Here below some basic MCQ’s of “Breathing and Exchange of Gases” with answer which is well explained. Let’s check one by one which is given below.
MCQ 1:
Which of the following statements about the respiratory system is correct?
A) The trachea is a muscular tube that can expand and contract.
B) Alveoli are the primary sites for gas exchange in the lungs.
C) The diaphragm is located above the lungs.
D) The bronchioles have a thick muscular wall to facilitate gas exchange.
Answer: B) Alveoli are the primary sites for gas exchange in the lungs.
Explanation: The alveoli are tiny air sacs in the lungs where oxygen and carbon dioxide are exchanged. They are lined with a thin layer of cells, allowing efficient gas exchange. The trachea is a rigid structure, not muscular; the diaphragm is below the lungs, and bronchioles have thin walls for gas exchange, not thick ones.
MCQ 2:
What is the primary muscle involved in the process of breathing?
A) Intercostal muscles
B) Diaphragm
C) Abdominal muscles
D) Pectoral muscles
Answer: B) Diaphragm
Explanation: The diaphragm is the main muscle responsible for breathing. When it contracts, it flattens, increasing the thoracic cavity’s volume and drawing air into the lungs. The intercostal muscles assist in expanding and contracting the ribcage but are secondary to the diaphragm.
MCQ 3:
Which of the following gases is primarily responsible for the stimulus to breathe in healthy individuals?
A) Oxygen
B) Carbon dioxide
C) Nitrogen
D) Hydrogen
Answer: B) Carbon dioxide
Explanation: The primary stimulus for breathing in healthy individuals is the level of carbon dioxide in the blood. When CO2 levels rise, it leads to an increase in respiratory rate to expel excess CO2 and maintain pH balance.
MCQ 4:
In the human body, the exchange of gases occurs primarily in the:
A) Bronchi
B) Trachea
C) Alveoli
D) Pharynx
Answer: C) Alveoli
Explanation: The alveoli are the functional units of the lungs where oxygen and carbon dioxide are exchanged. The bronchi and trachea are involved in conducting air but do not participate in gas exchange.
MCQ 5:
What is the role of surfactant in the lungs?
A) To transport oxygen
B) To reduce surface tension in the alveoli
C) To facilitate the movement of cilia
D) To filter out dust particles
Answer: B) To reduce surface tension in the alveoli
Explanation: Surfactant is a substance that reduces surface tension in the alveoli, preventing their collapse and making it easier for them to expand during inhalation. This is crucial for maintaining proper lung function.
MCQ 6:
Which part of the brain is primarily responsible for the regulation of breathing?
A) Cerebrum
B) Cerebellum
C) Medulla oblongata
D) Thalamus
Answer: C) Medulla oblongata
Explanation: The medulla oblongata is responsible for the automatic control of breathing. It detects changes in blood CO2 and O2 levels and adjusts the rate and depth of breathing accordingly.
MCQ 7:
Which of the following is the primary component of inhaled air?
A) Carbon dioxide
B) Nitrogen
C) Oxygen
D) Argon
Answer: B) Nitrogen
Explanation: Inhaled air is composed of about 78% nitrogen, 21% oxygen, and trace amounts of other gases, including carbon dioxide.
MCQ 8:
During inhalation, the pressure in the thoracic cavity:
A) Increases
B) Decreases
C) Remains the same
D) Fluctuates
Answer: B) Decreases
Explanation: During inhalation, the diaphragm contracts, expanding the thoracic cavity and lowering the pressure, which allows air to flow into the lungs.
MCQ 9:
What is the role of hemoglobin in the blood?
A) To transport nutrients
B) To carry oxygen
C) To regulate pH
D) To aid in digestion
Answer: B) To carry oxygen
Explanation: Hemoglobin is a protein in red blood cells that binds to oxygen in the lungs and transports it to tissues throughout the body.
MCQ 10:
The partial pressure of oxygen in the alveoli is approximately:
A) 40 mmHg
B) 100 mmHg
C) 760 mmHg
D) 21 mmHg
Answer: B) 100 mmHg
Explanation: The partial pressure of oxygen in the alveoli is around 100 mmHg, which facilitates the diffusion of oxygen into the blood.
MCQ 11:
What is the primary site of carbon dioxide exchange in the lungs?
A) Trachea
B) Bronchioles
C) Alveoli
D) Pleura
Answer: C) Alveoli
Explanation: The alveoli are the main sites where carbon dioxide is exchanged for oxygen during respiration.
MCQ 12:
Which of the following factors decreases the affinity of hemoglobin for oxygen?
A) Decreased temperature
B) Decreased pH
C) Decreased carbon dioxide concentration
D) Increased oxygen concentration
Answer: B) Decreased pH
Explanation: A decrease in pH (increased acidity) decreases hemoglobin’s affinity for oxygen, facilitating oxygen release in tissues where it is needed most.
MCQ 13:
Which structure prevents food from entering the trachea during swallowing?
A) Larynx
B) Pharynx
C) Epiglottis
D) Uvula
Answer: C) Epiglottis
Explanation: The epiglottis is a flap of cartilage that covers the trachea during swallowing, preventing food from entering the airway.
MCQ 14:
The primary function of the cilia in the respiratory tract is to:
A) Exchange gases
B) Filter and move mucus
C) Assist in vocalization
D) Provide structural support
Answer: B) Filter and move mucus
Explanation: Cilia are tiny hair-like structures that help to trap and move mucus and debris out of the respiratory tract, keeping the airways clear.
MCQ 15:
What is the tidal volume during normal resting breathing?
A) 150 mL
B) 500 mL
C) 1000 mL
D) 2500 mL
Answer: B) 500 mL
Explanation: Tidal volume is the amount of air inhaled or exhaled during normal breathing, which is approximately 500 mL in adults.
MCQ 16:
In which part of the respiratory system does gas exchange occur?
A) Nasal cavity
B) Lungs
C) Alveoli
D) Bronchi
Answer: C) Alveoli
Explanation: Gas exchange occurs specifically in the alveoli, where oxygen and carbon dioxide are exchanged between air and blood.
MCQ 17:
Which condition is characterized by inflammation of the bronchi?
A) Asthma
B) Pneumonia
C) Bronchitis
D) Emphysema
Answer: C) Bronchitis
Explanation: Bronchitis is the inflammation of the bronchial tubes, which can cause coughing and difficulty breathing.
