BODY FLUIDS AND CIRCULATION MCQs for NEET UG BIOLOGY — Medium, Page 4

91 Medium

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The possible blood groups of children born to parents having

A \times AB

groups are

View answer and explanation

Correct option: D

A, B, AB

Option D (

A, B, AB

) is correct because these are the only possible blood groups resulting from the given parental genotypes.

Solution approach

Correct Answer + Core Reason: $A, B, AB$ . The possible blood groups are determined by the possible combinations of alleles from the parents.

Step-by-Step Solution:

Step 1: Identify the possible genotypes of the parents. Parent 1 has blood group A, so their genotype can be $I^AI^A$ or $I^Ai$ . Parent 2 has blood group AB, so their genotype is $I^AI^B$ .

Step 2: Consider the possible crosses:
- If Parent 1 is $I^AI^A$ : $I^AI^A \times I^AI^B$ gives offspring with genotypes $I^AI^A$ (A) and $I^AI^B$ (AB).
- If Parent 1 is $I^Ai$ : $I^Ai \times I^AI^B$ gives offspring with genotypes $I^AI^A$ (A), $I^AI^B$ (AB), $I^Ai$ (A), and $I^Bi$ (B).

Step 3: Combine the possible blood groups from both crosses: A, AB, and B.

Step 4: Final Answer: A, B, AB

Why other options are wrong:
- Option A: $O, A, B$ - Incorrect because blood group O is not possible with the given parental genotypes.
- Option B: $O, A, B, AB$ - Incorrect because blood group O is not possible with the given parental genotypes.
- Option C: $O, A$ - Incorrect because blood group B and AB are possible.

Key Concepts:
- ABO blood group system
- Genotype and phenotype
- Punnett squares

Memory Aids:
- $I^A$ and $I^B$ are codominant, i is recessive.

Quick Tips:
- Draw Punnett squares to visualize the possible genotypes of the offspring.

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Atherosclerosis is associated with

View answer and explanation

Correct option: B

Coronary artery disease

Option B (Coronary artery disease) is correct because atherosclerosis is a primary cause of coronary artery disease.

Solution approach

Correct Answer + Core Reason: Coronary artery disease. Atherosclerosis is a major cause of coronary artery disease.

Step-by-Step Solution:

Step 1: Define atherosclerosis. Atherosclerosis is the buildup of plaque in the arteries.

Step 2: Define coronary artery disease. Coronary artery disease is the narrowing or blockage of the coronary arteries.

Step 3: Relate atherosclerosis to coronary artery disease. Atherosclerosis is a primary cause of coronary artery disease.

Step 4: Define hypertension. Hypertension is high blood pressure.

Step 5: Define angina. Angina is chest pain due to reduced blood flow to the heart.

Step 6: Define heart failure. Heart failure is the heart's inability to pump enough blood.

Step 7: Conclusion: Atherosclerosis is associated with coronary artery disease.

Why other options are wrong:
- Option A: Hyper tension: While hypertension can worsen atherosclerosis, it is not directly caused by it.
- Option C: Angina: Angina is a symptom of coronary artery disease, which is caused by atherosclerosis.
- Option D: Heart failure: Heart failure can be a consequence of coronary artery disease, which is caused by atherosclerosis.

Key Concepts:
- Atherosclerosis
- Coronary artery disease
- Hypertension
- Angina
- Heart failure

Memory Aids:
- Atherosclerosis leads to CAD (Coronary Artery Disease).

Quick Tips:
- Understand the relationship between atherosclerosis and coronary artery disease.

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What would happen if we cut the chordae tendineae of mitral valve?

View answer and explanation

Correct option: C

The flow of blood would decrease in aorta

Option D (The flow of blood would decrease in pulmonary artery) is incorrect. Option C (The flow of blood would decrease in aorta) is correct because the mitral valve prevents backflow from the left ventricle to the left atrium. If the chordae tendineae are cut, the mitral valve will not close properly, causing backflow and reducing the amount of blood ejected into the aorta.

Solution approach

Correct Answer + Core Reason: The flow of blood would decrease in aorta. Mitral valve incompetence reduces aortic flow.

Step-by-Step Solution:

Step 1: Understand the function of the mitral valve. The mitral valve prevents backflow of blood from the left ventricle to the left atrium.

Step 2: Understand the function of chordae tendineae. Chordae tendineae anchor the mitral valve leaflets to the papillary muscles.

Step 3: Explain the consequence of cutting the chordae tendineae. Cutting the chordae tendineae causes mitral valve prolapse and regurgitation.

Step 4: Explain the effect on blood flow to the aorta. Mitral regurgitation reduces the amount of blood ejected into the aorta.

Step 5: Explain the heart sounds. The first heart sound (lub) is associated with the closure of the AV valves (mitral and tricuspid), and the second heart sound (dub) is associated with the closure of the semilunar valves (aortic and pulmonary).

Step 6: Conclusion: Cutting the chordae tendineae of the mitral valve would decrease blood flow to the aorta.

Why other options are wrong:
- Option A: First heart sound 'lubb' will not be heard: The first heart sound will still be heard, although it may be altered due to the valve malfunction.
- Option B: The second heart sound 'dubb' will not be heard as it is associated with closure of mitral valve: The second heart sound is associated with the closure of the aortic and pulmonary valves, not the mitral valve.
- Option D: The flow of blood would decrease in pulmonary artery: The mitral valve affects blood flow to the aorta, not the pulmonary artery.

Key Concepts:
- Mitral valve function
- Chordae tendineae function
- Mitral regurgitation
- Aortic blood flow
- Heart sounds

Memory Aids:
- Mitral valve controls flow to the Aorta.

