Question 1

The trachea leads to the ________?

Accepted Answer

Answer reason: The trachea bifurcates at the carina into the right and left main bronchi, which conduct air into each lung. From the bronchi, airflow proceeds to smaller bronchioles and then to alveoli. The esophagus is a posterior gastrointestinal structure and not part of the airway, and pulmonary vessels are components of the circulatory system, not the conducting airways.

Question 2

Asthma is a/an?

Accepted Answer

Answer reason: Asthma is a chronic inflammatory airway disorder characterized by allergic hypersensitivity with IgE-mediated mast cell activation and eosinophilic inflammation, leading to bronchoconstriction and mucus production. It is not caused by bacteria, viruses, or fungi, though infections can trigger exacerbations. Therefore, it is best classified as an allergic disease.

Question 3

Which of the following is not a symptom of asthma?

Accepted Answer

Answer reason: Typical asthma symptoms include episodic wheezing, cough (often nocturnal), chest tightness, and dyspnea due to airway inflammation and bronchoconstriction. High blood sugar is not a manifestation of asthma. Hyperglycemia may occur secondary to systemic corticosteroid therapy but is not a symptom of the disease itself.

Question 4

Pneumonia is an infection of...?

Accepted Answer

Answer reason: Pneumonia is an acute infection of the lung parenchyma, particularly the alveoli, leading to inflammation and consolidation. It presents with cough, fever, dyspnea, and infiltrates on chest imaging. Therefore, it affects the lungs, not nerves, blood, or skin.

Question 5

In the following, which cartilage acts as a lid?

Accepted Answer

Answer reason: The epiglottis is an elastic cartilage that forms the superior part of the larynx and functions as a lid over the laryngeal inlet. During swallowing, it folds posteriorly to cover the airway and prevent aspiration. The thyroid and cricoid cartilages provide structural support to the larynx, and the arytenoids anchor the vocal cords; none of these act as a lid.

Question 6

Adam's apple is more prominent in?

Accepted Answer

Answer reason: The Adam’s apple is the laryngeal prominence of the thyroid cartilage. During puberty, testosterone drives marked growth and angulation of the thyroid cartilage in males, making the prominence larger and more visible. Females and children have smaller larynges with less prominent cartilage, so the Adam’s apple is less apparent.

Question 7

Blood is purified in the human body by?

Accepted Answer

Answer reason: In the lungs, oxygen diffuses into blood and binds to hemoglobin, converting deoxygenated (venous) blood to oxygenated (arterial) blood, which is often termed 'purified' in basic physiology. Carbon dioxide is the waste gas removed from blood, nitrogen is largely inert physiologically, and hydrogen gas is not involved in blood gas exchange.

Question 8

The common symptom of pulmonary TB is _____?

Accepted Answer

Answer reason: Pulmonary tuberculosis commonly presents with a chronic productive cough, often lasting more than two to three weeks and accompanied by sputum that may be blood-tinged. Other classic features include fever, night sweats, and weight loss. Headache, diarrhea, and peripheral leg swelling are not typical primary symptoms of pulmonary TB. Therefore, cough with sputum is the best answer.

Question 9

What is a primary clinical manifestation of pertussis in children?

Accepted Answer

Answer reason: Pertussis (whooping cough) is characterized by paroxysms of coughing followed by a high-pitched inspiratory "whoop," especially in children. Stridor is more typical of upper airway obstruction such as croup. Bradypnea and cyanosis can occur during severe coughing spells but are not primary or defining features. Therefore, the hallmark manifestation is the persistent paroxysmal cough with a whoop.

Question 10

The right lung is divided into how many lobes?

Accepted Answer

Answer reason: The right lung has three lobes: superior, middle, and inferior. These are separated by the horizontal fissure (between superior and middle lobes) and the oblique fissure (between middle and inferior lobes). In contrast, the left lung has two lobes due to space occupied by the heart.

Question 11

The left lung is divided into how many lobes?

