BODY FLUIDS AND CIRCULATION MCQs for NEET UG BIOLOGY — Medium, Page 5

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Which one of the following is matching pair?

View answer and explanation

Correct option: A

Lubb - Sharp closure of AV valves at the beginning of ventricular systole

Option A (Lubb - Sharp closure of AV valves at the beginning of ventricular systole) is correct because the "Lubb" sound corresponds to the closing of the atrioventricular valves.

Solution approach

Correct Answer + Core Reason: Lubb - Sharp closure of AV valves at the beginning of ventricular systole. This is the correct association between the heart sound and the valve closure.

Step-by-Step Solution:

Step 1: Recall the heart sounds and their causes.

Step 2:
- Lubb: Closure of AV valves (tricuspid and mitral) at the start of ventricular systole.
- Dup: Closure of semilunar valves (aortic and pulmonary) at the start of ventricular diastole.

Step 3: Evaluate each option:
- Option A is correct.
- Option B is incorrect because Dup is associated with the closure of semilunar valves, not their opening.
- Option C is incorrect because pulsation of the radial artery is due to blood flow, not valves.
- Option D is incorrect because the SA node initiates the heartbeat, not Purkinje fibers.

Why other options are wrong:
- Option B: Dup is the sound of semilunar valves closing, not opening.
- Option C: Radial artery pulsation is due to blood flow, not valves.
- Option D: SA node initiates the heartbeat, not Purkinje fibers.

Key Concepts:
- Heart sounds (Lubb and Dup)
- Cardiac cycle
- Valve function

Memory Aids:
- Lubb = AV valves close; Dup = Semilunar valves close

Quick Tips:
- Remember the sequence of events in the cardiac cycle and the corresponding heart sounds.

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Atherosclerosis is called

View answer and explanation

Correct option: A

Coronary artery disease

Option A (Coronary artery disease) is correct because atherosclerosis is a major underlying cause of coronary artery disease.

Solution approach

Correct Answer + Core Reason: Coronary artery disease. Atherosclerosis leads to narrowing of coronary arteries.

Step-by-Step Solution:
Step 1: Understand the question: The question asks for another name or a direct consequence of atherosclerosis.
Step 2: Recall the definition of atherosclerosis: Atherosclerosis is the buildup of plaque inside arteries.
Step 3: Relate atherosclerosis to CAD: When this buildup occurs in the coronary arteries, it leads to coronary artery disease.

Why other options are wrong:
- Option B: Angina is a symptom of CAD, not a synonym for atherosclerosis.
- Option C: Heart failure can result from CAD, but it's not the same as atherosclerosis.
- Option D: Hypertension (high blood pressure) can be a risk factor for atherosclerosis, but it's not the same condition.

Key Concepts:\nAtherosclerosis, Coronary Artery Disease (CAD).

Memory Aids:\nThink of atherosclerosis as the process, and CAD as the disease resulting from that process in the coronary arteries.

Quick Tips:\nFocus on the location of the atherosclerosis to determine the specific disease it causes.

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Papillary muscles are associated with

View answer and explanation

Correct option: B

Ventricles of heart

Option B (Ventricles of heart) is correct because papillary muscles are located within the ventricles of the heart.

Solution approach

Correct Answer + Core Reason: Ventricles of heart. Papillary muscles are located in the ventricles.

Step-by-Step Solution:

Step 1: Define papillary muscles: Papillary muscles are cone-shaped projections of muscle located in the ventricles of the heart.

Step 2: Identify location: They are attached to the cusps of the atrioventricular valves via chordae tendineae.

Why other options are wrong:
- Option A: Atria of heart: Papillary muscles are not found in the atria.
- Option C: Walls of Aorta: Papillary muscles are not associated with the aorta.
- Option D: None of these: Papillary muscles are associated with the ventricles of the heart.

Key Concepts:
- Papillary muscles
- Heart anatomy
- Ventricles

Memory Aids:
- Papillary muscles are in the Ventricles.

Quick Tips:
- Remember the location and function of papillary muscles in the heart.

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Parasympathetic neural signal decreases the cardiac output by

View answer and explanation

Correct option: D

Both (1) and (2)

Option D (Both (1) and (2)) is correct because parasympathetic signals decrease cardiac output by slowing the heart rate and conduction speed.

Solution approach

Correct Answer + Core Reason: Both (1) and (2). Parasympathetic signals decrease cardiac output by slowing heart rate and conduction speed.

Step-by-Step Solution:

Step 1: Understand the role of the parasympathetic nervous system in regulating cardiac function.

Step 2: Recall that the parasympathetic nervous system releases acetylcholine, which acts on the heart to decrease heart rate and contractility.

Step 3: Decreasing the speed of conduction of action potentials through the heart reduces the heart rate.

Step 4: Slowing down the rate of the heartbeat directly reduces the number of contractions per minute, thus decreasing cardiac output.

Step 5: Cardiac output is the product of heart rate and stroke volume; decreasing heart rate decreases cardiac output.

Why other options are wrong:
- Option A: Decreasing the speed of conduction of action potential is one way parasympathetic signals decrease cardiac output, but it's not the only way.
- Option B: Slowing down the rate of heartbeat is one way parasympathetic signals decrease cardiac output, but it's not the only way.
- Option C: Increasing the speed of blood in the vein is not a direct effect of parasympathetic neural signals on cardiac output.

Key Concepts:
- Parasympathetic Nervous System
- Cardiac Output
- Heart Rate
- Action Potential Conduction
- Acetylcholine

Memory Aids:
- Parasympathetic = "rest and digest" (slows heart).

