Gas Exchange in Humans
Each subtopic includes About section, revision page link, 10 preview questions, and practice CTAs.
Gas exchange surfaces
SubtopicGas exchange surfaces under Gas Exchange in Humans for Grade 11 IGCSE.
Preview questions (no answers)
- 1.
Which part of the system is the first to filter air as it enters from the nose?
A.Bronchi
B.Trachea
C.Alveoli
D.Bronchioles
- 2.
What describes the shape of the cells that make up the alveolar wall?
A.Cube-shaped (cuboidal)
B.Flattened (squamous)
C.Tall and narrow (columnar)
D.Round (spherical)
- 3.
What gas is found in a higher concentration in expired (exhaled) air than in inspired (inhaled) air?
A.Oxygen
B.Carbon dioxide
C.Nitrogen
D.Helium
- 4.
How many cell layers thick is the barrier between the air in the alveolus and the blood in the capillary?
A.One
B.Two
C.Three
D.Four
- 5.
How does the body's use of oxygen in aerobic respiration affect the concentration gradient at the gas exchange surface?
A.It increases the concentration of oxygen in the blood
B.It lowers the concentration of oxygen in the blood returning to the lungs
C.It makes the concentration of oxygen in the blood and alveoli equal
D.It has no effect on the concentration gradient
- 6.
Which of the following is a structural feature of the alveoli that speeds up the rate of diffusion?
A.A large distance between the air and the blood
B.A very thin basement membrane between the epithelium and endothelium
C.A thick layer of protective mucus over the exchange surface
D.The presence of many white blood cells within the alveolar air space
- 7.
What is the main difference between 'gas exchange' and 'ventilation'?
A.Ventilation is the movement of air into and out of the lungs; gas exchange is the diffusion of gases at the surface
B.Gas exchange is the movement of air; ventilation is the chemical breakdown of glucose
C.Ventilation occurs in the alveoli; gas exchange occurs in the trachea
D.There is no difference; they are two terms for the same process
- 8.
Which of these statements best summarizes the necessity of the ventilation system in humans?
A.To provide a large surface area for the storage of carbon dioxide
B.To continuously replace the air in the alveoli, maintaining a steep concentration gradient for diffusion
C.To pump blood through the lungs so that oxygen can be carried to the tissues
D.To filter out all nitrogen from the air before it reaches the alveoli
- 9.
If an individual suffers from 'pulmonary edema' (excess fluid in the lungs), the fluid primarily accumulates in the alveoli and interstitial spaces. How does this affect gas exchange?
A.It increases the concentration gradient by providing more solvent
B.It increases the diffusion distance, thereby slowing down the rate of gas exchange
C.It increases the surface area available for gas exchange
D.It decreases the partial pressure of in the blood
- 10.
Which of the following would be a compensatory mechanism if the surface area for gas exchange was reduced (e.g., in early-stage emphysema)?
A.Decreasing the breathing rate to conserve energy
B.Increasing the heart rate and ventilation rate to maintain the concentration gradient
C.Increasing the thickness of the alveolar wall to prevent further damage
D.Decreasing the production of red blood cells to reduce blood viscosity
Download the worksheet for Gas Exchange in Humans - Gas exchange surfaces to practice offline. It includes additional chapter-level practice questions.
Breathing and lung function
SubtopicBreathing and lung function under Gas Exchange in Humans for Grade 11 IGCSE.
Preview questions (no answers)
- 1.
Which gas has a concentration of nearly in inspired air but about (including noble gases) in expired air?
A.Oxygen
B.Nitrogen
C.Argon and others
D.Carbon dioxide
- 2.
What is the main role of the ribcage during breathing?
A.To digest food
B.To produce air
C.To protect the lungs and change thoracic volume
D.To filter the blood
- 3.
The temperature of expired air is generally ____ than the temperature of inspired air on a cold day.
A.Higher
B.Lower
C.The same
D.Unpredictable
- 4.
In the alveoli, carbon dioxide moves from the ____ to the ____.
A.Air; blood
B.Blood; air
C.Cilia; mucus
D.Lungs; heart
- 5.
Which gas has a higher partial pressure in the blood entering the lung capillaries than in the air inside the alveoli?
A.Oxygen
B.Nitrogen
C.Carbon dioxide
D.Argon
- 6.
Which of the following describes the percentage composition of carbon dioxide in exhaled air?
A.0.04%
B.21%
C.4%
D.16%
- 7.
What is the function of the macrophages found within the alveoli?
A.To produce surfactant
B.To carry oxygen to the heart
C.To engulf and digest dust and pathogens
D.To contract and help in exhalation
- 8.
Which of the following would be found in the highest concentration in the blood of a person who has been sitting in a room with a faulty gas heater producing ?
A.Oxyhemoglobin
B.Carboxyhemoglobin
C.Carbaminohemoglobin
D.Reduced hemoglobin
- 9.
What is the relationship between the partial pressure of oxygen in the atmosphere and the rate of aerobic respiration in a human?
A.They are directly proportional; higher atmospheric pressure always leads to faster respiration.
B.They are independent; respiration rate is determined by cellular energy demand, provided supply is sufficient.
C.Higher atmospheric pressure inhibits respiration by slowing down removal.
D.Respiration only occurs when atmospheric pressure is higher than internal lung pressure.
- 10.
Which of these processes is entirely passive (requires no ATP)?
A.Contraction of the diaphragm.
B.Diffusion of oxygen across the alveolar membrane.
C.Ciliary movement in the trachea.
D.Forced expiration during heavy exercise.
Download the worksheet for Gas Exchange in Humans - Breathing and lung function to practice offline. It includes additional chapter-level practice questions.