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Q1Science·Human PhysiologyPYQ 2024
Which one of the following is synthesised in human body that dilates blood vessels and increases blood flow?
- ANitric oxideCorrect
- BNitrous oxide
- CNitrogen dioxide
- DNitrogen pentoxide
Explanation
Correct. Nitric oxide (NO) is produced by endothelial cells lining blood vessels and acts as a vasodilator, relaxing smooth muscle and increasing blood flow.
Why the other options are incorrect
- Option B
Nitrous oxide (N₂O) is an anaesthetic gas used in surgery and dentistry; it is not the endogenous vasodilator synthesised by the body.
- Option C
Nitrogen dioxide (NO₂) is a toxic air pollutant formed during combustion processes and is not synthesised in the human body for vasodilation.
- Option D
Nitrogen pentoxide (N₂O₅) is an unstable chemical reagent with no biological role in the human body.
Q2Science·Human PhysiologyPYQ 2010
Which one of the following processes in the bodies of living organisms is a digestive process?
- ABreakdown of proteins into amino acidsCorrect
- BBreakdown of glucose into CO₂ and H₂O
- CConversion of glucose into glycogen
- DConversion of amino acids into proteins
Explanation
Correct. Digestion involves the hydrolysis of complex food molecules into simpler absorbable forms; proteases break proteins into amino acids in the stomach and small intestine.
Why the other options are incorrect
- Option B
The breakdown of glucose into CO₂ and H₂O is cellular respiration, an energy-releasing metabolic process, not digestion.
- Option C
Conversion of glucose into glycogen is glycogenesis, a biosynthetic storage process occurring in the liver and muscles.
- Option D
Conversion of amino acids into proteins is protein synthesis (translation), an anabolic process, not digestion.
Q3Science·Human PhysiologyPYQ 2007
Which one of the following parts of human brain is the regulating centre for swallowing and vomiting?
- ACerebellum
- BCerebrum
- CMedulla oblongataCorrect
- DPons
Explanation
Correct. The medulla oblongata contains vital reflex centres including the swallowing centre, vomiting centre, and other autonomic control centres for breathing and cardiovascular function.
Why the other options are incorrect
- Option A
The cerebellum coordinates voluntary movements and maintains balance and posture; it does not control swallowing or vomiting reflexes.
- Option B
The cerebrum handles higher cognitive functions such as thinking, memory, and voluntary motor control, not reflex centres for swallowing and vomiting.
- Option D
The pons relays signals between the cerebrum and cerebellum and helps regulate breathing rhythm, but the primary swallowing and vomiting centres are in the medulla oblongata.
Q4Science·Human PhysiologyPYQ 2007
In human body, which one of the following hormones regulates blood calcium and phosphate?
- AGlucagon
- BGrowth hormone
- CParathyroid hormoneCorrect
- DThyroxine
Explanation
Correct. Parathyroid hormone (PTH), secreted by the parathyroid glands, increases blood calcium by stimulating bone resorption, renal reabsorption of calcium, and activation of vitamin D.
Why the other options are incorrect
- Option A
Glucagon is secreted by alpha cells of the pancreas and raises blood glucose levels; it has no direct role in calcium or phosphate regulation.
- Option B
Growth hormone promotes overall body growth and protein synthesis but does not directly regulate blood calcium and phosphate levels.
- Option D
Thyroxine regulates basal metabolic rate; while thyroid C-cells secrete calcitonin for calcium regulation, thyroxine itself does not regulate calcium and phosphate.
Q5Science·Human PhysiologyPYQ 2006
What is the name of the vessel that delivers the nutrient-rich blood from the stomach and small intestine to the liver?
- ALeft hepatic artery
- BHepatic vein
- CRight hepatic artery
- DHepatic portal veinCorrect
Explanation
Correct. The hepatic portal vein carries nutrient-rich, deoxygenated blood from the stomach, intestines, spleen, and pancreas to the liver for processing.
Why the other options are incorrect
- Option A
The left hepatic artery supplies oxygenated blood to the left lobe of the liver; it does not carry nutrient-rich blood from the gut.
- Option B
The hepatic vein carries deoxygenated blood away from the liver to the inferior vena cava, not towards the liver from the intestines.
- Option C
The right hepatic artery supplies oxygen to the right lobe of the liver and is not the vessel transporting absorbed nutrients from the gut.
Q6Science·Human PhysiologyPYQ 2002
With reference to the blood in a normal person, which one of the following statements is correct?
- ACompared to arteries, veins are less numerous and hold less of the body's blood at any given time
- BBlood cells constitute about 70 per cent of the total volume of the blood
- CWhite Blood Cells (WBC) are made by lymph nodes only
- DThe blood has more platelets than WBCCorrect
Explanation
Correct. Normal platelet count is 1.5-4.0 lakh per microlitre while WBC count is only 4,000-11,000 per microlitre, making platelets far more numerous.
Why the other options are incorrect
- Option A
Veins actually hold about 60-70% of the body's total blood volume at any given time, making them more voluminous than arteries.
- Option B
Blood cells constitute about 45% of blood volume (haematocrit); plasma makes up the remaining 55%.
- Option C
WBCs are produced in bone marrow (primary site) and mature in lymph nodes, thymus, and spleen; lymph nodes are not the only source.
