Top 50+ Body Fluids and Circulation - Biology Questions and Answers For NEET 2024 Exam Preparation

Q1. When a leopard runs after you, the increase in heart rate is probably due to the __________.

1. sympathetic nerves
2. hypothalamus
3. increase in blood pressure
4. medullary accelerator centre

Answer: (b)

The hypothalamus is involved with what could be considered emotional responses such as a sudden increase in heart rate or irregular beat in situations of fear or anxiety.

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Q2. The atrial walls are ___ than the ventricular wall, and pressure generated in the atrial chambers is ___ than in the ventricles.

1. thinner, higher
2. thicker, higher
3. thinner, lower
4. thicker, lower

Answer: (c)

The atrium has thinner walls and generates lower pressures than the ventricles.

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Q3. Globulins contained in human blood plasma are primarily involved in

1. osmotic balance of body fluids
2. clotting of blood
3. oxygen transport in the blood
4. defence mechanisms of body.

Answer: (d)

Globulins in human blood plasma are primarily involved in defence mechanisms of body. Globulins like immunoglobulins act as antibodies that destroy bacteria, viruses and toxic substances that may enter into the blood from outside.

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Q4. Assertion : When there is a fall in the blood pressure due to loss of blood volume, this is compensated by vasoconstriction of veins.

Reason : Veins hold the extra amount of blood which can be shifted to the arteries as required.

1. If both Assertion and Reason are true but the Reason is not the correct explanation of the Assertion.
2. If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
3. If Assertion is true but Reason is false.
4. If both Assertion and Reason are false.

Answer: (b)

When the blood pressure of an individual decreases due to loss of blood volume, then vasoconstriction of veins occurs. This shifts the little amount of blood from veins to arteries.

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Q5. Person with blood group AB is considered as universal recipient because he has:

1. both A and B antigens on RBC but no antibodies in the plasma.
2. no antigen on RBC and no antibody in the plasma.
3. both A and B antibodies in the plasma.
4. both A and B antigens in the plasma but no antibodies.

Answer: (a)

Karl Landsteiner first reported ABO blood groups inhuman beings. A, B and O blood groups were discovered by Landsteiner in 1900 while AB blood group was found out by de Castello and Steini (1902).

ABO blood groups are determined by the gene I (isoagglutinin). There are three alleles. $I^{A}, I^{B}$ and $I^{O}$ of this gene.

Proteins produced by the $I^{A}$ and $I^{B}$ alleles are called A antigen and B antigen. Individuals with AB blood group have both antigen A and antigen B on their RBCs, and no antibodies for either of the antigens in their plasma.

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Q6. Which of the following statements are correct?

1. $Ca^{+2}$ is necessary for blood coagulation.
2. Coagulation in blood vessel is prevented during normal condition by heparin.
3. Clotting of blood involves changes of fibrinogen to fibrin by thrombin.
4. Blood clotting involves cascading process involving a number of factors present in the active form always.

1. (1), (3) and (4)
2. (1), (2) and (3)
3. (2) and (4)
4. (3) and (4)

Answer: (b)

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Q7. Which of the following is not correct for blood pressure?

1. It is not affected by atherosclerosis.
2. It is typically lower in veins than in arteries.
3. Diastolic pressure is higher than systolic pressure.
4. It is usually refers to as venous pressure of the systemic circulation.

1. (i), (ii) & (iii)
2. (i) & (iii)
3. (ii) & (iii)
4. (i), (iii) & (iv)

Answer: (d)

Blood pressure is the arterial pressure of blood exerted on the walls of arteries with each heartbeat. It is measured from the brachial artery and expressed as systolic pressure/diastolic pressure (i. e. 120/80 mmHg).

Blood pressure is affected by atherosclerosis (caused by deposits of calcium, fats, cholesterol, and fibrous tissue which make lumen narrow). Diastolic pressure is lower than systolic pressure. It refers to as arterial pressure of the systemic circulation.