Quick Tips:
- Remember that parasympathetic stimulation generally has the opposite effect of sympathetic stimulation on the heart.

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Assertion: In lymphatic system, lymph is known
as tissue fluid.

Reason: It comprises of plasma proteins, RBCs
and WBCs.

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 lymph is tissue fluid, but it does not contain RBCs.

Solution approach

Correct Answer + Core Reason: If Assertion is true but Reason is false. Lymph is tissue fluid, but it lacks RBCs.

Step-by-Step Solution:

Step 1: Analyze the Assertion: In the lymphatic system, lymph is known as tissue fluid. This statement is true. Lymph originates from tissue fluid, which is the fluid surrounding cells in tissues.

Step 2: Analyze the Reason: It comprises of plasma proteins, RBCs and WBCs. This statement is false. Lymph comprises plasma proteins and WBCs, but it does not contain RBCs.

Step 3: Determine the relationship between Assertion and Reason: The assertion is true, but the reason is false. Therefore, the correct answer is that the assertion is true, but the reason is false.

Step 4: Conclude: Therefore, the correct option is C.

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

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

Memory Aids:
- Remember that lymph is \"filtered\" tissue fluid and lacks RBCs.

Quick Tips:
- Understand the relationship between blood, tissue fluid, and lymph.

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Papillary muscles are found in mammalian

View answer and explanation

Correct option: B

Ventricles

Option B (Ventricles) is correct because papillary muscles are located in the ventricles of the heart and attach to the atrioventricular valves via chordae tendineae.

Solution approach

Correct Answer + Core Reason: Ventricles. Papillary muscles are found in the ventricles of the heart.

Step-by-Step Solution:

Step 1: Define papillary muscles: Papillary muscles are cone-shaped projections of muscle located in the ventricles of the heart.

Step 2: Identify function: They attach to the cusps of the atrioventricular valves (tricuspid and mitral) via chordae tendineae, preventing the valves from prolapsing into the atria during ventricular contraction.

Why other options are wrong:
- Option A: Auricles: Papillary muscles are not found in the auricles (atria).
- Option C: Pinna: The pinna is part of the external ear, not the heart.
- Option D: Eyes: Papillary muscles are not related to the eyes.

Key Concepts:
- Papillary muscles
- Heart anatomy
- Ventricles

Memory Aids:
- Papillary muscles are in the Ventricles.

Quick Tips:
- Remember the location and function of papillary muscles in the heart.

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Which of the following conditions cause erythroblastosis foetalis

View answer and explanation

Correct option: B

Mother

R{h^{ - Ve}}

and foetus

R{h^{ + Ve}}

Option B (Mother

R{h^{ - Ve}}

and foetus

R{h^{ + Ve}}

) is correct because erythroblastosis foetalis occurs when an Rh-negative mother carries an Rh-positive fetus, leading to the mother's immune system attacking the fetal red blood cells.

Solution approach

Correct Answer + Core Reason: Mother $R{h^{ - Ve}}$ and foetus $R{h^{ + Ve}}$ . This combination leads to Rh incompatibility and erythroblastosis foetalis.

Step-by-Step Solution:

Step 1: Understand Rh incompatibility. Rh incompatibility occurs when an Rh-negative mother carries an Rh-positive fetus.

Step 2: Explain the mechanism of erythroblastosis foetalis. During pregnancy or delivery, some fetal red blood cells can enter the mother's circulation. If the mother is Rh-negative and the fetus is Rh-positive, the mother's immune system recognizes the Rh-positive fetal red blood cells as foreign and produces anti-Rh antibodies.

Step 3: Explain the effect of anti-Rh antibodies on subsequent pregnancies. If the mother becomes pregnant with another Rh-positive fetus, the anti-Rh antibodies can cross the placenta and attack the fetal red blood cells, leading to erythroblastosis foetalis.

Step 4: Consider the other options. Erythroblastosis foetalis does not occur if the mother is Rh-positive or if both mother and fetus are Rh-negative.

Why other options are wrong:
- Option A: If the mother is $R{h^{ + Ve}}$ , there is no Rh incompatibility, so erythroblastosis foetalis will not occur.
- Option C: If both mother and foetus are $R{h^{ + Ve}}$ , there is no Rh incompatibility, so erythroblastosis foetalis will not occur.
- Option D: If both mother and foetus are $R{h^{ - Ve}}$ , there is no Rh incompatibility, so erythroblastosis foetalis will not occur.

Key Concepts:
- Rh incompatibility
- Erythroblastosis foetalis
- Anti-Rh antibodies

Memory Aids:
- Rh-negative mother + Rh-positive fetus = risk of erythroblastosis foetalis.

Quick Tips:
- Remember the conditions for Rh incompatibility.

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

View answer and explanation

Correct option: C

Peak P and Peak R together – Systolic and diastolic blood pressure

Option D (Peak P – Initiation of left atrial contraction only) is incorrect. Peak P represents the initiation of contraction of both atria, not just the left atria. Option A (Complex QRS – One complete Pulse) is incorrect because QRS represents ventricular depolarization, not a complete pulse. Option B (Peak T – Initiation of total cardiac contraction) is incorrect because T represents ventricular repolarization. Option C (Peak P and Peak R together – Systolic and diastolic blood pressure) is correct because the ECG indirectly reflects blood pressure changes during systole and diastole.

Solution approach

Correct Answer + Core Reason: Peak P and Peak R together – Systolic and diastolic blood pressure. While not a direct measurement, the ECG waves correlate with the phases of the cardiac cycle that influence blood pressure.

Step-by-Step Solution:

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

Step 2: P-wave: Atrial depolarization (atrial contraction).