Quick Tips:
- Remember the role of the mitral valve in preventing backflow to the left atrium.

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Removal of calcium from freshly collected blood would

View answer and explanation

Correct option: B

Prevent clotting

Option B (Prevent clotting) is correct because calcium ions are essential for several steps in the blood clotting cascade.

Solution approach

Correct Answer + Core Reason: Prevent clotting. Calcium is a crucial factor in the coagulation cascade.

Step-by-Step Solution:

Step 1: Understand the role of calcium in blood clotting.

Step 2: Calcium ions (Ca2+) are required for many steps in the coagulation cascade, including the activation of several clotting factors.

Step 3: Removal of calcium prevents these factors from being activated, thus preventing the formation of a blood clot.

Step 4: Conclusion: Removing calcium prevents the coagulation cascade from proceeding, thus preventing clotting.

Why other options are wrong:
- Option A: Delayed clotting: While reduced calcium might slow the process, complete removal prevents it entirely.
- Option C: Cause immediate clotting: Calcium is required for clotting, so its removal cannot cause immediate clotting.
- Option D: Prevent destruction of haemoglobin: Calcium is not directly involved in the destruction or preservation of hemoglobin.

Key Concepts:
- Blood coagulation cascade
- Role of calcium in blood clotting

Memory Aids:
- Calcium is essential for clotting: Remember that Ca2+ is a key component of the clotting process.

Quick Tips:
- Recall the steps of the coagulation cascade and the factors involved, including calcium.

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The

ABO

blood group are controlled by

View answer and explanation

Correct option: A

I-gene

Option A (I-gene) is correct because the ABO blood groups are determined by the I gene, which has three alleles:

I^A

,

I^B

, and i.

Solution approach

Correct Answer + Core Reason: I-gene. The ABO blood group system is controlled by the I gene.

Step-by-Step Solution:

Step 1: The question asks about the gene controlling ABO blood groups.

Step 2: Recall the genetics of ABO blood groups.

Step 3: The ABO blood group system is determined by the I gene, which codes for glycosyltransferases.

Step 4: The I gene has three alleles: $I^A$ , $I^B$ , and i. $I^A$ and $I^B$ are codominant, while i is recessive.

Why other options are wrong:
- Option B: c-gene is not related to ABO blood groups. It might be associated with other genetic traits, but not blood type.
- Option C: B-gene is not the correct designation. The allele is $I^B$ , part of the I gene system.
- Option D: n-gene is not related to ABO blood groups. It's a distractor with no relevance to the question.

Key Concepts:
- Genetics of ABO blood groups
- Alleles and codominance

Memory Aids:
- I gene for Immunoglobulin (related to blood group antigens)

Quick Tips:
- Remember the three alleles of the I gene and their inheritance patterns.

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Which one of the following has an open circulatory system?

View answer and explanation

Correct option: B

Periplaneta

Option B (Periplaneta) is correct because Periplaneta (cockroach) is an arthropod and possesses an open circulatory system.

Solution approach

Correct Answer + Core Reason: Periplaneta. Periplaneta (cockroach) is an arthropod and has an open circulatory system.

Step-by-Step Solution:

Step 1: Recall the characteristics of an open circulatory system.

Step 2: Remember that arthropods typically have open circulatory systems.

Step 3: Identify Periplaneta as a cockroach, which is an arthropod.

Step 4: Conclude that Periplaneta has an open circulatory system.

Why other options are wrong:
- Option A: Pheretima: Pheretima (earthworm) is an annelid and has a closed circulatory system.
- Option C: Hirudinaria: Hirudinaria (leech) is an annelid and has a closed circulatory system.
- Option D: Octopus: Octopus is a cephalopod mollusc and has a closed circulatory system.

Key Concepts:
- Open circulatory system
- Arthropods
- Annelids
- Molluscs

Memory Aids:
- Cockroach = Open

Quick Tips:
- Remember that arthropods are the primary group with open circulatory systems.

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If the systolic pressure is 120 mm Hg and diastolic pressure is 80 mm Hg. The pulse pressure is ____

View answer and explanation

Correct option: C

120-80 = 40 mm Hg

Option C (120-80 = 40 mm Hg) is correct because pulse pressure is calculated by subtracting diastolic pressure from systolic pressure.

Solution approach

Correct Answer + Core Reason: 120-80 = 40 mm Hg. Pulse pressure is the difference between systolic and diastolic blood pressure.

Step-by-Step Solution:

Step 1: Define systolic pressure. Systolic pressure is the maximum arterial pressure during ventricular contraction.

Step 2: Define diastolic pressure. Diastolic pressure is the minimum arterial pressure during ventricular relaxation.

Step 3: Define pulse pressure. Pulse pressure is the difference between systolic and diastolic pressure.

Step 4: Write the formula for pulse pressure. Pulse Pressure = Systolic Pressure - Diastolic Pressure

Step 5: Substitute the given values. Pulse Pressure = 120 mm Hg - 80 mm Hg

Step 6: Calculate the pulse pressure. Pulse Pressure = 40 mm Hg

Why other options are wrong:
- Option A: Multiplying systolic and diastolic pressure is incorrect.
- Option B: Adding systolic and diastolic pressure is incorrect.
- Option D: Dividing systolic by diastolic pressure gives a ratio, not the pulse pressure.

Key Concepts:
- Systolic pressure
- Diastolic pressure
- Pulse pressure

Memory Aids:
- Pulse Pressure = Systolic - Diastolic

Quick Tips:
- Remember the formula for pulse pressure: Systolic - Diastolic.

