Blood is a fluid connective tissue made of a fluid matrix, plasma, in which formed elements — red blood cells, white blood cells and platelets — remain suspended. Plasma makes up about 55% of blood volume and is 90–92% water; the remaining solutes include plasma proteins (fibrinogen, needed for clotting; globulins, mainly antibodies; and albumins, which maintain osmotic balance
Body Fluids and Circulation
Class 1113 previous-year questions from this chapter every option and the correct answer, free · where the marks are
1. Blood, blood groups and lymph
Exam focus: Rh incompatibility is a second-pregnancy problem, not a first one: an Rh-negative mother is not sensitised until her first Rh-positive baby's blood mixes with hers at delivery, so it is the second Rh-positive pregnancy onward that risks erythroblastosis foetalis, once anti-Rh antibodies already exist to cross the placenta — a timing detail NEET tests directly.
Body Fluids and Circulation — Full Chapter (Blood, Blood Groups and Lymph)
PW NEET
Full-chapter one-shot; early sections cover blood, formed elements, clotting, blood grouping, erythroblastosis foetalis and lymph.
ZoologyNEET 2023show ▾Which of the following statements are correct?
A. Basophils are the most abundant cells of the total WBCs.
B. Basophils secrete histamine, serotonin and heparin.
C. Basophils are involved in the inflammatory response.
D. Basophils have a kidney-shaped nucleus.
E. Basophils are agranulocytes.
Choose the correct answer from the options given below:
- A.D and E only
- B.C and E only
- C.B and C only✓
- D.A and B only
The worked solution is part of a paid pack.
ZoologyNEET 2022show ▾Given below are two statements:
Statement I: The coagulum is formed of a network of threads called thrombins.
Statement II: The spleen is the graveyard of erythrocytes.
In the light of the above statements, choose the most appropriate answer from the options given below:
- A.Statement I is incorrect but Statement II is correct✓
- B.Both Statement I and Statement II are correct
- C.Both Statement I and Statement II are incorrect
- D.Statement I is correct but Statement II is incorrect
The worked solution is part of a paid pack.
ZoologyNEET 2021show ▾Persons with 'AB' blood group are called 'universal recipients'. This is due to:
- A.Absence of antigens A and B on the surface of RBCs
- B.Absence of antigens A and B in plasma
- C.Presence of antibodies anti-A and anti-B on RBCs
- D.Absence of antibodies anti-A and anti-B in plasma✓
The worked solution is part of a paid pack.
ZoologyNEET 2021show ▾Which enzyme is responsible for the conversion of inactive fibrinogens to fibrins?
- A.Thrombin✓
- B.Renin
- C.Epinephrine
- D.Thrombokinase
The worked solution is part of a paid pack.
ZoologyNEET 2020show ▾Match the following columns and select the correct option.
Cell Feature (a) Eosinophils (i) Immune response (b) Basophils (ii) Phagocytosis (c) Neutrophils (iii) Release histaminase and destructive enzymes (d) Lymphocytes (iv) Release granules containing histamine
- A.(a)-(iii), (b)-(iv), (c)-(ii), (d)-(i)✓
- B.(a)-(iv), (b)-(i), (c)-(ii), (d)-(iii)
- C.(a)-(i), (b)-(ii), (c)-(iv), (d)-(iii)
- D.(a)-(ii), (b)-(i), (c)-(iii), (d)-(iv)
The worked solution is part of a paid pack.
2. Human heart, cardiac cycle and ECG
Exam focus: The SA node generates about 70-75 impulses a minute on its own, faster than any other part of the conduction system, which is exactly why it — not the AV node — is the pacemaker that sets heart rate. On an ECG, the P wave is atrial depolarisation and the T wave is ventricular repolarisation, but atrial repolarisation never gets a wave of its own because it is buried inside the much larger QRS complex.
Body Fluids and Circulation — Full Chapter (Human Heart, Cardiac Cycle and ECG)
PW NEET
Same one-shot; middle sections cover the human circulatory system, the heart's conducting system, nodal tissue, the cardiac cycle, and ECG.
BotanyNEET 2025show ▾Cardiac activities of the heart are regulated by:
A. Nodal tissue
B. A special neural centre in the medulla oblongata
C. Adrenal medullary hormones
D. Adrenal cortical hormones
Choose the correct answer from the options given below:
- A.A, B and C only✓
- B.A, B, C and D
- C.A, C and D only
- D.A, B and D only
Solution
The heart is myogenic — its rhythm comes from nodal tissue (A) — but is modulated by a neural centre in the medulla through the autonomic system (B) and by adrenaline and noradrenaline from the adrenal medulla (C). Adrenal cortical hormones do not regulate cardiac activity.
