Activity Compare the carbon dioxide levels in exhaled air and inhaled air.
Limewater is used to test for carbon dioxide. Carbon dioxide turns limewater milky or cloudy. 1. Blow through tube A. This bubbles exhaled air through the limewater.
2. Attach a vacuum pump to tube B. This bubbles inspired air (fresh air) through the limewater.
A
Test tube Limewater
Questions 1. Which test tube of limewater turned milky more quickly, test tube A or test tube B? 2. Why do you think this happened?
11.4 Interactions of the respiratory system
The respiratory system works with the circulatory system to provide oxygen to the body and remove carbon dioxide from the blood. Oxygen diffuses out of the alveoli into the bloodstream where it is carried around the body. Carbon dioxide is transported from the body to the lungs where it diffuses into the alveoli and is exhaled.
(Oxygen is absorbed) B
(Oxygen is released)
Fig. 9 Interactions of the respiratory and circulatory systems.
