Breathing and Exchange of Gases MCQ

Breathing and Exchange of Gases MCQ. Practice multiple choice questions on Breathing and Exchange of Gases, covering the human respiratory system, mechanism, gas transport and regulation.

Breathing and Exchange of Gases MCQ – Mock Online Test

Question 1: What is the primary purpose of breathing in organisms?

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Correct Answer: B. To exchange oxygen and carbon dioxide with the environment. Breathing facilitates the uptake of oxygen for energy production and the removal of carbon dioxide, a waste product of cellular respiration.

Question 2: Which gas is utilized by organisms to break down molecules and produce energy?

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Correct Answer: C. Oxygen (O₂). Oxygen is essential for cellular respiration, where it is used to break down glucose and other molecules to generate energy.

Question 3: What is the byproduct of energy production in cells?

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Correct Answer: C. Carbon dioxide (CO₂). Carbon dioxide is produced during cellular respiration as a waste product.

Question 4: How do lower invertebrates like sponges and flatworms exchange gases?

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Correct Answer: B. By simple diffusion across their body surface. Lower invertebrates have simple body structures that allow for direct gas exchange with the environment.

Question 5: What respiratory mechanism do earthworms utilize?

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Correct Answer: D. Moist cuticle. Earthworms exchange gases through their skin, which is kept moist for efficient diffusion.

Question 6: How do insects carry out gas exchange?

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Correct Answer: C. Tracheal tubes. Insects have a network of tubes called tracheae that deliver oxygen directly to their tissues.

Question 7: What is the function of the nasal chamber in the respiratory system?

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Correct Answer: C. Filtering, warming, and moistening inhaled air. The nasal chamber conditions the air before it enters the lungs.

Question 8: The pharynx is a common passage for:

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Correct Answer: A. Food and air. The pharynx is part of both the respiratory and digestive systems.

Question 9: Which structure is responsible for sound production?

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Correct Answer: C. Larynx. The larynx contains the vocal cords, which vibrate to produce sound.

Question 10: What is the role of the epiglottis?

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Correct Answer: B. To prevent food from entering the trachea. The epiglottis acts as a flap that covers the trachea during swallowing.

Question 11: The trachea is also known as the:

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Correct Answer: C. Windpipe. The trachea is the tube that carries air from the larynx to the bronchi.

Question 12: What are the two tubes that branch from the trachea called?

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Correct Answer: C. Bronchi. The trachea divides into two main bronchi, one leading to each lung.

Question 13: Bronchi further divide into smaller tubes called:

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Correct Answer: B. Bronchioles. Bronchioles are the finer branches of the bronchi within the lungs.

Question 14: Where does the actual exchange of gases take place in the lungs?

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Correct Answer: C. Alveoli. Alveoli are tiny air sacs in the lungs where oxygen and carbon dioxide are exchanged.

Question 15: Which organs are the primary sites for gas exchange in the human body?

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Correct Answer: B. Lungs. The lungs are specifically designed for efficient gas exchange.

Question 16: What is the membrane that encloses the lungs called?

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Correct Answer: C. Pleura. The pleura is a double-layered membrane that surrounds each lung.

Question 17: Which part of the respiratory system is responsible for transporting air but not involved in gas exchange?

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Correct Answer: B. Conducting part. The conducting part includes structures like the trachea, bronchi, and bronchioles that carry air to the alveoli.

Question 18: Which part of the respiratory system is responsible for the exchange of gases?

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Correct Answer: B. Respiratory part. The respiratory part includes the alveoli where gas exchange occurs.

Question 19: Where are the lungs located within the body?

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Correct Answer: C. Thoracic chamber. The thoracic chamber, or chest cavity, houses and protects the lungs.

Question 20: What separates the thoracic cavity from the abdominal cavity?

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Correct Answer: C. Diaphragm. The diaphragm is a dome-shaped muscle that forms the floor of the thoracic cavity.

Question 21: What is the process of taking in atmospheric air called?