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Q8. Select the incorrect statement from the following:

1. Different groups of animals have evolved the same method for transport.
2. Simple organisms like sponges and coelenterates circulate water from their surroundings through their body cavities to facilitate the cells to exchange substances.
3. Blood is the most commonly used body fluid by most of the higher organisms for transport.
4. Lymph also helps in the transport of certain substances in human.

Answer: (a)

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Q9. Neural signal through the sympathetic nervous (part of ANS) increases the cardiac output because of

1. Increasing the strength of ventricular contraction
2. Increasing the rate of heatbeat
3. Both (a) and (b)
4. Increasing the stimulation of vagus nerve

Answer: (c)

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Q10. Cardiac centre lies in

1. Pons
2. Medulla oblongata
3. Cerebrum
4. Epithalamus

Answer: (b)

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Q11. The given figure shows schematic plan of blood circulation in humans with labels A to D. Identify the label and give its functions?

1. C - Vena cava - takes blood from body parts to right auricle, $pCO_2$ = 45 mm Hg
2. A - Pulmonary vein - takes impure blood from body parts, $pO_2$ = 60 mm Hg
3. D - Dorsal aorta - takes blood from heart to body parts, $pO_2$ = 95 mm Hg
4. B - Pulmonary artery - takes blood from heart to lungs, $pO_2$ = 90 mm Hg

Answer: (a)

In the given figure: A is pulmonary vein which brings pure blood from lungs to left atrium, B is dorsal aorta which carries blood from heart to body parts, C is vena cava which carries impure blood from body parts to right auricle, and D is pulmonary artery which takes impure blood from heart to lungs.

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Q12. Which one of the following is correct?

1. Serum = Blood + Fibrinogen
2. Blood = Plasma + RBC + WBC
3. Lymph = Plasma + RBC + WBC
4. Plasma = Blood – Lymphocytes

Answer: (b)

Blood consists of plasma, RBC, WBC and platelets.

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Q13. Assertion: Body has the ability to alter cardiac output.

Reason: Body has the ability to alter the stroke volume as well as the heart rate.

1. If both the assertion and reason are true but the reason is not a correct explanation of the assertion.
2. If both the assertion and the reason are true and the reason is a correct explanation of the assertion.
3. If the assertion is true but the reason is false.
4. If both the assertion and reason are false.

Answer: (b)

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Q14. Life span of human RBCs is

1. 120 days
2. 9 days
3. 20 days
4. 90 days

Answer: (a)

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Q15. Pulmonary circulation includes

1. Pulmonary vein
2. Pulmonary artery
3. Lungs
4. All of these

Answer: (d)

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Q16. Which one of the following statements about blood constituents and transport of respiratory gases is most accurate?

1. RBCs transport oxygen whereas plasma transports only $CO_{2}$
2. RBCs transport oxygen whereas WBCs transport $CO_{2}$
3. RBCs as well as WBCs transport both oxygen and $CO_{2}$
4. RBCs as well as plasma transport both oxygen and $CO_{2}$

Answer: (d)

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Q17. Fastest distribution of some injectible material/ medicine and with no risk of any kind can be achieved by injecting it into the

1. Veins
2. Arteries
3. Lymph vessels
4. Muscles

Answer: (a)

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Q18. In veins, values are present to check backward flow to blood flowing at

1. high pressure
2. low pressure
3. atmospheric pressure
4. all of these

Answer: (b)

Veins bring blood from different body parts to the heart. The flow of blood in veins is not so fast because the blood in veins is under low pressure. Veins possess valves which prevent backward flow of blood.

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Q19. Assertion: An injury or trauma stimulates the platelets to release certain factors which regulate the mechanism of coagulation.

Reason: Calcium iron is very important for clotting of blood.

1. If both the assertion and reason are true but the reason is not a correct explanation of the assertion.
2. If both the assertion and the reason are true and the reason is a correct explanation of the assertion.
3. If the assertion is true but the reason is false.
4. If both the assertion and reason are false.