Step 3: QRS complex: Ventricular depolarization (ventricular contraction).

Step 4: T-wave: Ventricular repolarization (ventricular relaxation).

Step 5: Systolic pressure is related to ventricular contraction (QRS), and diastolic pressure is related to ventricular relaxation (T). P wave initiates atrial contraction and contributes to blood pressure.

Why other options are wrong:
- Option A: Complex QRS represents ventricular depolarization, not one complete pulse (cardiac cycle).
- Option B: Peak T represents ventricular repolarization, not the initiation of total cardiac contraction.
- Option D: Peak P represents the initiation of both left and right atrial contraction, not just the left.

Key Concepts:
- ECG components (P, QRS, T)
- Systole and diastole
- Cardiac cycle

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

Quick Tips:
- Understand the relationship between ECG waves and cardiac events.

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Which type of blood cells have 5-7 lobed nucleus?

View answer and explanation

Correct option: B

Neutrophils

Option B (Neutrophils) is correct because neutrophils are characterized by having a multi-lobed nucleus, typically with 3-5 lobes, but can sometimes have 5-7 lobes.

Solution approach

Correct Answer + Core Reason: Neutrophils. Neutrophils are characterized by a multi-lobed nucleus, typically with 3-5 lobes, but can sometimes have 5-7 lobes.

Step-by-Step Solution:

Step 1: Recall the characteristics of different types of white blood cells (leukocytes).

Step 2: Neutrophils are characterized by their multi-lobed nucleus.

Step 3: The number of lobes in a neutrophil's nucleus typically ranges from 3 to 5, but can sometimes be 5-7.

Why other options are wrong:
- Option A: Erythrocytes (red blood cells) do not have a nucleus in mammals.
- Option C: Eosinophils typically have a bi-lobed nucleus.
- Option D: Basophils typically have a bi-lobed or irregularly shaped nucleus, but not 5-7 lobed.

Key Concepts:
- Neutrophils
- Leukocytes (white blood cells)
- Nucleus

Memory Aids:
- Neutrophils = Numerous lobes in the nucleus.

Quick Tips:
- Remember the characteristic nuclear morphology of different types of leukocytes.

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What is the correct order or events occurring in blood clotting?
I. Conversion of fibrinogen to fibrin
II. Formation of clot
III. Thromboplastin formation
IV. Conversion of prothrombin to thrombin
Choose the correct option

View answer and explanation

Correct option: B

III, IV, I and II

Option B (III, IV, I and II) is correct because the correct sequence of events in blood clotting is: 1. Thromboplastin formation, 2. Conversion of prothrombin to thrombin, 3. Conversion of fibrinogen to fibrin, and 4. Formation of clot.

Solution approach

Correct Answer + Core Reason: III, IV, I and II. This is the correct sequence of blood clotting events.

Step-by-Step Solution:

Step 1: The question asks for the correct order of events in blood clotting.

Step 2: Recall the steps involved in the coagulation cascade.

Step 3: The correct sequence is:
1. Thromboplastin formation (III)
2. Conversion of prothrombin to thrombin (IV)
3. Conversion of fibrinogen to fibrin (I)
4. Formation of clot (II)

Why other options are wrong:
- Option A: Incorrect order.
- Option C: Incorrect order.
- Option D: Incorrect order.

Key Concepts:
- Blood clotting cascade
- Thromboplastin, prothrombin, thrombin, fibrinogen, fibrin

Memory Aids:
- Remember the order of the key players in the cascade.

Quick Tips:
- Understand the sequence of events in blood clotting.

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Deoxygenated blood from wall of heart is carried by

View answer and explanation

Correct option: A

Coronary sinus

Option A (Coronary sinus) is correct because the coronary sinus is a large vein on the posterior surface of the heart that collects deoxygenated blood from the heart wall and drains it into the right atrium.

Solution approach

Correct Answer + Core Reason: Coronary sinus. The coronary sinus collects deoxygenated blood from the heart wall and drains it into the right atrium.

Step-by-Step Solution:

Step 1: Identify the blood supply to the heart. The heart receives its blood supply through the coronary arteries.

Step 2: Understand the venous drainage of the heart. Deoxygenated blood from the heart muscle is collected by cardiac veins.

Step 3: Identify the coronary sinus. The coronary sinus is a large vein on the posterior surface of the heart that receives blood from most of the cardiac veins.

Step 4: Trace the path of deoxygenated blood. Deoxygenated blood from the heart wall is collected by cardiac veins, which drain into the coronary sinus, and then into the right atrium.

Why other options are wrong:
- Option B: The inferior vena cava carries deoxygenated blood from the lower body to the right atrium.
- Option C: The superior vena cava carries deoxygenated blood from the upper body to the right atrium.
- Option D: The pulmonary artery carries deoxygenated blood from the right ventricle to the lungs.

Key Concepts:
- Coronary circulation
- Coronary sinus
- Venous drainage

Memory Aids:
- Coronary = Heart
- Sinus = Collection point

Quick Tips:
- Remember that the coronary sinus is the main vein that drains deoxygenated blood from the heart wall.

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At high altitude, RBCs of human blood will

View answer and explanation

Correct option: A

Increase in number

Option A (Increase in number) is correct because at high altitudes, the body compensates for the lower oxygen availability by producing more red blood cells (RBCs) to increase the oxygen-carrying capacity of the blood.

Solution approach

Correct Answer + Core Reason: Increase in number. The body produces more RBCs at high altitudes.

Step-by-Step Solution:

Step 1: The question asks about the change in RBCs at high altitude.

Step 2: Recall the body's response to low oxygen levels (hypoxia).

