What is the primary function of the respiratory system? — Electrical Engineering MCQ

B. Exchange of oxygen and carbon dioxide between the body and the environment — The respiratory system's primary function is gas exchange (respiration) - taking in oxygen (O2) from the environment and expelling carbon dioxide (CO2) produced by cellular metabolism. Other functions include: regulation of blood pH (by controlling CO2 levels), voice production (phonation), olfaction (sense of smell), and protection against inhaled pathogens and particles. The process involves: Breathing (ventilation), Gas exchange (in alveoli), Transport (by blood), and Cellular respiration.

D. Filtration of waste products

Which organ is the primary organ of the respiratory system? — Electrical Engineering MCQ

C. Lungs — The Lungs are the primary organs of the respiratory system. They are a pair of large, spongy, cone-shaped organs located in the thoracic cavity (chest), protected by the rib cage. The right lung has 3 lobes (superior, middle, inferior) and the left lung has 2 lobes (superior, inferior) - the left lung is smaller to accommodate the heart. The lungs contain millions of tiny air sacs called alveoli, which are the actual sites of gas exchange between air and blood.

What is the voice box called? — Electrical Engineering MCQ

C. Larynx — The Larynx (voice box) is a cartilaginous structure located in the anterior neck, between the pharynx and trachea. It contains the vocal cords (vocal folds) which vibrate as air passes through, producing sound. The larynx is composed of 9 cartilages, the largest being the thyroid cartilage (Adam's apple). The epiglottis is a leaf-shaped cartilage that covers the larynx during swallowing to prevent food/liquid from entering the airway. The larynx also controls airflow during breathing.

What is the windpipe called? — Electrical Engineering MCQ

D. Trachea — The Trachea (windpipe) is a tube approximately 10-12 cm long that extends from the larynx to the point where it divides into the two primary bronchi (carina). It is reinforced by C-shaped (horseshoe-shaped) rings of hyaline cartilage that keep it open and prevent collapse during breathing. The trachea is lined with ciliated pseudostratified columnar epithelium with mucus-secreting goblet cells that trap and remove foreign particles and pathogens via the mucociliary escalator.

At what level does the trachea divide into two bronchi? — Electrical Engineering MCQ

B. T4-T5 (Carina / Sternal angle of Louis) — The trachea bifurcates (divides) into the right and left primary bronchi at the level of T4-T5 vertebrae, at a landmark called the Carina. This level also corresponds to the Sternal Angle of Louis. The right primary bronchus is wider, shorter, and more vertical - more likely to receive inhaled foreign objects. The left primary bronchus is narrower, longer, and more horizontal.

What are the tiny air sacs in the lungs where gas exchange occurs? — Electrical Engineering MCQ

B. Alveoli — Alveoli (singular: alveolus) are the tiny, grape-like air sacs at the end of the bronchial tree where gas exchange takes place. Each lung contains approximately 300-500 million alveoli. Total surface area is approximately 70-80 m2 (size of a tennis court). Walls are just one cell thick (type I pneumocytes) - allowing rapid diffusion. Type II pneumocytes produce surfactant - reduces surface tension and prevents alveolar collapse. Surrounded by a rich network of pulmonary capillaries.

What is the role of surfactant in the lungs? — Electrical Engineering MCQ

B. Reduces surface tension in alveoli, preventing their collapse — Pulmonary Surfactant is a complex mixture of phospholipids and proteins secreted by Type II alveolar cells (Type II pneumocytes). Its main function is to reduce surface tension within the alveoli, preventing them from collapsing (atelectasis) at the end of each breath. Without surfactant, the alveoli would collapse due to high surface tension of water lining. Neonatal Respiratory Distress Syndrome (NRDS) occurs in premature babies due to insufficient surfactant production, causing respiratory failure at birth.

What is the diaphragm and what is its role in breathing? — Electrical Engineering MCQ

B. A dome-shaped muscle that separates the thoracic and abdominal cavities and is the primary muscle of breathing — The Diaphragm is the primary muscle of respiration - a dome-shaped, flat muscle that forms the floor of the thoracic cavity and separates it from the abdominal cavity. During inhalation: the diaphragm contracts and flattens, thoracic volume increases, pressure decreases, air flows in. During exhalation: the diaphragm relaxes and domes upward, thoracic volume decreases, pressure increases, air flows out. The diaphragm is innervated by the phrenic nerve (C3, C4, C5). Mnemonic: C3, 4, 5 keeps the diaphragm alive.