MCQ 18:
The primary gas transported by hemoglobin is:
A) Nitrogen
B) Carbon monoxide
C) Oxygen
D) Carbon dioxide
Answer: C) Oxygen
Explanation: Hemoglobin’s primary function is to carry oxygen from the lungs to the tissues.
MCQ 19:
Which of the following conditions is most likely to result from smoking?
A) Asthma
B) Chronic bronchitis
C) Lung cancer
D) All of the above
Answer: D) All of the above
Explanation: Smoking can lead to various respiratory conditions, including asthma, chronic bronchitis, and lung cancer.
MCQ 20:
What is the main function of the respiratory system?
A) To circulate blood
B) To exchange gases
C) To regulate temperature
D) To digest food
Answer: B) To exchange gases
Explanation: The primary function of the respiratory system is to facilitate the exchange of oxygen and carbon dioxide between the body and the environment.
MCQ 21:
Which structure is responsible for the production of sound in the human body?
A) Trachea
B) Larynx
C) Pharynx
D) Bronchi
Answer: B) Larynx
Explanation: The larynx, or voice box, contains vocal cords and is responsible for sound production during speaking and singing.
MCQ 22:
What is the term for the maximum amount of air that can be inhaled after a normal tidal expiration?
A) Vital capacity
B) Inspiratory reserve volume
C) Expiratory reserve volume
D) Total lung capacity
Answer: B) Inspiratory reserve volume
Explanation: Inspiratory reserve volume is the additional air that can be inhaled beyond the normal tidal volume after a normal expiration.
MCQ 23:
The exchange of gases between the blood and tissues is known as:
A) External respiration
B) Internal respiration
C) Cellular respiration
D) Alveolar respiration
Answer: B) Internal respiration
Explanation: Internal respiration refers to the exchange of gases between blood and body tissues.
MCQ 24:
What happens to the diaphragm during exhalation?
A) It contracts and moves downwards.
B) It relaxes and moves upwards.
C) It remains stationary.
D) It changes shape.
Answer: B) It relaxes and moves upwards.
Explanation: During exhalation, the diaphragm relaxes and moves upwards, decreasing the volume of the thoracic cavity and forcing air out of the lungs.
MCQ 25:
Which of the following is a common symptom of respiratory diseases?
A) Nausea
B) Coughing
C) Abdominal pain
D) Skin rash
Answer: B) Coughing
Explanation: Coughing is a common symptom of respiratory diseases, helping to clear the airways of mucus and irritants.
MCQ 26:
The pleural cavity contains:
A) Air
B) Blood
C) Serous fluid
D) Lymph
Answer: C) Serous fluid
Explanation: The pleural cavity contains serous fluid, which lubricates the surfaces of the pleura and reduces friction during breathing.
MCQ 27:
What is the condition characterized by the destruction of alveoli?
A) Asthma
B) Emphysema
C) Chronic bronchitis
D) Pneumonia
Answer: B) Emphysema
Explanation: Emphysema is a chronic lung condition characterized by the destruction of alveoli, leading to difficulty in breathing.
MCQ 28:
Which of the following factors does NOT affect the rate of gas exchange?
A) Surface area of alveoli
B) Thickness of respiratory membrane
C) Temperature
D) Speed of blood flow
Answer: D) Speed of blood flow
Explanation: While speed of blood flow can influence oxygen transport, the rate of gas exchange itself is primarily affected by surface area, membrane thickness, and concentration gradients.
MCQ 29:
Which component of air has the highest partial pressure at sea level?
A) Oxygen
B) Carbon dioxide
C) Nitrogen
D) Water vapor
Answer: C) Nitrogen
Explanation: At sea level, nitrogen has the highest partial pressure, making up about 78% of the atmosphere.
MCQ 30:
The primary method of carbon dioxide transport in the blood is:
A) Dissolved in plasma
B) Bound to hemoglobin
C) As bicarbonate ions
D) All of the above
Answer: D) All of the above
Explanation: Carbon dioxide is transported in the blood in three forms: dissolved in plasma, bound to hemoglobin, and primarily as bicarbonate ions.
MCQ 31:
What structure divides the nasal cavity from the oral cavity?
A) Uvula
B) Epiglottis
C) Hard palate
D) Soft palate
Answer: C) Hard palate
Explanation: The hard palate separates the nasal cavity from the oral cavity, facilitating breathing and eating simultaneously.
MCQ 32:
Which respiratory condition is primarily characterized by wheezing and difficulty in breathing due to airway constriction?
A) Pneumonia
B) Asthma
C) Bronchitis
D) Emphysema
Answer: B) Asthma
Explanation: Asthma is characterized by wheezing and difficulty breathing due to inflammation and constriction of the airways.
MCQ 33:
The respiratory system helps regulate which of the following?
A) Blood glucose levels
B) Blood pH levels
C) Blood pressure
D) Body temperature
Answer: B) Blood pH levels
Explanation: The respiratory system plays a critical role in regulating blood pH by controlling the levels of carbon dioxide in the blood.
MCQ 34:
The air we breathe is predominantly composed of which gas?
A) Carbon dioxide
B) Nitrogen
C) Oxygen
D) Argon
Answer: B) Nitrogen
Explanation: The atmosphere is approximately 78% nitrogen, making it the most abundant gas we breathe.
MCQ 35:
What is the primary role of the alveolar epithelium?
A) To filter air
B) To facilitate gas exchange
C) To produce surfactant
D) To regulate airflow
Answer: B) To facilitate gas exchange
Explanation: The alveolar epithelium is primarily responsible for the exchange of oxygen and carbon dioxide between the air and the blood.
MCQ 36:
Which term refers to the volume of air remaining in the lungs after a maximal exhalation?
A) Tidal volume
B) Residual volume
C) Vital capacity
D) Inspiratory reserve volume
Answer: B) Residual volume
Explanation: Residual volume is the amount of air that remains in the lungs after a forceful exhalation, preventing lung collapse.
MCQ 37:
Which of the following structures is NOT part of the conducting zone of the respiratory system?
A) Trachea
B) Bronchi
C) Alveoli
D) Nasal cavity
Answer: C) Alveoli
Explanation: The conducting zone includes structures that transport air but do not participate in gas exchange. The alveoli are part of the respiratory zone.
MCQ 38:
In the human respiratory system, gas exchange occurs primarily through what type of diffusion?
