Biology

Respiration and Gas Exchange

958 Questions

Access a targeted set of questions on respiration and gas exchange for competitive exams. Topics include lung volumes, the mechanism of breathing, and respiratory anatomy. Understanding these physiological processes is essential for scoring well.

Lung volumes and capacitiesBreathing mechanismsRespiratory anatomyGas exchange processes

Respiration and Gas Exchange Questions

Multiple choice

The area between the two lungs is called

  1. pleural cavity

  2. thoracic cavity

  3. mediastinum

  4. abdominal cavity

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The mediastinum is the central compartment of the thoracic cavity between the two lungs. It contains the heart, great vessels, trachea, esophagus, and thymus gland. The pleural cavity surrounds individual lungs, while thoracic cavity is the broader term.

Multiple choice

Which among the following can be excluded from the functions of the lungs?

  1. The lungs serve as a reservoir of blood in the body.

  2. They form defence system against air-borne infection.

  3. They filter small blood clots formed in arteries.

  4. They maintain sterility of the body.

  5. They secrete immunoglobulin A.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Lungs filter gas micro-bubbles occurring in the venous blood stream such as those created during decompression after underwater diving. They also filter out small blood clots formed in veins.

Multiple choice

Which among the following structures is responsible for warming or cooling of inhaled air within 1 degree of body temperature?

  1. The laryngopharynx

  2. The oropharynx

  3. The larynx

  4. The nasopharynx

  5. The nasal cavity
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

The nasal cavity conditions the air to be received by the other areas of the respiratory tract. Owing to the large surface area provided by the nasal conchae, the air passing through the nasal cavity is warmed or cooled to within 1 degree of body temperature.

Multiple choice

In mammals, the process of ventilation is normally controlled by the autonomic nervous system. Which among the following statements does NOT characterise ventilation in humans?

  1. Pregnancy tends to increase ventilation.

  2. The tone of respiratory muscle is modulated by muscle spindles via a reflex arc.

  3. Ventilatory rate is usually controlled and determined by blood levels of oxygen as determined by metabolic rate.

  4. During moderate exercise, ventilation increases in proportion to metabolic production of carbon dioxide.

  5. Afferent neurons from the carotid bodies and aortic bodies are via the glossopharyngeal nerve.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Ventilatory rate (minute volume) is strictly controlled and determined primarily by blood levels of carbon dioxide as determined by metabolic rate. Blood levels of oxygen become important in hypoxia. These levels are sensed by chemoreceptors in the medulla oblongata for pH, and the carotid and aortic bodies for oxygen and carbon dioxide.

Multiple choice

Lung capacity is defined as the maximum air which can be held in the two lungs at any given time. Which among the following has the minimum value?

  1. Residual air

  2. Alveolar air

  3. Inspiratory reserve volume

  4. Expiratory reserve volume

  5. Vital capacity
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Some amount of air remains in the various parts of the respiratory tract also. The air in the trachea and bronchi (where no diffusion occurs) is called dead space air (350ml). The air remaining in the alveoli or air sacs is alveolar air (150mL).

Multiple choice

The adenoids are present in which part of the respiratory tract?

  1. Nasopharynx

  2. Primary bronchus

  3. Respiratory bronchiole

  4. Terminal bronchiole

  5. Alveolus
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

It extends from the base of the skull to the upper surface of the soft palate. It includes the space between the internal nares and the soft palate, and lies above the oral cavity. The adenoids are lymphoid tissue structures located in the posterior wall of the nasopharynx.

Multiple choice

Which of the following structures is responsible for warming or cooling of inhaled air within one degree of body temperature?

  1. The laryngopharynx

  2. The larynx

  3. The oropharynx

  4. The nasopharynx

  5. The nasal cavity
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The nasopharynx, extends from the base of the skull to the upper surface of the soft palate. It includes the space between the internal nares and the soft palate and lies above the oral cavity. The nasal cavity conditions the air to be received by the other areas of the respiratory tract. Owing to the large surface area provided by the nasal conchae, the air passing through the nasal cavity is warmed or cooled to within 1 degree of body temperature.

Multiple choice

Which of the following statements regarding the human lungs is INCORRECT?

  1. The development of the human lungs arises from the laryngotracheal groove.

  2. The upper horizontal fissure, separates the superior from the middle lobe.

  3. The inferior lobe is the smallest lobe of the right lung.

  4. The right lung has a higher volume, total capacity and weight than that of the left lung.

  5. The lower, oblique fissure, separates the inferior from the middle and superior lobes.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The middle lobe is the smallest lobe of the right lung. It is wedge-shaped and includes the part of the anterior border, and the anterior part of the base of the lung.

Multiple choice

Respiratory quotient (RQ) is one in case of

  1. fatty acids

  2. nucleic acids

  3. carbohydrates

  4. organic acids
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Respiratory quotient (RQ) is the ratio of CO2 produced to O2 consumed during respiration. For carbohydrates, the ratio is exactly 1 because the molecular formula of glucose (C6H12O6) gives equal moles of CO2 and H2O upon complete oxidation. Fatty acids have RQ less than 1 (about 0.7), organic acids have RQ greater than 1, and nucleic acids have variable RQ depending on their composition.

Multiple choice

Book lungs are the respiratory organs in:

  1. Protozoans

  2. Cnidarians

  3. Arthropods

  4. Amphibians

  5. Mammals
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Book lungs are respiratory organs found in arthropods, specifically arachnids (spiders, scorpions) and some myriapods. They are leaf-like, stacked structures that maximize gas exchange surface area. Protozoans use diffusion, cnidarians use direct diffusion, amphibians use skin/lungs/gills, and mammals use alveolar lungs - none have book lungs.