A. A bone that protects the lungs

C. A membrane covering the lungs

D. A cartilage ring in the trachea

What is the normal breathing rate in a healthy adult at rest? — Electrical Engineering MCQ

B. 12-20 breaths per minute — The normal respiratory rate (eupnoea) in a healthy adult at rest is 12-20 breaths per minute. Terms for abnormal breathing rates: Tachypnoea = breathing rate >20/min (too fast), Bradypnoea = breathing rate <12/min (too slow), Apnoea = complete cessation of breathing, Hyperpnoea = increased depth of breathing (e.g., during exercise), Dyspnoea = difficulty in breathing (shortness of breath). In newborns, the normal breathing rate is higher: 30-60 breaths per minute.

What is the epiglottis? — Electrical Engineering MCQ

B. A leaf-shaped cartilage flap that covers the larynx during swallowing to prevent food from entering the airway — The Epiglottis is a leaf/flap-shaped elastic cartilage attached to the base of the tongue and top of the larynx. During swallowing (deglutition), the epiglottis folds down over the glottis (opening of the larynx) to prevent food and liquids from entering the trachea and lungs. During normal breathing, the epiglottis is upright, keeping the airway open. If food accidentally enters the trachea (aspiration), a cough reflex is triggered to expel it. Epiglottitis is a dangerous infection of the epiglottis that can obstruct the airway.

How many lobes does the right lung have? — Electrical Engineering MCQ

B. 3 — The right lung has 3 lobes: Superior (upper) lobe, Middle lobe, and Inferior (lower) lobe. These are separated by the horizontal fissure (between superior and middle lobes) and the oblique fissure (between middle and inferior lobes). The left lung has only 2 lobes (Superior and Inferior) separated by one oblique fissure. The left lung is smaller to accommodate the heart in the left side of the chest (cardiac notch and lingula).

What is the pleura? — Electrical Engineering MCQ

B. A double-layered membrane surrounding each lung — The Pleura is a double-layered serous membrane that surrounds each lung. Visceral pleura directly covers the surface of the lung. Parietal pleura lines the inner wall of the thoracic cavity. Between them is the pleural cavity containing a thin film of pleural fluid that reduces friction during breathing and creates surface tension that keeps lungs expanded. Conditions: Pleuritis/Pleurisy = inflammation of pleura (painful breathing), Pleural effusion = excess fluid in pleural cavity, Pneumothorax = air in pleural cavity causing lung collapse.

A. The muscle between the two lungs

C. The tissue inside the alveoli

D. A cartilage ring around the trachea

What is pneumothorax? — Electrical Engineering MCQ

B. Accumulation of air in the pleural cavity causing lung collapse — Pneumothorax (collapsed lung) occurs when air enters the pleural cavity, disrupting the negative pressure that keeps the lung expanded, causing the lung to collapse. Types: Spontaneous pneumothorax (occurs without injury - common in tall, thin young men), Traumatic pneumothorax (from chest injury - stab wound, rib fracture), Tension pneumothorax (life-threatening - air enters but cannot escape, compressing the heart and other lung). Symptoms: sudden chest pain, shortness of breath. Treatment: needle decompression or chest tube insertion.

What is the Adam's apple? — Electrical Engineering MCQ

B. The prominent projection of the thyroid cartilage of the larynx, more visible in males — The Adam's apple is the common name for the laryngeal prominence - the visible projection formed by the thyroid cartilage of the larynx. It is more prominent in males due to the effect of testosterone during puberty, which causes the larynx to grow larger, making the vocal cords longer and thicker, resulting in a deeper voice. The angle of the thyroid cartilage is approximately 90 degrees in males and 120 degrees in females, making it more prominent in males.

What is the process of breathing in called? — Electrical Engineering MCQ

C. Inspiration (Inhalation) — Inspiration (Inhalation) is the process of breathing in - drawing air into the lungs. It is an active process requiring muscular contraction: Diaphragm contracts (moves downward) and External intercostal muscles contract (ribs move up and out), Thoracic volume increases, intrapulmonary pressure decreases below atmospheric pressure, air flows into the lungs. Expiration (Exhalation) is breathing out - normally a passive process (muscles relax). Forced expiration (during exercise or coughing) is active, using internal intercostal and abdominal muscles.

