Importance of Oxygen
Oxygen is crucial for animal survival. Nearly ninety percent of human's energy comes from the oxygen we breathe. "Oxygen is vital to [the] immune system, memory, thinking and sight" (1). One crucial role oxygen plays is in Cellular Respiration. Cellular Respiration is a process our body, specifically our cells, go through to produce energy. The most important parts of this process happen in the mitochondria of a cell (shown bellow). Oxygen (O₂) and glucose (C₆H₁₂O₆) are send into the mitochondria. The mitochondria produces carbon dioxide (CO₂), water (H₂O) and, most importantly, energy (ATP). ATP, otherwise known as Adenosine triphosphate, is three bonded phosphates. When the third bond is broken, turning the triphosphate into a diphosphate, energy is immediately released. Soon after, the mitochondria will go through cellular respiration again, and produce more ATP. This newly made energy will bond with a diphospate, making it into a triphosphate. And the cycle of Cellular Respiration continues.
The Respiratory System of Birds
Birds, like humans, need to bring oxygen to the rest of their body. Birds begin respiration by inhaling through tiny nostrils at the top of their beaks, sometimes called nares. (2) Next the air passes through the bird's nasal cavity. The air then travels through the larynx, into the trachea, and finally to the posterior air sacs. From there, a small portion of air will travel through the posterior air sacs and straight into the lungs. The remaining air continues into the ventrobronchi and dorsobronchi and finally into the lungs. Birds' lungs, like our lungs, are lined with alveoli. (3). When the bird breathes in a second time, the air is pushed into a lower set of air sacs. "The gas exchange occurs in both the alveoli of the lungs and the air capillaries lining the air sacs and bronchial tubes." (4) Oxygen passes to the blood through diffusion. On the second exhalation, the carbon dioxide that is a biproduct of cellular respiration is finally released from the body.
Fun Facts
- Birds can intake huge amounts of oxygen in each breath, due to the fact that oxygen is not limited to the lung capacity.
- Birds can have seven to nine air sacs (depending on species)
- Birds do not have a diaphragm
- "Bird lungs do not expand or contract like the lungs of mammals" (3)