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Save for spaced revision (free account)ZoologyNEET 2024show ▾Following are the stages of the pathway for conduction of an action potential through the heart:
A. AV bundle · B. Purkinje fibres · C. AV node · D. Bundle branches · E. SA node
Choose the correct sequence of the pathway from the options given below:
- A.A-E-C-B-D
- B.B-D-E-C-A
- C.E-A-D-B-C
- D.E-C-A-D-B✓
Solution
The impulse starts at the SA node, reaches the AV node, passes down the AV bundle, splits into the bundle branches and spreads through the Purkinje fibres: E, C, A, D, B.
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Save for spaced revision (free account)ZoologyNEET 2024show ▾Match List I with List II.
List I List II A. P wave I. Heart muscles are electrically silent B. QRS complex II. Depolarisation of ventricles C. T wave III. Depolarisation of atria D. T–P gap IV. Repolarisation of ventricles
Choose the correct answer from the options given below:
- A.A-III, B-II, C-IV, D-I✓
- B.A-II, B-III, C-I, D-IV
- C.A-IV, B-II, C-I, D-III
- D.A-I, B-III, C-IV, D-II
Solution
The P wave is atrial depolarisation (III); the QRS complex, ventricular depolarisation (II); the T wave, ventricular repolarisation (IV); in the T–P gap the heart is electrically silent (I).
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Save for spaced revision (free account)ZoologyNEET 2023show ▾Match List I with List II.
List I List II A. P-wave I. Beginning of systole B. Q-wave II. Repolarisation of ventricles C. QRS complex III. Depolarisation of atria D. T-wave IV. Depolarisation of ventricles
Choose the correct answer from the options given below:
- A.A-III, B-I, C-IV, D-II✓
- B.A-IV, B-III, C-II, D-I
- C.A-II, B-IV, C-I, D-III
- D.A-I, B-II, C-III, D-IV
The worked solution is part of a paid pack.
ZoologyNEET 2022show ▾Which one of the following statements is correct?
- A.Increased ventricular pressure causes closing of the semilunar valves
- B.The atrio-ventricular node (AVN) generates an action potential to stimulate atrial contraction
- C.The tricuspid and the bicuspid valves open due to the pressure exerted by the simultaneous contraction of the atria
- D.Blood moves freely from atrium to ventricle during joint diastole✓
The worked solution is part of a paid pack.
ZoologyNEET 2020show ▾The QRS complex in a standard ECG represents:
- A.Repolarisation of the atria
- B.Depolarisation of the atria
- C.Depolarisation of the ventricles✓
- D.Repolarisation of the ventricles
The worked solution is part of a paid pack.
ZoologyNEET 2019show ▾What would be the heart rate of a person if the cardiac output is 5 L, the blood volume in the ventricles at the end of diastole is 100 mL, and at the end of ventricular systole is 50 mL?
- A.50 beats per minute
- B.75 beats per minute
- C.100 beats per minute✓
- D.125 beats per minute
The worked solution is part of a paid pack.
ZoologyNEET 2019show ▾Match Column I with Column II:
Column I Column II (a) P-wave (i) Depolarisation of ventricles (b) QRS complex (ii) Repolarisation of ventricles (c) T-wave (iii) Coronary ischaemia (d) Reduction in the size of the T-wave (iv) Depolarisation of atria (v) Repolarisation of atria
- A.(a)-(iv), (b)-(i), (c)-(ii), (d)-(iii)✓
- B.(a)-(iv), (b)-(i), (c)-(ii), (d)-(v)
- C.(a)-(ii), (b)-(i), (c)-(v), (d)-(iii)
- D.(a)-(ii), (b)-(iii), (c)-(v), (d)-(iv)
The worked solution is part of a paid pack.
3. Double circulation and disorders
Exam focus: Double circulation exists because a four-chambered heart keeps oxygenated and deoxygenated blood from mixing — blood crosses the heart twice per cycle, once via the pulmonary route and once via the systemic route. NEET's disorder questions hinge on the exact numbers: normal blood pressure is around 120/80 mmHg, and a sustained reading at or above 140/90 mmHg marks hypertension.
Body Fluids and Circulation — Full Chapter (Double Circulation and Disorders)
PW NEET
Same one-shot; final sections cover double/portal circulation, regulation of cardiac activity, and disorders of the circulatory system.