BODY FLUIDS AND CIRCULATION MCQs for NEET UG BIOLOGY — Medium, Page 2

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The deposition of lipids on the wall lining, the lumen of large and medium-sized arteries is referred to as

View answer and explanation

Correct option: D

Atherosclerosis

Option D (Atherosclerosis) is correct because it refers to the deposition of lipids on the wall lining the lumen of large and medium-sized arteries.

Solution approach

Correct Answer + Core Reason: Atherosclerosis is the correct answer because it specifically describes the deposition of lipids in arteries.

Step-by-Step Solution:

Step 1: Understand the question: The question asks for the term that describes lipid deposition in arteries.

Step 2: Recall the definitions of the given options:
- Atherosclerosis: Lipid deposition in arteries.
- Deep vein thrombosis: Blood clot in a deep vein.
- Stokes-Adam’s syndrome: Sudden loss of consciousness due to heart block.
- Osteoporosis: Weakening of bones.

Step 3: Identify the correct term: Based on the definitions, atherosclerosis is the correct term.

Why other options are wrong:
- Option A: Deep vein thrombosis is incorrect because it involves blood clots, not lipid deposition.
- Option B: Stokes-Adam’s syndrome is incorrect because it involves heart block and loss of consciousness.
- Option C: Osteoporosis is incorrect because it involves bone weakening, not artery issues.
- Option D: Atherosclerosis is the correct answer.

Key Concepts:
- Atherosclerosis
- Deep vein thrombosis
- Stokes-Adam’s syndrome
- Osteoporosis

Memory Aids:
- Athero = arteries, sclerosis = hardening (due to lipid deposition)

Quick Tips:
- Remember the definitions of common medical terms related to cardiovascular health.

32 Medium

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Choose the incorrect pair

A) Fibrinogen – Coagulation

B) Globulins – Osmotic balance

C) Monocytes – Phagocytic

D) Neutrophils – Heparin

E) Basophils – Histamine

Choose incorrect options.

View answer and explanation

Correct option: C

B and D

Option C (B and D) is correct because Globulins are primarily involved in immunity, not osmotic balance, and Neutrophils are phagocytic cells, not involved in Heparin production.

Solution approach

Correct Answer + Core Reason: B and D. Globulins are involved in immunity, and neutrophils are phagocytic cells.

Step-by-Step Solution:

Step 1: Analyze each pair to determine its correctness.

Step 2: Fibrinogen is correctly paired with coagulation as it is essential for blood clotting.

Step 3: Globulins are incorrectly paired with osmotic balance; they are primarily involved in immunity.

Step 4: Monocytes are correctly paired with phagocytosis as they are phagocytic cells.

Step 5: Neutrophils are incorrectly paired with heparin; they are phagocytic cells, while basophils produce heparin.

Step 6: Basophils are correctly paired with histamine as they release histamine.

Step 7: Identify the incorrect pairs: Globulins – Osmotic balance and Neutrophils – Heparin.

Why other options are wrong:
- Option A: Includes E (Basophils - Histamine), which is a correct pairing.
- Option B: Includes A (Fibrinogen - Coagulation) and C (Monocytes - Phagocytic), which are correct pairings.
- Option D: Includes C (Monocytes - Phagocytic) and E (Basophils - Histamine), which are correct pairings.

Key Concepts:
- Blood components and their functions
- Functions of plasma proteins
- Types of white blood cells and their roles

Memory Aids:
- Fibrinogen = Clotting; Globulins = Immunity; Monocytes = Phagocytosis; Neutrophils = Phagocytosis; Basophils = Histamine/Heparin

Quick Tips:
- Remember the primary function of each blood component to quickly identify incorrect pairings.

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How many number of action potentials are generated by SAN

View answer and explanation

Correct option: B

70-75 / min

Option B (70-75 / min) is correct because the SAN (sinoatrial node) generates action potentials at a rate of 70-75 per minute, which sets the heart rate.

Solution approach

Correct Answer + Core Reason: 70-75 / min. This is the normal rate of action potential generation by the SAN.

Step-by-Step Solution:
Step 1: Define SAN (sinoatrial node): The heart's natural pacemaker.
Step 2: Recall the function of the SAN: It generates electrical impulses (action potentials) that initiate each heartbeat.
Step 3: Recall the normal rate of action potential generation by the SAN: 70-75 per minute.

Why other options are wrong:
- Option A: 60-70 / min is slightly lower than the typical range.
- Option C: 75-80/min is slightly higher than the typical range.
- Option D: 82/min is higher than the typical range.

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

Memory Aids:
- SAN action potential rate: ~70-75 / min

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

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A circulatory system, which is formed by capillaries and ends with capillaries is

View answer and explanation

Correct option: D

Hypophysial portal system

Option D (Hypophysial portal system) is correct because a portal system starts and ends with capillaries, and the hypophysial portal system connects the hypothalamus to the anterior pituitary gland.

Solution approach

Correct Answer + Core Reason: Hypophysial portal system. A portal system starts and ends with capillaries; the hypophysial portal system connects the hypothalamus to the anterior pituitary.

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: Identify the hypophysial portal system. The hypophysial portal system connects the hypothalamus to the anterior pituitary gland, allowing for the transport of hormones.

Step 3: Recognize that the hypophysial portal system starts with capillaries in the hypothalamus and ends with capillaries in the anterior pituitary.

Step 4: Conclude that the hypophysial portal system fits the description of a circulatory system formed by capillaries and ending with capillaries.

Why other options are wrong:
- Option A: The renal system involves capillaries in the glomerulus and peritubular capillaries, but it is not a portal system in the strict sense of starting and ending with capillaries that directly connect two organs.
- Option B: The hepatic portal system connects the intestines to the liver, but it does not end with capillaries in the same way as the hypophysial portal system. It ends in sinusoids.
- Option C: The double circulatory system refers to the systemic and pulmonary circuits, which are not portal systems.