A) Simple diffusion
B) Facilitated diffusion
C) Active transport
D) Osmosis
Answer: A) Simple diffusion
Explanation: Gas exchange occurs by simple diffusion, where oxygen and carbon dioxide move from areas of higher concentration to areas of lower concentration.
MCQ 39:
Which of the following is the most effective method for increasing lung capacity?
A) Breathing through the mouth
B) Deep breathing exercises
C) Rapid shallow breathing
D) Holding breath for long periods
Answer: B) Deep breathing exercises
Explanation: Deep breathing exercises help to expand the lungs and increase lung capacity by fully utilizing the respiratory system.
MCQ 40:
What is the primary function of the nasal cavity?
A) To produce sound
B) To warm and moisten inhaled air
C) To filter blood
D) To facilitate gas exchange
Answer: B) To warm and moisten inhaled air
Explanation: The nasal cavity helps to warm and humidify the air before it reaches the lungs, as well as filter out particles.
MCQ 41:
Which gas is a byproduct of cellular respiration?
A) Oxygen
B) Nitrogen
C) Carbon dioxide
D) Hydrogen
Answer: C) Carbon dioxide
Explanation: Carbon dioxide is produced as a waste product during cellular respiration when cells metabolize glucose for energy.
MCQ 42:
What is the term for an increased breathing rate that can occur during exercise?
A) Bradypnea
B) Tachypnea
C) Hyperventilation
D) Hypoventilation
Answer: B) Tachypnea
Explanation: Tachypnea refers to an increased breathing rate, which often occurs during physical activity to meet the body’s increased oxygen demand.
MCQ 43:
The respiratory membrane is composed of:
A) Alveolar epithelium and capillary endothelium
B) Mucous membrane and ciliated epithelium
C) Ciliated epithelium and cartilage
D) Simple squamous epithelium and connective tissue
Answer: A) Alveolar epithelium and capillary endothelium
Explanation: The respiratory membrane consists of the alveolar epithelium and the endothelium of capillaries, facilitating gas exchange.
MCQ 44:
Which of the following is a symptom of a respiratory infection?
A) Joint pain
B) Skin rash
C) Coughing
D) Nausea
Answer: C) Coughing
Explanation: Coughing is a common symptom of respiratory infections, helping to clear mucus and pathogens from the airways.
MCQ 45:
The primary function of the intercostal muscles during respiration is to:
A) Control the diaphragm
B) Change the volume of the thoracic cavity
C) Facilitate gas exchange
D) Produce sound
Answer: B) Change the volume of the thoracic cavity
Explanation: The intercostal muscles contract to expand and elevate the ribcage, increasing the volume of the thoracic cavity during inhalation.
MCQ 46:
What is the effect of high altitude on oxygen availability?
A) Increased oxygen availability
B) No effect on oxygen availability
C) Decreased oxygen availability
D) Oxygen becomes toxic
Answer: C) Decreased oxygen availability
Explanation: At high altitudes, the partial pressure of oxygen is lower, resulting in decreased oxygen availability for respiration.
MCQ 47:
What mechanism allows for the movement of oxygen from the alveoli into the blood?
A) Active transport
B) Osmosis
C) Diffusion
D) Filtration
Answer: C) Diffusion
Explanation: Oxygen moves from the alveoli to the blood in the capillaries by diffusion, due to the concentration gradient.
MCQ 48:
Which type of cells produce surfactant in the alveoli?
A) Type I alveolar cells
B) Type II alveolar cells
C) Macrophages
D) Endothelial cells
Answer: B) Type II alveolar cells
Explanation: Type II alveolar cells are responsible for producing surfactant, which reduces surface tension and prevents alveolar collapse.
MCQ 49:
What is a common effect of bronchoconstriction?
A) Increased airflow
B) Decreased airflow
C) Increased lung volume
D) Decreased blood pressure
Answer: B) Decreased airflow
Explanation: Bronchoconstriction narrows the airways, leading to decreased airflow to and from the lungs.
MCQ 50:
Which part of the respiratory system is involved in both respiration and digestion?
A) Larynx
B) Pharynx
C) Trachea
D) Bronchi
Answer: B) Pharynx
Explanation: The pharynx is a shared passageway for both air (respiration) and food (digestion).
MCQ 51:
Which of the following is a long-term effect of smoking on the respiratory system?
A) Improved lung function
B) Increased lung elasticity
C) Chronic obstructive pulmonary disease (COPD)
D) Enhanced gas exchange
Answer: C) Chronic obstructive pulmonary disease (COPD)
Explanation: Smoking is a major risk factor for developing COPD, which includes conditions like chronic bronchitis and emphysema.
MCQ 52:
Which of the following changes occurs during deep inhalation?
A) Diaphragm relaxes
B) Intercostal muscles relax
C) Thoracic cavity volume decreases
D) Thoracic cavity volume increases
Answer: D) Thoracic cavity volume increases
Explanation: During deep inhalation, the diaphragm contracts and the intercostal muscles elevate the ribs, increasing thoracic cavity volume.
MCQ 53:
The primary role of the respiratory system in thermoregulation is to:
A) Control blood pressure
B) Regulate body temperature through breathing
C) Maintain pH balance
D) Filter toxins
Answer: B) Regulate body temperature through breathing
Explanation: The respiratory system helps regulate body temperature by facilitating heat exchange with the environment through breathing.
MCQ 54:
Which gas law explains the relationship between the pressure and volume of gases in the lungs?
A) Dalton’s law
B) Henry’s law
C) Boyle’s law
D) Charles’s law
Answer: C) Boyle’s law
Explanation: Boyle’s law states that the pressure of a gas is inversely related to its volume at constant temperature, applicable to lung mechanics during inhalation and exhalation.
MCQ 55:
What occurs during external respiration?
A) Gas exchange between blood and tissues
B) Gas exchange between the lungs and blood
C) Cellular respiration
D) Metabolic processes in cells
Answer: B) Gas exchange between the lungs and blood
Explanation: External respiration refers to the exchange of oxygen and carbon dioxide between the lungs and the bloodstream.
MCQ 56:
What is the significance of the pulmonary surfactant?
A) It transports oxygen in the blood.
B) It increases surface tension in the alveoli.
C) It prevents alveolar collapse.
D) It acts as a barrier to pathogens.
Answer: C) It prevents alveolar collapse.
Explanation: Pulmonary surfactant reduces surface tension in the alveoli, preventing them from collapsing during exhalation.
