SNC 2P - Biology - Respiratory System

On average, we breathe in and out 15 times per minute and we move 10 000 L of air in and out of the lungs each day.  Wow!!

The respiratory system provides oxygen to the cells in the body that require it.  It also removes carbon dioxide produced as the body uses energy to grow, repair and move.

Let's take a trip through the respiratory system:

Oxygen enters through the mouth and the nasal cavity (nose), passes the pharnyx (throat) and larnyx (voice box), then travels down the trachea (windpipe).  

The trachea continues into the bronchus or bronchial tube, which splits into two bronchi.  

In the two lungs, the bronchi split into bronchioles, which branch off into smaller and smaller regions, ending in tiny air sacs called alveoli.  

The alveoli diffuse oxygen into the  capillaries (tiny blood vessels) that surround them.  

The blood travels around the body, dropping off oxygen to the cells, while picking up carbon dioxide waste, which travels back to the lungs for exhalation   from the body.  This process of providing oxygen and removing carbon dioxide is called gas exchange.  Humans carry out gas exchange using their lungs, while fish use their gills and frogs even use their skin to an extent for breathing.

The respiratory system obviously relies on breathing and this is accomplished through the use of the diaphragm, a thin muscle that sits under the lungs. 
The diaphragm contracts and flattens when you inhale, creating a vacuum effect that pulls air into the lungs. When you exhale, the diaphragm relaxes and the air is pushed out of lungs.

Now, let's make like our lungs, and expand (our minds).