Step 3: At high altitudes, the air is thinner, and the partial pressure of oxygen is lower. This leads to hypoxia. The body responds by increasing the production of red blood cells (RBCs) to increase the oxygen-carrying capacity of the blood. This process is stimulated by the hormone erythropoietin, which is released by the kidneys in response to hypoxia.

Why other options are wrong:
- Option B: The number of RBCs increases, not decreases.
- Option C: The size of RBCs does not significantly decrease at high altitude.
- Option D: The size of RBCs does not significantly increase at high altitude.

Key Concepts:
- Adaptation to high altitude
- Erythropoiesis
- Hypoxia

Memory Aids:
- More RBCs = More oxygen carrying capacity.

Quick Tips:
- Remember that the body compensates for low oxygen by producing more RBCs.

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Which of the following option describes all the components of human blood?

View answer and explanation

Correct option: C

Rh and ABO blood group

Option C (Rh and ABO blood group) is correct because the ABO and Rh blood group systems are the two most clinically significant blood group systems in humans.

Solution approach

Correct Answer + Core Reason: Rh and ABO blood group. These are the two major blood group systems in humans.

Step-by-Step Solution:

Step 1: Identify the major blood group systems in humans.

Step 2: The two most important blood group systems are the ABO system and the Rh system.

Step 3: The ABO system determines blood types A, B, AB, and O, while the Rh system determines Rh positivity or negativity.

Why other options are wrong:
- Option A: A and B blood groups are part of the ABO system, but not all components.
- Option B: AB and O blood groups are part of the ABO system, but not all components.
- Option D: Rh and AB blood group only includes one component of the ABO system.

Key Concepts:
- ABO blood group system
- Rh blood group system

Memory Aids:
- Remember that both ABO and Rh factors are important for blood transfusions.

Quick Tips:
- Know the different blood group systems and their significance in blood transfusions.

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A man with blood group A marries AB blood group woman. Which type of progeny indicate that the man is not homozygous?

View answer and explanation

Correct option: B

B

Option B (B) is correct because if the man were homozygous (AA), he could only pass on A alleles. The presence of B blood group offspring indicates he must be heterozygous (AO) to contribute an O allele.

Solution approach

Correct Answer + Core Reason: B. The presence of a B blood group offspring indicates the man is heterozygous.

Step-by-Step Solution:

Step 1: Understand blood group genetics.

Step 2: Blood group A can be either homozygous (AA) or heterozygous (AO).

Step 3: Blood group AB has the genotype AB.

Step 4: If the man is homozygous (AA), the possible genotypes of the offspring are AA and AB (from A + A and A + B respectively).

Step 5: If the man is heterozygous (AO), the possible genotypes of the offspring are AA, AB, AO, and BO (from A + A, A + B, O + A, and O + B respectively).

Step 6: The presence of a B blood group offspring (genotype BO) indicates that the man must be heterozygous (AO) to contribute the O allele.

Why other options are wrong:
- Option A: AB: AB offspring can result from both homozygous (AA) and heterozygous (AO) fathers.
- Option C: A: A offspring can result from both homozygous (AA) and heterozygous (AO) fathers.
- Option D: O: O offspring is impossible because the mother is AB and cannot donate an O allele.

Key Concepts:
- Blood group genetics
- Genotypes and phenotypes
- Punnett squares

Memory Aids:
- Remember that blood type O is recessive (ii).

Quick Tips:
- Practice blood group inheritance problems using Punnett squares.

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Most of our cells are surrounded by

View answer and explanation

Correct option: C

Extra cellular fluid

Option C (Extra cellular fluid) is correct because most of our cells are surrounded by extracellular fluid, which provides nutrients and removes waste.

Solution approach

Correct Answer + Core Reason: Extra cellular fluid. Cells are bathed in extracellular fluid, which facilitates nutrient exchange and waste removal.

Step-by-Step Solution:

Step 1: Define extracellular fluid: Extracellular fluid (ECF) is the fluid that surrounds cells in multicellular organisms. It includes interstitial fluid, plasma, and transcellular fluid.

Step 2: Explain the function of ECF: ECF provides a medium for the exchange of nutrients, gases, and waste products between cells and the blood.

Step 3: Relate ECF to cell environment: Most cells in the body are in direct contact with ECF.

Step 4: Conclude: Therefore, most of our cells are surrounded by extracellular fluid.

Why other options are wrong:
- Option A (Blood): Blood is a fluid connective tissue that circulates within blood vessels, but it does not directly surround most cells.
- Option B (Intra cellular fluid): Intracellular fluid is the fluid inside cells, not surrounding them.
- Option D (Pure water): Cells are not surrounded by pure water; they are surrounded by a complex fluid containing various ions, proteins, and other molecules.

Key Concepts:
- Extracellular fluid (ECF)
- Intracellular fluid (ICF)
- Interstitial fluid
- Fluid compartments of the body

Memory Aids:
- \"Extra\" means outside, so extracellular fluid is outside the cells.

Quick Tips:
- Remember the difference between intracellular and extracellular fluid.

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Arteries are best defined as the vessels which

View answer and explanation

Correct option: A

Carry blood away from the heart to different organs

Option A (Carry blood away from the heart to different organs) is correct because arteries are defined as blood vessels that carry blood away from the heart.

Solution approach

Correct Answer + Core Reason: Carry blood away from the heart to different organs. This is the defining characteristic of arteries.

Step-by-Step Solution:
Step 1: Define arteries: Blood vessels that carry blood away from the heart.
Step 2: Define veins: Blood vessels that carry blood towards the heart.
Step 3: Define capillaries: Small blood vessels that connect arteries and veins.
Step 4: Relate arteries to their function of carrying blood away from the heart.