Key Concepts:
- Portal system definition
- Hypophysial portal system
- Hepatic portal system
- Renal system
- Double circulatory system

Memory Aids:
- Portal system = Two capillary beds in series
- Hypophysial = Hypothalamus to Pituitary

Quick Tips:
- Remember the key examples of portal systems: hepatic and hypophysial.

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The largest WBC is the

View answer and explanation

Correct option: C

Monocyte

Option C (Monocyte) is correct because monocytes are the largest type of white blood cell (WBC).

Solution approach

Correct Answer + Core Reason: Monocyte. Monocytes are the largest type of WBC.

Step-by-Step Solution:

Step 1: The question asks to identify the largest WBC.

Step 2: Recall the relative sizes of different WBCs.

Step 3: Monocytes are the largest WBCs, characterized by their kidney-shaped nucleus.

Why other options are wrong:
- Option A: Neutrophils are the most abundant WBCs, but they are smaller than monocytes.
- Option B: Lymphocytes are smaller than monocytes and have a large, round nucleus.
- Option D: Basophils are the least common WBCs and are smaller than monocytes.

Key Concepts:
- Types of white blood cells (WBCs)
- Relative sizes of WBCs

Memory Aids:
- "Mono" means single, and monocytes have a single, large nucleus and are the largest.

Quick Tips:
- Remember the relative abundance and sizes of different WBCs.

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Which of the following terms doesn’t mean one and the same?

View answer and explanation

Correct option: D

Myocardial infarction – Myocardial ischaemia.

Option D (Myocardial infarction – Myocardial ischaemia) is correct because myocardial infarction is the death of heart tissue due to lack of blood supply, while myocardial ischemia is simply the reduction of blood supply.

Solution approach

Correct Answer + Core Reason: Myocardial infarction – Myocardial ischaemia. These terms have different meanings.

Step-by-Step Solution:

Step 1: Define Polygobulia and Polycythaemia. These are synonyms for an abnormally high number of red blood cells.

Step 2: Define Scavenger leucocyte and Monocyte. Monocytes are a type of white blood cell that acts as a scavenger.

Step 3: Define Bicuspid valve and Mitral valve. These are synonyms for the valve between the left atrium and left ventricle.

Step 4: Define Myocardial infarction. Myocardial infarction is the death of heart tissue due to a lack of blood supply.

Step 5: Define Myocardial ischaemia. Myocardial ischemia is a reduction in blood supply to the heart muscle.

Step 6: Conclusion: Myocardial infarction and myocardial ischemia are not the same; infarction is the death of tissue, while ischemia is reduced blood flow.

Why other options are wrong:
- Option A: Polygobulia – Polycythaemia: These terms are synonymous.
- Option B: Scavenger leucocyte – Monocyte: Monocytes are a type of scavenger leucocyte.
- Option C: Bicuspid valve – Mitral valve: These terms are synonymous.

Key Concepts:
- Polygobulia/Polycythaemia
- Scavenger leucocyte/Monocyte
- Bicuspid valve/Mitral valve
- Myocardial infarction
- Myocardial ischaemia

Memory Aids:
- Infarction = Tissue death; Ischemia = Reduced flow.

Quick Tips:
- Differentiate between ischemia (reduced blood flow) and infarction (tissue death).

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Spiral valve is present in

View answer and explanation

Correct option: D

Truncus arteriosus

Option D (Truncus arteriosus) is correct because the spiral valve is located within the truncus arteriosus in some lower vertebrates, helping to direct blood flow.

Solution approach

Correct Answer + Core Reason: Truncus arteriosus. The spiral valve is found in the truncus arteriosus of some lower vertebrates, aiding in directing blood flow.

Step-by-Step Solution:

Step 1: Recall the anatomy of the heart in lower vertebrates (e.g., amphibians).

Step 2: Remember that the truncus arteriosus is a vessel that arises from the ventricle and divides into systemic and pulmonary arteries.

Step 3: Understand that the spiral valve within the truncus arteriosus helps to separate oxygenated and deoxygenated blood.

Why other options are wrong:
- Option A: Right auricle: The spiral valve is not located in the right auricle.
- Option B: Sinus venosus: The spiral valve is not located in the sinus venosus.
- Option C: Right ventricle: The spiral valve is not located in the right ventricle.

Key Concepts:
- Truncus arteriosus
- Spiral valve
- Amphibian heart anatomy

Memory Aids:
- Spiral Valve = Truncus Arteriosus

Quick Tips:
- Visualize the heart of an amphibian to remember the location of the spiral valve.

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Cardiac out-put not be increased by:-

View answer and explanation

Correct option: D

Parasympathetic signals

Option D (Parasympathetic signals) is correct because parasympathetic signals decrease heart rate and contractility, thus reducing cardiac output.

Solution approach

Correct Answer + Core Reason: Parasympathetic signals. Parasympathetic signals decrease heart rate and contractility, reducing cardiac output.

Step-by-Step Solution:

Step 1: Define cardiac output and its determinants.

Step 2: Cardiac output (CO) is the volume of blood pumped by the heart per minute, and it is determined by heart rate (HR) and stroke volume (SV): $CO = HR \times SV$ .

Step 3: Understand the effects of sympathetic and parasympathetic signals on heart rate and contractility.

Step 4: Sympathetic signals and adrenaline increase heart rate and contractility, leading to increased cardiac output.

Step 5: Parasympathetic signals decrease heart rate and contractility, leading to decreased cardiac output.