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Correct Answer: B. Inspiration. Inspiration is the active process of drawing air into the lungs.

Question 22: What is the process of releasing air from the lungs called?

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Correct Answer: B. Expiration. Expiration is the process of expelling air from the lungs.

Question 23: What drives the movement of air into and out of the lungs?

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Correct Answer: C. Pressure gradient. Air flows from an area of high pressure to low pressure.

Question 24: Which muscle plays a major role in breathing by altering the volume of the thoracic cavity?

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Correct Answer: B. Diaphragm. The diaphragm is the primary muscle involved in breathing.

Question 25: What is the function of the intercostal muscles during breathing?

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Correct Answer: C. They assist in expanding and contracting the rib cage. The intercostal muscles help change the thoracic cavity’s size during breathing.

Question 26: What does tidal volume refer to?

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Correct Answer: C. The volume of air inhaled or exhaled during a normal breath. Tidal volume is the amount of air exchanged during quiet breathing.

Question 27: What is the additional volume of air that can be forcibly inhaled after a normal inhalation called?

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Correct Answer: B. Inspiratory reserve volume. It’s the extra air that can be inhaled beyond the normal tidal volume.

Question 28: What is the additional volume of air that can be forcibly exhaled after a normal exhalation called?

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Correct Answer: C. Expiratory reserve volume. It’s the extra air that can be exhaled beyond the normal tidal volume.

Question 29: What is the volume of air that remains in the lungs even after a forceful exhalation called?

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Correct Answer: D. Residual volume. This air ensures that the lungs don’t collapse completely.

Question 30: What does inspiratory capacity represent?

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Correct Answer: C. The maximum volume of air a person can inhale after a normal exhalation. It includes tidal volume and inspiratory reserve volume.

Question 31: What does expiratory capacity represent?

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Correct Answer: C. The maximum volume of air a person can exhale after a normal inhalation. It includes tidal volume and expiratory reserve volume.

Question 32: What does functional residual capacity represent?

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Correct Answer: B. The volume of air remaining in the lungs after a normal exhalation. It includes expiratory reserve volume and residual volume.

Question 33: What does vital capacity represent?

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Correct Answer: C. The maximum volume of air a person can exhale after a forceful inhalation. It includes inspiratory reserve volume, tidal volume, and expiratory reserve volume.

Question 34: What does total lung capacity represent?

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Correct Answer: D. The total volume of air the lungs can hold after a maximum inhalation. It includes all lung volumes.

Question 35: What are the primary sites of gas exchange in the lungs?

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Correct Answer: C. Alveoli. Alveoli are tiny air sacs surrounded by capillaries for efficient gas exchange.

Question 36: By what process are oxygen and carbon dioxide exchanged in the lungs and tissues?

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Correct Answer: C. Diffusion. Gases move from areas of high concentration to low concentration.

Question 37: What is the term for the pressure exerted by an individual gas within a mixture of gases?

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Correct Answer: B. Partial pressure. It determines the movement of each gas independently.

Question 38: What constitutes the diffusion membrane through which gases are exchanged in the alveoli?

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Correct Answer: C. The alveolar wall, capillary wall, and their basement membranes. This thin membrane allows for efficient gas exchange.

Question 39: What is the primary medium for the transport of oxygen and carbon dioxide in the body?

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Correct Answer: B. Blood. Blood carries oxygen from the lungs to the tissues and carbon dioxide from the tissues to the lungs.

Question 40: Which respiratory pigment in red blood cells binds to oxygen?

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Correct Answer: C. Hemoglobin. Hemoglobin greatly increases the oxygen-carrying capacity of blood.

Question 41: What is formed when oxygen binds with hemoglobin?

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Correct Answer: C. Oxyhemoglobin. This is the form in which oxygen is transported in the blood.

Question 42: What type of curve illustrates the relationship between the partial pressure of oxygen and the percentage saturation of hemoglobin with oxygen?

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Correct Answer: C. Sigmoid curve. The oxygen dissociation curve shows how oxygen saturation changes with varying oxygen partial pressures.