MCQ 57:
The term “hypercapnia” refers to:
A) Low levels of oxygen
B) High levels of carbon dioxide
C) High levels of nitrogen
D) Low levels of carbon dioxide
Answer: B) High levels of carbon dioxide
Explanation: Hypercapnia is the condition characterized by an excess of carbon dioxide in the bloodstream.
MCQ 58:
Which respiratory condition is characterized by a “hacking” cough and mucus production?
A) Asthma
B) Chronic bronchitis
C) Emphysema
D) Pneumonia
Answer: B) Chronic bronchitis
Explanation: Chronic bronchitis is marked by a persistent cough with mucus production due to inflammation of the bronchial tubes.
MCQ 59:
Which type of lung volume represents the total amount of air the lungs can hold?
A) Tidal volume
B) Vital capacity
C) Total lung capacity
D) Residual volume
Answer: C) Total lung capacity
Explanation: Total lung capacity is the maximum amount of air the lungs can hold, including all volumes (tidal volume, inspiratory reserve volume, expiratory reserve volume, and residual volume).
MCQ 60:
What is the primary stimulus for the body to initiate breathing?
A) Low oxygen levels
B) High carbon dioxide levels
C) High blood pressure
D) Low blood sugar
Answer: B) High carbon dioxide levels
Explanation: The primary driver for the urge to breathe is the concentration of carbon dioxide in the blood; high levels stimulate the respiratory centers in the brain.
MCQ 61:
In which part of the brain is the respiratory control center located?
A) Cerebrum
B) Cerebellum
C) Medulla oblongata
D) Pons
Answer: C) Medulla oblongata
Explanation: The medulla oblongata contains the primary respiratory control centers, regulating the rhythm and rate of breathing.
MCQ 62:
The condition where the alveoli are filled with fluid, leading to impaired gas exchange, is known as:
A) Asthma
B) Bronchitis
C) Pneumonia
D) Emphysema
Answer: C) Pneumonia
Explanation: Pneumonia causes inflammation of the alveoli and can fill them with fluid or pus, impairing gas exchange.
MCQ 63:
Which structure serves as the primary site for the filtration of inhaled air?
A) Lungs
B) Nasal cavity
C) Trachea
D) Pharynx
Answer: B) Nasal cavity
Explanation: The nasal cavity serves as the primary filtration system for inhaled air, trapping dust and pathogens through mucus and cilia.
MCQ 64:
What is the most common cause of respiratory acidosis?
A) Hyperventilation
B) Hypoventilation
C) Excessive exercise
D) Exposure to cold air
Answer: B) Hypoventilation
Explanation: Hypoventilation leads to an accumulation of carbon dioxide, resulting in respiratory acidosis due to decreased blood pH.
MCQ 65:
The term “atelectasis” refers to:
A) Inflammation of the lungs
B) Collapse of part or all of a lung
C) Excess fluid in the lungs
D) Narrowing of the airways
Answer: B) Collapse of part or all of a lung
Explanation: Atelectasis is a condition characterized by the collapse of lung tissue, leading to reduced gas exchange.
MCQ 66:
What is the purpose of the respiratory mucosa?
A) To facilitate gas exchange
B) To trap and clear pathogens
C) To produce surfactant
D) To regulate blood flow
Answer: B) To trap and clear pathogens
Explanation: The respiratory mucosa produces mucus that traps dust and pathogens, which are then moved out of the airways by cilia.
MCQ 67:
What is the main action of the diaphragm during inhalation?
A) It relaxes.
B) It contracts.
C) It flattens.
D) It elevates the ribs.
Answer: B) It contracts.
Explanation: During inhalation, the diaphragm contracts and moves downward, increasing the thoracic cavity’s volume and drawing air into the lungs.
MCQ 68:
Which type of respiration involves the use of oxygen by cells to produce energy?
A) External respiration
B) Internal respiration
C) Cellular respiration
D) Alveolar respiration
Answer: C) Cellular respiration
Explanation: Cellular respiration is the metabolic process by which cells use oxygen to produce energy (ATP) and release carbon dioxide as a byproduct.
MCQ 69:
What is the primary cause of asthma attacks?
A) Air pollution
B) Allergens
C) Exercise
D) All of the above
Answer: D) All of the above
Explanation: Asthma attacks can be triggered by various factors, including air pollution, allergens, and exercise.
MCQ 70:
Which part of the respiratory system is primarily responsible for filtering, warming, and humidifying air?
A) Alveoli
B) Bronchi
C) Nasal cavity
D) Trachea
Answer: C) Nasal cavity
Explanation: The nasal cavity plays a crucial role in filtering, warming, and humidifying the air before it reaches the lungs.
MCQ 71:
What type of cells are responsible for the immune response in the alveoli?
A) Type I alveolar cells
B) Type II alveolar cells
C) Alveolar macrophages
D) Endothelial cells
Answer: C) Alveolar macrophages
Explanation: Alveolar macrophages are immune cells that reside in the alveoli and help to engulf and destroy pathogens.
MCQ 72:
The lungs are surrounded by a double-layered membrane known as:
A) Mucosa
B) Serosa
C) Pleura
D) Peritoneum
Answer: C) Pleura
Explanation: The pleura is a double-layered membrane that surrounds the lungs and lines the thoracic cavity, providing a lubricated surface for lung movement.
MCQ 73:
Which lung capacity includes tidal volume and the inspiratory reserve volume?
A) Vital capacity
B) Functional residual capacity
C) Total lung capacity
D) Inspiratory capacity
Answer: D) Inspiratory capacity
Explanation: Inspiratory capacity is the sum of tidal volume and inspiratory reserve volume, representing the maximum amount of air that can be inhaled after a normal expiration.
MCQ 74:
What role do the respiratory and circulatory systems play in maintaining homeostasis?
A) They regulate blood glucose levels.
B) They maintain acid-base balance through gas exchange.
C) They control body temperature.
D) They detoxify the blood.
Answer: B) They maintain acid-base balance through gas exchange.
Explanation: The respiratory and circulatory systems work together to regulate pH levels in the blood by controlling the levels of carbon dioxide and oxygen.
MCQ 75:
What is the main factor that drives oxygen from the lungs into the blood?
A) Temperature
B) Partial pressure gradient
C) Humidity
D) Blood flow rate
Answer: B) Partial pressure gradient
Explanation: The movement of oxygen from the lungs into the blood occurs due to the partial pressure gradient, with oxygen moving from an area of higher pressure (lungs) to lower pressure (blood).