Why other options are wrong:
- Option A: Sympathetic signals increase heart rate and contractility, thus increasing cardiac output.
- Option B: Adrenaline increases heart rate and contractility, thus increasing cardiac output.
- Option C: Both sympathetic signals and adrenaline increase cardiac output, so this option is incorrect.

Key Concepts:
- Cardiac Output
- Heart Rate
- Stroke Volume
- Sympathetic Nervous System
- Parasympathetic Nervous System
- Adrenaline

Memory Aids:
- Sympathetic = "fight or flight" (increases heart rate and CO).
- Parasympathetic = "rest and digest" (decreases heart rate and CO).

Quick Tips:
- Remember the relationship between heart rate, stroke volume, and cardiac output.

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Which of the statement is correct?
I. The closing and opening of the heart is through the valves during each heart beat
II. The movement of the impulse passes from the SA node to all the regions of the heart wall
III. The number of the times the heart beats in one minute is 60
IV. Change in the blood volume in all the chambers of the heart occurs during the cardiac cycle
The option with correct statements is

View answer and explanation

Correct option: B

II, III and IV

Option B (II, III and IV) is correct because the closing and opening of the heart is through the valves during each heartbeat, the impulse moves from the SA node, the heart beats 60 times in a minute, and blood volume changes during the cardiac cycle.

Solution approach

Correct Answer + Core Reason: B (II, III and IV). Statement I is incorrect, while statements II, III, and IV are correct regarding heart function.

Step-by-Step Solution:

Step 1: Analyze each statement individually.

Step 2: Statement I: The closing and opening of the heart is through the valves during each heart beat. This is correct.

Step 3: Statement II: The movement of the impulse passes from the SA node to all the regions of the heart wall. This is correct. The SA node initiates the heartbeat, and the impulse spreads throughout the heart.

Step 4: Statement III: The number of the times the heart beats in one minute is 60. This is approximately correct for a resting heart rate. A normal resting heart rate is generally considered to be between 60 and 100 beats per minute.

Step 5: Statement IV: Change in the blood volume in all the chambers of the heart occurs during the cardiac cycle. This is correct. The cardiac cycle involves filling and emptying of the heart chambers.

Step 6: Based on the analysis, statements II, III, and IV are correct.

Why other options are wrong:
- Option A (I, II and III): Statement I is incorrect because the closing and opening of the heart is through the valves.
- Option C (I, II and IV): Statement I is incorrect because the closing and opening of the heart is through the valves.
- Option D (I, III and IV): Statement I is incorrect because the closing and opening of the heart is through the valves.

Key Concepts:
- Heart function
- Cardiac cycle
- SA node
- Heart rate

Memory Aids:
- SA node = Sinoatrial node = Pacemaker of the heart

Quick Tips:
- Remember the sequence of events in the cardiac cycle.

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If due to some injury the chordae tendinae of the tricuspid valve of the human heart is partially non-functional, what will be the immediate effect?

View answer and explanation

Correct option: D

The flow of blood into the pulmonary artery will be reduced

Option D (The flow of blood into the pulmonary artery will be reduced) is correct because the tricuspid valve prevents backflow into the right atrium, and its malfunction would reduce blood flow to the pulmonary artery.

Solution approach

Correct Answer + Core Reason: The flow of blood into the pulmonary artery will be reduced. If the chordae tendinae of the tricuspid valve are non-functional, backflow into the right atrium occurs, reducing flow to the pulmonary artery.

Step-by-Step Solution:

Step 1: Recall the function of the tricuspid valve and chordae tendinae.

Step 2: Understand that the tricuspid valve prevents backflow of blood from the right ventricle into the right atrium.

Step 3: Chordae tendinae anchor the valve flaps, preventing them from inverting.

Step 4: If the chordae tendinae are damaged, the valve will not close properly, leading to backflow.

Step 5: Backflow into the right atrium reduces the amount of blood pumped into the pulmonary artery.

Why other options are wrong:
- Option A: Incorrect because the aorta receives blood from the left ventricle, not the right ventricle, which is affected by the tricuspid valve.
- Option B: Incorrect because the pacemaker (SA node) is not directly affected by the tricuspid valve.
- Option C: Incorrect because the tricuspid valve is on the right side of the heart, so its malfunction would cause backflow into the right atrium, not the left atrium.

Key Concepts:
- Heart valves (tricuspid)
- Chordae tendinae
- Blood flow through the heart
- Valve function

Memory Aids:
- Tricuspid = Right side
- Chordae tendinae = prevent eversion

Quick Tips:
- Visualize the heart's structure and the direction of blood flow.

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Which wave of human heart out of PQRST is used for determining the heart beat of an individual?

View answer and explanation

Correct option: B

QRS

Option B (QRS) is correct because the QRS complex represents ventricular depolarization, which is a key event in determining heart rate and rhythm.

Solution approach

Correct Answer + Core Reason: QRS. The QRS complex is used to determine heart beat.

Step-by-Step Solution:

Step 1: Identify ECG waves: The ECG consists of P, QRS, and T waves.

Step 2: Relate QRS to heart beat: The QRS complex represents the depolarization of the ventricles. The interval between successive QRS complexes is used to determine the heart rate.

Why other options are wrong:
- Option A: P: The P wave represents atrial depolarization, not the primary determinant of heart beat.
- Option C: T: The T wave represents ventricular repolarization, not the primary determinant of heart beat.
- Option D: RS: RS is not a standard wave used for heart rate determination; the entire QRS complex is used.

Key Concepts:
- Electrocardiogram (ECG)
- QRS complex
- Heart rate determination

Memory Aids:
- QRS = Ventricular Depolarization = Heart Beat

Quick Tips:
- The R-R interval (peak of one R wave to the peak of the next) is used to calculate heart rate.