Accepted Answer

Answer reason: The left lung has two lobes—superior and inferior—separated by the oblique fissure. It lacks a middle lobe due to the space taken by the cardiac notch for the heart. In contrast, the right lung has three lobes.

Question 12

Cyanosis is caused in case of..?

Accepted Answer

Answer reason: Cyanosis is a bluish discoloration of skin and mucosa from increased deoxygenated hemoglobin in capillary blood. It occurs when arterial oxygen saturation is low or when tissues extract excessive oxygen due to poor perfusion. Hydration status, glucose level, or total blood volume do not directly cause the bluish color. Therefore, it is due to lack of oxygen.

Question 13

Asthma mainly affects?

Accepted Answer

Answer reason: Asthma is a chronic inflammatory disease of the airways leading to bronchoconstriction, mucus hypersecretion, and airway hyperresponsiveness. These processes occur in the bronchi and bronchioles of the lungs, producing wheeze, cough, and dyspnea. The heart, kidneys, and brain are not the primary organs affected in asthma.

Question 14

Normal respiratory rate is ....?

Accepted Answer

Answer reason: In resting adults, the normal respiratory rate is approximately 12–20 breaths per minute. A range of 16–18 falls squarely within this expected normal range. The other options represent abnormally high rates that would indicate tachypnea. Therefore, 16–18 is the best answer.

Question 15

............. in our body is a cartilaginous box which helps in sound production?

Accepted Answer

Answer reason: The larynx, or voice box, is a cartilaginous structure housing the vocal folds, which vibrate to produce sound. It consists of several cartilages (thyroid, cricoid, arytenoid, etc.). The pleura is a serous membrane around the lungs, the epiglottis prevents aspiration, and alveoli are the sites of gas exchange—none are primarily for phonation.

Question 16

Blue skin of a newborn indicates lack of?

Accepted Answer

Answer reason: Blue discoloration (cyanosis) reflects increased deoxygenated hemoglobin in the blood, indicating hypoxemia/poor oxygenation. In newborns, central cyanosis suggests respiratory or cardiac compromise and requires urgent evaluation. Hypoglycemia or calcium imbalance does not cause blue skin, and iron deficiency more typically causes pallor rather than cyanosis.

Question 17

Pneumonia is inflammation of?

Accepted Answer

Answer reason: Pneumonia is an infection causing inflammation of the lung parenchyma, particularly the alveoli, leading to consolidation and impaired gas exchange. It is most commonly due to bacterial, viral, or atypical pathogens. Inflammation of the intestines is enteritis, of the brain is encephalitis, and of the kidneys is nephritis, not pneumonia.

Question 18

Surfactant secreted by type... alveolar epithelial cells?

Accepted Answer

Answer reason: Pulmonary surfactant is produced by type II alveolar epithelial cells (type II pneumocytes). These cells synthesize phospholipids, chiefly dipalmitoylphosphatidylcholine, and secrete it into the alveoli to reduce surface tension. This action prevents alveolar collapse (atelectasis) at end-expiration and improves lung compliance.

Question 19

Which of these diseases affects the human lung?

Accepted Answer

Answer reason: Silicosis is a pneumoconiosis causing fibrotic changes in lung parenchyma from silica dust exposure. Pleurisy is inflammation of the pleura surrounding the lungs, producing pleuritic chest pain and affecting lung expansion. Bronchitis is inflammation of the bronchi, leading to cough and mucus production. Therefore, all listed conditions affect the lungs or their surrounding structures.

Question 20

Which of the following is not a lung disease?

Accepted Answer

Answer reason: COPD, asthma, and pneumonia are diseases of the respiratory system that affect the airways and/or lung parenchyma, leading to airflow limitation or alveolar inflammation/infection. Hepatitis is inflammation of the liver, a hepatic condition, not a pulmonary disorder. Therefore, among the options, hepatitis is the one that is not a lung disease.

