Gas Exchange
The respiratory system is equally important for the living things as the digestive system. Respiration is the process by which animals exchange oxygen and carbon dioxide gases with their environment. [1] Oxygen is important to both humans and animals because each cell in their bodies needs oxygen for the cellular respiration. Cellular respiration is the process of oxidizing food molecules, like glucose, to carbon dioxide and water.
The energy released during the cellular respiration is trapped in the form of ATP for use by all the energy-consuming activities of the cell. The processes take place in mitochondria. In other words, without food and oxygen, living organisms will not have energy to move or survive. [2]
Human Respiratory System
Our bodies are amazing machines that run many processes simultaneously. While some of the processes are triggered by our intentions (food intake or moving our mussels), some of them are not noticeable for us in our daily life. One of the examples is breathing. We just do it without paying special attention to the whole process, unless you are under water and you are very conscious about your breathing. Now let’s have an intention to take a deep breath and try to listen to your body senses to see what happens !
When you inhale, the air along with Oxygen enters our body through the mouth and the nose and passes by the larynx and the trachea. The trachea is a tube-like portion of the respiratory tract that connects the larynx with the bronchial parts of the lungs. The larynx is one of my favorites organs because it holds the vocal cords and if you love singing I am convinced you will become a big fan of it as well. Each bronchus then divides again forming the bronchial tubes which in turn divide into many smaller tubes in lungs. Now, notice how your chest extends! That means that air fills out your lungs which consists of tiny sacs called alveoli. The average adult's lungs contain about 600 million of these spongy, air-filled sacs that are surrounded by capillaries. The inhaled oxygen passes into the alveoli and then diffuses through the capillaries into the arterial blood. This oxygenated blood travels to the heart, from where it is pumped to different parts of the body. The cells in the tissues and organs absorb the oxygen in the blood and releases carbon dioxide. The blood that carries carbon dioxide, travels to the lungs. The carbon dioxide is absorbed by the alveoli, and is expelled through exhalation.[3]
Newt Respiratory System
The respiratory system of newts is unique as these little amphibians undergo drastic changes from their birth to adulthood in the way they receive oxygen to their cute little bodies. Newts are born with gills but then begin to develop lungs as efts to help with breathing as they move to land habitat. [4] As adults, red-spotted newts return to aquatic life, but surprisingly do not develop gills, and instead have lungs in the aquatic life stage! Also, newts have an ability to obtain oxygen through the skin and that is why their skin has to remain moist all the time. [5]
Gills are an organ in fish and other aquatic animals which help them with breathing when they are underwater. The diagram below shows you the process of breathing through gills for our newts when they are babies. Water is very dense and oxygen is dissolved in the water. However, the concentration of oxygen in the water is very low. That is why gills have to provide a large surface area for gas exchange. To circulate water past the gills, newt babies move their gills. The flow of blood in the gills is in the opposite direction that water passes over the gills. [6] As water is forced across gills membranes, dissolved oxygen in the water is taken up by tiny blood vessels and veins, while the carbon dioxide is exchanged.
Gills are an organ in fish and other aquatic animals which help them with breathing when they are underwater. The diagram below shows you the process of breathing through gills for our newts when they are babies. Water is very dense and oxygen is dissolved in the water. However, the concentration of oxygen in the water is very low. That is why gills have to provide a large surface area for gas exchange. To circulate water past the gills, newt babies move their gills. The flow of blood in the gills is in the opposite direction that water passes over the gills. [6] As water is forced across gills membranes, dissolved oxygen in the water is taken up by tiny blood vessels and veins, while the carbon dioxide is exchanged.
The skin newts is also used as a respiratory surface but it does not have much surface area compared to lungs or gills respiratory organs. That's why newts also rely on other respiratory organs during different stages of their life (gills or lungs). Newt skin has a lot of blood vessels going through it. Since the blood vessels are so close to their skin, diffusion occurs right there. [7]
Efts and adult newts have lungs. These lungs are not as evolved as mammal lungs. Amphibians do not have a diaphragm to push air into and from lungs. That is why breathing through the lungs is forced. One way is when the muscles begin pulling air through mouth or nose into something called the "buccal cavity." The muscles then move the floor of the mouth and this pushes the air out of the mouth into the lungs. As we discussed above the skin breathing is also contributing in the newts respiratory process as lungs cannot provide enough oxygen when they are under water. [8]