Biological processes
Cards (2)
- Breathing in
- intercostal muscles Contract and ribs move upwards and outwards.
- Diaphragm Contracts and flattens.
- Volume of thorax is increases causing pressure to decreases
- Atmospheric pressure is greater than pressure in the lungs
- Air is drawn into lungs.
- Breathing out
- Intercostal muscles relax and ribs move downwards and inwards.
- Diaphragm relaxes and moves up.
- Volume of thorax decreases causing pressure to increase
- Atmospheric pressure is lower than pressure in the lungs.
- Air moves out of lungs