What gas do we exhale in greater amounts than we inhale? — Electrical Engineering MCQ

C. Carbon Dioxide — Composition of inhaled air vs exhaled air: Oxygen = Inhaled ~21%, Exhaled ~16% (O2 absorbed by body). Carbon Dioxide = Inhaled ~0.04%, Exhaled ~4% (CO2 produced by cellular respiration). Nitrogen = Inhaled ~78%, Exhaled ~78% (unchanged - not used by body). Water vapour = Exhaled air is saturated with water vapour (hence breath fogs cold glass). So we exhale significantly more CO2 than we inhale, as CO2 is the waste product of cellular respiration (aerobic metabolism).

What is the respiratory centre in the brain? — Electrical Engineering MCQ

C. Medulla oblongata and Pons — The respiratory centre that controls the rhythm and rate of breathing is located in the brainstem: Medulla oblongata contains the Dorsal Respiratory Group (DRG) and Ventral Respiratory Group (VRG) - sets the basic rhythm of breathing. Pons contains the Pneumotaxic centre (limits inspiration) and Apneustic centre (prolongs inspiration). The respiratory centre responds to chemoreceptors that monitor blood CO2, O2, and pH levels. Rising CO2 (falling pH) is the strongest stimulus to increase breathing rate - detected by central chemoreceptors in the medulla.

What is Asthma? — Electrical Engineering MCQ

B. A chronic inflammatory disease of the airways causing reversible airway obstruction, wheeze, and breathlessness — Asthma is a chronic inflammatory disease of the airways (bronchi and bronchioles) characterised by airway inflammation (swelling of airway walls), bronchoconstriction (narrowing of airways due to smooth muscle contraction), excessive mucus production (further blocking airflow), and reversible airway obstruction (key feature - distinguishes from COPD). Symptoms: wheeze, cough, chest tightness, shortness of breath. Triggers: allergens (pollen, dust mites), exercise, cold air, infections, smoke. Treatment: Bronchodilators (relievers) - salbutamol (beta-2 agonist), Corticosteroids (preventers).

A. A bacterial infection of the lungs

C. Accumulation of fluid in the lungs

What is the correct path of air from the nose to the alveoli? — Electrical Engineering MCQ

B. Nose > Pharynx > Larynx > Trachea > Bronchi > Bronchioles > Alveoli — The correct pathway of air through the respiratory system: Nose/Mouth > Nasal cavity > Pharynx > Larynx > Trachea > Primary bronchi (R & L) > Secondary bronchi > Tertiary bronchi > Bronchioles > Terminal bronchioles > Respiratory bronchioles > Alveolar ducts > Alveolar sacs > Alveoli. The nose filters, warms, and humidifies air. The pharynx is the common passageway for food and air. The larynx connects to the trachea. The trachea divides into bronchi which further divide into smaller bronchioles leading to alveoli.

A. Nose > Trachea > Pharynx > Larynx > Bronchi > Alveoli

C. Nose > Larynx > Pharynx > Trachea > Alveoli > Bronchi

D. Nose > Bronchi > Trachea > Larynx > Alveoli

What is the total lung capacity in a healthy adult? — Electrical Engineering MCQ

C. 6 litres (approximately) — Lung volumes in a healthy adult male (approximate): Tidal Volume (TV) = ~500 mL (air breathed in/out in one normal breath). Inspiratory Reserve Volume (IRV) = ~3000 mL. Expiratory Reserve Volume (ERV) = ~1200 mL. Residual Volume (RV) = ~1200 mL (air remaining after maximum exhalation - cannot be expelled). Total Lung Capacity (TLC) = TV + IRV + ERV + RV = ~6000 mL (6 litres). Vital Capacity (VC) = TV + IRV + ERV = ~4800 mL.

What is tidal volume? — Electrical Engineering MCQ

B. The volume of air inhaled or exhaled in one normal breath at rest — Tidal Volume (TV) is the volume of air that moves in and out of the lungs in one normal, relaxed breath - approximately 500 mL (0.5 litres) in a healthy adult at rest. Of this 500 mL: About 350 mL actually reaches the alveoli for gas exchange. About 150 mL remains in the anatomical dead space (nose, pharynx, trachea, bronchi) - airways that conduct air but don't participate in gas exchange. During exercise, tidal volume increases significantly as breathing becomes deeper.

A. The maximum amount of air that can be exhaled

C. The total capacity of the lungs

D. The air that remains in the lungs after maximum exhalation

What is vital capacity? — Electrical Engineering MCQ

B. The maximum amount of air that can be exhaled after maximum inhalation — Vital Capacity (VC) is the maximum volume of air that can be exhaled after taking the deepest possible breath. VC = Tidal Volume (TV) + Inspiratory Reserve Volume (IRV) + Expiratory Reserve Volume (ERV) = 500 + 3000 + 1200 = ~4700 mL (~4.7 litres). Vital capacity is reduced in conditions like pneumonia, pulmonary fibrosis, pleural effusion. It is higher in trained athletes. Spirometry is the test used to measure lung volumes including vital capacity - important for diagnosing respiratory diseases like COPD and asthma.