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Open circulatory system is present in

View answer and explanation

Correct option: C

Arthropods and Mollusca

Option C (Arthropods and Mollusca) is correct because arthropods and most molluscs (except cephalopods) have open circulatory systems.

Solution approach

Correct Answer + Core Reason: Arthropods and Mollusca. Arthropods and most molluscs have open circulatory systems.

Step-by-Step Solution:

Step 1: Recall the definition of an open circulatory system.

Step 2: Remember that in an open circulatory system, blood (hemolymph) is not always contained within vessels and bathes the tissues directly.

Step 3: Identify that arthropods (like insects and crustaceans) have an open circulatory system.

Step 4: Identify that most molluscs (except cephalopods like squid and octopus) have an open circulatory system.

Why other options are wrong:
- Option A: Arthropods and mammals: Mammals have a closed circulatory system.
- Option B: Mollusca and aves: Aves (birds) have a closed circulatory system.
- Option D: Mammals and aves: Both mammals and birds have closed circulatory systems.

Key Concepts:
- Open circulatory system
- Arthropods
- Molluscs
- Mammals
- Aves

Memory Aids:
- Open = Arthropods & most Molluscs

Quick Tips:
- Remember the key differences between open and closed circulatory systems.

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Father’s blood group is A and his son has O group. Which of the blood groups cannot be present in mother?

View answer and explanation

Correct option: D

AB

Option D (AB) is correct because if the father is A and the son is O, the mother must have at least one 'i' allele, which is not possible if the mother is AB.

Solution approach

Correct Answer + Core Reason: AB. If the father is A and the son is O, the mother cannot be AB.

Step-by-Step Solution:

Step 1: Father's blood group is A, so his genotype can be $I^AI^A$ or $I^Ai$ .

Step 2: Son's blood group is O, so his genotype is $ii$ .

Step 3: For the son to have genotype $ii$ , both parents must contribute an 'i' allele. Therefore, the father must have the genotype $I^Ai$ .

Step 4: If the mother has blood group A, her genotype can be $I^AI^A$ or $I^Ai$ . If the mother has blood group B, her genotype can be $I^BI^B$ or $I^Bi$ . If the mother has blood group O, her genotype is $ii$ . If the mother has blood group AB, her genotype is $I^AI^B$ .

Step 5: If the mother is AB ( $I^AI^B$ ), she cannot contribute an 'i' allele to the son. Therefore, the mother cannot have blood group AB.

Why other options are wrong:
- Option A: A - Incorrect because if the mother is A ( $I^AI^A$ or $I^Ai$ ), she can contribute an 'i' allele if her genotype is $I^Ai$ .
- Option B: B - Incorrect because if the mother is B ( $I^BI^B$ or $I^Bi$ ), she can contribute an 'i' allele if her genotype is $I^Bi$ .
- Option C: O - Incorrect because if the mother is O ( $ii$ ), she can contribute an 'i' allele.

Key Concepts:
- ABO blood group system
- Genotype and phenotype
- Inheritance patterns

Memory Aids:
- Remember that 'i' is recessive and $I^A$ and $I^B$ are codominant.

Quick Tips:
- Work backwards from the child's genotype to determine the possible parental genotypes.

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Maximum amount of oxygen is lost from the blood in the

View answer and explanation

Correct option: A

Capillaries surrounding the tissue cells

Option A (Capillaries surrounding the tissue cells) is correct because oxygen is released from the blood into the tissues at the capillaries surrounding the tissue cells due to the concentration gradient.

Solution approach

Correct Answer + Core Reason: Capillaries surrounding the tissue cells. Oxygen is lost to tissues at capillaries.

Step-by-Step Solution:

Step 1: The question asks where the maximum amount of oxygen is lost from the blood.

Step 2: Recall the function of different blood vessels in oxygen transport.

Step 3: Oxygen is transported in the blood bound to hemoglobin in red blood cells. Oxygen is released from the blood into the tissues at the capillaries surrounding the tissue cells. This is where the concentration gradient favors oxygen diffusion from the blood into the tissues.

Why other options are wrong:
- Option B: Arteries carry oxygenated blood away from the heart. They do not lose significant amounts of oxygen.
- Option C: Capillaries surrounding the alveoli are where oxygen is *gained* by the blood, not lost.
- Option D: The left auricle (atrium) of the heart receives oxygenated blood from the lungs, but oxygen is not lost there.

Key Concepts:
- Oxygen transport in blood
- Function of capillaries, arteries, and heart chambers
- Gas exchange in tissues and lungs

Memory Aids:
- Capillaries are where exchange happens (oxygen out, carbon dioxide in).

Quick Tips:
- Remember the direction of blood flow and gas exchange in different parts of the circulatory system.

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Systemic heart refers to

View answer and explanation

Correct option: A

Enteric heart in lower vertebrates

Option A (Enteric heart in lower vertebrates) is correct because systemic heart refers to the enteric heart in lower vertebrates.

Solution approach

Correct Answer + Core Reason: Enteric heart in lower vertebrates. Systemic heart in lower vertebrates is also known as the enteric heart.

Step-by-Step Solution:

Step 1: Understand the term \"systemic heart.\" The systemic heart refers to the main circulatory pump that delivers blood to the body's tissues.

Step 2: Consider the heart structure in different vertebrates. In lower vertebrates, the heart structure and function can differ significantly from higher vertebrates.

Step 3: Relate the term \"enteric heart\" to lower vertebrates. The enteric heart is a term sometimes used to describe the systemic heart in certain lower vertebrates.