Answer: (a)

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Q20. Electrocardiogram is a measure of

1. Ventricular contraction
2. Heart rate
3. Volume of blood pumped
4. Electrical activity of heart

Answer: (d)

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Q21. Sinus venosus is/are present in which of the following animals?

1. Fishes
2. Amphibians
3. Reptiles
4. Birds
5. Mammals

1. (i) and (iv) only
2. (i) only
3. (i), (ii) and (iii)
4. (i), (iii) and (iv)

Answer: (c)

Sinus venosus is found only in fishes, amphibians and reptiles.

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Q22. Rh incompatibility in first pregnancy occurs when

1. During the delivery of first child
2. Foetus develop its heart completely
3. When foetal organs completely develop
4. Never occur in the first pregnancy

Answer: (a)

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Q23. Which one of the following animals has two separate circulatory pathways?

1. Whale
2. Lizard
3. Shark
4. Frog

Answer: (a)

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Q24. The lymph serves to

1. return the interstitial fluid to the blood
2. transport CO₂ to the lungs
3. return the WBCs and RBCs to the lymph nodes
4. transport O₂ to the brain.

Answer: (a)

Lymph (also called tissue fluid in the intercellular spaces) is the colourless liquid found within the lymphatic system. An important function of lymph is to return interstitial fluid back to the blood. The interstitial fluid is the filtered form of the blood without the cellular components and plasma proteins.

It consists of water containing dissolved materials. It receives $CO_2$ , nitrogenous waste products, hormones and other synthetic substances from the tissue cells and enters the lymph capillaries to discharge them into blood.

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Q25. T-wave on an ECG represents

1. Repolarization of ventricles
2. Depolarization of ventricles
3. Repolarization of atria
4. Depolrization of atria

Answer: (a)

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Q26. Erythroblastosis fetalis is caused when fertilisation takes place between gametes of

1. $Rh^{+}$ female and $Rh^{–}$ male
2. $Rh^{–}$ female and $Rh^{+$ male
3. $Rh^{+}$ female and $Rh^{+}$ male
4. $Rh^{–}$ female and $Rh^{–}$ male

Answer: (b)

If fertilisation takes place between gametes of $Rh^{–}$ female and $Rh^{+}$ male then the resulting fetus' blood is $Rh^{+}$.

The $Rh^{+}$ blood of the fetus stimulates the formation of anti Rh factors in the mother's blood. In second pregnancy (with $Rh^{+}$ fetus), the anti Rh factors of the mother's blood destroy the fetal red blood corpuscles.

This is called erythroblastosis fetalis. Newborn may survive but it is often anaemic. The $Rh^{–}$ child does not suffer.

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Q27. The figure shows blood circulation in humans with labels A to D. Select the option which gives correct identification of label and functions of the part.

1. B - Capillary: Thin without muscle layer and wall two cell layers thick
2. D - Pulmonary vein: Takes oxygenated blood to heart, $pO_2$ = 95 mmHg
3. C - Vein: Thin walled and blood flows in jerks/spurts
4. A - Artery: Thick walled and blood flows evenly

Answer: (b)

A - Artery: Carries blood from heart to different body parts. It is thick-walled and elastic. The flow of blood in it is intermittent.

B - Capillary: Nutrients, hormones, gases etc. can diffuse into tissue cells through capillaries and vice versa. It is thin-walled, and only one layer thick resting on basement membrane.

C - Vein: Brings blood from different body parts to the heart. It is thin-walled and acts as low-resistance conduct for blood flow.

D - Pulmonary vein: Two pulmonary veins from each lung transport the oxygenated blood to the left atrium.

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Q28. Assertion: Circulation in amphibians and reptiles is called incomplete double circulation.

Reason: Deoxygenated and oxygenated blood get mixed up in the single ventricle pumps out mixed blood.

1. If both the assertion and reason are true but the reason is not a correct explanation of the assertion.
2. If both the assertion and the reason are true and the reason is a correct explanation of the assertion.
3. If the assertion is true but the reason is false.
4. If both the assertion and reason are false.