Question 21

Emphysema is a disease of?

Accepted Answer

Answer reason: Emphysema is a form of chronic obstructive pulmonary disease characterized by permanent enlargement of distal air spaces with destruction of alveolar walls. This reduces elastic recoil, causes air trapping, and impairs gas exchange in the lungs. Therefore, it is a disease of the lungs.

Question 22

Pus in the pleural cavity is?

Accepted Answer

Answer reason: Empyema is the presence of purulent material (pus) within the pleural space, usually from a bacterial infection or complicated parapneumonic effusion. Hemothorax is blood in the pleural cavity, pneumothorax is air, and pleural effusion refers to fluid in general that is not specifically pus. Therefore, empyema specifically denotes pus in the pleural cavity.

Question 23

First cry of baby indicates?

Accepted Answer

Answer reason: The newborn’s first cry accompanies initiation of pulmonary respiration as the lungs expand with air. This cry helps clear residual fluid from the airways and distributes surfactant, improving alveolar stability. It signals successful transition to effective oxygenation. It is not a sign of hunger, pain, or fever at the moment of birth.

Question 24

The exchange of gases in lungs occurs in?

Accepted Answer

Answer reason: Gas exchange occurs across the thin respiratory membrane lining the alveoli where capillary blood meets inspired air, allowing diffusion of O2 and CO2. The bronchi and trachea are conducting airways without significant diffusion function. The pleura is a serous membrane surrounding the lungs and does not participate in gas exchange.

Question 25

The functional unit of the lungs is?

Accepted Answer

Answer reason: Alveoli are the terminal sacs where gas exchange occurs across the thin alveolar–capillary membrane, making them the functional unit of the lungs. The bronchi and trachea are conducting airways and do not participate in gas exchange. The diaphragm is a respiratory muscle, not a lung unit.

Question 26

The main symptom of asthma is?

Accepted Answer

Answer reason: Asthma is characterized by airway inflammation and reversible bronchoconstriction, leading to dyspnea as a cardinal symptom. Patients typically report shortness of breath with wheezing, chest tightness, and cough, especially at night or with triggers. Fever is not a primary feature unless there is a concurrent infection, and vomiting or diarrhea are unrelated gastrointestinal symptoms.

Question 27

Exchange of gases in humans occurs in?

Accepted Answer

Answer reason: Gas exchange in humans occurs across the alveolar-capillary membrane in the alveoli. These sacs provide a vast surface area and have extremely thin walls formed by type I pneumocytes to facilitate diffusion of O2 and CO2. The bronchi, larynx, and pharynx are conducting airways and do not participate significantly in gas exchange.

Question 28

Which are is also known as Air sac?

Accepted Answer

Answer reason: Alveoli are the tiny saclike structures at the ends of the bronchioles and are commonly called air sacs. They provide a large surface area for gas exchange across the alveolar-capillary membrane. The trachea and bronchi are conducting airways, and the lungs are the whole organs, not the individual air sacs. Therefore, alveoli is the correct term.

Question 29

During breathing, air from pharynx enters to?

Accepted Answer

Answer reason: During inspiration, air moves nose/mouth → pharynx → larynx → trachea. The trachea is the next major conducting airway before it divides into the main bronchi. Bronchi, bronchioles, and alveoli are progressively distal structures. Thus, from the pharynx, air proceeds to the trachea among the options listed.

Question 30

What is the typical symptom of lung cancer?

Accepted Answer

Answer reason: Hemoptysis (coughing up blood) is a classic presenting symptom of lung cancer due to tumor invasion of bronchial mucosa and fragile neovasculature. Diarrhea is a gastrointestinal symptom and not typical of lung malignancy. Jaundice suggests hepatobiliary disease or extensive metastasis, not a common initial manifestation. Headache can occur with brain metastases but is not a typical early symptom.

Question 31

Tuberculosis most commonly affects _____?

