Inhalation is the act of breathing in. The diaphragm and intercostal muscles contract and the lungs expand.
The expansion of the lungs causes a drop in air pressure within the lungs. The air in the lungs is now at a lower pressure than the air outside, so air is drawn in from the atmosphere to the lungs (high pressure to low pressure).
z z
Exhalation is the act of breathing out. The diaphragm and intercostal muscles relax and the lungs return to their original volume.
Now, the air pressure within the lungs is greater than the air outside, so air is pushed out of the lungs to the atmosphere (high pressure to low pressure).
Inhalation High pressure
Exhalation Low pressure
Low pressure
High pressure
Diaphragm
Diaphragm Health of the Respiratory System
Our respiratory system may be negatively affected by a number of factors. Some of these conditions can have a genetic cause or be due to infection by microorganisms. Other diseases may be caused by poor lifestyle choices, such as smoking.
Some common diseases of the respiratory system include lung cancer, asthma and bronchitis.
Health of the human respiratory system
Research a disease of the human respiratory system. Source and cite information under the following headings:
1. Cause 2. Signs and symptoms 3. Prevention 4. Treatment
Prepare a short presentation for your classmates. 141