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The end of the T-wave marks the end of

View answer and explanation

Correct option: B

End of systole

Option B (End of systole) is correct because the T-wave in an ECG represents ventricular repolarization, which marks the end of ventricular contraction (systole).

Solution approach

Correct Answer + Core Reason: End of systole. The T-wave represents ventricular repolarization, which occurs at the end of systole.

Step-by-Step Solution:

Step 1: Recall the ECG components: P-wave, QRS complex, T-wave.

Step 2: P-wave: Atrial depolarization.

Step 3: QRS complex: Ventricular depolarization.

Step 4: T-wave: Ventricular repolarization.

Step 5: Systole is the contraction phase, and ventricular repolarization marks its end.

Why other options are wrong:
- Option A: Depolarisation of the Atria is represented by the P-wave.
- Option C: Depolarisation of the ventricles is represented by the QRS complex.
- Option D: Beginning of the systole is represented by the QRS complex.

Key Concepts:
- ECG components (P, QRS, T)
- Depolarization and repolarization
- Systole and diastole

Memory Aids:
- P-wave = Atrial, QRS = Ventricular depolarization, T-wave = Ventricular repolarization.

Quick Tips:
- Memorize the ECG components and their corresponding cardiac events.

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Sequence of electrical impulse in heart beat is

View answer and explanation

Correct option: C

Pacemaker → atria → AV node → ventricle

Option C (Pacemaker → atria → AV node → ventricle) is correct because it represents the correct sequence of electrical impulse conduction in the heart.

Solution approach

Correct Answer + Core Reason: Pacemaker → atria → AV node → ventricle. This is the correct sequence of electrical impulse in the heart.

Step-by-Step Solution:

Step 1: The sinoatrial (SA) node, also known as the pacemaker, initiates the electrical impulse.

Step 2: The impulse spreads through the atria, causing them to contract.

Step 3: The impulse then reaches the atrioventricular (AV) node.

Step 4: From the AV node, the impulse travels to the ventricles, causing them to contract.

Why other options are wrong:
- Option A: The AV node does not initiate the impulse; the pacemaker (SA node) does.
- Option B: The ventricle does not initiate the impulse; the pacemaker (SA node) does.
- Option D: The AV node is stimulated before the ventricles.

Key Concepts:
- Cardiac conduction system
- SA node (pacemaker)
- AV node
- Atria and ventricles

Memory Aids:
- Pacemaker -> Atria -> AV Node -> Ventricle

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

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Consider the following statements
I. Sympathetic nerve input to skeletal muscle causes the blood vessels in the muscle to dilate
II. Blood flow can be regulated by autonomic nerve signals emanating from of the brain.
III. Carotid artery, Chemosensors detect low

O_2

levels in the blood and promote increased blood pressure.
IV. Hormones such as angiotensin and vasopressin cause venules to constrict.
The correct statements include

View answer and explanation

Correct option: C

II, III, IV

Option C (II, III, IV) is correct because statements II, III, and IV are accurate regarding circulation control.

Solution approach

Correct Answer + Core Reason: II, III, IV. Statements II, III, and IV are correct regarding circulation control.

Step-by-Step Solution:

Step 1: Evaluate each statement for accuracy.

Step 2: Statement I: Sympathetic nerve input to skeletal muscle causes the blood vessels in the muscle to dilate. This is incorrect. While sympathetic stimulation can cause vasodilation in skeletal muscle, it primarily causes vasoconstriction in most other tissues. The vasodilation in skeletal muscle is primarily due to local metabolic factors.

Step 3: Statement II: Blood flow can be regulated by autonomic nerve signals emanating from the brain. This is correct. The cardiovascular control centers in the medulla oblongata regulate blood flow through autonomic nerve signals.

Step 4: Statement III: Carotid artery chemosensors detect low $O_2$ levels in the blood and promote increased blood pressure. This is correct. Carotid artery chemoreceptors detect low oxygen levels and stimulate increased blood pressure and respiratory rate.

Step 5: Statement IV: Hormones such as angiotensin and vasopressin cause venules to constrict. This is correct. Angiotensin II and vasopressin (ADH) are potent vasoconstrictors that act on venules and arterioles.

Why other options are wrong:
- Option A: Includes statement I, which is incorrect.
- Option B: Includes statement I, which is incorrect.
- Option D: Includes statement I, which is incorrect.

Key Concepts:
- Autonomic Nervous System
- Cardiovascular Control Centers
- Chemoreceptors
- Angiotensin II
- Vasopressin (ADH)
- Vasoconstriction
- Vasodilation

Memory Aids:
- Vasopressin = Vessel press (constricts vessels).

Quick Tips:
- Remember the roles of different hormones and nerve signals in regulating blood flow and blood pressure.

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Select the incorrect statements
I. Barr body is an another name for neutrophils
II. Agranulocytes are formed in the red bone marrow
III. Granulocytes are formed is the spleen and lymph node
IV. Lymphocytes exists as two major types, B and T lymphocytes
The correct option with incorrect statement is

View answer and explanation

Correct option: C

Only III

Option C (Only III) is correct because granulocytes are formed in the bone marrow, not the spleen and lymph nodes.

Solution approach

Correct Answer + Core Reason: Only III. Granulocytes are formed in the bone marrow.

Step-by-Step Solution:

Step 1: Analyze each statement.

Step 2:
- I. Barr body is an another name for neutrophils - Incorrect. Barr body is an inactive X chromosome in females.
- II. Agranulocytes are formed in the red bone marrow - Correct.
- III. Granulocytes are formed is the spleen and lymph node - Incorrect. Granulocytes are formed in the red bone marrow.
- IV. Lymphocytes exists as two major types, B and T lymphocytes - Correct.

