For my steam project I decided to do a model of the trachea and the gas exchange that occurs within the trachea as well. The objective was to highlight the importance of the trachea and its structure while also highlighting the role of gaseous exchange of both oxygen and carbon dioxide both within the trachea and the alveoli. The way I did it was I used a water bottle to be the initial structure of the trachea as it is a similar shape and hold compared to one in a human. I used a paper towel to simulate the hyaline cartilage within the trachea. The cartilage within the trachea is c-shaped as it is used to both hold the trachea in place and also allow it to collapse just slightly enough to be able to allow food and air pass without it collapsing completely. If there was no cartilage within the trachea then the trachea would collapse completely and our food would get stuck and we would essentially suffocate to death. The cartilage also helps as it has ciliated and mucous producing epithelium that sweep microorganisms and dust particles away from the lungs. The gas exchange that happens within the trachea also extends from the mouth to the lungs. The way it works is that oxygen will be inhaled where it will go down the trachea and lead to the bronchi. The red beads represent oxygen as it moves through the trachea down into the lungs and the blood that will then lead to the alveoli so that the carbon dioxide diffuses through the blood to be exhaled. The interchanging red and blue beads represent the gaseous exchange in alveoli that will make it so carbon dioxide is able to be exhaled. Gas is exchanged in the lungs at the site of the alveoli. The exchange of gases occurs in the alveoli and is possible because they are surrounded by membranes filled with capillaries. These membranes allow for diffusion in respiration to happen. The carbon dioxide diffuses through the capillaries and into the alveoli through the same process. Oxygen and carbon dioxide are transported around the body dissolved in blood. Both gases bind to the protein hemoglobin in red blood cells, although oxygen does so more effectively than carbon dioxide. Some carbon dioxide also dissolves in blood plasma. This lets oxygen and carbon dioxide diffuse, or move freely, between the respiratory system and the bloodstream. Oxygen molecules attach to red blood cells, which travel back to the heart. At the same time, the carbon dioxide molecules in the alveoli are blown out of the body the next time a person exhales.Gas exchange allows the body to replenish the oxygen and eliminate the carbon dioxide. Doing both is necessary for survival. This is what the water bottle, paper towel, red beads, and blue beads are supposed to represent. The trachea is vital in its part in gaseous exchange which is why I wanted to portray that for this particular steam project.