MCQ 76:
What is the main physiological effect of hypoxia?
A) Increased respiratory rate
B) Decreased respiratory rate
C) Decreased heart rate
D) Increased blood pressure
Answer: A) Increased respiratory rate
Explanation: Hypoxia, or low oxygen levels in the tissues, triggers an increase in respiratory rate to enhance oxygen intake.
MCQ 77:
Which of the following terms describes the volume of air that can be forcibly exhaled after a normal expiration?
A) Tidal volume
B) Expiratory reserve volume
C) Inspiratory reserve volume
D) Vital capacity
Answer: B) Expiratory reserve volume
Explanation: Expiratory reserve volume is the amount of air that can be forcibly exhaled after a normal tidal expiration.
MCQ 78:
The law that states that the total pressure of a gas mixture is equal to the sum of the partial pressures of its components is known as:
A) Boyle’s law
B) Dalton’s law
C) Henry’s law
D) Charles’s law
Answer: B) Dalton’s law
Explanation: Dalton’s law states that the total pressure of a gas mixture is the sum of the partial pressures of each individual gas in the mixture.
MCQ 79:
Which of the following best describes the “sneeze reflex”?
A) A protective mechanism to expel air quickly to clear irritants
B) A mechanism to increase oxygen intake
C) A process of gas exchange
D) A method of regulating blood pH
Answer: A) A protective mechanism to expel air quickly to clear irritants
Explanation: The sneeze reflex is a protective action that expels air rapidly from the lungs to remove irritants from the nasal cavity.
MCQ 80:
The primary function of the larynx is to:
A) Filter inhaled air
B) Produce sound
C) Facilitate gas exchange
D) Control breathing rate
Answer: B) Produce sound
Explanation: The larynx, often referred to as the voice box, is primarily responsible for sound production and protecting the airway during swallowing.
MCQ 81:
Which of the following conditions is characterized by the destruction of alveoli and loss of elastic recoil?
A) Asthma
B) Emphysema
C) Chronic bronchitis
D) Pneumonia
Answer: B) Emphysema
Explanation: Emphysema is a form of chronic obstructive pulmonary disease (COPD) that involves the destruction of alveolar walls, leading to reduced gas exchange and loss of lung elasticity.
MCQ 82:
What does the term “dyspnea” refer to?
A) Abnormal lung sounds
B) Difficulty breathing
C) Coughing up blood
D) Rapid breathing
Answer: B) Difficulty breathing
Explanation: Dyspnea is the medical term used to describe difficulty or labored breathing.
MCQ 83:
Which structure is responsible for the exchange of gases in the lungs?
A) Trachea
B) Bronchi
C) Alveoli
D) Larynx
Answer: C) Alveoli
Explanation: Alveoli are the small air sacs in the lungs where the exchange of oxygen and carbon dioxide takes place.
MCQ 84:
What is the role of hemoglobin in respiration?
A) To transport carbon dioxide only
B) To transport oxygen and carbon dioxide
C) To regulate blood pH
D) To enhance the diffusion of gases
Answer: B) To transport oxygen and carbon dioxide
Explanation: Hemoglobin binds oxygen in the lungs for transport to tissues and carries carbon dioxide back to the lungs for exhalation.
MCQ 85:
Which of the following is a common cause of restrictive lung disease?
A) Asthma
B) Cystic fibrosis
C) Emphysema
D) Chronic bronchitis
Answer: B) Cystic fibrosis
Explanation: Cystic fibrosis is a genetic disorder that affects the lungs and leads to the production of thick mucus, resulting in restrictive lung disease.
MCQ 86:
What is the significance of the respiratory rate in assessing health?
A) It indicates the efficiency of the circulatory system.
B) It reflects metabolic activity in the body.
C) It determines lung capacity.
D) It indicates the oxygen-carrying capacity of blood.
Answer: B) It reflects metabolic activity in the body.
Explanation: The respiratory rate can be an indicator of the body’s metabolic demands and overall health, particularly during exercise or illness.
MCQ 87:
What is the primary purpose of the epiglottis?
A) To filter air
B) To produce sound
C) To prevent food from entering the trachea
D) To facilitate gas exchange
Answer: C) To prevent food from entering the trachea
Explanation: The epiglottis is a flap of tissue that covers the trachea during swallowing, preventing food and liquid from entering the airway.
MCQ 88:
Which of the following describes the term “hypoxia”?
A) Increased levels of carbon dioxide
B) Decreased levels of oxygen
C) Elevated breathing rate
D) Fluid accumulation in the lungs
Answer: B) Decreased levels of oxygen
Explanation: Hypoxia refers to a deficiency in the amount of oxygen reaching the tissues.
MCQ 89:
During expiration, which of the following occurs?
A) The diaphragm contracts
B) The volume of the thoracic cavity increases
C) The intercostal muscles relax
D) Air is drawn into the lungs
Answer: C) The intercostal muscles relax
Explanation: During expiration, the intercostal muscles relax, leading to a decrease in thoracic cavity volume and allowing air to be expelled from the lungs.
MCQ 90:
Which gas law describes the solubility of a gas in a liquid?
A) Boyle’s law
B) Charles’s law
C) Henry’s law
D) Dalton’s law
Answer: C) Henry’s law
Explanation: Henry’s law states that the amount of gas that dissolves in a liquid is proportional to the partial pressure of that gas above the liquid.
MCQ 91:
What is the primary role of the ciliated epithelium in the respiratory tract?
A) To facilitate gas exchange
B) To produce surfactant
C) To trap and move mucus and debris
D) To regulate airflow
Answer: C) To trap and move mucus and debris
Explanation: Ciliated epithelium helps trap particles and pathogens in mucus and moves them out of the respiratory tract towards the throat for clearance.
MCQ 92:
Which condition is characterized by the irreversible dilation of the bronchi?
A) Asthma
B) Bronchiectasis
C) Cystic fibrosis
D) Pneumonia
Answer: B) Bronchiectasis
Explanation: Bronchiectasis is a condition that involves the permanent enlargement of parts of the airways of the lung, often due to infection or obstruction.
MCQ 93:
What is the term for the amount of air inhaled or exhaled during normal breathing?
A) Tidal volume
B) Vital capacity
C) Expiratory reserve volume
D) Inspiratory reserve volume
Answer: A) Tidal volume
Explanation: Tidal volume is the volume of air inhaled or exhaled with each breath during normal respiration.