Accepted Answer

Answer reason: Mycobacterium tuberculosis is transmitted via airborne droplets and typically establishes infection in the lungs after inhalation. Pulmonary TB is the most common presentation because bacilli are deposited in the alveoli and taken up by alveolar macrophages. While extrapulmonary TB can involve organs such as the kidneys, bones, or skin, these are less frequent than pulmonary disease.

Question 32

The tube that carries air into the lungs is?

Accepted Answer

Answer reason: The trachea, or windpipe, conducts air from the larynx to the bronchi and then to the lungs. The esophagus carries food to the stomach, not air. The ureter transports urine from the kidneys to the bladder. The larynx is the voice box above the trachea and does not deliver air to the lungs directly.

Question 33

Residual air volume of lungs is?

Accepted Answer

Answer reason: Residual volume is the amount of air remaining in the lungs after a maximal forced expiration. In healthy adults it averages about 1.2–1.5 liters, helping keep alveoli open and allowing continuous gas exchange between breaths. Among the provided choices, 1.5 litres is the best match.

Question 34

On a flow-volume loop, obstructive lung disease shifts the loop to the?

Accepted Answer

Answer reason: Obstructive diseases (e.g., COPD, asthma) cause air trapping with increased residual volume and often increased total lung capacity. On flow-volume loops, this translates to a shift toward higher lung volumes, which is displayed to the left on standard plots. The expiratory limb also shows a concave, scooped-out appearance due to reduced expiratory flow. Therefore, the loop shifts to the left.

Question 35

What is the normal range for adult respiratory rate?

Accepted Answer

Answer reason: Normal adult respiratory rate is 12–20 breaths per minute at rest. Rates above this (e.g., 25–40 or 32–60) indicate tachypnea and are typical of younger children or infants, not healthy adults. Recognizing normal ranges helps detect early respiratory compromise.

Question 36

Lungs are enclosed in?

Accepted Answer

Answer reason: The lungs are enclosed by the pleura, a serous membrane with visceral and parietal layers separated by a thin fluid-filled pleural cavity that reduces friction during breathing. Periosteum covers bone, perichondrium covers cartilage, and pericardium encloses the heart. Therefore, the correct covering for the lungs is the pleural membrane.

Question 37

The gaseous exchange in alveoli is a type of?

Accepted Answer

Answer reason: Oxygen and carbon dioxide move across the thin alveolar–capillary membrane by simple diffusion, driven by partial pressure gradients. No carrier proteins or ATP are required, and hemoglobin binding helps maintain the gradient. Osmosis refers specifically to water movement, and active transport uses energy. While diffusion is a form of passive transport, the most specific mechanism here is simple diffusion.

Question 38

The diaphragm helps in which function of lungs?

Accepted Answer

Answer reason: The diaphragm is the primary muscle of inspiration. When it contracts, thoracic volume increases and intrathoracic pressure falls, drawing air into the lungs. Relaxation allows passive exhalation. It is not involved in digestion, circulation, or general excretion.

Question 39

The primary bronchi divide into smaller tubes called?

Accepted Answer

Answer reason: In the conducting airways, the trachea bifurcates into the right and left primary bronchi, which branch into progressively smaller airways that become bronchioles. The trachea is proximal to the bronchi, not a smaller division. Alveoli are terminal gas-exchange sacs, and capillaries are blood vessels, not airways. Therefore, the smaller tubes are bronchioles.

Question 40

Which muscles assist diaphragm in breathing?

Accepted Answer

Answer reason: Ventilation is driven primarily by the diaphragm, with the intercostal muscles assisting by elevating and expanding the rib cage during inspiration and aiding forced expiration. External intercostals increase thoracic volume, while internal intercostals help with active exhalation. Cardiac and smooth muscles are not responsible for the mechanics of breathing.

Question 41

Lack of oxygen is termed?