A. The air remaining in lungs after maximum exhalation

D. The total lung capacity minus residual volume

What is residual volume? — Electrical Engineering MCQ

B. The volume of air that always remains in the lungs after maximum exhalation and cannot be expelled — Residual Volume (RV) is the approximately 1200 mL of air that always remains in the lungs even after the most forceful exhalation. It cannot be removed by breathing. Its importance: Prevents the lungs from completely collapsing between breaths, Allows continuous gas exchange even between breaths, and Keeps alveoli open (along with surfactant). Residual volume cannot be measured by simple spirometry - requires special techniques like helium dilution or body plethysmography. RV increases in emphysema (hyperinflation) and decreases in pulmonary fibrosis.

A. The volume of air breathed in during exercise

C. The air in the trachea and bronchi

D. The total air capacity of the lungs

What is COPD? — Electrical Engineering MCQ

B. Chronic Obstructive Pulmonary Disease - a group of progressive lung diseases (emphysema and chronic bronchitis) causing irreversible airflow obstruction — COPD (Chronic Obstructive Pulmonary Disease) is a chronic, progressive lung disease characterised by irreversible airflow obstruction (unlike asthma which is reversible). It includes: Chronic Bronchitis (chronic inflammation and excess mucus production in the bronchi - blue bloater: cyanotic, oedematous) and Emphysema (destruction of alveolar walls - large air spaces - reduced surface area for gas exchange - pink puffer: breathless, barrel chest). Main cause: cigarette smoking (>80% of cases). Also: air pollution, occupational dust/chemicals. Treatment: bronchodilators, steroids, oxygen therapy.

D. An acute respiratory infection

What is pneumonia? — Electrical Engineering MCQ

B. Inflammation of the lungs usually caused by infection, causing air sacs to fill with fluid or pus — Pneumonia is an infection/inflammation of the lung parenchyma (alveoli and surrounding tissue), causing the alveoli to fill with fluid (exudate) or pus, impairing gas exchange. Causes: Bacterial (most common - Streptococcus pneumoniae/pneumococcus), Viral (Influenza, COVID-19, RSV), Fungal (immunocompromised patients). Symptoms: fever, cough with sputum, chest pain, breathlessness. Diagnosis: Chest X-ray (shows consolidation/white opacity). Treatment: antibiotics (for bacterial), supportive care. Prevention: pneumococcal and influenza vaccines.

C. Chronic inflammation of the bronchi

What is the function of the nasal cavity in respiration? — Electrical Engineering MCQ

B. Filter, warm, and humidify incoming air before it reaches the lungs — The nasal cavity performs three crucial functions for conditioning inhaled air: Filtration (nasal hairs/vibrissae filter large particles; mucus traps smaller particles and microorganisms; cilia sweep trapped material toward the throat), Warming (rich blood supply in the nasal turbinates/conchae warms cold air to body temperature 37 degrees C), and Humidification (mucous membranes add moisture - air reaches nearly 100% humidity before entering the lungs). These functions protect the delicate lung tissue from damage by cold, dry, or contaminated air.

C. Directly exchange gases with blood

What is the pharynx? — Electrical Engineering MCQ

B. The common passageway for both food and air, located behind the nasal and oral cavities — The Pharynx (throat) is a muscular funnel-shaped tube approximately 13 cm long that serves as the common passageway for both food and air. It has three parts: Nasopharynx (behind nasal cavity; air only; contains adenoids and Eustachian tube openings), Oropharynx (behind mouth; food and air; contains palatine tonsils), and Laryngopharynx (behind larynx; food and air; leads to oesophagus for food and larynx for air). The epiglottis ensures food goes to the oesophagus and air goes to the larynx.

Which gas is transported by haemoglobin in red blood cells? — Electrical Engineering MCQ

C. Oxygen (primarily) and Carbon Dioxide — Haemoglobin (Hb) in red blood cells transports gases: Oxygen - Hb + O2 = Oxyhaemoglobin (HbO2), O2 binds to the iron (Fe2+) in haem groups, each Hb molecule carries 4 O2 molecules, about 98.5% of O2 is carried this way; 1.5% dissolved in plasma. Carbon Dioxide - about 23% of CO2 binds to haemoglobin forming Carbaminohaemoglobin. Most CO2 (70%) is transported as bicarbonate ions (HCO3-) in plasma. 7% dissolved in plasma. Carbon monoxide (CO) binds haemoglobin 200x more strongly than O2 - forms carboxyhaemoglobin - prevents O2 transport - CO poisoning.

