Gas Exchange Flashcards
features of gas exchange
- large SA
- thin surface
- good blood supply
- good ventilation with air
what is ventilation
The process of taking air in and forcing air out of the breathing system
how does thorax move in inhaling
moves upwards and outwards
how does thorax move in exhaling
moves downwards and inwards
when diaphragm contracts
it flattens downwards and the chest cavity expands vertically
when the diaphragm relaxes
it moves back up and the chest cavity is compressed
intercostal muscles
are antagonistic muscles, when one relaxes the other contracts
during inhalation
the air is sucked in, first, the diaphragm contracts, flattening and pushing down on the abdomen, then the external intercostal muscles contract, pushing the rib-cage up and out and the internal intercostal muscles relaxes. this makes the volume of the chest cavity increase and the air pressure of the thorax falls below atmospheric pressure and is sucked in
during exhalation
the air is forced out first, the diaphragm relaxes and the pressure form the abdomen pushes it back into a dome shape, then the external intercostal muscles relaxes
and pressure form the rib-cage, pushes it back down
and the internal intercostal muscles contracts. this makes the volume of the chest cavity decrease and the air pressure of the thorax rises above atmospheric pressure and is forced out
