Science Form 3 Chapter 2

• Inhalation

• Exhalation

• Inhalation

• Exhalation

• Rib cage moves downwards and inwards

• Rib cage moves upwards and outwards

• Higher pressure in the lungs

• Air pressure in the thoracic cavity decrease

• Thoracic cavity becomes smaller

• Diaphragm muscles relax

• Diaphragm become flat

• Higher pressure in the lungs

• Air pressure in the thoracic cavity decrease

• Thoracic cavity becomes bigger

• Diaphragm muscles contract

• Diaphragm become flat

The bigger thoracic cavity will __________ the air pressure in the thoracic cavity.

• increase

• decrease

The smaller thoracic cavity will __________ the air pressure in the thoracic cavity.

• increase

• decrease

During inhalation, the intercostal muscles __________.

• contract

• relax

During exhalation, the intercostal muscles __________.

• contract

• relax

When the diaphragm muscles relax, it will

• curve upwards

• flat