MCQ 94:
Which structure prevents the collapse of the trachea?
A) Bronchi
B) Alveoli
C) Cartilaginous rings
D) Pleura
Answer: C) Cartilaginous rings
Explanation: The trachea is supported by C-shaped cartilaginous rings that keep it open and prevent collapse.
MCQ 95:
Which of the following is a sign of respiratory distress?
A) Regular heart rate
B) Shallow breathing
C) Increased energy levels
D) High blood pressure
Answer: B) Shallow breathing
Explanation: Shallow breathing is a common sign of respiratory distress, indicating inadequate ventilation or gas exchange.
MCQ 96:
What is the effect of asthma on the airways?
A) Widening of the airways
B) Inflammation and constriction of the airways
C) Complete blockage of the airways
D) Thickening of the alveolar walls
Answer: B) Inflammation and constriction of the airways
Explanation: Asthma is characterized by inflammation and constriction of the airways, leading to difficulty in breathing.
MCQ 97:
What is the primary function of the pleural fluid?
A) To facilitate gas exchange
B) To provide lubrication for lung movement
C) To trap pathogens
D) To maintain blood pressure
Answer: B) To provide lubrication for lung movement
Explanation: Pleural fluid acts as a lubricant, allowing the lungs to move smoothly against the chest wall during respiration.
MCQ 98:
Which of the following statements about the trachea is correct?
A) It is a muscular tube.
B) It has complete cartilage rings.
C) It connects the larynx to the bronchi.
D) It is lined with simple squamous epithelium.
Answer: C) It connects the larynx to the bronchi.
Explanation: The trachea is a tube that connects the larynx to the bronchi, allowing air to pass into the lungs.
MCQ 99:
What is the primary control center for voluntary breathing?
A) Cerebellum
B) Medulla oblongata
C) Pons
D) Cerebrum
Answer: D) Cerebrum
Explanation: The cerebrum is involved in voluntary control of breathing, while the medulla oblongata controls involuntary breathing.
MCQ 100:
What is a common complication of chronic bronchitis?
A) Lung cancer
B) Pulmonary embolism
C) Heart failure
D) Pneumothorax
Answer: C) Heart failure
Explanation: Chronic bronchitis can lead to right-sided heart failure (cor pulmonale) due to increased pressure in the pulmonary circulation.
MCQ 101:
Which structure in the respiratory system is primarily responsible for sound production?
A) Larynx
B) Trachea
C) Bronchi
D) Alveoli
Answer: A) Larynx
Explanation: The larynx, or voice box, contains vocal cords that vibrate to produce sound when air passes through.
MCQ 102:
Which condition is characterized by the presence of fluid in the pleural cavity?
A) Pneumonia
B) Pleural effusion
C) Pulmonary fibrosis
D) Asthma
Answer: B) Pleural effusion
Explanation: Pleural effusion occurs when excess fluid accumulates in the pleural space, which can impair breathing and gas exchange.
MCQ 103:
What is the term for the maximum amount of air that can be exhaled after a maximum inhalation?
A) Tidal volume
B) Vital capacity
C) Expiratory reserve volume
D) Total lung capacity
Answer: B) Vital capacity
Explanation: Vital capacity is the maximum amount of air that can be forcibly exhaled after a maximum inhalation, reflecting lung function.
MCQ 104:
Which of the following is a common test used to assess lung function?
A) ECG
B) Spirometry
C) X-ray
D) CT scan
Answer: B) Spirometry
Explanation: Spirometry is a common pulmonary function test that measures the volume of air inhaled and exhaled, helping to assess lung function.
MCQ 105:
The movement of gases across the respiratory membrane occurs via:
A) Active transport
B) Diffusion
C) Osmosis
D) Filtration
Answer: B) Diffusion
Explanation: Gas exchange in the lungs occurs through diffusion, where oxygen moves from areas of higher concentration in the alveoli to lower concentration in the blood, and vice versa for carbon dioxide.
MCQ 106:
Which of the following can trigger an asthma attack?
A) Cold air
B) Exercise
C) Allergens
D) All of the above
Answer: D) All of the above
Explanation: Asthma attacks can be triggered by a variety of factors, including cold air, exercise, and allergens.
MCQ 107:
The primary function of type II alveolar cells is to:
A) Produce surfactant
B) Facilitate gas exchange
C) Phagocytize pathogens
D) Regulate airflow
Answer: A) Produce surfactant
Explanation: Type II alveolar cells are responsible for producing pulmonary surfactant, which reduces surface tension in the alveoli and prevents collapse.
MCQ 108:
What is the term for the forced expiration of air from the lungs?
A) Inhalation
B) Exhalation
C) Inspiration
D) Ventilation
Answer: B) Exhalation
Explanation: Exhalation refers to the process of expelling air from the lungs.
MCQ 109:
Which of the following structures is NOT part of the lower respiratory tract?
A) Trachea
B) Bronchi
C) Larynx
D) Alveoli
Answer: C) Larynx
Explanation: The larynx is considered part of the upper respiratory tract, while the trachea, bronchi, and alveoli are part of the lower respiratory tract.
MCQ 110:
Which of the following factors can affect respiratory rate?
A) Body temperature
B) Physical activity
C) Emotional state
D) All of the above
Answer: D) All of the above
Explanation: Respiratory rate can be influenced by various factors, including body temperature, physical activity levels, and emotional states like anxiety or stress.
MCQ 111:
What is the main characteristic of obstructive lung diseases?
A) Decreased lung volume
B) Increased lung volume
C) Reduced airflow due to airway narrowing
D) Abnormal lung tissue
Answer: C) Reduced airflow due to airway narrowing
Explanation: Obstructive lung diseases, such as asthma and chronic bronchitis, are characterized by reduced airflow due to narrowing of the airways.
MCQ 112:
Which lung volume cannot be measured directly using spirometry?
A) Tidal volume
B) Inspiratory reserve volume
C) Expiratory reserve volume
D) Residual volume
Answer: D) Residual volume
Explanation: Residual volume is the amount of air remaining in the lungs after maximum exhalation and cannot be measured directly by spirometry.
MCQ 113:
Which of the following describes the process of ventilation?
A) Gas exchange in the alveoli
B) Movement of air into and out of the lungs
C) Transport of gases in the blood
D) Cellular use of oxygen
Answer: B) Movement of air into and out of the lungs
Explanation: Ventilation refers to the mechanical process of moving air into and out of the lungs.
