NEET Biology: Human Physiology Practice Questions
15 free multiple-choice questions on Human Physiology for NEET Biology, each with the correct answer and a step-by-step explanation. Attempt a question, then reveal the solution to check your reasoning.
Practice thousands more Human Physiology questions in the app →Q1. Which muscle plays the most crucial role in the process of breathing (ventilation)?
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Correct answer: C — Diaphragm
The diaphragm is the primary muscle responsible for inhalation, as its contraction causes it to move downward, increasing the volume of the thoracic cavity.
Q2. Which component of blood is primarily responsible for transporting the majority of oxygen from the lungs to the rest of the body?
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Correct answer: B — Red blood cells
Red blood cells contain hemoglobin, which binds reversibly with oxygen, thus facilitating its transport throughout the circulatory system.
Q3. Hemoglobin in red blood cells is primarily responsible for the transport of which gas in the circulatory system?
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Correct answer: D — Oxygen
Hemoglobin contains iron, which binds reversibly with oxygen, allowing it to be effectively transported from the lungs to the rest of the body tissues.
Q4. Which of the following is a chronic respiratory condition resulting from prolonged exposure to irritating dusts and fumes in an industrial setting?
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Correct answer: A — Chronic Obstructive Pulmonary Disease (COPD)
Chronic exposure to industrial pollutants leads to chronic lung diseases like COPD, which involves persistent inflammation and airflow limitation.
Q5. Hypertension is generally classified based on the cause. Which type of hypertension is most commonly associated with kidney disease and hormonal imbalances?
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Correct answer: B — Secondary Hypertension
Secondary hypertension refers to high blood pressure caused by an underlying medical condition, such as kidney disease, endocrine disorders, or thyroid issues. This contrasts with essential (primary) hypertension, which is the most common form.
Q6. During stable angina, the chest pain is primarily caused by the imbalance between myocardial oxygen supply and demand during physical exertion. What is the main underlying structural issue causing this limitation?
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Correct answer: D — Fixed narrowing of coronary arteries due to atherosclerosis
Stable angina occurs when the fixed narrowing of the coronary arteries (atherosclerosis) limits blood flow during increased myocardial oxygen demand (like during exercise).
Q7. What is the interval that measures the time taken for the electrical impulse to travel from the atria to the ventricles?
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Correct answer: A — PR interval
The PR interval measures the time delay between the start of atrial depolarization (P wave) and the start of ventricular depolarization (QRS complex).
Q8. The accumulation of inflammatory cells (like eosinophils and mast cells) in the bronchial walls is characteristic of which stage of the asthma disease process?
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Correct answer: C — Late chronic phase
Chronic inflammation and cellular infiltration characterize the chronic phase of asthma, leading to persistent airway remodeling.
Q9. Which valve is responsible for preventing the backflow of blood from the left ventricle into the left atrium during ventricular systole?
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Correct answer: A — Mitral valve
The aortic valve controls flow from the left ventricle to the aorta, and the mitral valve controls flow between the left atrium and left ventricle. During ventricular systole, the mitral valve closes to prevent backflow into the atrium, while the aortic valve opens to allow ejection into the aorta. The question refers to the valve preventing backflow into the atrium, which is the mitral valve (incorrectly phrased in options, needs re-evaluation of flow path). Corrected context: The valve preventing backflow from ventricle to atrium during systole is the Mitral valve. Let's rephrase to ensure clarity on the specific valve action related to backflow.
Q10. Which of the following is a major macromolecule dissolved in the lymph?
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Correct answer: B — Lipids (Fats)
As lymph collects waste products and absorbed fats from the body tissues, lipids (fats) are significant components.
Q11. Where does the flow of air change direction in the human respiratory system?
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Correct answer: A — Bronchus
Air flows from the trachea into the bronchi, which further divide into bronchioles, demonstrating a change in pathway direction as it moves deeper into the lungs.
Q12. Heart failure primarily results from a failure of the heart to perform which basic function?
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Correct answer: D — Regulation of systemic blood pressure
Heart failure is fundamentally a failure of the myocardium (heart muscle) to pump blood effectively to meet the body's metabolic demands, which impacts systemic blood pressure regulation.
Q13. The blood flow in the pulmonary circulation is responsible for which physiological process?
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Correct answer: A — Exchange of oxygen and carbon dioxide
The pulmonary circulation facilitates the exchange of gases (oxygenation) between blood and air in the lungs.
Q14. If the heart rate of a person increases while the stroke volume remains constant, what happens to the overall cardiac output?
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Correct answer: C — Cardiac output increases
Since Cardiac Output (CO) = Heart Rate (HR) × Stroke Volume (SV), if HR increases and SV is constant, the total Cardiac Output will increase proportionally.
Q15. The blood vessels supplying the cardiac muscle itself are primarily categorized as:
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Correct answer: B — Arteries
The coronary arteries supply oxygenated blood directly to the myocardium (heart muscle) via the coronary circulation.
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