Biology

Respiration and Gas Exchange

989 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

Fill in the numbered blank (ii).

Directions: Choose the best option to fill in the blank.

Yawning is an involuntary ______(i)______ in which your mouth opens up wide and you inhale deeply, followed by _____(ii)_____. When you say involuntary, this means that you have no _____(iii)_____ over this action much like other reflexes such as blinking or sneezing. Yawns are not _____(iv)______ only to human beings as all other animals do this. Despite a lot of _____(v)_____, we still know little about the causes of yawning.

  1. breathing

  2. exhaling

  3. resting

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

Exhale means to blow forth or breathe out. 'Breathing' cannot be the answer as it should be followed by 'out' to make sense here.

Multiple choice

Which of the following statements is FALSE regarding the surfactants?

  1. It is a fraction part of a lipoprotein called dipalmitoyl phosphatidyl-choline.

  2. It is synthesized by alveolar type II cells.

  3. Alveolar surface area decreases during expiration, the surfactant decreases the surface tension at a constant rate.

  4. When surfactant density gets decreased during expansion, surface tension initially rises rapidly, then begins to fall until it reaches the starting point.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

During expansion, i.e. during the act of inspiration,  the surfactant density decreases which makes the surface tension strong enough to make the alveoli collapse again. So, the surface tension will constantly rise not as the option states that it will increase, then decrease.

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.