How Humans and Fish Obtain Oxygen We as humans need a way to gather oxygen from our enviroment to survive. In response our body has a system that carries out respiration which is the distrubition of oxygen to the blood and the disposal of the waste product carbon dioxide. In the human breathing process the first step is the breath in. First we open the mouth and expand our lungs to bring in air. The first place the air travles into our mouths which is an opening in the human body used for taking in air, food, and the releasing of carbon dioxide this is the first place the air travles through. Then it must pass the e