Gas Exchange in Humans
Each subtopic includes About section, revision page link, 10 preview questions, and practice CTAs.
Structure of gas exchange system
SubtopicStructure of gas exchange system under Gas Exchange in Humans for Grade 12 IGCSE.
Preview questions (no answers)
- 1.
How does the short diffusion distance in the alveoli benefit gas exchange?
A.It slows down the rate of gas movement
B.It makes gas exchange faster
C.It prevents pathogens from entering the blood
D.It increases the pressure in the lungs
- 2.
What is the collective name for the structures that protect the lungs and heart?
A.The vertebral column
B.The pelvic girdle
C.The ribcage
D.The pectoral girdle
- 3.
Which of the following is true about the respiratory system?
A.The right lung has two lobes
B.The lungs contain muscle tissue to pump air
C.Gas exchange occurs in the bronchioles
D.Air is warmed and moistened in the nasal cavity
- 4.
What is the function of the cartilage in the bronchi?
A.To produce red blood cells
B.To keep the airways open
C.To allow for gas exchange
D.To pump air into the alveoli
- 5.
Which of the following is true about the structure of the bronchioles compared to the bronchi?
A.Bronchioles have more cartilage than bronchi.
B.Bronchioles are wider than bronchi.
C.Bronchioles lack cartilage but contain smooth muscle.
D.Bronchioles are lined with a thicker layer of mucus than bronchi.
- 6.
During inspiration, what happens to the pressure inside the lungs (intrapulmonary pressure) relative to the atmospheric pressure?
A.It becomes equal to atmospheric pressure.
B.It becomes higher than atmospheric pressure.
C.It becomes lower than atmospheric pressure.
D.It fluctuates but always stays higher.
- 7.
Which structure is located immediately superior to the trachea?
A.The bronchi
B.The larynx
C.The diaphragm
D.The alveoli
- 8.
In the structure of the alveolus, the role of Type II pneumocytes is critical because they:
A.Form the main structural barrier for diffusion
B.Differentiate into Type I pneumocytes when the alveolar wall is damaged
C.Act as the primary receptors for CO2 levels in the lung
D.Are the only cells capable of ciliary movement in the lower tract
- 9.
Which of these features of the gas exchange system is an adaptation specifically for maintaining a steep concentration gradient?
A.The presence of C-shaped cartilage rings
B.A dense network of constantly flowing blood in capillaries
C.The presence of mucus-secreting goblet cells
D.The thinness of the squamous epithelial cells
- 10.
How does the structural absence of cartilage in the bronchioles relate to their function?
A.It allows the airways to remain permanently open regardless of pressure
B.It allows the airway diameter to be significantly adjusted by smooth muscle
C.It facilitates the diffusion of gases directly through the bronchiole wall
D.It prevents the trapping of air during expiration
Download the worksheet for Gas Exchange in Humans - Structure of gas exchange system to practice offline. It includes additional chapter-level practice questions.
Breathing and ventilation
SubtopicBreathing and ventilation under Gas Exchange in Humans for Grade 12 IGCSE.
Preview questions (no answers)
- 1.
In the human respiratory system, what are the smallest tubes that lead directly to the alveoli?
A.Bronchi
B.Trachea
C.Bronchioles
D.Larynx
- 2.
Which of these components of cigarette smoke is known to specifically damage or paralyze the cilia?
A.Nicotine
B.Carbon monoxide
C.Tar
D.Nitrogen
- 3.
What is the approximate percentage of carbon dioxide in inhaled air?
A.21%
B.16%
C.0.04%
D.4%
- 4.
Which of the following describes the wall of a capillary?
A.Thick and muscular
B.One cell thick
C.Reinforced with cartilage
D.Composed of multiple layers of epithelial cells
- 5.
What is the main reason why humans need a specialized gas exchange system rather than relying on diffusion through the skin?
A.The surface area to volume ratio of a human is too small
B.The skin is too moist for gas exchange
C.Oxygen cannot dissolve in the blood without lungs
D.The distance between the skin and the heart is too great
- 6.
Which property of a gas exchange surface is provided by the dense network of capillaries?
A.A thin barrier
B.A large surface area
C.Maintenance of a steep concentration gradient
D.A moist surface
- 7.
How does the body react to a very high concentration of in the blood?
A.The heart rate decreases to conserve oxygen
B.The depth and rate of breathing increase
C.The internal intercostal muscles remain relaxed
D.The diaphragm stops contracting to prevent more air intake
- 8.
What is the immediate effect of the contraction of the external intercostal muscles?
A.The ribs are pulled downward and inward, increasing thoracic pressure.
B.The ribs are pulled upward and outward, decreasing thoracic pressure.
C.The diaphragm is pulled downward, increasing thoracic volume.
D.The lungs are compressed, forcing air out of the alveoli.
- 9.
How does the body compensate for the presence of carboxyhemoglobin in a regular smoker?
A.By increasing the number of red blood cells (polycythemia) to boost oxygen-carrying capacity.
B.By decreasing the breathing rate to allow more time for oxygen to bind.
C.By shrinking the alveoli to increase the pressure of oxygen.
D.By reducing the heart rate to lower oxygen demand.
- 10.
Which of the following correctly pairs the respiratory structure with its tissue type?
A.Alveoli - Ciliated columnar epithelium
B.Trachea - Stratified squamous epithelium
C.Alveoli - Simple squamous epithelium
D.Bronchioles - Hyaline cartilage rings
Download the worksheet for Gas Exchange in Humans - Breathing and ventilation to practice offline. It includes additional chapter-level practice questions.