lungs and gas exchange

Question 1

what is inspiration

Answer 1

• diaphragm and intercostal muscles contract
• ribcage moves up and out
• volume in thoracic cavity increases so air pressure in lungs decreases
• air drawn into lungs
• an active process, using energy

Question 2

what is expiration

Answer 2

• diaphragm and intercostal muscles relax
• ribcage moves down and in
• volume in thoracic cavity decreases so air pressure in lungs increases
• air drawn out of lungs
• a passive process, not using energy

Question 3

functions of lungs

Answer 3

large surface area and good ventilation
good blood supply
moist and thin walls