Breathing and Exchange of Gases MCQs

Examine the peripheral chemoreceptors in respiratory regulation:

I. Associated with aortic arch and carotid artery.
II. Recognize changes in CO₂ and H⁺ concentration.
III. Send necessary signals to rhythm centre for remedial actions.
IV. Role of oxygen in the regulation of respiratory rhythm is quite insignificant.

Which statement combination regarding the role of oxygen in respiratory rhythm regulation is accurate?

I. The role of oxygen in the regulation of respiratory rhythm is quite insignificant.
II. Respiratory rhythm is primarily regulated by CO₂ and H⁺ ion concentrations.
III. High oxygen concentration is the primary trigger for the chemosensitive area.
IV. Oxygen receptors in carotid artery directly drive normal resting respiratory rhythm.

Consider the clinical features of Asthma:

I. Characterized by difficulty in breathing.
II. Causes wheezing sound during breathing.
III. Caused by inflammation of bronchi and bronchioles.
IV. Caused by breakdown of alveolar walls.

Consider the clinical features of Emphysema:

I. Chronic disorder.
II. Alveolar walls are damaged.
III. Respiratory surface is decreased.
IV. One of the major causes is cigarette smoking.

Analyze Occupational Respiratory Disorders:

I. Common in industries involving grinding or stone-breaking.
II. So much dust is produced that body defense mechanisms cannot cope.
III. Long exposure causes inflammation leading to fibrosis (proliferation of fibrous tissues).
IV. Causes serious lung damage, and workers should wear protective masks.

Match the disorder with its primary underlying pathology:

I. Asthma → Inflammation of bronchi and bronchioles.
II. Emphysema → Damage to alveolar walls decreasing respiratory surface.
III. Occupational Respiratory Disorders → Proliferation of fibrous tissues (fibrosis).
IV. Emphysema → Proliferation of bronchial cartilage.

Which brain region matches correctly with its respiratory regulatory function?

I. Medulla → Respiratory rhythm centre.
II. Pons → Pneumotaxic centre.
III. Medulla → Chemosensitive area adjacent to rhythm centre.
IV. Cerebellum → Pneumotaxic centre.

Compare gas exchange values and percentages between O₂ and CO₂ transport:

I. O₂ carried by RBCs = 97%; CO₂ carried by RBCs = 20–25%.
II. O₂ carried in plasma = 3%; CO₂ carried in plasma = 7%.
III. CO₂ carried as bicarbonate = 70%.
IV. 100 mL oxygenated blood delivers 5 mL O₂; 100 mL deoxygenated blood delivers 4 mL CO₂.

Consider the neural control mechanisms regulating human breathing rate:

I. Pneumotaxic centre signals rhythm centre to reduce duration of inspiration.
II. Reducing duration of inspiration alters the respiratory rate.
III. Chemosensitive area signals rhythm centre upon sensing increase in CO₂ and H⁺.
IV. Rhythm centre increases oxygen consumption in mitochondria directly.

Consider the following comprehensive statements regarding Human Respiratory System:

I. Trachea divides at the level of the 5th thoracic vertebra into primary bronchi.
II. Diffusion membrane consists of three layers with total thickness less than 1 mm.
III. Solubility of CO₂ is 20–25 times higher than O₂.
IV. Major cause of emphysema is cigarette smoking.