Step 4: Conclude that the systemic heart in lower vertebrates is the enteric heart.

Why other options are wrong:
- Option B: The two ventricles together in humans: This refers to the pumping chambers of the heart in mammals, but not the systemic heart in lower vertebrates.
- Option C: The heart that contracts under stimulation from nervous system: While the nervous system influences heart rate, this is not the definition of the systemic heart.
- Option D: Left auricle and left ventricle in higher vertebrates: This refers to a specific part of the heart in higher vertebrates (mammals, birds), not the systemic heart in lower vertebrates.

Key Concepts:
- Systemic circulation
- Vertebrate heart anatomy
- Evolution of the heart

Memory Aids:
- Systemic = System-wide circulation

Quick Tips:
- Remember that heart structure and function vary across different vertebrate groups.

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Pulse beat is measured from

View answer and explanation

Correct option: A

Arteries

Option A (Arteries) is correct because pulse beat is measured from arteries, as they carry blood under high pressure from the heart, allowing for a palpable pulsation.

Solution approach

Correct Answer + Core Reason: Arteries. Pulse beat is measured from arteries due to the pressure of blood flow.

Step-by-Step Solution:

Step 1: Recall where pulse beat is measured.

Step 2: Pulse beat is the rhythmic throbbing felt in arteries due to the pressure of blood being pumped by the heart. Veins have lower pressure and capillaries are too small to easily feel a pulse.

Why other options are wrong:
- Option B: Veins have lower pressure and are not used to measure pulse beat.
- Option C: Capillaries are too small to easily feel a pulse.
- Option D: Nerves do not carry blood and are not related to pulse beat.

Key Concepts:
- Pulse beat
- Arteries
- Blood pressure

Memory Aids:
- Pulse is felt in Arteries.

Quick Tips:
- Remember that pulse is related to the pressure in arteries.

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The state of heart, when it is not pumping blood effectively enough to meet the needs of the body, is :

View answer and explanation

Correct option: A

Heart failure

Option A (Heart failure) is correct because heart failure is defined as the heart's inability to pump blood effectively enough to meet the body's needs.

Solution approach

Correct Answer + Core Reason: Heart failure. Heart failure is the inability of the heart to pump blood effectively.

Step-by-Step Solution:

Step 1: Define heart failure. Heart failure occurs when the heart cannot pump enough blood to meet the body's needs.

Step 2: Define cardiac arrest. Cardiac arrest is the sudden loss of heart function, breathing, and consciousness.

Step 3: Define heart attack. A heart attack occurs when blood flow to the heart is blocked.

Step 4: Define angina. Angina is chest pain caused by reduced blood flow to the heart.

Step 5: Compare the definitions. The question describes heart failure.

Why other options are wrong:
- Option B: Cardiac arrest: This is incorrect. Cardiac arrest is a sudden cessation of heart function, not necessarily related to pumping effectiveness.
- Option C: Heart attack: This is incorrect. A heart attack is caused by a blockage of blood flow to the heart muscle.
- Option D: Angina: This is incorrect. Angina is chest pain due to reduced blood flow, not the heart's inability to pump effectively.

Key Concepts:
- Heart failure definition
- Cardiac arrest definition
- Heart attack definition
- Angina definition

Memory Aids:
- Heart failure = Heart's pumping power fails.

Quick Tips:
- Differentiate between heart failure, heart attack, and cardiac arrest.

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SAN can generate impulses

View answer and explanation

Correct option: A

70 – 75 min

^ - 1

Option A (70 – 75 min

^ - 1

) is correct because the sinoatrial node (SAN) typically generates impulses at a rate of 70-75 per minute.

Solution approach

Correct Answer + Core Reason: 70 – 75 min $^ - 1$ . This is the normal firing rate of the SAN.

Step-by-Step Solution:
Step 1: Define SAN (sinoatrial node): The heart's natural pacemaker, located in the right atrium.
Step 2: Recall the normal firing rate of the SAN.
Step 3: The SAN generates electrical impulses that initiate each heartbeat.
Step 4: The normal firing rate is typically between 60-100 beats per minute, but the resting rate is usually 70-75.

Why other options are wrong:
- Option B: 50 – 55 min $^ - 1$ is too low; it would indicate bradycardia.
- Option C: 100 – 150 min $^ - 1$ is too high; it would indicate tachycardia.
- Option D: 35– 40 min $^ - 1$ is very low and indicates a serious problem.

Key Concepts:
- Sinoatrial node (SAN)
- Heart rate
- Pacemaker

Memory Aids:
- SAN firing rate: ~70-75 bpm

Quick Tips:
- Know the function of the SAN and its normal firing rate.

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Cardiac center is present in

View answer and explanation

Correct option: B

Medulla oblongata

Option B (Medulla oblongata) is correct because the cardiac center, which regulates heart rate and contractility, is located in the medulla oblongata.

Solution approach

Correct Answer + Core Reason: Medulla oblongata. The cardiac center is located in the medulla oblongata.

Step-by-Step Solution:

Step 1: Recall the basic anatomy of the brain.

Step 2: Remember that the medulla oblongata controls vital functions such as heart rate, breathing, and blood pressure.

Step 3: Identify the cardiac center as a specific region within the medulla oblongata responsible for regulating heart function.

Why other options are wrong:
- Option A: Cerebrum is responsible for higher-level cognitive functions.
- Option C: Pons is involved in regulating breathing and sleep cycles.
- Option D: Epithalamus is involved in regulating the sleep-wake cycle and hormone secretion.