MCQ 114:
What is the primary effect of pulmonary fibrosis on the lungs?
A) Increased elasticity
B) Thickening of lung tissue
C) Decreased surface area
D) Both B and C
Answer: D) Both B and C
Explanation: Pulmonary fibrosis results in thickening and scarring of lung tissue, which can decrease surface area for gas exchange.
MCQ 115:
Which of the following is a common sign of pneumonia?
A) Increased lung capacity
B) Sharp chest pain during inhalation
C) Normal respiratory rate
D) Clear sputum production
Answer: B) Sharp chest pain during inhalation
Explanation: Sharp chest pain that worsens with inhalation is a common symptom of pneumonia due to pleuritic involvement.
MCQ 116:
What is the primary purpose of the bronchial smooth muscle?
A) To produce mucus
B) To facilitate gas exchange
C) To regulate airway diameter
D) To trap pathogens
Answer: C) To regulate airway diameter
Explanation: The bronchial smooth muscle constricts or relaxes to regulate the diameter of the airways, affecting airflow to the lungs.
MCQ 117:
What is the primary role of the diaphragm during exhalation?
A) It contracts.
B) It relaxes and moves upward.
C) It flattens.
D) It increases lung volume.
Answer: B) It relaxes and moves upward.
Explanation: During exhalation, the diaphragm relaxes and moves upward, decreasing the volume of the thoracic cavity and pushing air out of the lungs.
MCQ 118:
Which of the following is true regarding the respiratory system?
A) It is involved in the regulation of blood pH.
B) It solely relies on the circulatory system for gas transport.
C) It does not have any role in thermoregulation.
D) It only functions during physical activity.
Answer: A) It is involved in the regulation of blood pH.
Explanation: The respiratory system plays a critical role in maintaining acid-base balance by regulating carbon dioxide levels, which affect blood pH.
MCQ 119:
What is the primary cause of respiratory alkalosis?
A) Hyperventilation
B) Hypoventilation
C) Decreased oxygen levels
D) High carbon dioxide levels
Answer: A) Hyperventilation
Explanation: Respiratory alkalosis occurs when there is excessive breathing (hyperventilation), leading to decreased carbon dioxide levels and increased blood pH.
MCQ 120:
What is the primary purpose of the nasal conchae?
A) To filter and humidify air
B) To produce mucus
C) To facilitate gas exchange
D) To regulate airflow
Answer: A) To filter and humidify air
Explanation: The nasal conchae increase the surface area of the nasal cavity, helping to filter, warm, and humidify the incoming air.
MCQ 121:
What is the condition known as “sleep apnea”?
A) Inability to breathe during sleep
B) Rapid breathing during sleep
C) Chronic cough during sleep
D) Increased heart rate during sleep
Answer: A) Inability to breathe during sleep
Explanation: Sleep apnea is a disorder characterized by repeated interruptions in breathing during sleep, leading to decreased oxygen levels.
MCQ 122:
Which factor is most important in determining oxygen saturation of hemoglobin?
A) Blood pH
B) Temperature
C) Partial pressure of oxygen
D) Carbon dioxide levels
Answer: C) Partial pressure of oxygen
Explanation: The saturation of hemoglobin with oxygen is primarily influenced by the partial pressure of oxygen in the blood.
MCQ 123:
What is the name of the breathing pattern characterized by deep, labored breaths often seen in metabolic acidosis?
A) Kussmaul breathing
B) Cheyne-Stokes respiration
C) Biot’s respiration
D) Apneustic breathing
Answer: A) Kussmaul breathing
Explanation: Kussmaul breathing is a deep, labored breathing pattern often associated with metabolic acidosis, such as in diabetic ketoacidosis.
MCQ 124:
Which of the following structures helps to equalize pressure in the middle ear?
A) Eustachian tube
B) Trachea
C) Larynx
D) Bronchi
Answer: A) Eustachian tube
Explanation: The Eustachian tube connects the middle ear to the nasopharynx and helps to equalize pressure in the middle ear.
MCQ 125:
What is the primary method of carbon dioxide transport in the blood?
A) Dissolved in plasma
B) Bound to hemoglobin
C) As bicarbonate ions
D) All of the above
Answer: D) All of the above
Explanation: Carbon dioxide is transported in the blood in three ways: dissolved in plasma, bound to hemoglobin, and primarily as bicarbonate ions.
MCQ 126:
The respiratory rate is typically controlled by which part of the brain?
A) Cerebrum
B) Medulla oblongata
C) Cerebellum
D) Hypothalamus
Answer: B) Medulla oblongata
Explanation: The medulla oblongata contains centers that regulate the rate and depth of breathing, responding to carbon dioxide and oxygen levels.
MCQ 127:
Which of the following best describes “pulmonary edema”?
A) Inflammation of the bronchi
B) Fluid accumulation in the lungs
C) Collapse of the alveoli
D) Infection of lung tissue
Answer: B) Fluid accumulation in the lungs
Explanation: Pulmonary edema refers to the buildup of fluid in the lung tissue and alveoli, impairing gas exchange.
MCQ 128:
What is the role of surfactant in the lungs?
A) To trap pathogens
B) To enhance gas exchange
C) To reduce surface tension in alveoli
D) To regulate airflow
Answer: C) To reduce surface tension in alveoli
Explanation: Surfactant reduces surface tension in the alveoli, preventing collapse and facilitating easier expansion during breathing.
MCQ 129:
Which of the following lung volumes represents the total amount of air the lungs can hold?
A) Tidal volume
B) Vital capacity
C) Total lung capacity
D) Residual volume
Answer: C) Total lung capacity
Explanation: Total lung capacity is the maximum amount of air the lungs can hold, including tidal volume, inspiratory reserve volume, expiratory reserve volume, and residual volume.
MCQ 130:
What is the purpose of the nasal cavity?
A) Gas exchange
B) Humidification and filtration of air
C) Sound production
D) Regulation of blood pH
Answer: B) Humidification and filtration of air
Explanation: The nasal cavity warms, humidifies, and filters the air as it is inhaled before it reaches the lungs.
MCQ 131:
What is the primary cause of hypoxemia?
A) High altitude
B) Obstruction of airways
C) Poor ventilation
D) All of the above
Answer: D) All of the above
Explanation: Hypoxemia, or low blood oxygen levels, can result from high altitude, airway obstruction, and poor ventilation.
