ventilation

Question 1

what happens to the respiratory system during inhalation?

Answer 1

1. the diaphragm contracts and flattens down
2. external intercostal muscles contract
3. internal intercostal muscles relax
4. the ribcage is raised upwards and outwards
   this is because when initial pressure in thoracic cavity is below atm pressure, air is drawn into lungs, and volume increases

Question 2

what happens to the respiratory system during exhalation?

Answer 2

1. diaphragm relaxes and arches up
2. external intercostal muscles relax
3. internal intercostal muscles contract
4. rib cage moves downwards and inwards
   this is because the initial pressure in the thoracic cavity is above atm pressure, air is forced out lungs, and volume increases