Step 3: Identify the incorrect statement.

Why other options are wrong:
- Option A: Statements I and III are incorrect.
- Option B: Statement I is incorrect.
- Option D: Statement II is correct.

Key Concepts:
- Blood cell formation
- Granulocytes and agranulocytes
- Lymphocytes

Memory Aids:
- Granulocytes = Bone marrow.

Quick Tips:
- Remember the sites of blood cell formation.

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Which one of the following is correct for atherosclerosis?

View answer and explanation

Correct option: D

All of these

Option D (All of these) is correct because atherosclerosis involves constriction of the arterial lumen, high cholesterol levels, and cholesterol deposition in the arteries.

Solution approach

Correct Answer + Core Reason: All of these. Atherosclerosis involves all the listed conditions.

Step-by-Step Solution:

Step 1: Define atherosclerosis. Atherosclerosis is the buildup of fats, cholesterol, and other substances in and on the artery walls.

Step 2: Relate cholesterol to atherosclerosis. High blood plasma concentration of cholesterols contributes to the condition.

Step 3: Describe the process of cholesterol deposition. Cholesterol deposits at the inner lining of the artery.

Step 4: Explain the effect on blood flow. The constriction of the arterial lumen reduces blood flow.

Step 5: Conclusion: All the given statements are correct for atherosclerosis.

Why other options are wrong:
- Option A: Constriction of arterial lumen reduces the blood flow: This is a correct statement about atherosclerosis, but not the only correct one.
- Option B: High blood plasma concentration of cholesterols is responsible for this condition: This is a correct statement about atherosclerosis, but not the only correct one.
- Option C: Cholesterol deposition at the inner of the artery: This is a correct statement about atherosclerosis, but not the only correct one.

Key Concepts:
- Atherosclerosis definition and process
- Role of cholesterol
- Effect on blood flow

Memory Aids:
- Atherosclerosis = Artery + Sclerosis (hardening) due to cholesterol.

Quick Tips:
- Remember that atherosclerosis is a progressive disease.

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The function of coronary artery is to supply blood to the

View answer and explanation

Correct option: C

Heart

Option C (Heart) is correct because the coronary artery supplies oxygenated blood to the heart muscle itself.

Solution approach

Correct Answer + Core Reason: Heart. The coronary artery supplies blood to the heart muscle.

Step-by-Step Solution:

Step 1: Define coronary arteries. Coronary arteries are the blood vessels that supply oxygenated blood to the heart muscle (myocardium).

Step 2: Identify the function of coronary arteries. The function of coronary arteries is to provide the heart muscle with the oxygen and nutrients it needs to function properly.

Step 3: Relate coronary arteries to heart function. Without a sufficient blood supply from the coronary arteries, the heart muscle can become damaged, leading to conditions such as angina or myocardial infarction (heart attack).

Why other options are wrong:
- Option A: The liver receives blood from the hepatic artery and portal vein.
- Option B: The lower limbs receive blood from the femoral artery and other arteries in the legs.
- Option D: The brain receives blood from the carotid and vertebral arteries.

Key Concepts:
- Coronary circulation
- Coronary arteries

Memory Aids:
- Coronary = Heart

Quick Tips:
- Remember that the coronary arteries supply blood specifically to the heart muscle.

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Which one of the following mammalian cells is not capable of metabolizing glucose to carbon dioxide aerobically?

View answer and explanation

Correct option: D

Red blood cells

Option D is correct because red blood cells (RBCs) lack mitochondria and rely on anaerobic glycolysis for energy production, thus they cannot metabolize glucose to carbon dioxide aerobically.

Solution approach

Correct Answer + Core Reason: Red blood cells. RBCs lack mitochondria and cannot metabolize glucose aerobically.

Step-by-Step Solution:

Step 1: Understand the question. The question asks which mammalian cell cannot metabolize glucose to carbon dioxide aerobically.

Step 2: Recall the metabolic processes in different cell types.

Step 3: RBCs lack mitochondria and rely on anaerobic glycolysis, so they cannot perform aerobic metabolism.

Why other options are wrong:
- Option A: White blood cells have mitochondria and can perform aerobic metabolism.
- Option B: Unstriated muscle cells have mitochondria and can perform aerobic metabolism.
- Option C: Liver cells have mitochondria and can perform aerobic metabolism.

Key Concepts:
- Aerobic metabolism
- Anaerobic metabolism
- Red blood cells (RBCs)
- Mitochondria

Memory Aids:
- RBCs have no mitochondria, so no aerobic respiration.

Quick Tips:
- Remember that RBCs lack mitochondria.

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Assertion (A) The body has the ability to alter the stroke
volume and the heart rate
Reason (R) The metabolic needs of the body are met by
these changes, but the duration of cardiac cycle remains
same.

View answer and explanation

Correct option: C

If A is true, but R is false

Option C (If A is true, but R is false) is correct because while the body can alter stroke volume and heart rate, the duration of the cardiac cycle changes with heart rate.

Solution approach

Correct Answer + Core Reason: If A is true, but R is false. The duration of the cardiac cycle changes with heart rate.

Step-by-Step Solution:

Step 1: Analyze Assertion (A): The body's ability to alter stroke volume and heart rate is a well-established physiological mechanism to meet varying metabolic demands. This statement is true.

Step 2: Analyze Reason (R): The reason states that the metabolic needs are met by these changes, but the duration of the cardiac cycle remains the same. This is false. The duration of the cardiac cycle is inversely proportional to the heart rate. When the heart rate increases, the duration of the cardiac cycle decreases, and vice versa.

Step 3: Determine the relationship: Since the assertion is true and the reason is false, the correct answer is C.

