Science chapter practice
Practise 80+ Human Physiology MCQs for UPSC Prelims in Science, including 14+ previous year questions. The sample set below is shown with correct answers and explanations.
12 sample questions are shown here; sign up free to practise all 80.
Which one of the following is synthesised in human body that dilates blood vessels and increases blood flow?
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.
Which one of the following processes in the bodies of living organisms is a digestive process?
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.
Which one of the following parts of human brain is the regulating centre for swallowing and vomiting?
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.
In human body, which one of the following hormones regulates blood calcium and phosphate?
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.
What is the name of the vessel that delivers the nutrient-rich blood from the stomach and small intestine to the liver?
Explanation
Correct. The hepatic portal vein carries nutrient-rich, deoxygenated blood from the stomach, intestines, spleen, and pancreas to the liver for processing.
With reference to the blood in a normal person, which one of the following statements is correct?
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.
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:
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).
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
Explanation
Correct. Gonads secrete progesterone (B); pituitary secretes growth hormone (C); pancreas secretes insulin (A); adrenal glands secrete cortisone (D).
The blood glucose level is commonly expressed as:
Explanation
Correct. Blood glucose is universally expressed as mg/dL (milligrams per decilitre); normal fasting blood glucose is 70-100 mg/dL.
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
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).
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
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).
Arteries supplying blood to the heart are called:
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.
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