Why other options are wrong:
- Option B: Capillaries connect arteries and veins, but arteries themselves don't break up into capillaries and reunite to form veins. That's the capillary network's function.
- Option C: This describes a portal system, which is a specific arrangement of veins, not the general definition of arteries.
- Option D: While many arteries carry oxygenated blood, it's not the defining characteristic. Pulmonary arteries carry deoxygenated blood.

Key Concepts:
- Arteries
- Veins
- Capillaries
- Blood vessel function

Memory Aids:
- Arteries = Away from the heart

Quick Tips:
- Distinguish between arteries and veins based on their direction of blood flow.

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Which one of the following statements is correct regarding blood pressure?

View answer and explanation

Correct option: C

190/110 mmHg may harm vital organs like brain and kidney

Option C (190/110 mmHg may harm vital organs like brain and kidney) is correct because this blood pressure reading is severely hypertensive and poses a significant risk to organ function.

Solution approach

Correct Answer + Core Reason: 190/110 mmHg may harm vital organs like brain and kidney. This blood pressure is severely hypertensive and dangerous.

Step-by-Step Solution:

Step 1: Understand normal blood pressure ranges. Normal blood pressure is around 120/80 mmHg.

Step 2: Recognize hypertension. Hypertension is high blood pressure, typically above 140/90 mmHg.

Step 3: Evaluate the given options. 190/110 mmHg is significantly higher than normal and indicates severe hypertension.

Step 4: Understand the consequences of severe hypertension. Severely high blood pressure can damage vital organs like the brain and kidneys.

Step 5: Conclusion: 190/110 mmHg may harm vital organs like the brain and kidney.

Why other options are wrong:
- Option A: 100/55 mmHg is considered an ideal blood pressure: This is incorrect. This blood pressure is lower than the ideal range.
- Option B: 105/50 mmHg makes one very active: This is incorrect. Blood pressure does not directly determine activity levels, and this reading is low.
- Option D: 130/90 mmHg is considered high and requires treatment: While 130/90 mmHg is elevated, it is not as immediately dangerous as 190/110 mmHg and may not always require immediate treatment depending on other risk factors.

Key Concepts:
- Blood pressure ranges (normal, elevated, hypertension)
- Consequences of hypertension

Memory Aids:
- Remember the normal blood pressure range: approximately 120/80 mmHg.

Quick Tips:
- Recognize that very high blood pressure readings require immediate medical attention.

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It is commonly said that ladies are protected from heart attacks in reproductive period i.e., from puberty to menopause because;

View answer and explanation

Correct option: A

Level of HDL is high due to oestrogen production

Option A (Level of HDL is high due to oestrogen production) is correct because estrogen increases HDL levels, which helps protect against heart attacks.

Solution approach

Correct Answer + Core Reason: Level of HDL is high due to oestrogen production. Oestrogen increases HDL levels, which are protective.

Step-by-Step Solution:

Step 1: Understand the role of HDL. High-density lipoprotein (HDL) helps remove cholesterol from the arteries.

Step 2: Understand the role of LDL. Low-density lipoprotein (LDL) contributes to cholesterol buildup in the arteries.

Step 3: Relate oestrogen to HDL levels. Oestrogen increases HDL levels.

Step 4: Explain the protective effect. Higher HDL levels protect against heart attacks.

Step 5: Conclusion: Ladies are protected due to high HDL levels caused by oestrogen.

Why other options are wrong:
- Option B: Level of HDL remains lower during this period: This is incorrect. Oestrogen increases HDL levels.
- Option C: Level of LDL and HDL remain in balance: While balance is important, the protective effect is primarily due to increased HDL.
- Option D: Level of LDL is high due to oestrogen production: This is incorrect. Oestrogen increases HDL, not LDL.

Key Concepts:
- HDL and LDL cholesterol
- Role of oestrogen
- Protection against heart attacks

Memory Aids:
- HDL = Healthy; Oestrogen increases HDL.

Quick Tips:
- Remember the beneficial effect of HDL and the influence of oestrogen.

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The heartbeat of a person increases at the time of an interview due to secretion of

View answer and explanation

Correct option: B

Adrenaline

Option B (Adrenaline) is correct because adrenaline is released during stressful situations, increasing heart rate.

Solution approach

Correct Answer + Core Reason: Adrenaline. Adrenaline is released during stress, increasing heart rate.

Step-by-Step Solution:

Step 1: Understand the body's response to stress.

Step 2: Recognize that during stressful situations, such as an interview, the body activates the sympathetic nervous system.

Step 3: The sympathetic nervous system releases adrenaline (epinephrine) and noradrenaline (norepinephrine).

Step 4: Adrenaline increases heart rate, blood pressure, and alertness, preparing the body for "fight or flight."

Why other options are wrong:
- Option A: Renin is involved in regulating blood pressure through the renin-angiotensin-aldosterone system (RAAS), but it does not directly cause an immediate increase in heart rate during stress.
- Option C: ADH (antidiuretic hormone) regulates water reabsorption in the kidneys and does not directly cause an immediate increase in heart rate during stress.
- Option D: ACTH (adrenocorticotropic hormone) stimulates the adrenal cortex to release cortisol, which is involved in long-term stress response, but it does not directly cause an immediate increase in heart rate.

Key Concepts:
- Adrenaline (Epinephrine)
- Sympathetic Nervous System
- Stress Response
- Renin-Angiotensin-Aldosterone System (RAAS)
- Antidiuretic Hormone (ADH)
- Adrenocorticotropic Hormone (ACTH)

Memory Aids:
- Adrenaline = Action!