Key Concepts:
- Brain Anatomy
- Medulla Oblongata
- Cardiac Center

Memory Aids:
- Medulla = Mandatory (for vital functions).

Quick Tips:
- Associate vital functions with the medulla oblongata.

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The difference between blood and lymph is

View answer and explanation

Correct option: B

Blood has RBCs and WBCs, while lymph has only WBCs

Option B (Blood has RBCs and WBCs, while lymph has only WBCs) is correct because lymph is essentially filtered blood plasma with white blood cells, but lacking red blood cells.

Solution approach

Correct Answer + Core Reason: Blood has RBCs and WBCs, while lymph has only WBCs. Lymph lacks RBCs but contains WBCs.

Step-by-Step Solution:

Step 1: Define blood: Blood is a fluid connective tissue that contains red blood cells (RBCs), white blood cells (WBCs), platelets, and plasma.

Step 2: Define lymph: Lymph is a fluid derived from tissue fluid that circulates through the lymphatic system. It contains white blood cells (lymphocytes) but lacks red blood cells.

Step 3: Compare blood and lymph: Blood contains both RBCs and WBCs, while lymph primarily contains WBCs and lacks RBCs.

Step 4: Conclude: Therefore, the difference between blood and lymph is that blood has RBCs and WBCs, while lymph has only WBCs.

Why other options are wrong:
- Option A (Blood has RBCs and WBCs, while lymph has no cells): Incorrect because lymph contains WBCs.
- Option C (Blood has WBCs, while lymph has RBCs): Incorrect because blood has both RBCs and WBCs, and lymph has WBCs but not RBCs.
- Option D (Blood has dissolve salt, while lymph has no cells): Incorrect because lymph contains cells (WBCs) and also has dissolved salts.

Key Concepts:
- Blood composition
- Lymph composition
- Red blood cells (RBCs)
- White blood cells (WBCs)
- Lymphatic system

Memory Aids:
- Remember that lymph is part of the immune system, so it contains WBCs.

Quick Tips:
- Understand the key differences between blood and lymph composition.

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Cause of closure of semilunar valves in human heart is

View answer and explanation

Correct option: C

Ventricular diastole and decrease in ventricular pressure

Option C (Ventricular diastole and decrease in ventricular pressure) is correct because the semilunar valves close when the ventricles relax (diastole) and the pressure in the ventricles drops below the pressure in the arteries.

Solution approach

Correct Answer + Core Reason: Ventricular diastole and decrease in ventricular pressure. Semilunar valves close when ventricular pressure falls below arterial pressure during diastole.

Step-by-Step Solution:

Step 1: Understand the function of semilunar valves (aortic and pulmonary valves).

Step 2: These valves prevent backflow of blood from the arteries into the ventricles.

Step 3: They close when the pressure in the ventricles decreases during ventricular diastole.

Step 4: This pressure decrease is lower than the pressure in the aorta and pulmonary artery, causing the valves to shut.

Why other options are wrong:
- Option A: Ventricular diastole and increase in ventricular pressure is incorrect because ventricular pressure decreases during diastole.
- Option B: Ventricular systole and increase in ventricular pressure is incorrect because this is when the semilunar valves open, not close.
- Option D: Atrial diastole and decrease in atrial pressure is irrelevant to the closure of semilunar valves, which are located between the ventricles and the arteries.

Key Concepts:
- Semilunar Valves
- Ventricular Systole
- Ventricular Diastole
- Blood Pressure

Memory Aids:
- "SL valves Shut during diastole".

Quick Tips:
- Focus on the pressure gradient between the ventricles and arteries.

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The wall of the ventricles are much thicker than that of atrium because

View answer and explanation

Correct option: A

It has to pump the blood

Option A (It has to pump the blood) is correct because the ventricles need thicker walls to generate the force required to pump blood to the lungs and the rest of the body.

Solution approach

Correct Answer + Core Reason: It has to pump the blood. The ventricles require thicker walls to generate the force needed to pump blood to the lungs and the rest of the body.

Step-by-Step Solution:

Step 1: Recall the function of the ventricles.

Step 2: Understand that ventricles pump blood to the lungs and the rest of the body.

Step 3: Recognize that pumping blood requires more force than receiving blood.

Step 4: Therefore, ventricles need thicker walls to generate the necessary force.

Why other options are wrong:
- Option B: Incorrect because receiving blood does not require thick walls; the atria receive blood and have thinner walls.
- Option C: Incorrect because the position of the ventricles below the atria does not necessitate thicker walls.
- Option D: Incorrect because storing blood is not the primary function of the ventricles; their primary function is to pump blood.

Key Concepts:
- Ventricular function
- Pumping blood
- Cardiac muscle thickness

Memory Aids:
- Ventricles = Vigorous pumping

Quick Tips:
- Relate the structure of the heart chambers to their function.

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In a cardiac output of 5250 ml per minute, with 75 heart beats per minute, the stroke volume is

View answer and explanation

Correct option: D

70 ml

Option D (70 ml) is correct because stroke volume is calculated by dividing cardiac output by heart rate: 5250 ml/min / 75 beats/min = 70 ml/beat.

Solution approach

Correct Answer + Core Reason: 70 ml. Stroke volume is cardiac output divided by heart rate.

Step-by-Step Solution:

Step 1: Define cardiac output. Cardiac output (CO) is the amount of blood pumped by the heart per minute.

Step 2: Define stroke volume. Stroke volume (SV) is the amount of blood pumped by the heart per beat.

Step 3: Define heart rate. Heart rate (HR) is the number of heart beats per minute.

