Aerobic respiration needs oxygen, and it produces carbon dioxide as a waste product. The human respiratory system contains the organs that allow us to get the oxygen we need and to remove the waste carbon dioxide we do not need. It contains these parts:
Each bronchus divides further in the lungs into smaller tubes called bronchioles. At the end of each bronchiole, there is a group of tiny air sacs. These air sacs have bulges called alveoli to increase their surface area.
The table describes the changes involved:
|Diaphragm||Contracts and moves downwards||Relaxes and moves upwards|
|Intercostal muscles||Contract, moving the ribs upwards and outwards||Relax, letting the ribs move downwards and inwards|
|Volume of ribcage||Increases||Decreases|
|Pressure inside the chest||Decreases below atmospheric pressure||Increases above atmospheric pressure|
|Movement of air||Moves into the lungs||Moves out of the lungs|