Quick Tips:
- Remember that adrenaline is the primary hormone responsible for the immediate "fight or flight" response.

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Application +4 | -1

As per

\text{ABO}

blood grouping system, the blood group of father is

\mathrm{B}^{+},

mother is

\mathrm{A}^{+}

and child is

\mathrm{O}^{+}.

Their respective genotype can be

{{\text{A}}.\,\,{{\text{I}}^{\text{B}}}{\text{i}}/{{\text{I}}^{\text{A}}}{\text{i}}/{\text{ii}}}

{{\text{B}}.\,\,{{\text{I}}^{\text{B}}}{{\text{I}}^{\text{B}}}/{{\text{I}}^{\text{A}}}{{\text{I}}^{\text{A}}}/{\text{ii}}}

{{\text{C}}.\,\,{{\text{I}}^{\text{A}}}{{\text{I}}^{\text{B}}}/{\text{i}}{{\text{I}}^{\text{A}}}/{{\text{I}}^{\text{B}}}{\text{i}}}

{{\text{D}}.\,\,{{\text{I}}^{\text{A}}}{\text{i}}/{{\text{I}}^{\text{B}}}{\text{i}}/{{\text{I}}^{\text{A}}}{\text{i}}}

{{\text{E}}.\,\,{\text{i}}{{\text{I}}^{\text{B}}}/{\text{i}}{{\text{I}}^{\text{A}}}/{{\text{I}}^{\text{A}}}{{\text{I}}^{\text{B}}}}

Choose the most appropriate answer from the options given below:

View answer and explanation

Correct option: D

A only

Option D (A only) is correct because the genotypes

I^B i

,

I^A i

, and

ii

are the only possible combination that results in the given blood groups for father, mother, and child respectively.

Solution approach

Correct Answer + Core Reason: A only. The genotypes must be $I^B i$ , $I^A i$ , and $ii$ to produce the given phenotypes.

Step-by-Step Solution:

Step 1: Father is B+, so his genotype can be $I^BI^B$ or $I^Bi$ . Mother is A+, so her genotype can be $I^AI^A$ or $I^Ai$ . Child is O+, so their genotype must be $ii$ .

Step 2: Since the child is $ii$ , both parents must have at least one 'i' allele. Therefore, the father must be $I^Bi$ and the mother must be $I^Ai$ .

Step 3: Check the given options:
- A: $I^Bi / I^Ai / ii$ - This is a valid combination.
- B: $I^BI^B / I^AI^A / ii$ - This is invalid because the father and mother must have 'i' allele.
- C: $I^AI^B / iI^A / I^Bi$ - This is invalid because the child must be $ii$ .
- D: $I^Ai / I^Bi / I^Ai$ - This is invalid because the child must be $ii$ .
- E: $iI^B / iI^A / I^AI^B$ - This is invalid because the child must be $ii$ .

Step 4: Only option A is valid.

Why other options are wrong:
- Option B: C & B only - Incorrect because option B is invalid.
- Option C: D & E only - Incorrect because both options D and E are invalid.
- Option A: B only - Incorrect because option B is invalid.

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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Analyzing +4 | -1

Which of the following statements about the control of circulation in humans is incorrect?

View answer and explanation

Correct option: A

Sympathetic nerve input to skeletal muscle causes the blood vessels in the muscle to dilate.

Option A (Sympathetic nerve input to skeletal muscle causes the blood vessels in the muscle to dilate) is correct because while sympathetic stimulation can cause vasodilation, it is primarily due to local metabolic factors, not direct sympathetic input.

Solution approach

Correct Answer + Core Reason: Sympathetic nerve input to skeletal muscle causes the blood vessels in the muscle to dilate. While sympathetic stimulation can cause vasodilation, it is primarily due to local metabolic factors.

Step-by-Step Solution:

Step 1: Evaluate each statement for accuracy.

Step 2: Statement A: 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 B: Blood flow can be regulated by autonomic nerve signals emanating from cardiovascular control centres in the medulla of the brain. This is correct. The cardiovascular control centers in the medulla oblongata regulate blood flow through autonomic nerve signals.

Step 4: Statement C: 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 D: 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 B: This statement is correct about blood flow regulation.
- Option C: This statement is correct about the function of carotid artery chemosensors.
- Option D: This statement is correct about the effects of angiotensin and vasopressin.

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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Remembering +4 | -1

The QRS complex in a standard ECG represents

View answer and explanation

Correct option: C

Depolarisation of ventricles

Option C (Depolarisation of ventricles) is correct because the QRS complex represents the electrical activity associated with ventricular depolarization, leading to ventricular contraction.

Solution approach

Correct Answer + Core Reason: Depolarisation of ventricles. The QRS complex represents ventricular depolarization.

Step-by-Step Solution:

Step 1: Define ECG waves: An ECG consists of several waves, including P, QRS complex, and T waves.

Step 2: Identify QRS complex: The QRS complex represents the electrical activity associated with the depolarization of the ventricles, which leads to ventricular contraction.

Why other options are wrong:
- Option A: Repolarisation of auricles: Repolarization of the atria is masked by the QRS complex.
- Option B: Depolarisation of auricles: The P wave represents atrial depolarization.
- Option D: Repolarisation of ventricles: The T wave represents ventricular repolarization.

Key Concepts:
- Electrocardiogram (ECG)
- Depolarization and repolarization
- P wave, QRS complex, T wave

Memory Aids:
- QRS = Ventricular Depolarization

Quick Tips:
- Remember the specific events represented by each wave on the ECG.