Accepted Answer

Answer reason: Hypoxia is the condition of reduced oxygen availability at the tissue level. Apnea refers to cessation of breathing, not necessarily tissue oxygen lack. Dyspnea is the subjective sensation of difficult breathing. Anemia is decreased hemoglobin concentration; it may contribute to hypoxia but is not the term for lack of oxygen itself.

Question 42

The process of expelling air from the lungs is called?

Accepted Answer

Answer reason: Expelling air from the lungs occurs during exhalation. During this phase, the diaphragm and intercostal muscles relax, thoracic volume decreases, and alveolar pressure rises above atmospheric pressure, driving air out. Inhalation is the intake of air, while filtration and circulation are unrelated processes.

Question 43

The process of oxygen entering blood in lungs is called?

Accepted Answer

Answer reason: In the alveoli, oxygen moves down its partial pressure gradient across the alveolar–capillary membrane into capillary blood by simple diffusion. This passive process requires no energy and is driven by the higher alveolar PO2 relative to venous blood. Digestion pertains to the GI tract, filtration describes pressure-driven movement across membranes such as in kidneys, and circulation refers to bulk flow of blood, not molecular transfer.

Question 44

The structure that prevents food entry into the trachea is?

Accepted Answer

Answer reason: During swallowing, the epiglottis folds down to cover the laryngeal inlet, preventing aspiration of food into the trachea and directing the bolus into the esophagus. The uvula and soft palate elevate to close off the nasopharynx, not the airway. The tongue primarily propels the bolus posteriorly. Therefore, the epiglottis is the structure that prevents food entry into the trachea.

Question 45

Which gas is absorbed by the lungs during respiration?

Accepted Answer

Answer reason: During external respiration, oxygen diffuses from the alveoli into pulmonary capillary blood along its partial pressure gradient. Carbon dioxide moves in the opposite direction to be exhaled. Nitrogen is largely inert and not significantly absorbed, and hydrogen is not a major component of inspired air. Therefore, the lungs absorb oxygen.

Question 46

One of the commonest complications of chronic asthma is?

Accepted Answer

Answer reason: Chronic asthma features airway inflammation and mucus hypersecretion, which can obstruct bronchi and lead to segmental or lobar collapse—atelectasis—a frequent complication, especially during exacerbations. Pneumothorax can occur but is uncommon and usually related to severe attacks or barotrauma. Emphysema and pulmonary fibrosis are not typical direct complications of asthma. Therefore, atelectasis is the most common complication among the options.

Question 47

Larynx is the part of ------- system?

Accepted Answer

Answer reason: The larynx sits between the pharynx and trachea and functions as part of the airway. It facilitates phonation and protects the lower respiratory tract by closing the glottis during swallowing via the epiglottis. Therefore, it belongs to the respiratory system.

Question 48

What are the symptoms of asthma?

Accepted Answer

Answer reason: Typical asthma symptoms include chest tightness and expiratory wheezing due to bronchoconstriction and airway inflammation. Sneezing is more characteristic of allergic rhinitis rather than asthma. Therefore, the correct combination is tightness in the chest and wheezing.

Question 49

Concentration of oxygen in expired (exhaled) air is about-?

Accepted Answer

Answer reason: Inspired air contains about 21% oxygen, but oxygen is extracted in the alveoli during gas exchange. Mixed expired air therefore has a lower oxygen fraction, approximately 16%, while carbon dioxide rises to around 4%. Values of 0% or 21% are inconsistent with normal physiology. Thus, 16% best reflects the O2 concentration in exhaled air.

Question 50

Which two diseases are included under COPD?

Accepted Answer

Answer reason: COPD is defined by persistent, largely irreversible airflow limitation and is classically composed of chronic bronchitis and emphysema. Chronic bronchitis features chronic productive cough due to airway inflammation and mucus hypersecretion, while emphysema involves alveolar destruction and air trapping. Asthma is typically reversible, and pneumonia, tuberculosis, lung cancer, bronchiectasis, and pleural effusion are distinct conditions not included under COPD.

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