Step 4: State the formula. The formula relating these is: $CO = SV \times HR$

Step 5: Rearrange the formula to solve for stroke volume: $SV = \frac{{CO}}{{HR}}$

Step 6: Substitute the given values: $SV = \frac{{5250 \text{{ ml/min}}}}{{75 \text{{ beats/min}}}}$

Step 7: Calculate the stroke volume: $SV = 70 \text{{ ml/beat}}$

Why other options are wrong:
- Option A: 60 ml: This is incorrect. It is likely a calculation error.
- Option B: 80 ml: This is incorrect. It is likely a calculation error.
- Option C: 55 ml: This is incorrect. It is likely a calculation error.

Key Concepts:
- Cardiac output
- Stroke volume
- Heart rate
- Formula: $CO = SV \times HR$

Memory Aids:
- CO = SV x HR (Cardiac Output = Stroke Volume x Heart Rate).

Quick Tips:
- Remember the formula relating cardiac output, stroke volume, and heart rate.

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Chordae tendinae are found in

View answer and explanation

Correct option: B

Ventricles of heart

Option B (Ventricles of heart) is correct because chordae tendinae are fibrous cords that connect the atrioventricular valves to the papillary muscles in the ventricles.

Solution approach

Correct Answer + Core Reason: Ventricles of heart. Chordae tendinae are located in the ventricles and attach to the atrioventricular valves.

Step-by-Step Solution:

Step 1: Recall the anatomy of the heart.

Step 2: Chordae tendinae are tendon-like cords that connect the atrioventricular valves (tricuspid and mitral valves) to the papillary muscles in the ventricles.

Step 3: These structures prevent the valves from prolapsing back into the atria during ventricular contraction.

Why other options are wrong:
- Option A: Atria of heart: The atria do not contain chordae tendinae. They are primarily receiving chambers for blood returning to the heart.
- Option C: Joints of legs: Joints of legs contain ligaments and tendons related to skeletal muscle movement, not chordae tendinae.
- Option D: Joints of hands: Joints of hands contain ligaments and tendons related to skeletal muscle movement, not chordae tendinae.

Key Concepts:
- Heart anatomy
- Function of chordae tendinae
- Location of heart structures

Memory Aids:
- Chordae tendinae = cords in the ventricles

Quick Tips:
- Visualize the heart structure to remember the location of different components.

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In which, blood circulation starts and ends in capillaries?

View answer and explanation

Correct option: A

Portal system

Option A (Portal system) is correct because a portal system is defined as a system where blood passes through two sets of capillaries before returning to the heart.

Solution approach

Correct Answer + Core Reason: Portal system. Blood circulation starts and ends in capillaries in a portal system.

Step-by-Step Solution:

Step 1: Define a portal system. A portal system is a circulatory pathway where blood passes through two capillary beds in series before returning to the heart.

Step 2: Consider the other options. A capillary system is a general term for blood vessels connecting arteries and veins. An arterial system refers to the arteries carrying blood away from the heart. A lymphatic system is a separate system for fluid drainage and immune function.

Step 3: Identify the correct option. Only the portal system has blood circulation starting and ending in capillaries.

Why other options are wrong:
- Option B: Capillary system is a general term and doesn't specifically define a system starting and ending in capillaries.
- Option C: Arterial system carries blood away from the heart, not starting and ending in capillaries.
- Option D: Lymphatic system is a separate system, not a blood circulatory system.

Key Concepts:
- Portal system
- Capillary beds
- Blood circulation

Memory Aids:
- Portal system = two capillary beds in series.

Quick Tips:
- Remember the definition of a portal system.

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Patient with unknown blood group needs immediate blood transfusion. In this case, which blood do you suggest to give that patient immediately?

View answer and explanation

Correct option: D

Blood group-O

Option D (Blood group-O) is correct because blood group O is the universal donor and can be transfused to patients with unknown blood groups in emergencies.

Solution approach

Correct Answer + Core Reason: Blood group-O. Blood group O is the universal donor.

Step-by-Step Solution:

Step 1: Recall blood group compatibility: Blood group O lacks A and B antigens on the surface of red blood cells. Therefore, it can be safely transfused to individuals with any blood type (A, B, AB, or O) without causing an immune reaction.

Step 2: Explain the concept of universal donor: Blood group O is known as the \"universal donor\" because it can be given to anyone in an emergency when the recipient's blood type is unknown.

Step 3: Conclude: Therefore, in the case of a patient with an unknown blood group needing immediate blood transfusion, blood group O is the safest option.

Why other options are wrong:
- Option A (Blood group-B): Incorrect because blood group B has B antigens, which can cause a reaction in individuals with blood group A or O.
- Option B (Blood group-AB): Incorrect because blood group AB has both A and B antigens, which can cause a reaction in individuals with blood group A, B, or O. Blood group AB is the universal recipient, not the universal donor.
- Option C (Blood group-A): Incorrect because blood group A has A antigens, which can cause a reaction in individuals with blood group B or O.

Key Concepts:
- Blood groups (A, B, AB, O)
- Antigens and antibodies
- Blood transfusion compatibility
- Universal donor (O)
- Universal recipient (AB)

Memory Aids:
- Remember that O is the \"original\" blood type and can be given to everyone.

Quick Tips:
- Understand the principles of blood group compatibility and the roles of antigens and antibodies.

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In mammals, which blood vessel would normally carry largest amount of urea?

View answer and explanation

Correct option: C

Hepatic vein

Option C (Hepatic vein) is correct because the hepatic vein carries blood from the liver, which is where urea is produced as a byproduct of protein metabolism.