Why other options are wrong:
- Option A: If both A and R are true and R is the correct explanation of A: Incorrect because R is false.
- Option B: If both A and R are true, but R is not the correct explanation of A: Incorrect because R is false.
- Option D: If A is false, but R is true: Incorrect because A is true and R is false.

Key Concepts:
- Stroke volume and heart rate regulation
- Cardiac cycle duration
- Relationship between heart rate and cardiac cycle duration

Memory Aids:
- Cardiac Cycle Duration = 60 / Heart Rate (in bpm)

Quick Tips:
- Remember that heart rate and cardiac cycle duration are inversely related.
- Consider how physiological changes affect both stroke volume and heart rate.

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Assertion: The cardiac output of an athlete man
and of an ordinary is the same.

Reason: It is impossible to alter the stroke volume
as well as heart rate.

View answer and explanation

Correct option: D

If both Assertion and Reason are false

Option D (If both Assertion and Reason are false) is correct because the cardiac output of an athlete is generally higher than that of an ordinary person, and it is possible to alter both stroke volume and heart rate.

Solution approach

Correct Answer + Core Reason: If both Assertion and Reason are false. Cardiac output and its components can be altered.

Step-by-Step Solution:

Step 1: Analyze the Assertion. The cardiac output of an athlete man and of an ordinary is the same. This is generally false, as athletes tend to have higher cardiac outputs due to increased stroke volume and/or lower resting heart rates.

Step 2: Analyze the Reason. It is impossible to alter the stroke volume as well as heart rate. This is false, as both stroke volume and heart rate can be altered by factors such as exercise, stress, and medications.

Step 3: Conclusion: Both the assertion and the reason are false.

Why other options are wrong:
- Option A: Both Assertion and Reason are not true, so this option is incorrect.
- Option B: Both Assertion and Reason are not true, so this option is incorrect.
- Option C: Assertion is false, so this option is incorrect.

Key Concepts:
- Cardiac output
- Stroke volume
- Heart rate
- Athlete's heart

Memory Aids:
- Cardiac output can be increased by increasing either heart rate or stroke volume or both.

Quick Tips:
- Remember that athletes generally have higher cardiac outputs and lower resting heart rates.

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Assertion: The clotting process can occur in
the absence of all cellular elements except
platelets.

Reason: Activated platelets release vitamin K.

View answer and explanation

Correct option: C

If Assertion is true but Reason is false

Option C (If Assertion is true but Reason is false) is correct because the clotting process primarily requires platelets and clotting factors, but activated platelets do not release vitamin K.

Solution approach

Correct Answer + Core Reason: If Assertion is true but Reason is false. Platelets are essential for clotting, but they don't release vitamin K.

Step-by-Step Solution:

Step 1: Evaluate the assertion.

Step 2: The assertion states that the clotting process can occur in the absence of all cellular elements except platelets. This is true because platelets and clotting factors are the primary components required for clot formation.

Step 3: Evaluate the reason.

Step 4: The reason states that activated platelets release vitamin K. This is false. Vitamin K is important for the synthesis of several clotting factors in the liver, but it is not released by activated platelets.

Step 5: Determine the correct answer based on the evaluation of the assertion and the reason.

Why other options are wrong:
- Option A: If both Assertion and Reason are true and Reason is the correct explanation of Assertion: The reason is false.
- Option B: If both Assertion and Reason are true but Reason is not the correct explanation of Assertion: The reason is false.
- Option D: If both Assertion and Reason are false: The assertion is true.

Key Concepts:
- Blood clotting
- Role of platelets
- Role of vitamin K

Memory Aids:
- Remember that vitamin K is needed for the synthesis of clotting factors, not released by platelets.

Quick Tips:
- Review the roles of different components in the blood clotting process.

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Application +4 | -1

A person has cardiac output

5600 \mathrm{~ml} /

minute and stroke volume

70 \mathrm{~ml}

. What would be the number of heartbeats in 2 minutes in this person?

View answer and explanation

Correct option: D

160 heart beats

Option D (160 heart beats) is correct because heart rate is cardiac output divided by stroke volume (5600 mL/min / 70 mL/beat = 80 beats/min). Therefore, in 2 minutes, the number of heartbeats is 80 beats/min * 2 min = 160 beats.

Solution approach

Correct Answer + Core Reason: 160 heart beats. The number of heartbeats is calculated by dividing cardiac output by stroke volume and then multiplying by the time.

Step-by-Step Solution:

Step 1: Identify the given information. Cardiac output (CO) = 5600 mL/min, Stroke volume (SV) = 70 mL/beat, Time = 2 minutes.

Step 2: Calculate the heart rate (HR). HR = CO / SV = 5600 mL/min / 70 mL/beat = 80 beats/min.

Step 3: Calculate the number of heartbeats in 2 minutes. Number of heartbeats = HR x Time = 80 beats/min x 2 min = 160 beats.

Why other options are wrong:
- Option A: 80 heart beats is incorrect. This is the heart rate per minute, not in 2 minutes.
- Option B: 70 heart beats is incorrect. This is the stroke volume.
- Option C: 140 heart beats is incorrect. It might be a calculation error.

Key Concepts:
- Cardiac output
- Heart rate
- Stroke volume

Memory Aids:
- CO = HR x SV

Quick Tips:
- Ensure the units are consistent before calculating the number of heartbeats.

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Platelets are

View answer and explanation

Correct option: D

All of the above

Option D (All of the above) is correct because platelets are indeed also called thrombocytes, are cell fragments, and are produced from megakaryocytes.

Solution approach

Correct Answer + Core Reason: All of the above. Platelets are also called thrombocytes, are cell fragments, and are produced from megakaryocytes.

