Mechanisms of Breathing

Question 1

what is air pressure

Answer 1

particles of air in a volume or space

pressure always tries to equalise itself (low pressure, high pressure mixing and matching)

Question 2

what happens during inspiration

Answer 2

• the external intercostal muscles contract
• flatten the diaphragm
• the ribs grow outward and upward
• the chest cavity gets larger and pressure in the lungs decreases
• air moves into the lungs from the higher outside pressure

Question 3

what happens during expiration

Answer 3

• the external intercostal muscles relax causing the rib cage to come inward and downwards
• the diaphragm relaxes, pushing back up
• the chest cavity decreases and the pressure in the lungs increases
• air flows out the lungs

Question 4

what happens during exercise to one’s breathing

Answer 4

• expiration becomes an active process
• the internal intercostal muscles contract and pull the rib cage down
• this increases thoracic pressure (speed of expiration)
• therefore air flow is greater