Solution approach

Correct Answer + Core Reason: Hepatic vein. The liver produces urea, which is then transported via the hepatic vein.

Step-by-Step Solution:

Step 1: Recall the role of the liver in urea production.

Step 2: The liver converts ammonia (toxic) to urea (less toxic) through the urea cycle.

Step 3: Urea is then released into the bloodstream.

Step 4: The hepatic vein carries blood from the liver to the inferior vena cava.

Step 5: Therefore, the hepatic vein will have the highest concentration of urea.

Why other options are wrong:
- Option A: Renal vein carries blood away from the kidneys after urea has been filtered out.
- Option B: Dorsal aorta carries oxygenated blood to the body, not specifically urea-rich blood.
- Option D: Hepatic portal vein carries blood from the digestive system to the liver, before urea is produced.

Key Concepts:
- Urea Cycle
- Liver Function
- Hepatic Vein
- Renal Vein
- Hepatic Portal Vein

Memory Aids:
- Think of the liver as the "urea factory" and the hepatic vein as the "exit route".

Quick Tips:
- Remember that the liver is the primary site of urea production.

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Which of the following carries glucose from digestive tract to liver?

View answer and explanation

Correct option: B

Hepatic portal vein

Option B (Hepatic portal vein) is correct because the hepatic portal vein carries blood rich in nutrients, including glucose, from the digestive tract to the liver for processing and storage.

Solution approach

Correct Answer + Core Reason: Hepatic portal vein. The hepatic portal vein carries glucose from the digestive tract to the liver.

Step-by-Step Solution:

Step 1: Recall the function of the hepatic portal vein.

Step 2: The hepatic portal vein is a blood vessel that carries blood from the digestive tract (stomach, intestines, spleen, and pancreas) to the liver. This blood is rich in nutrients, including glucose, which the liver processes and stores.

Why other options are wrong:
- Option A: Hepatic artery carries oxygenated blood to the liver, not glucose from the digestive tract.
- Option C: Pulmonary vein carries oxygenated blood from the lungs to the heart, not glucose from the digestive tract to the liver.
- Option D: None of these is incorrect because option B is correct.

Key Concepts:
- Hepatic portal system
- Hepatic portal vein
- Liver function

Memory Aids:
- Hepatic Portal Vein = Digestive tract to Liver.

Quick Tips:
- Remember the role of the hepatic portal vein in nutrient transport.

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Besides RBC, blood plasma also carries

{O_2}

in solution. The percentage is

View answer and explanation

Correct option: D

3\%

Option D (

3\%

) is correct because blood plasma carries a small percentage of oxygen in solution, with the majority being transported by hemoglobin in RBCs.

Solution approach

Correct Answer + Core Reason: $3\%$ . Blood plasma carries a small percentage of oxygen in solution.

Step-by-Step Solution:

Step 1: Understand the context: The question asks about the percentage of oxygen carried by blood plasma in solution, not bound to hemoglobin.

Step 2: Recall the physiology: Most oxygen is transported by hemoglobin in red blood cells (RBCs). A small amount is dissolved directly in the plasma.

Step 3: Identify the correct percentage: The percentage of oxygen carried by blood plasma in solution is approximately 3%.

Why other options are wrong:
- Option A: $7\%$ is incorrect because it overestimates the amount of oxygen carried by plasma in solution.
- Option B: $20-25\%$ is incorrect because this range represents the approximate percentage of carbon dioxide transported by blood, not oxygen in plasma.
- Option C: $70\%$ is incorrect because this value is much higher than the actual percentage of oxygen carried by plasma in solution. The majority is carried by hemoglobin.

Key Concepts:
- Oxygen transport in blood
- Role of hemoglobin
- Role of blood plasma

Memory Aids:
- Remember that most oxygen is bound to hemoglobin inside RBCs.

Quick Tips:
- Pay attention to whether the question is asking about oxygen carried by plasma or by RBCs.

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In human heart, identify the correct statements a I. Volume of both the atria is the greater than the volume and both ventricles II. Volume of both the ventricle is greater than the volume of both the atria III. Inter-ventricular septum separates the right and the left atria IV. Atrio ventricular septum don’t separates the atrium and ventricle Choose the correct option accordingly

View answer and explanation

Correct option: B

 II only

Option B (II only) is correct because the volume of both ventricles is greater than the volume of both atria.

Solution approach

Correct Answer + Core Reason: II only. The volume of the ventricles is greater than that of the atria.

Step-by-Step Solution:

Step 1: Statement I is incorrect. The atria are smaller in volume than the ventricles.

Step 2: Statement II is correct. The ventricles are larger and need to pump blood to the entire body or lungs.

Step 3: Statement III is incorrect. The interventricular septum separates the right and left ventricles, not the atria.

Step 4: Statement IV is incorrect. The atrioventricular septum separates the atria and ventricles.

Why other options are wrong:
- Option A: Includes incorrect statements.
- Option C: Includes incorrect statements.
- Option D: Includes incorrect statements.

Key Concepts:
- Heart anatomy
- Atria and ventricles
- Septa

Memory Aids:
- Ventricles are larger because they pump blood further.

Quick Tips:
- Visualize the heart's structure.

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Heart of man is

View answer and explanation

Correct option: A

Myogenic

Option A (Myogenic) is correct because the human heart's contractions are initiated by specialized muscle cells (SA node) within the heart itself, not by nerve impulses.

Solution approach

Correct Answer + Core Reason: Myogenic. The human heart's contractions are initiated by muscle cells within the heart.

Step-by-Step Solution:

Step 1: Understand the difference between myogenic and neurogenic hearts.