Q7Science·Human PhysiologyPYQ 2001
Match List I with List II and select the correct answer using the codes given below the Lists:
List I (Substance) — List II (Physiological role)
I. Ptyalin — A) Converts angiotensinogen in blood into angiotensin
II. Pepsin — B) Digests starch
III. Renin — C) Digests proteins
IV. Oxytocin — D) Hydrolyses fats
— E) Induces contraction of smooth muscles
Codes:
- AI-B, II-C, III-A, IV-ECorrect
- BI-C, II-D, III-B, IV-E
- CI-B, II-C, III-E, IV-A
- DI-C, II-A, III-B, IV-D
Explanation
Correct. Ptyalin (salivary amylase) digests starch (B); pepsin digests proteins in the stomach (C); renin converts angiotensinogen to angiotensin for blood pressure regulation (A); oxytocin induces uterine smooth muscle contraction (E).
Why the other options are incorrect
- Option B
This incorrectly assigns protein digestion to ptyalin and fat hydrolysis to pepsin; ptyalin acts on starch and pepsin on proteins.
- Option C
This incorrectly pairs renin with smooth muscle contraction and oxytocin with angiotensin conversion, reversing their actual roles.
- Option D
This pairing is entirely incorrect; ptyalin digests starch not proteins, and renin acts on angiotensinogen not starch.
Q8Science·Human PhysiologyPYQ 2000
Match List I (Endocrine glands) with List II (Hormones secreted) and select the correct answer:
I. Gonads — II. Pituitary — III. Pancreas — IV. Adrenal
A) Insulin — B) Progesterone — C) Growth hormone — D) Cortisone
- AI-C, II-B, III-D, IV-A
- BI-B, II-C, III-D, IV-A
- CI-B, II-C, III-A, IV-DCorrect
- DI-C, II-B, III-A, IV-D
Explanation
Correct. Gonads secrete progesterone (B); pituitary secretes growth hormone (C); pancreas secretes insulin (A); adrenal glands secrete cortisone (D).
Why the other options are incorrect
- Option A
This incorrectly assigns growth hormone to gonads and progesterone to pituitary; gonads secrete progesterone and pituitary secretes growth hormone.
- Option B
This incorrectly pairs pancreas with cortisone and adrenal with insulin; pancreas secretes insulin and adrenal cortex secretes cortisone.
- Option D
This incorrectly assigns growth hormone to gonads and progesterone to pituitary, reversing their correct glands.
Q9Science·Human PhysiologyPYQ 2000
The blood glucose level is commonly expressed as:
- Amm of Hg
- Bmilligram per decilitreCorrect
- Cparts per million
- Dgrams per litre
Explanation
Correct. Blood glucose is universally expressed as mg/dL (milligrams per decilitre); normal fasting blood glucose is 70-100 mg/dL.
Why the other options are incorrect
- Option A
mm of Hg (millimetres of mercury) is used to measure blood pressure, not blood glucose concentration.
- Option C
Parts per million (ppm) is used for trace quantities in water quality or air pollution measurements, not for blood glucose.
- Option D
Grams per litre is not the standard clinical unit for blood glucose; mg/dL is the accepted convention.
Q10Science·Human PhysiologyPYQ 1999
Match the hormones in List I with items in List II:
I. Adrenaline — II. Estrogen — III. Insulin — IV. Pheromones
A) Anger, fear, danger — B) Attracting partners through sense of smell — C) Females — D) Glucose
- AI-A, II-C, III-D, IV-BCorrect
- BI-C, II-A, III-D, IV-B
- CI-A, II-C, III-B, IV-D
- DI-C, II-A, III-B, IV-D
Explanation
Correct. Adrenaline is the fight-or-flight hormone released during anger, fear, and danger (A); estrogen is the primary female sex hormone (C); insulin regulates blood glucose (D); pheromones attract partners through smell (B).
Why the other options are incorrect
- Option B
This incorrectly pairs adrenaline with females and estrogen with anger/fear, reversing the well-known associations.
- Option C
This wrongly assigns insulin to partner attraction and pheromones to glucose regulation.
- Option D
This is entirely incorrect, swapping adrenaline with estrogen and insulin with pheromones.
Q11Science·Human PhysiologyPYQ 1999
Match List I (Drugs/Chemicals) with List II (Their uses):
I. Atropine — II. Ether — III. Nitroglycerine — IV. Pyrethrin
A) Local anaesthesia — B) Heart trouble — C) Dilation of pupil — D) Mosquito control
- AI-A, II-C, III-B, IV-D
- BI-A, II-C, III-D, IV-B
- CI-C, II-A, III-B, IV-DCorrect
- DI-C, II-A, III-D, IV-B
Explanation
Correct. Atropine dilates the pupil (C); ether is a local/general anaesthetic (A); nitroglycerine treats angina and heart trouble (B); pyrethrin is a natural insecticide for mosquito control (D).
Why the other options are incorrect
- Option A
This wrongly pairs atropine with local anaesthesia; atropine is used for pupil dilation (mydriasis) in ophthalmology.
- Option B
This reverses the roles of nitroglycerine and pyrethrin; nitroglycerine treats angina (heart trouble), not mosquito control.
- Option D
This incorrectly assigns mosquito control to nitroglycerine; nitroglycerine is a vasodilator used for treating heart conditions.
Q12Science·Human PhysiologyPYQ 1997
Arteries supplying blood to the heart are called:
- ACarotid arteries
- BHepatic arteries
- CCoronary arteriesCorrect
- DPulmonary arteries
Explanation
Correct. Coronary arteries arise from the aorta and supply oxygenated blood to the heart muscle (myocardium); blockage of these arteries leads to heart attacks.
Why the other options are incorrect
- Option A
Carotid arteries supply blood to the brain, neck, and face, not to the heart muscle itself.
- Option B
Hepatic arteries supply oxygenated blood to the liver, not to the heart.
- Option D
Pulmonary arteries carry deoxygenated blood from the heart to the lungs for oxygenation; they do not supply the heart muscle.