The Lungs

air enters through nose, along trachea, bbronchi and bronchioles

the air finally reaches airfilled sacs - alveol.  The walls of these are the surface where the exchange of gases takes place

lungs are protected by ribs - movementof the ribs and the diadiaphragm help to produce breathing movements

gasses pass both ways through the alveoli - oxygen passes from the air in the alveoli to the blood in the capilliaries, CO2 passes from the blood into the alveoli

How lungs are adapted for exchange

LARGE SURFACE AREA - provides more space for molecules to pass through, the alveoli are very…