Step 2: Recall that a myogenic heart initiates its own contractions through specialized muscle cells, while a neurogenic heart requires nerve impulses to initiate contractions.

Step 3: Recognize that the human heart contains the sinoatrial (SA) node, a group of specialized muscle cells that act as the heart's pacemaker.

Step 4: Conclude that the human heart is myogenic because its contractions are initiated by the SA node, not by nerve impulses.

Why other options are wrong:
- Option B: Neurogenic hearts are found in some invertebrates, where nerve impulses initiate contractions.
- Option C: Cardiogenic refers to the origin of the heart during embryonic development, not the mechanism of heart beat initiation.
- Option D: Digenic is not a relevant term in this context.

Key Concepts:
- Myogenic Heart
- Neurogenic Heart
- Sinoatrial (SA) Node

Memory Aids:
- Myo = Muscle (myogenic heart is muscle-driven).

Quick Tips:
- Remember the SA node as the heart's natural pacemaker.

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Chordae tendinae

View answer and explanation

Correct option: C

Prevent the AV valves flaps from everting

Option C (Prevent the AV valves flaps from everting) is correct because chordae tendinae prevent the atrioventricular (AV) valve flaps from prolapsing back into the atria during ventricular contraction.

Solution approach

Correct Answer + Core Reason: Prevent the AV valves flaps from everting. Chordae tendinae prevent the atrioventricular (AV) valve flaps from prolapsing back into the atria during ventricular contraction.

Step-by-Step Solution:

Step 1: Define chordae tendinae and their location.

Step 2: Recall that chordae tendinae are fibrous cords that connect the AV valves to the papillary muscles in the ventricles.

Step 3: Understand that their primary function is to prevent the valve flaps from inverting into the atria during ventricular contraction.

Why other options are wrong:
- Option A: Incorrect because chordae tendinae are *close* to AV valves, and are connected to them.
- Option B: Incorrect because semilunar valves open due to pressure differences, not chordae tendinae.
- Option D: Incorrect because chordae tendinae are located in the ventricles, not the auricles (atria).

Key Concepts:
- Chordae tendinae
- Atrioventricular (AV) valves
- Valve function
- Ventricular contraction

Memory Aids:
- Chordae = cords
- Tendinae = tendons
- Prevent eversion = prevent flipping back

Quick Tips:
- Visualize the heart's structure and the function of its components.

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

View answer and explanation

Correct option: D

Pulse will rise and BP will fall.

Option D (Pulse will rise and BP will fall) is correct because the body attempts to compensate for blood loss by increasing heart rate (pulse) while blood pressure drops due to decreased blood volume.

Solution approach

Correct Answer + Core Reason: Pulse will rise and BP will fall. This is the body's initial response to blood loss.

Step-by-Step Solution:

Step 1: Understand the body's response to blood loss.

Step 2: When a person loses blood, the blood volume decreases. This leads to a drop in blood pressure (BP).

Step 3: To compensate for the reduced blood volume and maintain blood flow to vital organs, the heart rate increases, leading to a rise in pulse.

Step 4: Therefore, initially, the pulse will rise, and the BP will fall.

Why other options are wrong:
- Option A: Pulse and BP both will fall: While BP will fall, the pulse will initially rise as a compensatory mechanism.
- Option B: Pulse will fall and BP will rise: This is the opposite of what happens initially. BP falls due to blood loss, and pulse rises to compensate.
- Option C: Both pulse and BP will rise: While the body tries to compensate, the initial effect of blood loss is a drop in BP.

Key Concepts:
- Blood pressure regulation
- Heart rate regulation
- Physiological response to blood loss

Memory Aids:
- Think of the body trying to "catch up" after blood loss: Heart rate increases to compensate for the falling blood pressure.

Quick Tips:
- Remember that the body has compensatory mechanisms to maintain homeostasis during blood loss.

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Which one of the following is a matching pair of a certain body feature and its value/count in a normal human adult?

View answer and explanation

Correct option: B

Blood sugar - 70 – 100 mg/100 mL
(fasting)

Option B is correct because the normal fasting blood sugar level in a healthy human adult ranges from 70 to 100 mg/100 mL.

Solution approach

Correct Answer + Core Reason: Blood sugar - 70 – 100 mg/100 mL (fasting). This range represents the normal fasting blood glucose level in humans.

Step-by-Step Solution:

Step 1: Understand the question. The question asks for a matching pair of a body feature and its normal value in a human adult.

Step 2: Evaluate each option.

Step 3: Option A: Urea levels are typically higher than 5-10 mg/100 mL.\nOption B: Fasting blood sugar levels are normally between 70-100 mg/100 mL.\nOption C: Total blood volume is usually 5-6 liters, not just 5-6.\nOption D: ESR values are different for males and females, but the given range is incorrect.

Step 4: Select the correct option based on normal physiological values.

Why other options are wrong:
- Option A: Urea levels are typically higher than 5-10 mg/100 mL. This value is too low for normal blood urea levels.
- Option C: Total blood volume is usually expressed in liters (5-6 liters), not as a dimensionless number.
- Option D: The ESR range provided is not accurate for Wintrobe method. Normal ESR values vary with age and sex, and the given ranges are incorrect.

Key Concepts:
- Normal physiological values
- Blood glucose regulation
- Urea levels in blood
- Erythrocyte sedimentation rate (ESR)
- Blood volume

Memory Aids:
- Remember the normal ranges for common blood tests.

Quick Tips:
- Familiarize yourself with normal physiological values to quickly identify incorrect options.

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