The Nature of Science 11 The Respiratory System Contents
LO 4, 6 Biological World strand LO 6, 7 Nature of Science strand
11.1 Structure and function of the respiratory system. . . . . . 117
11.2 Gas exchange in the alveoli . . 118 11.3 Inhalation and exhalation . . . 119 11.4 Interactions of the respiratory system . . . . . . . . . . . 121
11.5 The respiratory system and health . . . . . . . . . . . 122
Why it matters
A constant supply of oxygen is vital for life. The energy contained in glucose is released using oxygen in a process called cellular respiration. The respiratory system takes in oxygen every time we inhale. Oxygen is transported in the bloodstream to every cell in the body. Carbon dioxide is formed as a waste product of cellular respiration and is carried in the bloodstream back to the lungs. It is removed from the body every time we exhale.
The respiratory system consists of the airways, lungs, diaphragm, ribs and intercostal muscles. The function of the respiratory system is to exchange gases with the circulatory system. The respiratory system interacts with the circulatory system to provide every cell in the body with oxygen and to remove carbon dioxide and water vapour.
SL
Activity Estimate your lung capacity: Lung capacity is the amount of air that your lungs can hold. Blow up a balloon as much as you can with one breath. Tie the balloon. Measure the circumference of the balloon. Compare your lung capacity with the rest of the class. (Tip: before starting the activity blow the balloon up a few times to stretch it.)
