Lungs Flashcards
Describe the path that air takes when it is inhaled into the lungs for gas exchange.
The air enters through the mouth and nose and travels down the trachea.
The trachea splits into two bronchi.
Bronchi branch into bronchioles.
It ends in the alveoli where the gas exchange takes place.
What are the lungs responsible for?
Gas exchange
Explain the process of exhalation.
The external intercostal muscles relax, pulling the ribcage down and in.
The diaphragm relaxes and moves upwards.
This decreases the pressure and volume of the thorax so air is pushed out of the lungs.
Explain how oxygen and carbon dioxide are exchanged in the alveoli.
The concentration of carbon dioxide is greater in the blood surrounding the alveoli than in the air.
Carbon dioxide therefore diffuses down the concentration gradient, into the air in the alveoli.
The concentration of oxygen is lower in the blood surrounding the alveoli than in the air.
Oxygen diffuses down the concentration gradient, into the blood.
