Respiratory System in Humans and Animals

Free sample questions

Respiratory System in Humans and Animals — sample Biology questions with answers

1. Question 1

   What are the main characteristics of an efficient gas exchange surface in the human respiratory system?

   • A$\text{Large surface area, thin walls, and good blood supply}$
   • B$\text{Small surface area, thick walls, and poor blood supply}$
   • C$\text{Large surface area, thick walls, and good blood supply}$
   • D$\text{Small surface area, thin walls, and poor blood supply}$

   Answer: A. $\text{Large surface area, thin walls, and good blood supply}$

   An efficient gas exchange surface needs a large surface area, thin walls for rapid diffusion, and a good blood supply to maintain a concentration gradient.

2. Question 2

   Through which structure does air enter the human respiratory system?

   • A$\text{Nose}\to \text{Pharynx}\to \text{Larynx}\to \text{Trachea}\to \text{Bronchus}\to \text{Bronchiole}\to \text{Alveolus}$
   • B$\text{Nose}\to \text{Larynx}\to \text{Pharynx}\to \text{Trachea}\to \text{Bronchiole}\to \text{Bronchus}\to \text{Alveolus}$
   • C$\text{Mouth}\to \text{Trachea}\to \text{Pharynx}\to \text{Larynx}\to \text{Bronchus}\to \text{Bronchiole}\to \text{Alveolus}$
   • D$\text{Nose}\to \text{Pharynx}\to \text{Trachea}\to \text{Larynx}\to \text{Bronchus}\to \text{Bronchiole}\to \text{Alveolus}$

   Answer: A. $\text{Nose} \rightarrow \text{Pharynx} \rightarrow \text{Larynx} \rightarrow \text{Trachea} \rightarrow \text{Bronchus} \rightarrow \text{Bronchiole} \rightarrow \text{Alveolus}$

   The correct order is: nose, pharynx, larynx, trachea, bronchus, bronchiole, and alveolus. The larynx is located after the pharynx, not before.

3. Question 3

   What is the function of the epiglottis during swallowing?

   • A$\text{Closes the pharynx to prevent food from entering the trachea}$
   • B$\text{Closes the larynx to prevent food from entering the oesophagus}$
   • C$\text{Closes the trachea to prevent food from entering the oesophagus}$
   • D$\text{Closes the oesophagus to prevent air from entering the stomach}$

   Answer: B. $\text{Closes the larynx to prevent food from entering the oesophagus}$

   The epiglottis covers the larynx during swallowing to prevent food from entering the trachea, not directly the pharynx or trachea.

4. Question 4

   During inspiration, what happens to the diaphragm and intercostal muscles?

   • A$\text{Diaphragm contracts and flattens; intercostal muscles contract lifting the ribs}$
   • B$\text{Diaphragm relaxes and becomes dome-shaped; intercostal muscles relax lowering the ribs}$
   • C$\text{Diaphragm contracts and becomes dome-shaped; intercostal muscles relax lowering the ribs}$
   • D$\text{Diaphragm relaxes and flattens; intercostal muscles contract lifting the ribs}$

   Answer: A. $\text{Diaphragm contracts and flattens; intercostal muscles contract lifting the ribs}$

   Inspiration occurs when the diaphragm contracts (flattens) and the intercostal muscles contract (lift ribs), increasing thoracic volume.

5. Question 5

   What is the change in air pressure in the thoracic cavity during expiration?

   • A$\text{Air pressure in the thoracic cavity increases above atmospheric pressure}$
   • B$\text{Air pressure in the thoracic cavity decreases below atmospheric pressure}$
   • C$\text{Air pressure in the thoracic cavity equals atmospheric pressure}$
   • D$\text{Air pressure in the thoracic cavity does not change}$

   Answer: A. $\text{Air pressure in the thoracic cavity increases above atmospheric pressure}$

   During expiration, thoracic volume decreases causing air pressure in the lungs to rise above atmospheric pressure, so air moves out.