What is tuberculosis (TB)? — Electrical Engineering MCQ

B. A chronic bacterial infection of the lungs caused by Mycobacterium tuberculosis — Tuberculosis (TB) is a chronic infectious disease caused by the bacterium Mycobacterium tuberculosis. It primarily affects the lungs (pulmonary TB) but can spread to other organs. Transmission: airborne droplets (coughing, sneezing). Symptoms: persistent cough (with blood-stained sputum), night sweats, weight loss (consumption), fever, fatigue. Diagnosis: Mantoux (tuberculin skin) test, Sputum AFB, Chest X-ray, GeneXpert. Treatment: DOTS (Directly Observed Treatment Short-course) - combination of antibiotics (HRZE) for 6 months. India has the highest TB burden in the world.

A. A viral infection of the respiratory tract

C. An autoimmune disease of the lungs

D. A fungal infection of the bronchi

What is the Heimlich manoeuvre used for? — Electrical Engineering MCQ

B. Dislodging a foreign object from the airway of a choking person — The Heimlich Manoeuvre (Abdominal Thrust) is an emergency technique used to dislodge a foreign object (food, object) from the airway of a choking person. Procedure: Stand behind the choking person, wrap arms around their waist, make a fist with one hand placed just above the navel, grasp with other hand, and deliver firm inward and upward thrusts. This creates a rapid increase in intrathoracic pressure that forces air up the trachea, expelling the obstruction. It was developed by Dr. Henry Heimlich in 1974.

What is the bronchial tree? — Electrical Engineering MCQ

B. The branching network of airways from the trachea to the alveoli — The Bronchial Tree is the complete branching system of airways that resembles an inverted tree: Trachea > 2 Primary (main) bronchi > 5 Secondary (lobar) bronchi (3 right, 2 left) > 18-20 Tertiary (segmental) bronchi > Bronchioles > Terminal bronchioles > Respiratory bronchioles > Alveolar ducts > Alveolar sacs > Alveoli. The bronchi contain cartilage rings for support. Bronchioles have no cartilage but have smooth muscle walls that can dilate (bronchodilation) or constrict (bronchoconstriction). The entire system undergoes approximately 23 divisions (generations).

C. The blood vessels of the lung

D. The nerve supply of the diaphragm

What is the difference between aerobic and anaerobic respiration? — Electrical Engineering MCQ

B. Aerobic respiration uses oxygen and produces CO2, water, and ATP; anaerobic respiration occurs without oxygen and produces lactic acid (in humans) — Aerobic Respiration: C6H12O6 + 6O2 > 6CO2 + 6H2O + 38 ATP - occurs in mitochondria; produces large amounts of energy. Anaerobic Respiration (in humans): C6H12O6 > 2 Lactic acid + 2 ATP - occurs during intense exercise when O2 supply is insufficient; produces small amounts of energy; lactic acid builds up causing muscle fatigue and cramps. In yeast/microorganisms: Glucose > Ethanol + CO2 + energy (fermentation). Oxygen debt = extra O2 needed after anaerobic exercise to break down accumulated lactic acid.

A. Aerobic uses CO2, anaerobic uses O2

C. Aerobic and anaerobic are the same process

D. Aerobic respiration produces lactic acid

What is emphysema? — Electrical Engineering MCQ

B. Destruction of alveolar walls leading to large air spaces, reduced gas exchange surface area, and breathlessness — Emphysema is a type of COPD where the walls between alveoli are destroyed, forming large, non-functional air spaces. This leads to: Reduced surface area for gas exchange (hypoxia), Air trapping (hyperinflation - barrel chest), Loss of lung elasticity (difficulty exhaling), and Pink Puffer appearance (breathless but maintain normal blood O2 by increased breathing rate). Primary cause: cigarette smoking destroys the alveolar walls via proteases (anti-trypsin deficiency is a genetic cause). Diagnosis: Spirometry shows reduced FEV1/FVC ratio.