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The correct route through which pulse making impulse travels in the heart is

View answer and explanation

Correct option: D

SA node

\to

AV node

\to

Bundle of his

\to

Purkinje fibres

\to

Heart muscle

Option D (SA node

\to

AV node

\to

Bundle of his

\to

Purkinje fibres

\to

Heart muscle) is correct because it represents the correct sequence of impulse conduction in the heart.

Solution approach

Correct Answer + Core Reason: SA node $\to$ AV node $\to$ Bundle of his $\to$ Purkinje fibres $\to$ Heart muscle. This is the correct sequence of electrical impulse conduction in the heart.

Step-by-Step Solution:

Step 1: Identify the sinoatrial (SA) node. The SA node is the heart's natural pacemaker, initiating the electrical impulse.

Step 2: Identify the atrioventricular (AV) node. The AV node receives the impulse from the SA node and delays it slightly.

Step 3: Identify the Bundle of His. The Bundle of His receives the impulse from the AV node and transmits it down the interventricular septum.

Step 4: Identify the Purkinje fibers. The Purkinje fibers receive the impulse from the Bundle of His and distribute it throughout the ventricular myocardium.

Step 5: Trace the path of the impulse. The impulse travels from the SA node to the AV node, then to the Bundle of His, then to the Purkinje fibers, and finally to the heart muscle, causing contraction.

Why other options are wrong:
- Option A: The sequence is incorrect; the SA node initiates the impulse, not the AV node.
- Option B: The sequence is incorrect; the SA node initiates the impulse, not the AV node.
- Option C: The sequence is incorrect; the impulse does not travel directly from the SA node to the Purkinje fibers.

Key Concepts:
- Cardiac conduction system
- SA node
- AV node
- Bundle of His
- Purkinje fibers

Memory Aids:
- SA AV Bundle Purkinje (SABP)

Quick Tips:
- Remember the correct sequence of impulse conduction in the heart.

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Understanding +4 | -1

Lymph is an important carrier for the transport of

View answer and explanation

Correct option: D

Both (a) and (b)

Option D (Both (a) and (b)) is correct because lymph transports both nutrients and hormones, facilitating their distribution throughout the body.

Solution approach

Correct Answer + Core Reason: Both (a) and (b). Lymph transports both nutrients and hormones.

Step-by-Step Solution:

Step 1: Understand the composition and function of lymph. Lymph is a fluid derived from tissue fluid that circulates through the lymphatic system.

Step 2: Recall the role of lymph in nutrient transport. Lymph absorbs fats and fat-soluble vitamins from the digestive system and transports them to the bloodstream.

Step 3: Recall the role of lymph in hormone transport. Lymph can transport hormones from endocrine glands to target tissues.

Step 4: Consider the other options. Platelets are primarily found in blood, not lymph.

Why other options are wrong:
- Option A: While lymph does transport nutrients, it also transports hormones, making option D more complete.
- Option B: While lymph does transport hormones, it also transports nutrients, making option D more complete.
- Option C: Platelets are primarily found in blood, not lymph.

Key Concepts:
- Lymphatic system
- Lymph composition and function
- Nutrient transport
- Hormone transport

Memory Aids:
- Lymph = fluid from tissues.

Quick Tips:
- Remember the key functions of the lymphatic system.

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World blood donation day is observed on

View answer and explanation

Correct option: D

14th June

Option D (14th June) is correct because World Blood Donation Day is observed annually on June 14th to raise awareness about the need for safe blood and blood products.

Solution approach

Correct Answer + Core Reason: 14th June. This is the internationally recognized day for blood donation awareness.

Step-by-Step Solution:

Step 1: Recall the date for World Blood Donation Day.

Step 2: World Blood Donation Day is observed on June 14th each year.

Why other options are wrong:
- Option A: 22nd August is not World Blood Donation Day.
- Option B: 4th February is not World Blood Donation Day.
- Option C: 17th October is not World Blood Donation Day.

Key Concepts:
- World Blood Donation Day
- Importance of blood donation

Memory Aids:
- Think of June as the start of summer, a time for giving (blood donation).

Quick Tips:
- Remember the specific date for important health awareness days.

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Remembering +4 | -1

Which of the following are phagocytic in nature?

View answer and explanation

Correct option: B

Neutrophil, monocyte and macrophage

Option B (Neutrophil, monocyte and macrophage) is correct because these cells are all capable of phagocytosis, engulfing and digesting pathogens and cellular debris.

Solution approach

Correct Answer + Core Reason: Neutrophil, monocyte and macrophage. These are all phagocytic cells.

Step-by-Step Solution:

Step 1: Recall the process of phagocytosis: Phagocytosis is the process of engulfing and digesting particles or cells.

Step 2: Identify phagocytic cells: Neutrophils, monocytes, and macrophages are all phagocytic.

Step 3: Relate to the options: Option B includes only phagocytic cells.

Why other options are wrong:
- Option A: Basophils are not primarily phagocytic; they release histamine and other mediators.
- Option C: Basophils are not primarily phagocytic.
- Option D: Acidophils (eosinophils) are involved in parasitic infections and allergic reactions, and lymphocytes are involved in adaptive immunity; neither are primarily phagocytic.

Key Concepts:
- Phagocytosis
- Neutrophils
- Monocytes
- Macrophages

Memory Aids:
- Phagocytes eat pathogens.

Quick Tips:
- Remember the different types of white blood cells and their functions.

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Understanding +4 | -1

Clotting of blood is to

View answer and explanation

Correct option: A

Seal up wounds and prevent blood loss.

Option A (Seal up wounds and prevent blood loss) is correct because the primary function of blood clotting is to stop bleeding by forming a clot at the site of injury.