MCQ 132:
What happens during the process of inhalation?
A) Diaphragm relaxes
B) Thoracic volume decreases
C) Intercostal muscles contract
D) Pressure in the thoracic cavity increases
Answer: C) Intercostal muscles contract
Explanation: During inhalation, the diaphragm contracts and the intercostal muscles contract, increasing thoracic volume and decreasing pressure, allowing air to flow in.
MCQ 133:
What is the term for a persistent cough that produces mucus?
A) Non-productive cough
B) Productive cough
C) Dry cough
D) Reflex cough
Answer: B) Productive cough
Explanation: A productive cough is one that brings up mucus or phlegm from the respiratory tract.
MCQ 134:
What is the primary stimulus for breathing in a healthy individual?
A) Low oxygen levels
B) High carbon dioxide levels
C) Blood pH changes
D) Temperature changes
Answer: B) High carbon dioxide levels
Explanation: In healthy individuals, increased carbon dioxide levels in the blood are the primary stimulus for initiating breathing.
MCQ 135:
Which of the following describes the term “atelectasis”?
A) Expansion of the lungs
B) Complete or partial collapse of a lung
C) Infection of the lungs
D) Inflammation of the bronchi
Answer: B) Complete or partial collapse of a lung
Explanation: Atelectasis refers to the collapse of part or all of a lung, leading to reduced gas exchange.
MCQ 136:
Which type of lung cancer is most commonly associated with smoking?
A) Adenocarcinoma
B) Small cell lung cancer
C) Squamous cell carcinoma
D) Large cell carcinoma
Answer: B) Small cell lung cancer
Explanation: Small cell lung cancer is strongly associated with smoking and tends to grow quickly and spread rapidly.
MCQ 137:
What is the primary function of the intercostal muscles?
A) To facilitate gas exchange
B) To regulate airflow
C) To aid in the mechanics of breathing
D) To trap pathogens
Answer: C) To aid in the mechanics of breathing
Explanation: The intercostal muscles assist with the mechanics of breathing by helping to expand and contract the thoracic cavity.
MCQ 138:
Which gas has the highest partial pressure in the atmosphere?
A) Oxygen
B) Nitrogen
C) Carbon dioxide
D) Argon
Answer: B) Nitrogen
Explanation: Nitrogen constitutes about 78% of the atmosphere and thus has the highest partial pressure compared to other gases.
MCQ 139:
Which type of respiration involves the exchange of gases at the cellular level?
A) External respiration
B) Internal respiration
C) Cellular respiration
D) Pulmonary ventilation
Answer: B) Internal respiration
Explanation: Internal respiration refers to the exchange of gases between the blood and body tissues.
MCQ 140:
Which of the following is true about bronchial asthma?
A) It is caused by an infection.
B) It involves airway inflammation and obstruction.
C) It is only a childhood disease.
D) It cannot be managed.
Answer: B) It involves airway inflammation and obstruction.
Explanation: Asthma is characterized by airway inflammation, bronchoconstriction, and increased mucus production, leading to obstruction and difficulty breathing.
MCQ 141:
What is the main function of alveolar macrophages?
A) To produce surfactant
B) To trap and digest pathogens
C) To facilitate gas exchange
D) To produce mucus
Answer: B) To trap and digest pathogens
Explanation: Alveolar macrophages are immune cells that reside in the alveoli, where they help trap and digest pathogens and debris.
MCQ 142:
Which of the following best describes the term “cheyne-stokes respiration”?
A) Rapid, shallow breathing
B) Alternating periods of deep and shallow breaths
C) Prolonged periods of apnea
D) Irregular breathing patterns
Answer: B) Alternating periods of deep and shallow breaths
Explanation: Cheyne-Stokes respiration is characterized by alternating periods of deep, rapid breathing and periods of apnea.
MCQ 143:
What is the most common cause of acute bronchitis?
A) Bacterial infection
B) Viral infection
C) Environmental pollutants
D) Allergens
Answer: B) Viral infection
Explanation: Acute bronchitis is most commonly caused by viral infections, often following a cold or respiratory infection.
MCQ 144:
Which of the following conditions is characterized by the inability of the lungs to adequately exchange gases?
A) COPD
B) Asthma
C) Pulmonary fibrosis
D) All of the above
Answer: D) All of the above
Explanation: All these conditions can impair the lungs’ ability to effectively exchange gases, resulting in decreased oxygenation.
MCQ 145:
What role do the accessory muscles of respiration play?
A) They assist with gas exchange.
B) They help during forced breathing.
C) They maintain lung elasticity.
D) They regulate airflow.
Answer: B) They help during forced breathing.
Explanation: Accessory muscles of respiration, such as the sternocleidomastoid and scalene muscles, are engaged during forceful inhalation or exhalation.
MCQ 146:
Which of the following is an effect of cigarette smoking on the respiratory system?
A) Increased mucus production
B) Dilation of the bronchi
C) Strengthening of alveolar walls
D) Decreased risk of infections
Answer: A) Increased mucus production
Explanation: Cigarette smoking leads to increased mucus production and can cause chronic inflammation and damage to the airways.
MCQ 147:
Which of the following structures helps to protect the lungs from pathogens?
A) Alveoli
B) Mucociliary escalator
C) Diaphragm
D) Pleura
Answer: B) Mucociliary escalator
Explanation: The mucociliary escalator is a defense mechanism that traps and moves pathogens and particles out of the respiratory tract.
MCQ 148:
What is the function of the respiratory muscles?
A) To filter air
B) To regulate blood pH
C) To facilitate breathing
D) To produce surfactant
Answer: C) To facilitate breathing
Explanation: The respiratory muscles, including the diaphragm and intercostal muscles, are essential for the process of ventilation, allowing for the intake and expulsion of air.
MCQ 149:
What does a spirometer measure?
A) Blood pressure
B) Blood oxygen levels
C) Lung volumes and airflow
D) Heart rate
Answer: C) Lung volumes and airflow
Explanation: A spirometer is an instrument used to measure lung volumes and airflow, providing valuable information about lung function.
MCQ 150:
Which part of the respiratory system is responsible for the majority of airway resistance?
A) Alveoli
B) Trachea
C) Bronchi and bronchioles
D) Larynx
Answer: C) Bronchi and bronchioles
Explanation: The bronchi and bronchioles provide the majority of airway resistance due to their smaller diameter compared to the trachea, affecting airflow
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