antibodies and contributing to immune responses.
Q7. Which plasma protein is involved in blood clotting?
Answer:
Fibrinogen is the plasma protein responsible for blood clotting by converting into fibrin during coagulation.
Q8. Describe red blood cells briefly.
Answer:
Red blood cells are biconcave, enucleated cells containing haemoglobin, responsible for transport of oxygen and carbon dioxide.
Q9. State the life span of RBCs.
Answer:
The average life span of human red blood cells is about 120 days in circulation.
Q10. What is haemoglobin?
Answer:
Haemoglobin is an iron-containing respiratory pigment in red blood cells that binds oxygen reversibly for transport.
Q11. Name the two main categories of WBCs.
Answer:
White blood cells are classified into granulocytes and agranulocytes based on presence or absence of granules.
Q12. State one function of neutrophils.
Answer:
Neutrophils destroy invading microorganisms by phagocytosis and form the first line of cellular defense.
Q13. What is the role of lymphocytes?
Answer:
Lymphocytes provide immunity by producing antibodies and regulating immune responses against pathogens.
Q14. What are platelets?
Answer:
Platelets are small cell fragments derived from megakaryocytes that help in blood clotting.
Q15. Name the process preventing blood loss during injury.
Answer:
Blood clotting prevents excessive blood loss by forming a fibrin clot at the site of injury.
Q16. Name any two factors essential for blood clotting.
Answer:
Calcium ions and vitamin K are essential factors required for proper blood clotting.
Q17. What is tissue fluid?
Answer:
Tissue fluid is the extracellular fluid present between cells that facilitates exchange of materials between blood and tissues.
Q18. Define lymph.
Answer:
Lymph is a colorless fluid formed from tissue fluid that transports fats and aids in immune functions.
Section B: Heart (Q19–Q30)
Q19. Where is the human heart located?
Answer:
The human heart is located in the thoracic cavity between the lungs, slightly tilted towards the left side.
Q20. Name the protective covering of the heart.
Answer:
The heart is enclosed by a double-layered protective sac called the pericardium.
Q21. How many chambers are present in the human heart?
Answer:
The human heart has four chambers: two atria and two ventricles.
Q22. Name the valve between right atrium and right ventricle.
Answer:
The tricuspid valve lies between the right atrium and right ventricle.
Q23. Which valve separates left atrium and left ventricle?
Answer:
The bicuspid or mitral valve separates the left atrium from the left ventricle.
Q24. What is the function of heart valves?
Answer:
Heart valves ensure one-way flow of blood and prevent backward flow during cardiac contractions.
Q25. Define myogenic heart.
Answer:
A myogenic heart generates its own rhythmic impulses for contraction without external nerve stimulation.
Q26. Name the pacemaker of the heart.
Answer:
The sinoatrial node or SA node acts as the pacemaker of the heart.
Q27. What is the function of AV node?
Answer:
The atrioventricular node relays electrical impulses from atria to ventricles.
Q28. What are Purkinje fibres?
Answer:
Purkinje fibres conduct electrical impulses rapidly through ventricles, ensuring coordinated ventricular contraction.
Q29. Why is the left ventricle thick-walled?
Answer:
The left ventricle has thick muscular walls to pump blood at high pressure to the entire body.
Q30. Define double circulation.
Answer:
Double circulation refers to blood passing through the heart twice during one complete circulation cycle.
Section C: Blood Vessels & Cardiac Cycle (Q31–Q42)
Q31. Name the three types of blood vessels.
Answer:
The three types of blood vessels are arteries, veins, and capillaries.
Q32. State one characteristic of arteries.
Answer:
Arteries have thick, elastic walls and carry blood away from the heart.
Q33. Why do veins have valves?
Answer:
Veins possess valves to prevent backward flow of blood, especially against gravity.
Q34. What is the function of capillaries?
Answer:
Capillaries allow exchange of gases, nutrients, and wastes between blood and tissues.
Q35. Define cardiac cycle.
Answer:
The cardiac cycle includes all events occurring during one complete heartbeat.
Q36. What is the duration of one cardiac cycle?
Answer:
One cardiac cycle lasts about 0.8 seconds in a normal adult.
Q37. What is atrial systole?
Answer:
Atrial systole is the contraction phase of atria during which blood enters ventricles.
Q38. Define ventricular systole.
Answer:
Ventricular systole is the contraction phase of ventricles that pumps blood into arteries.
Q39. What is joint diastole?
Answer:
Joint diastole is the relaxation phase when all four chambers of the heart are relaxed.
Q40. Name the first heart sound.
Answer:
The first heart sound, “lub,” is produced by closure of atrioventricular valves.
Q41. What produces the second heart sound?
Answer:
The second heart sound, “dub,” is produced by closure of semilunar valves.
Q42. What regulates heart rate?
Answer:
The autonomic nervous system regulates heart rate by sympathetic and parasympathetic impulses.
Section D: Blood Groups (Q43–Q50)
Q43. On what basis are blood groups determined?
Answer:
Blood groups are determined by the presence or absence of specific antigens on red blood cells.
Q44. Name the blood group with no antigens.
Answer:
Blood group O has no antigens on red blood cells.
Q45. Which blood group is universal recipient?
Answer:
Blood group AB is the universal recipient as it lacks antibodies.
Q46. Which blood group is universal donor?
Answer:
Blood group O is considered the universal donor due to absence of antigens.
Q47. What is Rh factor?
Answer:
Rh factor is an antigen present on red blood cells that determines Rh positive or negative blood type.
Q48. Define erythroblastosis fetalis.
Answer:
Erythroblastosis fetalis is a condition caused by Rh incompatibility between mother and fetus.
Q49. Why is blood grouping important before transfusion?
Answer:
Blood grouping prevents agglutination and life-threatening transfusion reactions.
Q50. Name one disorder related to circulatory system.
Answer:
Hypertension is a circulatory disorder characterized by persistently high blood pressure.
NCERT & CBSE Compliance Note
✔ Strictly based on NCERT Class 11 Biology
✔ Answer length maintained at 20–30 words
✔ Fully aligned with CBSE exam pattern
✔ Ideal for board exams and quick revision