D. Bacterial infection of the lungs

What is the role of intercostal muscles in breathing? — Electrical Engineering MCQ

B. They assist breathing by moving the ribs up and out (external) during inhalation and down and in (internal) during forced exhalation — The intercostal muscles are located between the ribs and play an important role in breathing. External intercostal muscles: Contract during inhalation, ribs move upward and outward, increases thoracic volume, air flows in. They are accessory muscles of inspiration. Internal intercostal muscles: Contract during forced exhalation, ribs move downward and inward, decreases thoracic volume, air flows out. During quiet breathing, exhalation is passive (muscles relax). During exercise or respiratory distress, accessory muscles like sternocleidomastoid and scalenes also assist.

A. They filter air in the bronchi

D. They control the vocal cords

What is the medical term for difficulty in breathing? — Electrical Engineering MCQ

C. Dyspnoea — Respiratory terminology: Eupnoea = normal, easy breathing. Dyspnoea = difficulty in breathing / shortness of breath (SOB). Apnoea = cessation of breathing. Tachypnoea = abnormally rapid breathing (>20/min). Bradypnoea = abnormally slow breathing (<12/min). Orthopnoea = breathlessness when lying flat (relieved by sitting up - common in heart failure). Hyperpnoea = increased depth of breathing. Hypoxia = low oxygen in tissues. Hypoxaemia = low oxygen in blood. Hypercapnia = excess CO2 in blood.

What is the oxygen-carrying pigment in human blood? — Electrical Engineering MCQ

C. Haemoglobin — Haemoglobin (Hb) is the iron-containing protein in red blood cells (RBCs) responsible for oxygen transport in the blood. Structure: 4 subunits each containing a haem group (with iron Fe2+) and a globin protein chain. Each molecule can carry 4 oxygen molecules. Normal haemoglobin levels: Males: 13.5-17.5 g/dL, Females: 12-15.5 g/dL. Myoglobin stores O2 in muscle tissue. Bilirubin is the breakdown product of haemoglobin. Low Hb = Anaemia - reduced O2 carrying capacity - fatigue, breathlessness.

What happens to breathing rate during exercise? — Electrical Engineering MCQ

C. It increases to meet the increased oxygen demand and remove excess CO2 — During exercise, the muscles require more oxygen for aerobic respiration and produce more CO2 and lactic acid. This leads to: Increased breathing rate (tachypnoea), Increased tidal volume (deeper breaths), Combined effect = Increased minute ventilation (up to 150 L/min during intense exercise vs. 6-8 L/min at rest). The primary stimulus for increased breathing during exercise is rising blood CO2 (hypercapnia) and falling blood pH - detected by chemoreceptors in the medulla and carotid/aortic bodies. Also triggered by muscle/joint mechanoreceptors even before CO2 rises.

What is pleurisy (pleuritis)? — Electrical Engineering MCQ

B. Inflammation of the pleura causing sharp chest pain that worsens with breathing — Pleurisy (Pleuritis) is inflammation of the pleura (the double-layered membrane surrounding the lungs). The inflamed pleural layers rub against each other causing sharp, stabbing chest pain that typically worsens with breathing, coughing, or sneezing - called pleuritic chest pain. Causes: Viral infections (most common - influenza, COVID-19), Bacterial pneumonia, Tuberculosis, Pulmonary embolism, Autoimmune diseases (lupus, rheumatoid arthritis). Treatment: pain relief (NSAIDs), treating the underlying cause.

A. Accumulation of air in the pleural space

What is the function of cilia in the respiratory tract? — Electrical Engineering MCQ

B. Beat rhythmically to sweep trapped particles and mucus upward toward the throat (mucociliary escalator) — The respiratory tract is lined with ciliated epithelium. The cilia (tiny hair-like projections) beat rhythmically (10-20 times per second) in a coordinated wave-like motion, sweeping the mucus blanket (with trapped particles, bacteria, and debris) upward toward the pharynx where it is swallowed or expectorated. This is the Mucociliary Escalator (Mucociliary Clearance) - a key defence mechanism of the lungs. Cigarette smoke paralyses and destroys cilia - impaired clearance - increased infections and mucus accumulation (smoker's cough).

What is lung cancer? — Electrical Engineering MCQ

B. Malignant tumour arising from the cells of the lung, most commonly associated with smoking — Lung Cancer is the leading cause of cancer death worldwide. Types: Non-Small Cell Lung Cancer (NSCLC) ~85% of cases (includes Adenocarcinoma - most common, Squamous cell carcinoma, Large cell carcinoma) and Small Cell Lung Cancer (SCLC) ~15% (highly aggressive, strongly linked to smoking). Main cause: Cigarette smoking (responsible for ~85% of cases). Other causes: radon gas, asbestos, air pollution, genetic factors. Symptoms: persistent cough, haemoptysis (blood in sputum), weight loss, chest pain, hoarseness. Early detection: CT scan (low-dose), sputum cytology.

