* Inhaling: Pigs breathe in air through their nostrils. The air travels down the trachea (windpipe) and into the two main bronchi, which lead to the lungs.
* Gas Exchange: The bronchi branch out into smaller and smaller airways called bronchioles, ending in tiny air sacs called alveoli. In the alveoli, oxygen from the inhaled air passes into the blood, while carbon dioxide, a waste product from the body, passes from the blood into the alveoli to be exhaled.
* Exhaling: The pig breathes out, expelling the carbon dioxide-rich air.
In short, the pig's lungs are responsible for taking in oxygen, which is essential for survival, and expelling carbon dioxide, a waste product of cellular processes.