Answer: (b)

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Q29. How many times a red blood corpuscle will have to pass through the heart in its journey from hepatic artery to the aorta?

1. Only once
2. Two times
3. Several times
4. Four times

Answer: (b)

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Q30. Rate of heart is determined by

1. AVN
2. SAN
3. Purkinje fibres
4. Bundle of His

Answer: (b)

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Q31. Erythropoiesis starts in

1. red bone marrow
2. spleen
3. kidney
4. liver

Answer: (a)

Erythropoiesis is the formation of red blood cells (erythrocytes) which occurs in the red bone marrow.

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Q32. Which of the following is true about hypertension?

1. It affects vital organs like brain and kidney.
2. It leads to cardiac diseases.
3. It repeats the check of blood pressure of an individual as 140/90 or higher, it shows hypertensions.
4. All the above

Answer: (d)

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Q33. Hepatic portal system starts from

1. Kidney to liver
2. Digestive system to liver
3. Liver to heart
4. Liver to kidney

Answer: (b)

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Q34. Lymph is known as

1. Interstitial fluid
2. Tissue fluid
3. Both (a) and (b)
4. Plasma

Answer: (c)

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Q35. The cardiac pacemaker in a patient fails to function normally. The doctors find that an artificial pacemaker is to be grafted in him. It is likely that it will be grafted at the site of

1. Purkinje system
2. atrioventricular bundle
3. sinoatrial node
4. atrioventricular node

Answer: (c)

The artificial pacemaker is a small battery operated electrical stimulator planted beneath the skin under right clavicle while the string/cable is passed via superior vena cava, right atrium and allowed to rest against the tip of the right ventricle. It is an electrical device used for covering up any deficiency of myogenic functioning so as to make heart beat normally.

Sinoatrial node is known as pacemaker of the heart. It helps in the generation and conduction of heart beat. It is located in the walls of the right atria just below the opening of superior venacva. The sympathetic nerves release the neurotransmitters and activates the SA node and generates electric impulse which is conducted as heart beat through out the heart.

When the cardiac pacemaker in a patient fails to function normally a artificial pacemaker is implanted at the site of SA node.

It is a medical device which uses electrical impulse, generated by electrodes to contract the heart muscles, and regulate the heart beat.

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Q36. Fastest distribution of some injectible material/ medicine and with no risk of any kind can be achieved by injecting it into the

1. muscles
2. veins
3. arteries
4. lymph vessels.

Answer: (b)

Intravenous injection is given for rapid distribution of drugs/substance. Intra-muscular injection is given for producing local effect.

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Q37. The duration of cardiac cycle in a normal man is

1. 80 seconds
2. 0.8 seconds
3. 60 seconds
4. 72 seconds

Answer: (b)

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Q38. Which statement is true for WBC?

1. In deficiency, cancer is caused
2. Non-nucleated
3. Manufactured in thymus
4. Can squeeze through blood capillaries

Answer: (d)

WBCs are the colourless nucleated amoeboid cells that can squeeze through blood capillaries by a process known as diapedesis. The increase in their number causes leukaemia, a cancer. WBCs are of two types, granulocytes (formed in bone marrow) and agranulocytes (formed in bone marrow and thymus).

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Q39. During cardiac cycle, about _________ % of ventricular filling occurs prior to atrial contraction. _________ % ventricular filling occurs due to atrial contraction

1. 70, 30
2. 50, 50
3. 30, 70
4. 10, 90

Answer: (a)

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Q40. If a person is loosing blood continuously due to injury then what will be the effect on his pulse and BP initially?

1. Pulse will fall and BP will rise.
2. Pulse and BP both will fall.
3. Both pulse and BP will rise.
4. Pulse will rise and BP will fall.

Answer: (d)

If a person is losing blood continuously due to injury then his pulse will rise and BP will fall.

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Q41. Cardiac activity could be moderated by the autonomous-neutral system. Tick the correct answer.

