The diagram illustrates changes in air pressure taking place inside the lungs during a complete cycle of breathing. Atmospheric pressure is 101 kPa. At which point on the diagram are the ribs beginning to be lowered?
Answer/Explanation
Ans
A
Question
What helps oxygen to be absorbed rapidly into the blood in the lungs? A Air breathed in has less oxygen than air breathed out. B Alveoli have thick walls and a large surface area. C Alveoli have thin walls and a large surface area. D The concentration of oxygen in the blood is higher than in the alveoli.
Answer/Explanation
Ans
C
Question
During exercise, receptors detect a change in the blood and cause the breathing rate to increase. What change do the receptors detect and where are they found in the body?
Answer/Explanation
Ans
A
Question
Which row shows the features of the gas exchange surface in humans?