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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