Question 43: How is a small percentage of carbon dioxide transported in the blood?

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Correct Answer: C. Bound to hemoglobin as carbaminohemoglobin. This is a minor transport mechanism for carbon dioxide.

Question 44: Which enzyme catalyzes the formation of bicarbonate ions from carbon dioxide and water in the blood?

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Correct Answer: A. Carbonic anhydrase. This enzyme speeds up the conversion of carbon dioxide to bicarbonate ions.

Question 45: What is the major form in which carbon dioxide is transported in the blood?

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Correct Answer: B. As bicarbonate ions. This is the most efficient way to transport carbon dioxide in the blood.

Question 46: Which system in the body plays a major role in regulating respiration?

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Correct Answer: C. Neural system. The nervous system controls the rate and depth of breathing.

Question 47: Where is the respiratory rhythm center located?

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Correct Answer: B. Medulla oblongata. The medulla oblongata in the brainstem controls the basic rhythm of breathing.

Question 48: Which center in the brain can moderate the functions of the respiratory rhythm center?

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Correct Answer: B. Pneumotaxic center. The pneumotaxic center helps fine-tune the breathing pattern.

Question 49: Which area in the brain is highly sensitive to changes in CO₂ and hydrogen ion (H⁺) concentrations?

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Correct Answer: A. Chemosensitive area. This area helps regulate breathing based on blood CO₂ and H⁺ levels.

Question 50: Where are the receptors that can detect changes in CO₂ and H⁺ concentrations located?

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Correct Answer: A. Aortic arch and carotid artery. These receptors send signals to the brain to adjust breathing.

Question 51: What is a common respiratory disorder characterized by inflammation and narrowing of the airways?

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Correct Answer: C. Asthma. Asthma often involves wheezing and difficulty breathing.

Question 52: Which respiratory disorder is characterized by damage to the alveolar walls, leading to reduced gas exchange?

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Correct Answer: D. Emphysema. Emphysema is a chronic obstructive pulmonary disease (COPD).

Question 53: What type of respiratory disorders can be caused by long-term exposure to dust, fumes, or chemicals in the workplace?

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Correct Answer: B. Occupational respiratory disorders. These disorders are specific to certain work environments.

Question 54: Which of the following is NOT a characteristic of asthma?

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Correct Answer: D. Damage to alveolar walls. Damage to alveolar walls is a characteristic of emphysema, not asthma.

Question 55: Which of the following is a major cause of emphysema?

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Correct Answer: B. Cigarette smoking. Cigarette smoking is a leading cause of emphysema.

Question 56: What is the primary cause of occupational respiratory disorders?

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Correct Answer: C. Exposure to workplace pollutants. Occupational respiratory disorders are caused by inhaling harmful substances in the workplace.

Question 57: Which of the following is a common symptom of occupational respiratory disorders?

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Correct Answer: B. Cough. Cough is a common symptom of various respiratory disorders, including occupational ones.

Question 58: Which of the following occupations is NOT typically associated with a high risk of occupational respiratory disorders?

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Correct Answer: C. Office work. Office work typically does not involve exposure to high levels of respiratory hazards.

Question 59: What is the purpose of wearing protective masks in industries with high dust levels?

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Correct Answer: B. To reduce the risk of occupational respiratory disorders. Protective masks filter out dust and other harmful particles.

Question 60: Which of the following is NOT a common type of occupational respiratory disorder?

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Correct Answer: B. Pneumonia. Pneumonia is usually caused by an infection, not occupational exposure.

Question 61: What is the term for the scarring of lung tissue caused by long-term exposure to dust or other irritants?

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Correct Answer: D. Fibrosis. Fibrosis is the formation of excess fibrous tissue in the lungs, leading to stiffness and reduced function.

Question 62: Which of the following is NOT a preventive measure for occupational respiratory disorders?

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Correct Answer: C. Taking antibiotics. Antibiotics are not effective against occupational respiratory disorders as they are not caused by bacterial infections.