Solution approach

Correct Answer + Core Reason: Seal up wounds and prevent blood loss. Clotting prevents excessive bleeding.

Step-by-Step Solution:

Step 1: Define blood clotting: Blood clotting, also known as coagulation, is the process by which blood changes from a liquid to a gel, forming a blood clot.

Step 2: Explain the function of blood clotting: The primary function of blood clotting is to stop bleeding by sealing up wounds and preventing blood loss.

Step 3: Conclude: Therefore, clotting of blood is to seal up wounds and prevent blood loss.

Why other options are wrong:
- Option B (Slow down the movement of blood inside the blood vessels): Incorrect. Clotting is localized at the site of injury and does not slow down blood flow in general.
- Option C (Trap oxygen inside the blood so that it can be carried around more easily): Incorrect. Oxygen transport is the function of red blood cells, not blood clots.
- Option D (Trap harmful germs inside the blood and prevent them from harming the body): Incorrect. While clots can trap some germs, the primary function of clotting is to stop bleeding, not to trap germs. The immune system is responsible for fighting germs.

Key Concepts:
- Blood clotting (coagulation)
- Hemostasis
- Function of blood clots

Memory Aids:
- Remember that clotting \"closes\" wounds.

Quick Tips:
- Understand the basic steps involved in blood clotting.

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Blood pressure is controlled by

View answer and explanation

Correct option: A

Adrenal

Option A (Adrenal) is correct because the adrenal glands secrete hormones like adrenaline that affect blood pressure.

Solution approach

Correct Answer + Core Reason: Adrenal. The adrenal glands secrete hormones that regulate blood pressure.

Step-by-Step Solution:

Step 1: Identify the question: Which gland controls blood pressure?

Step 2: Recall hormones involved in blood pressure regulation.

Step 3: Adrenal glands secrete hormones like adrenaline (epinephrine) and aldosterone, which affect blood pressure.

Step 4: Conclusion: Adrenal glands control blood pressure.

Why other options are wrong:
- Option B: Thyroid hormones affect metabolism, indirectly influencing blood pressure, but not the primary regulator.
- Option C: Thymus is involved in immune function, not blood pressure regulation.
- Option D: Corpus luteum is involved in female reproductive function, not blood pressure regulation.

Key Concepts:
- Endocrine System
- Hormonal Regulation of Blood Pressure
- Adrenal Gland Hormones (Adrenaline, Aldosterone)

Memory Aids:
- Adrenal = Adrenaline = Blood Pressure.

Quick Tips:
- Focus on glands that secrete hormones directly involved in cardiovascular function.

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Which of the following is the largest lymphatic vessels of the human body?

View answer and explanation

Correct option: B

Thoracic duct

Option B (Thoracic duct) is correct because the thoracic duct is the largest lymphatic vessel in the human body.

Solution approach

Correct Answer + Core Reason: Thoracic duct. The thoracic duct is the largest lymphatic vessel in the human body.

Step-by-Step Solution:

Step 1: Identify the lymphatic vessels listed in the options.

Step 2: Recall the relative sizes of the lymphatic vessels.

Step 3: The thoracic duct collects lymph from the majority of the body and is the largest lymphatic vessel.

Step 4: The right lymphatic duct is smaller and drains lymph from the upper right quadrant of the body.

Step 5: Lacteals are small lymphatic vessels within the small intestine villi.

Step 6: Cisterna chyli is a dilated sac at the lower end of the thoracic duct.

Step 7: Therefore, the thoracic duct is the largest.

Why other options are wrong:
- Option A: Lacteal duct: Lacteals are small lymphatic vessels in the small intestine, not the largest.
- Option C: Cisterna chyli: The cisterna chyli is a sac-like structure that forms the beginning of the thoracic duct, but it is not the largest vessel itself.
- Option D: Right lymphatic duct: The right lymphatic duct is smaller than the thoracic duct and drains only the upper right quadrant of the body.

Key Concepts:
- Lymphatic system
- Lymphatic vessels
- Thoracic duct
- Right lymphatic duct
- Lacteals
- Cisterna chyli

Memory Aids:
- Think of \

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Understanding +4 | -1

Why 1st child of Rh⁺ husband and Rh^- wife doesn’t have erythroblastosis foetalis?

View answer and explanation

Correct option: C

Due to the absence of Rh antibodies in mother’s blood

Option C (Due to the absence of Rh antibodies in mother’s blood) is correct because the mother's immune system has not yet been exposed to the Rh antigen and therefore has not produced Rh antibodies.

Solution approach

Correct Answer + Core Reason: Due to the absence of Rh antibodies in mother’s blood. The mother's immune system hasn't been exposed to the Rh antigen in the first pregnancy, so no antibodies are present.

Step-by-Step Solution:\nStep 1: Understand the mechanism of Rh incompatibility.\nStep 2: Recall that Rh antibodies are produced only after exposure to the Rh antigen.\nStep 3: Apply this to the question: In the first pregnancy, the mother hasn't been exposed, so no antibodies are present.

Why other options are wrong:
- Option A: Due to the absence of Rh antigen in mother’s blood. This is incorrect; the mother is Rh-negative, meaning she lacks the Rh antigen, but the issue is the absence of antibodies, not antigens.
- Option B: Due to the presence of Rh antibodies in mother’s blood. This is incorrect; the problem arises when antibodies are present, not absent.
- Option D: Both (a) and (©). This is incorrect because while (c) is correct, (a) is not the primary reason.

Key Concepts:
- Rh incompatibility
- Rh antibodies
- Sensitization

Memory Aids:
- No exposure, no antibodies.

Quick Tips:
- Remember that Rh antibodies are only produced after exposure to the Rh antigen.

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