How does the respiratory system in humans compare to the respiratory system in a perch and the starfish? Ideas and links are included.
Respiration is a necessity for all aerobic organisms. This is so because their cells have to use oxygen as the terminal electron acceptor in the electron transport chain in the biochemical production of cellular energy. Literally thousands of different organ systems have evolved to assure oxygen delivery to the tissues that need it. Organisms also need a way to rid tissues of the carbon dioxide waste of cellular metabolism, and use the respiratory and circulatory systems for this as well. The respiratory system works closely with the circulatory system. The design and function of the respiratory system depends in part on the type of circulation an animal has.
When asked to compare organ systems, the aim is to draw similarities and differences between organisms; in this case the three organisms differ in complexity. We will examine them in the order of increasing complexity, starting with the starfish.
In starfish - (from wikkipedia - http://en.wikipedia.org/wiki/Starfish#Circulation_and_respiration)
"There are three places on the sea star where circulation occurs. These are the perivisceral coelom (the space inside the body not occupied by the organs), the water vascular system, and the hemal system. Hemal channels form rings around the mouth (the oral hemal ring), closer to the top of the starfish (the aboral hemal ring), and around the digestive system (the gastric hemal ring). The axial sinus, a portion of the body cavity, connects the three rings. Each ray also has hemal channels running next to the gonads. There ...
Comparative respiratory information is embedded.