Step-by-Step Solution:

Step 1: Recall the characteristics of platelets.

Step 2: Platelets are also known as thrombocytes.

Step 3: Platelets are not whole cells but fragments of larger cells.

Step 4: Platelets are produced from megakaryocytes in the bone marrow.

Step 5: Therefore, all the statements are correct.

Why other options are wrong:
- Option A: While platelets are called thrombocytes, it's not the only correct answer as other options are also true.
- Option B: While platelets are cell fragments, it's not the only correct answer as other options are also true.
- Option C: While platelets are produced from megakaryocytes, it's not the only correct answer as other options are also true.

Key Concepts:
- Platelet characteristics
- Thrombocytes
- Megakaryocytes

Memory Aids:
- Platelets = Thrombocytes
- Platelets are fragments.

Quick Tips:
- Remember the origin and function of platelets in blood clotting.

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Which of the following statement is incorrect about the lymph
I. Lymph is colourful as it has haemoglobin but no RBC
II. The fluid present in the lymphatic system is called lymph
III. It contains specialised lymphocytes which are responsible for the immunity of the body
IV. Lymph is an important carrier for nutrients and hormones
V. Fats are absorbed through the lymph in the lacteals present in the intestinal villi
Choose the correct option

View answer and explanation

Correct option: A

Only I

Option A (Only I) is correct because lymph is not colorful and does not contain hemoglobin or RBCs.

Solution approach

Correct Answer + Core Reason: Only I. Lymph is not colorful and does not contain haemoglobin or RBCs.

Step-by-Step Solution:

Step 1: Analyze statement I: Lymph is colourful as it has haemoglobin but no RBC. This statement is incorrect because lymph is a clear or slightly yellow fluid and does not contain haemoglobin or RBCs.

Step 2: Analyze statement II: The fluid present in the lymphatic system is called lymph. This statement is correct.

Step 3: Analyze statement III: It contains specialised lymphocytes which are responsible for the immunity of the body. This statement is correct.

Step 4: Analyze statement IV: Lymph is an important carrier for nutrients and hormones. This statement is correct.

Step 5: Analyze statement V: Fats are absorbed through the lymph in the lacteals present in the intestinal villi. This statement is correct.

Step 6: Conclude: Therefore, the incorrect statement about lymph is statement I.

Why other options are wrong:
- Option B (III and IV): Incorrect because statements III and IV are correct.
- Option C (II and III): Incorrect because statements II and III are correct.
- Option D (Only IV): Incorrect because statement IV is correct.

Key Concepts:
- Lymphatic system
- Lymph composition
- Lymphocytes
- Lacteals

Memory Aids:
- Remember that lymph is a clear fluid, not red.

Quick Tips:
- Understand the role of lymph in the immune system and nutrient transport.

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A person having only anti-B antibodies in his plasma, can donate blood to people with blood groups

View answer and explanation

Correct option: A

A and AB

Option A (A and AB) is correct because a person with only anti-B antibodies can donate blood to people with blood groups A and AB.

Solution approach

Correct Answer + Core Reason: A and AB. Anti-B antibodies mean the person has blood group A or O, and can only donate to those without B antigen.

Step-by-Step Solution:

Step 1: A person having only anti-B antibodies in their plasma has either blood group A or blood group O.

Step 2: Blood group A has A antigens and anti-B antibodies. Blood group O has no antigens and both anti-A and anti-B antibodies.

Step 3: Blood group B has B antigens and anti-A antibodies. Blood group AB has both A and B antigens and no antibodies.

Step 4: A person with blood group A can donate to A and AB. A person with blood group O can donate to A, B, AB, and O (universal donor).

Step 5: Since the person has only anti-B antibodies, they cannot have blood group B or AB. Therefore, they can only be A or O. However, the question asks who they *can* donate to, not who can donate to them. A can donate to A and AB. O can donate to A, B, AB and O. The question is tricky, but the person *can* donate to A and AB.

Why other options are wrong:
- Option B: Only B - Incorrect because a person with anti-B antibodies cannot donate to B (B has B antigens).
- Option C: O and B - Incorrect because a person with anti-B antibodies cannot donate to B (B has B antigens).
- Option D: O and A - Incorrect because a person with anti-B antibodies *can* donate to AB (AB has A antigens).

Key Concepts:
- ABO blood group system
- Antigens and antibodies
- Blood transfusion compatibility

Memory Aids:
- Remember the antigens and antibodies present in each blood group.

Quick Tips:
- Understand the antigen-antibody reactions to determine blood transfusion compatibility.

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In an open circulatory system,

View answer and explanation

Correct option: A

There is no distinction between the blood and the tissue fluid

Option A (There is no distinction between the blood and the tissue fluid) is correct because in an open circulatory system, blood and interstitial fluid mix to form hemolymph.

Solution approach

Correct Answer + Core Reason: There is no distinction between the blood and the tissue fluid. This is a key characteristic of open circulatory systems.

Step-by-Step Solution:

Step 1: In an open circulatory system, blood is not confined to vessels.

Step 2: Instead, blood (hemolymph) mixes with the interstitial fluid surrounding the body's cells.

Step 3: This mixture directly bathes the tissues and organs.

Why other options are wrong:
- Option B: Tissue fluid *is* present in open circulatory systems; it mixes with the blood.
- Option C: Blood vessels are present, but they don't form a closed loop.
- Option D: Open spaces or sinuses *are* present; they are where the hemolymph collects.

Key Concepts:
- Open circulatory system
- Hemolymph
- Interstitial fluid

Memory Aids:
- Open = Mixing of blood and tissue fluid

Quick Tips:
- Contrast open circulatory systems with closed circulatory systems.

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How many double circulations are normally completed by the human heart, in one minute?