1. The parasympathetic system stimulates heart rate and stroke volume
2. The parasympathetic system decreases the heart rate but increase stroke volume
3. The sympathetic system stimulates heart rate and stroke volume
4. The sympathetic system decreases the heart rate but increase stroke volume

Answer: (c)

Neural signals through the sympathetic nerves can increase the rate of the heartbeat, the strength of ventricular contraction and stimulate the cardiac output. Thus the sympathetic system is involved in stimulating heart rate and stroke volume.

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Q42. Which type of white blood cells are concerned with the release of histamine and the natural anticoagulant heparin?

1. Eosinophils
2. Neutrophils
3. Monocytes
4. Basophils

Answer: (d)

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Q43. The given figure shows schematic plan of blood circulation in humans with labels A to D. Identify the label and give its functions

1. D - Dorsal aorta - Takes blood from heart to body parts, $pO_2$ = 95 mm Hg
2. C - Vena cava - Takes blood from body parts to right auricle, $pCO_2$ = 45 mm Hg
3. A - Pulmonary vein - Takes impure blood from body parts, $pO_2$ = 60 mm Hg
4. B - Pulmonary artery - Takes blood from heart to lungs, $pO_2$ = 90 mm Hg

Answer: (b)

In the given figure, A is pulmonary vein which brings pure blood from lungs to left atrium, B is dorsal aorta which carries blood from heart to body parts, C is vena cava which carries impure blood from body parts to right auricle and D is pulmonary artery which takes impure blood from heart to lungs.

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Q44. An atrioventricular valve prevents the back flow or leakage of blood from the

1. Left atrium into the left ventricle
2. Right ventricle into the right atrium
3. Aorta into the left ventricle
4. Pulmonary vein into the right atrium

Answer: (b)

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Q45. Given below is the ECG of a normal human. Which one of its components is correctly interpreted?

1. Peak P - Initiation of left atrial contraction only
2. Peak P and Peak R together - Systolic and diastolic blood pressures
3. Complex QRS - One complete pulse
4. Peak T - Initiation of total cardiac contraction

Answer: (c)

ECG (Electrocardiogram) is a graphic sketching of the variations in electrical potential caused by the excitation of the heart muscle and detected at the body surface. The normal ECG is a scalar representation that shows deflections resulting from cardiac activity.

It comprises the P wave, QRS complex, T wave and U wave. QRS complex: It represents the depolarization of the ventricles which initiates the ventricular contraction.

The contraction starts shortly after Q and marks the beginning of the systole. Hence QRS complex shows one complete pulse.

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Q46. Assertion: Starting of ventricular diastole leads to closure of semi lunar valves.

Reason: Ventricular diastole leads to fall in ventricular pressure.

1. If both the assertion and reason are true but the reason is not a correct explanation of the assertion.
2. If both the assertion and the reason are true and the reason is a correct explanation of the assertion.
3. If the assertion is true but the reason is false.
4. If both the assertion and reason are false.

Answer: (b)

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Q47. ECG depicts the depolarization and repolarization processes during the cardiac cycle. In the ECG of a normal healthy individual one of the following waves is not represented.

1. Repolarization of atria
2. Depolarization of atria
3. Depolarization of ventricles
4. Repolarization of ventricles

Answer: (a)

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Q48. Lymph differs from blood in possessing

1. more RBC and WBC
2. only WBC
3. more RBC and few WBC
4. more WBC and few RBC

Answer: (b)

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Q49. The accompanying diagram shows three stages in the cardiac cycle, Which of the following sequence is correct?

1. 2, 3, 1
2. 2, 1, 3
3. 1, 2, 3
4. 3, 1, 2

Answer: (b)

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Q50. Which one of the components of ECG in human is correctly interpreted below ?

1. Complex QRS-One complete Pulse
2. Peak P and Peak R together-Systolic and diastolic blood pressures
3. Peak T - Initiation of total cardiac contraction
4. Peak P- Initiation of left atrial contraction only

Answer: (b)

Peak P-causes diastolic phase in ventricle while R-Peak causes systole in ventricle means diastolic and systolic phases represented by P & R.

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