Question 63: What is the primary function of the respiratory system?

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Correct Answer: C. To exchange gases between the body and the environment. The respiratory system facilitates the uptake of oxygen and release of carbon dioxide.

Question 64: Which of the following is NOT a component of the conducting part of the respiratory system?

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Correct Answer: C. Alveoli. Alveoli are part of the respiratory part, where gas exchange occurs.

Question 65: What is the role of pleural fluid?

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Correct Answer: B. To reduce friction between the lungs and the chest wall. Pleural fluid allows the lungs to move smoothly during breathing.

Question 66: Which of the following is NOT a step involved in respiration?

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Correct Answer: B. Digestion. Digestion is part of the digestive system, not the respiratory system.

Question 67: What is the primary muscle involved in inspiration?

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Correct Answer: A. Diaphragm. The diaphragm contracts during inhalation, increasing the volume of the thoracic cavity.

Question 68: What is the term for the pressure within the lungs?

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Correct Answer: C. Intrapulmonary pressure. Intrapulmonary pressure changes during breathing to allow for air movement.

Question 69: What is the additional volume of air a person can inspire by a forcible inspiration called?

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Correct Answer: B. Inspiratory reserve volume. It is the extra volume of air that can be inhaled forcefully after a normal inspiration.

Question 70: What is the volume of air remaining in the lungs even after a forcible expiration called?

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Correct Answer: D. Residual volume. It ensures that the lungs do not collapse completely.

Question 71: What happens to the diaphragm during inhalation?

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Correct Answer: B. It contracts and moves downwards. The diaphragm’s contraction increases the volume of the thoracic cavity, allowing for lung expansion.

Question 72: What happens to the intercostal muscles during inhalation?

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Correct Answer: B. They contract. The intercostal muscles contract to lift the rib cage, further expanding the thoracic cavity.

Question 73: What happens to the volume of the thoracic cavity during exhalation?

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Correct Answer: B. It decreases. The relaxation of the diaphragm and intercostal muscles reduces the thoracic cavity volume, expelling air from the lungs.

Question 74: What is the relationship between lung volume and intrapulmonary pressure?

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Correct Answer: B. As lung volume increases, intrapulmonary pressure decreases. This pressure difference drives air into the lungs during inhalation.

Question 75: What is the primary factor that drives the diffusion of gases across the respiratory membrane?

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Correct Answer: B. Partial pressure gradient. Gases move from an area of higher partial pressure to an area of lower partial pressure.

Question 76: What is the partial pressure of oxygen (pO₂) in the alveoli compared to the pulmonary capillaries?

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Correct Answer: A. Higher in the alveoli. This difference in pO₂ drives the diffusion of oxygen from the alveoli into the blood.

Question 77: What is the partial pressure of carbon dioxide (pCO₂) in the tissues compared to the systemic capillaries?

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Correct Answer: A. Higher in the tissues. This difference in pCO₂ drives the diffusion of carbon dioxide from the tissues into the blood.

Question 78: What is the approximate percentage of oxygen transported in the blood bound to hemoglobin?

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Correct Answer: D. 97%. Hemoglobin significantly increases the blood’s oxygen-carrying capacity.

Question 79: What is the main form in which carbon dioxide is transported in the blood?

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Correct Answer: C. As bicarbonate ions. Bicarbonate ions in the plasma are the primary means of carbon dioxide transport.

Question 80: What is the role of carbonic anhydrase in carbon dioxide transport?

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Correct Answer: B. It catalyzes the conversion of carbon dioxide and water to carbonic acid. Carbonic acid then dissociates into bicarbonate ions.

Question 81: What happens to the oxygen dissociation curve when the pH of the blood decreases (becomes more acidic)?

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Correct Answer: B. It shifts to the right. A decrease in pH (increased acidity) reduces hemoglobin’s affinity for oxygen, promoting oxygen release in the tissues.

Question 82: What is the Bohr effect?