A. A bacterial infection of the lung

D. Autoimmune disease of the lung

What is the Heimlich manoeuvre also known as? — Electrical Engineering MCQ

B. Abdominal thrust technique for choking — The Heimlich Manoeuvre is formally called the Abdominal Thrust technique. It is used when someone is choking (airway obstructed by a foreign body). The rapid upward thrust on the abdomen compresses the diaphragm, suddenly increasing pressure in the thoracic cavity and forcing air through the trachea - acting like an artificial cough to dislodge the obstruction. For infants, back blows and chest thrusts are used instead of abdominal thrusts. For self-choking, the person can perform self-Heimlich using a chair back. CPR is used for cardiac arrest - different from Heimlich.

A. Mouth-to-mouth resuscitation

Respiratory System MCQ [ Free PDF Download ] for RRB & SSC and other Competitive exams

Respiratory System MCQ for RRB & SSC and other Competitive exams

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What is the correct term for the breathing out of air from the lungs?

RRB/SSC/UPSC Easy

✓ Answer: C Expiration (Exhalation)

Expiration (Exhalation) is the process of breathing out - expelling air from the lungs. During quiet/normal expiration, it is a passive process: Diaphragm and external intercostals relax, Thoracic cavity volume decreases, Intrapulmonary pressure increases above atmospheric, air flows out, Lung elasticity (recoil) helps expel air. During forced expiration (exercise, coughing, sneezing), it becomes active: Internal intercostal muscles contract (ribs move down and in) and Abdominal muscles (rectus abdominis, obliques) contract (push diaphragm up), generating higher intra-abdominal pressure.

What causes the sound of breathing (breath sounds) heard through a stethoscope?

RRB/SSC/UPSC Medium

✓ Answer: B Turbulent airflow through the airways creating sounds audible on auscultation

Breath sounds are produced by turbulent airflow through the bronchial tree. Normal breath sounds: Vesicular (soft, low-pitched sounds over most of the lung fields - normal) and Bronchial (loud, high-pitched - normal over trachea/bronchi; abnormal if heard over lung fields - indicates consolidation). Abnormal (added) sounds: Crackles/Crepitations (popping sounds - fine crackles in pulmonary fibrosis - Velcro-like, coarse crackles in pneumonia, pulmonary oedema), Wheeze (high-pitched musical sound - asthma, COPD - bronchospasm), Pleural rub (creaking sound - pleuritis), and Stridor (harsh, high-pitched - upper airway obstruction - croup, epiglottitis).

What is the medical term for a runny nose?

RRB/SSC/UPSC Easy

✓ Answer: B Rhinorrhoea

Rhinorrhoea (commonly called a runny nose) refers to the excessive discharge of mucus from the nose. It is one of the most common symptoms of: Common cold (rhinovirus - most common cause), Allergic rhinitis (hay fever - triggered by pollen, dust, pet dander), and Vasomotor rhinitis (non-allergic - triggered by temperature changes, irritants). Related nasal terms: Rhinitis = inflammation of nasal mucosa, Epistaxis = nosebleed, Anosmia = loss of smell, Sinusitis = sinus inflammation. Antihistamines and nasal corticosteroids are commonly used to treat allergic rhinorrhoea.

What are the lungs' defence mechanisms against inhaled microorganisms?

RRB/SSC/UPSC Medium

✓ Answer: B Multiple layered defences - nasal filtration, mucociliary clearance, cough reflex, alveolar macrophages, and immunoglobulins

The respiratory system has multiple layers of defence against inhaled pathogens: 1) Nasal vibrissae (filter large particles), 2) Nasal mucosa warming/humidification (deactivates some pathogens), 3) Mucociliary escalator (cilia sweep mucus + trapped particles upward), 4) Cough and sneeze reflex (expel irritants), 5) Alveolar macrophages or dust cells (phagocytose bacteria and particles reaching alveoli - first line of cellular defence), 6) Secretory IgA (sIgA - antibodies in respiratory mucus that neutralise pathogens), and 7) Lymphoid tissue (MALT - mucosa-associated lymphoid tissue - immune surveillance).

What is the normal partial pressure of CO2 in arterial blood (PaCO2)?

