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

Which of the following statements is FALSE regarding respiratory distress syndrome in premature infants?

  1. Their ability to form DPPC is limited.

  2. High pressure is required to ventilate the lungs.

  3. Their lung compliance is low.

  4. Alveoli favours to overexpand and frequently explode at the end of inspiration.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This statement is incorrect. In respiratory distress syndrome, the lungs alveoli are collapsed not expanded. The expanded alveoli, which sometimes burst is a signature characteristic of emphysema, not the respiratory distress syndrome.

Multiple choice

Pneumotaxic centre functions primarily to

  1. inhibit inspiration

  2. prolonged expiration

  3. discharge inspiratory action potentials

  4. decreases respiratory rate
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The pneumotaxic centre is a network of neurons in the rostral dorsal lateral pons. Its main function is to inhibit inspiration and thus regulating inspiratory volume and rate.

Multiple choice

The minute ventilation will not be increased by

  1. hypoxia

  2. exercise

  3. an increase in arterial pH

  4. an increase in arterial partial pressure of carbon dioxide
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Alveolar ventilation gives the oxygen necessary for oxidative metabolism and elucidates the CO2 produced by these metabolic processes. Therefore, it is appropriate that the main physiologic stimuli to respiration are an elevation in the PCO2 and a reduction in the PO2 (hypoxemia).

Multiple choice

When an individual is at rest, the adequate ventilation is maintained through

  1. external intercostal muscle

  2. internal intercostal muscles

  3. intercostal space

  4. diaphragm
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The diaphragm alone can maintain adequate ventilation at rest. The muscles aid the flattened diaphragm in generating sufficient inspiratory pressure to maintain adequate ventilation, both when awake and during rest.

Multiple choice

The trachea is prevented from collapsing due to the presence of

  1. bony rings

  2. fibrous rings

  3. cartilage rings

  4. all of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The trachea (windpipe) is reinforced with 16-20 C-shaped rings of hyaline cartilage that prevent it from collapsing during inhalation when intrathoracic pressure drops. The cartilage rings are incomplete posteriorly (C-shaped) to allow the esophagus to expand during swallowing. Bony rings do not exist in the trachea.

Multiple choice

Contractions of the external intercostal muscles bring about

  1. decrease in the volume of thoracic cavity

  2. increase in the volume of thoracic cavity

  3. volume of thoracic cavity does not change

  4. flattening of the diaphragm

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

Contractions of the external intercostal muscles bring about increase in the volume of thoracic cavity.

Multiple choice

Which of the following are the respiratory organs in aquatic whales?

  1. Gills

  2. Lungs

  3. Skin

  4. Tracheae
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Whales are mammals and breathe through lungs, not gills. They must surface to breathe air through blowholes. While they are aquatic, they retain mammalian respiratory systems. Gills are for fish, skin respiration is for some amphibians, and tracheae are for insects. This question tests understanding of evolutionary adaptations in aquatic mammals.

Multiple choice

How is respiration accomplished in arthropods?

  1. By lungs and gills

  2. By book lungs and tracheae

  3. By lungs and tracheae

  4. By book lungs, tracheae and gills
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Arthropods use multiple respiratory structures depending on their habitat and size. Aquatic arthropods (like crabs) use gills. Terrestrial arachnids (scorpions, spiders) use book lungs. Insects use tracheae (tubular respiratory system). No single option covers all arthropods - only option D correctly includes all three respiratory structures found across the phylum.

Multiple choice

Which of the following statements is/are false?

a. When the pressure within the lungs is less than the atmospheric pressure, inspiration occurs. b. Both the lungs are covered by triple layer of pleura, having pleural fluid between them. c. Respiratory rhythm centre is responsible for maintaining and moderating the respiratory rhythm in humans.

  1. Only a

  2. Only a and b

  3. Only b

  4. Only b and c

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

This is the correct option as this statement is false. Both the lungs are covered by double layer of pleura, having pleural fluid between them.

Multiple choice

The conducting part of the respiratory system is the part starting with the external nostrils up to the terminal bronchioles. Which of the following is not a function of the conducting part?

  1. It brings the air to body temperature.

  2. It is the site of actual diffusion of oxygen and carbon dioxide between the alveoli and a network of tiny blood vessels called capillaries.

  3. It humidifies the atmospheric air.

  4. It clears the atmospheric air.

  5. It transports the atmospheric air to the alveoli.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This is the correct option as this is not a function of the conducting part. Alveoli and their ducts form the exchange part of the respiratory system.