Breathing organs and the human air passage — practice questions

Question 1 · difficulty L1 · recall

Which structure prevents food from entering the glottis during swallowing?

• A. Epiglottis
• B. Trachea
• C. Pleura
• D. Diaphragm

Question 2 · difficulty L2 · understanding

Why are incomplete cartilaginous rings present in the tracheal wall?

• A. They produce mucus for gas exchange
• B. They help keep the airway from collapsing while allowing flexibility
• C. They contract to draw air into the lungs
• D. They contain the respiratory pigment haemoglobin

Question 3 · difficulty L2 · understanding

Airway X is supported by cartilaginous rings and divides into two primary branches, while airway Y is a smaller branch within the lung that lacks such complete ring-like support and ultimately leads toward alveolar ducts. Which structures are X and Y?

• A. Alveolus and bronchus
• B. Bronchiole and trachea
• C. Pharynx and larynx
• D. Trachea and bronchiole

Question 4 · difficulty L3 · application

An inhaled particle passes through the external nostrils and nasal chamber. Which sequence correctly traces its route toward the gas-exchange surface?

• A. Trachea → pharynx → larynx → alveoli → bronchi
• B. Larynx → pharynx → bronchioles → trachea → alveoli
• C. Pharynx → larynx → trachea → bronchi → bronchioles → alveoli
• D. Pharynx → trachea → oesophagus → bronchi → alveoli

Question 5 · difficulty L3 · application

A blockage occurs after the trachea has divided but before air reaches the bronchioles of the left lung. Which structure is most directly obstructed?

• A. Left primary bronchus
• B. Left pleural cavity
• C. Pharynx
• D. Alveolar membrane

Question 6 · difficulty L3 · understanding

In humans, respiration occurs in the following steps. Arrange these steps in the correct order. A. Diffusion of $\mathrm{O}_2$ and $\mathrm{CO}_2$ between blood and tissues B. Diffusion of $\mathrm{O}_2$ and $\mathrm{CO}_2$ across alveolar membrane C. Pulmonary ventilation by which atmospheric air is drawn in and $\mathrm{CO}_2$ rich alveolar air is released out D. Cellular respiration E. Transport of gases by the blood Choose the correct answer from the options given below

• A. $\mathrm{A}, \mathrm{B}, \mathrm{C}, \mathrm{D}, \mathrm{E}$
• B. $\mathrm{E}, \mathrm{A}, \mathrm{C}, \mathrm{D}, \mathrm{B}$
• C. $\mathrm{C}, \mathrm{B}, \mathrm{E}, \mathrm{A}, \mathrm{D}$
• D. $\mathrm{C}, \mathrm{A}, \mathrm{B}, \mathrm{E}, \mathrm{D}$

Question 7 · difficulty L3 · understanding

$$\text { Match List I with List II: }$$ $$\text { List I }$$ $$\text { List II }$$ A. Molluscs I. Pulmonary respiration only B. Reptiles II. Branchial respiration C. Adult amphibians III. Cellular respiration D. Amoeba IV. Pulmonary and cutaneous respiration Choose the correct answer from the options given below:

• A. A-II, B-I, C-IV, D-III
• B. A-I, B-II, C-IV, D-III
• C. A-II, B-I, C-III, D-IV
• D. A-III, B-II, C-I, D-IV

Question 8 · difficulty L3 · understanding

Select the sequence of steps in Respiration. (A) Diffusion of gases (O 2 and CO 2 ) across alveolar membrane. (B) Diffusion of O 2 and CO 2 between blood and tissues. (C) Transport of gases by the blood (D) Pulmonary ventilation by which atmospheric air is drawn in and CO 2 rich alveolar air is released out. (E) Utilisation of O 2 by the cells for catabolic reactions are resultant release of CO 2 Choose the correct answer from the options given below :

• A. (D), (A), (C), (B), (E)
• B. (C), (B), (A), (E), (D)
• C. (B), (C), (E), (D), (A)
• D. (A), (C), (B), (E), (D)

Question 9 · difficulty L3 · understanding

Identify the region of human brain which has pneumotaxic centre that alters respiratory rate by reducing the duration of inspiration.

• A. Cerebrum
• B. Medulla
• C. Pons
• D. Thalamus

Question 10 · difficulty L3 · understanding

Which of the following is not the function of conducting part of respiratory system?

• A. It clears inhaled air from foreign particles
• B. Inhaled air is humidified
• C. Temperature of inhaled air is brought to body temperature
• D. Provides surface for diffusion of O 2 and CO 2