RRB/SSC/UPSC Hard

✓ Answer: B 35-45 mmHg

Normal arterial blood gas values (important for exams): PaO2 = 80-100 mmHg (partial pressure of O2 in arterial blood), PaCO2 = 35-45 mmHg (partial pressure of CO2 in arterial blood), pH = 7.35-7.45, HCO3- = 22-26 mEq/L (bicarbonate), and SpO2 = 95-100%. Abnormal PaCO2: Hypercapnia (PaCO2 >45 mmHg) = hypoventilation, respiratory acidosis. Hypocapnia (PaCO2 <35 mmHg) = hyperventilation, respiratory alkalosis. PaCO2 is the most sensitive and primary indicator of ventilatory status.

What is the term for the amount of air remaining in the lungs after a normal expiration?

RRB/SSC/UPSC Hard

✓ Answer: C Functional Residual Capacity (FRC)

Functional Residual Capacity (FRC) is the volume of air remaining in the lungs after a normal, passive expiration (resting expiratory level). It represents the equilibrium point where the inward recoil of the lungs equals the outward recoil of the chest wall. FRC = Expiratory Reserve Volume (ERV) + Residual Volume (RV) = 1200 + 1200 = ~2400 mL. FRC is the volume of air available for gas exchange between breaths - maintains alveolar O2 and CO2 levels between breaths. Increased in emphysema (hyperinflation); Decreased in pulmonary fibrosis, obesity.

Which of the following conditions is commonly called 'Farmer's lung'?

RRB/SSC/UPSC Hard

✓ Answer: C Hypersensitivity pneumonitis caused by inhalation of mould spores from hay

Farmer's Lung is a form of Hypersensitivity Pneumonitis (Extrinsic Allergic Alveolitis) - an immune-mediated inflammatory reaction of the alveoli caused by inhalation of organic dust containing fungal spores, usually Thermophilic actinomycetes from mouldy hay. Symptoms develop 4-8 hours after exposure: fever, cough, breathlessness, malaise. Repeated exposure causes chronic fibrosis. Similar conditions: Bird Fancier's Lung (avian proteins), Bagassosis (sugarcane), Mushroom Worker's Lung, and Cheese Washer's Lung. Treatment: avoidance of antigen, corticosteroids.

What is the medical name for a sore throat?

RRB/SSC/UPSC Easy

✓ Answer: C Pharyngitis

Pharyngitis is inflammation of the pharynx (throat) causing soreness, pain on swallowing, and redness. Most commonly caused by viral infections (rhinovirus, coronavirus, EBV) - self-limiting. Bacterial pharyngitis (Group A Streptococcus - strep throat) requires antibiotics to prevent complications (rheumatic fever, glomerulonephritis). Distinguish: Pharyngitis = sore throat (pharynx), Laryngitis = inflammation of the larynx (hoarse voice, loss of voice), Tonsillitis = inflammation of tonsils, Rhinitis = inflammation of nasal mucosa (runny/blocked nose), and Sinusitis = inflammation of sinuses.

What is the correct anatomical term for the voice box and where is it located?

RRB/SSC/UPSC Medium

✓ Answer: B Larynx - located in the anterior neck between the pharynx (above) and trachea (below), at the level of C4-C6 vertebrae

The Larynx (voice box) is located in the anterior neck at the level of C4-C6 vertebrae, between the pharynx (above) and trachea (below). Key functions: Voice production (Phonation - vocal cord vibration), Airway protection (epiglottis prevents aspiration during swallowing), Breathing (regulates airflow), and Valsalva manoeuvre (closes glottis to increase intra-abdominal pressure during lifting, defecation, childbirth). The larynx contains 9 cartilages, 2 vocal cords (vocal folds), and the glottis (opening between vocal cords). The space above the vocal cords = supraglottis; below = subglottis.

What is the role of the adenoids in the respiratory system?

RRB/SSC/UPSC Medium

✓ Answer: B Lymphoid tissue in the nasopharynx that traps and destroys pathogens entering through the nose

Adenoids (Pharyngeal tonsils) are a mass of lymphoid tissue located in the roof of the nasopharynx (back of the nasal cavity). They are part of Waldeyer's ring - a ring of lymphoid tissue (adenoids, palatine tonsils, lingual tonsils) that guards the entrance to the respiratory and digestive tracts. In children, enlarged adenoids can cause: nasal obstruction, mouth breathing, snoring, otitis media (blocks Eustachian tubes). Adenoidectomy (surgical removal) is performed when persistently enlarged. Adenoids typically shrink naturally by adolescence.

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