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Correct Answer: D. All of the above. The Bohr effect encompasses the influence of pH, temperature, and carbon dioxide on hemoglobin’s oxygen affinity.

Question 83: What is the Haldane effect?

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Correct Answer: A. The effect of oxygen on carbon dioxide binding to hemoglobin. Oxygenation of blood in the lungs decreases its affinity for carbon dioxide, facilitating its release.

Question 84: What is the role of the enzyme carbonic anhydrase in carbon dioxide transport?

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Correct Answer: A. It converts carbon dioxide to carbonic acid. This reaction occurs in the red blood cells, allowing for efficient carbon dioxide transport as bicarbonate ions.

Question 85: Where is the respiratory rhythm center located in the brain?

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Correct Answer: C. Medulla oblongata. The medulla oblongata controls the basic rhythm of breathing.

Question 86: What is the role of the pneumotaxic center in respiration?

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Correct Answer: D. It can moderate the functions of the respiratory rhythm center. The pneumotaxic center helps fine-tune the breathing pattern.

Question 87: What is the primary stimulus for changes in the rate and depth of breathing?

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Correct Answer: B. Blood carbon dioxide levels. An increase in blood carbon dioxide levels triggers an increase in breathing rate and depth.

Question 88: Where are the peripheral chemoreceptors that can detect changes in blood oxygen levels located?

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Correct Answer: A. Aortic arch and carotid bodies. These chemoreceptors send signals to the brain to adjust breathing in response to changes in blood oxygen levels.

Question 89: What is the effect of increased carbon dioxide levels on the pH of the cerebrospinal fluid (CSF)?

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Correct Answer: B. It decreases the pH (makes it more acidic). Carbon dioxide reacts with water in the CSF to form carbonic acid, which dissociates and lowers the pH.

Question 90: What is the response of the respiratory system to an increase in the acidity of the CSF?

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Correct Answer: B. Breathing becomes faster and deeper. The chemosensitive area in the medulla oblongata detects the increased acidity and stimulates the respiratory centers to increase ventilation.

Question 91: What is the role of the aortic and carotid bodies in the regulation of respiration?

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Correct Answer: B. They detect changes in blood oxygen levels. These peripheral chemoreceptors are sensitive to decreases in blood oxygen levels and signal the brain to increase ventilation.

Question 92: What is the primary mechanism by which respiration is regulated during exercise?

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Correct Answer: D. All of the above. Multiple factors, including increased carbon dioxide, lactic acid, and signals from the motor cortex, contribute to increased ventilation during exercise.

Question 93: What is the effect of high altitude on respiration?

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Correct Answer: B. Breathing becomes faster and deeper. The lower partial pressure of oxygen at high altitudes triggers an increase in ventilation to compensate for the reduced oxygen availability.

Question 94: Which of the following is NOT a disorder of the respiratory system?

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Correct Answer: C. Arthritis. Arthritis is a joint disorder, not a respiratory disorder.

Question 95: What is the primary cause of emphysema?

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Correct Answer: C. Smoking. Smoking is a major risk factor for emphysema, which involves damage to the alveolar walls.

Question 96: What is a common symptom of asthma?

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Correct Answer: D. All of the above. Asthma is characterized by airway inflammation and constriction, leading to various respiratory symptoms.

Question 97: What is the primary cause of occupational respiratory disorders?

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Correct Answer: C. Exposure to workplace pollutants. Occupational respiratory disorders result from inhaling harmful substances in the work environment.

Question 98: Which of the following is a preventive measure for occupational respiratory disorders?

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Correct Answer: D. All of the above. These measures help reduce exposure to harmful substances and promote early detection of any respiratory problems.

Question 99: What is the leading cause of lung cancer?

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Correct Answer: B. Smoking. Smoking is the most significant risk factor for lung cancer.

Question 100: Which of the following is NOT a function of the respiratory system?

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Correct Answer: D. Nutrient absorption. Nutrient absorption is a function of the digestive system, not the respiratory system.

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