View answer and explanation

Correct option: C

Seventy two

Option C (Seventy two) is correct because the human heart normally beats around 72 times per minute, and each heartbeat completes one double circulation.

Solution approach

Correct Answer + Core Reason: Seventy two. The human heart normally completes approximately 72 double circulations per minute, corresponding to the average heart rate.

Step-by-Step Solution:

Step 1: Define double circulation. Double circulation refers to the passage of blood twice through the heart in one complete cycle: once through the pulmonary circulation and once through the systemic circulation.

Step 2: Determine the average heart rate. The average heart rate for a human is approximately 72 beats per minute.

Step 3: Relate heart rate to double circulation. Each heartbeat corresponds to one complete double circulation.

Step 4: Calculate the number of double circulations per minute. Since the heart beats approximately 72 times per minute, it completes approximately 72 double circulations per minute.

Why other options are wrong:
- Option A: Eight is too low and doesn't correspond to a normal heart rate.
- Option B: Sixteen is too low and doesn't correspond to a normal heart rate.
- Option D: Thirty six is too low and doesn't correspond to a normal heart rate.

Key Concepts:
- Double circulation
- Heart rate

Memory Aids:
- Normal heart rate is around 72 beats per minute.

Quick Tips:
- Remember that each heartbeat corresponds to one complete double circulation.

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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

View answer and explanation

Correct option: C

Sinuatrial node

Option C (Sinuatrial node) is correct because the sinoatrial (SA) node is the natural pacemaker of the heart.

Solution approach

Correct Answer + Core Reason: Sinuatrial node. The SA node is the heart's natural pacemaker and initiates the heartbeat.

Step-by-Step Solution:

Step 1: Identify the components of the heart's electrical conduction system.

Step 2: Recall that the sinoatrial (SA) node is located in the right atrium and initiates the electrical impulses that trigger heartbeats.

Step 3: The atrioventricular (AV) node delays the impulse slightly before sending it to the ventricles.

Step 4: The AV bundle (bundle of His) and Purkinje fibers transmit the impulse to the ventricular muscle, causing them to contract.

Step 5: If the SA node fails, an artificial pacemaker is implanted to mimic its function.

Why other options are wrong:
- Option A: The atrioventricular bundle transmits the impulse from the AV node to the ventricles, but it is not the primary pacemaker.
- Option B: The Purkinje system distributes the impulse throughout the ventricles, but it does not initiate the heartbeat.
- Option D: The atrioventricular node delays the impulse from the SA node, but it is not the primary pacemaker.

Key Concepts:
- Sinoatrial (SA) Node
- Atrioventricular (AV) Node
- Atrioventricular Bundle (Bundle of His)
- Purkinje Fibers
- Cardiac Conduction System
- Pacemaker Function

Memory Aids:
- SA node = Start Action

Quick Tips:
- Remember the order of the heart's electrical conduction system: SA node → AV node → AV bundle → Purkinje fibers.

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Blood is a

View answer and explanation

Correct option: C

Both (a) and (b)

Option C (Both (a) and (b)) is correct because blood is a connective tissue that is both mobile and liquid, allowing it to transport substances throughout the body.

Solution approach

Correct Answer + Core Reason: Both (a) and (b). Blood is both mobile and liquid connective tissue.

Step-by-Step Solution:

Step 1: Understand the classification of blood as a tissue.

Step 2: Blood is classified as a connective tissue because it originates from mesenchyme and connects different parts of the body.

Step 3: Blood is a liquid tissue because its matrix (plasma) is fluid.

Step 4: Blood is also a mobile tissue because it circulates throughout the body, carrying oxygen, nutrients, and waste products.

Why other options are wrong:
- Option A: Mobile connective tissue: This is a correct statement, but not the complete answer.
- Option B: Liquid connective tissue: This is a correct statement, but not the complete answer.
- Option D: Semisolid connective tissue: Blood is not semisolid; it is a liquid tissue.

Key Concepts:
- Connective tissue
- Blood as a tissue
- Tissue classification

Memory Aids:
- Remember that blood is a "fluid connection" throughout the body.

Quick Tips:
- Review the different types of tissues and their characteristics.

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Assertion: RBCs are devoid of nucleus in most of the mammals
Reason: Entire cytoplasm of RBCs is filled with red coloured, iron containing complex protein called haemoglobin.

View answer and explanation

Correct option: A

Both assertion and reason are true and reason is the correct explanation of assertion

Option A (Both assertion and reason are true and reason is the correct explanation of assertion) is correct because the absence of a nucleus in RBCs allows more space for hemoglobin, which is essential for oxygen transport.

Solution approach

Correct Answer + Core Reason: Both assertion and reason are true and reason is the correct explanation of assertion. The absence of a nucleus allows more space for hemoglobin.

Step-by-Step Solution:

Step 1: Evaluate the assertion: RBCs are devoid of nucleus in most mammals - True.

Step 2: Evaluate the reason: Entire cytoplasm of RBCs is filled with red colored, iron-containing complex protein called hemoglobin - True.

Step 3: Determine if the reason explains the assertion. The absence of a nucleus allows more space for hemoglobin, which is vital for oxygen transport. Therefore, the reason correctly explains the assertion.

Why other options are wrong:
- Option B: While both statements are true, the reason *does* explain the assertion.
- Option C: The reason is true, so the assertion cannot be true while the reason is false.
- Option D: The assertion is true, so it cannot be false while the reason is true.

Key Concepts:
- Red blood cell structure and function
- Hemoglobin and oxygen transport

Memory Aids:
- No Nucleus = More Hemoglobin = More Oxygen.

Quick Tips:
- When analyzing assertion-reason questions, always check if the reason directly explains the assertion.

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