The water is forced over the gills by the movement of the fish through the water. The fish 's blood absorbs the oxygen from the water and then transports it to each body cell for respiration. In the blood vessels the blood flows in the opposite direction to the water that flows through the lamellae. This flow is called the counter-current system. The amount of oxygen that diffuses into the blood is maximized by this system by maintaining the concentration gradient the whole way through. This is done when the blood that is the most oxygenated meets the most oxygenated water, and the least oxygenated blood meets the water that is the least oxygenated. If the blood and the water flowed in the same direction the blood would eventually reach the
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The filaments require the water for support and to hold apart the lamellae which creates a large surface area. If fish were out in air the efficiency of the diffusion of the gases would greatly decrease. This is because the surface area: volume ratio would reduce as the filaments and lamellae on the gills would stick together. The fish would also no longer have the water to keep the gas exchange system moist which would cause the gills to dry out and prevent the gases from diffusing into the blood.
Gas Exchange in Mammals
A large majority of mammals live on the land meaning their oxygen comes from the air. Because of this their gas exchange system has a risk of drying out which is why it is located inside their bodies to reduce the loss of water. The oxygen concentration in air is high making it easy to …show more content…
The rib cage provides protection to prevent injury and allows a difference in the internal and external air pressure to be obtained which avoids the lungs collapsing. The trachea is where the air enters into the lungs. Further down the trachea it splits into two tubes called bronchi, and these split into even smaller tubes called bronchioles. Rings of cartilage are what hold open and keep the shape of these tubes. The end of bronchioles contain tiny air sacs which are called alveoli. This is where the gas exchange takes place. The alveoli create a large moist surface area for gas exchange to occur, allowing more oxygen to diffuse at once. They are also well supplied with blood. Capillaries surround the alveoli so the gases can diffuse between the air and the blood. Oxygen from the air in the alveoli diffuses into the blood and as this happens carbon dioxide from the blood diffuses into the alveoli. Mucus in the trachea and the bronchioles help to keep them moist and clean and to stop unwanted particles getting into the gas exchange system. It is important the alveoli stays moist in order for the oxygen to dissolve and diffuse into the blood. Because the lungs are deep inside the body they are kept moist as it is harder for it to
The filaments require the water for support and to hold apart the lamellae which creates a large surface area. If fish were out in air the efficiency of the diffusion of the gases would greatly decrease. This is because the surface area: volume ratio would reduce as the filaments and lamellae on the gills would stick together. The fish would also no longer have the water to keep the gas exchange system moist which would cause the gills to dry out and prevent the gases from diffusing into the blood.
Gas Exchange in Mammals
A large majority of mammals live on the land meaning their oxygen comes from the air. Because of this their gas exchange system has a risk of drying out which is why it is located inside their bodies to reduce the loss of water. The oxygen concentration in air is high making it easy to …show more content…
The rib cage provides protection to prevent injury and allows a difference in the internal and external air pressure to be obtained which avoids the lungs collapsing. The trachea is where the air enters into the lungs. Further down the trachea it splits into two tubes called bronchi, and these split into even smaller tubes called bronchioles. Rings of cartilage are what hold open and keep the shape of these tubes. The end of bronchioles contain tiny air sacs which are called alveoli. This is where the gas exchange takes place. The alveoli create a large moist surface area for gas exchange to occur, allowing more oxygen to diffuse at once. They are also well supplied with blood. Capillaries surround the alveoli so the gases can diffuse between the air and the blood. Oxygen from the air in the alveoli diffuses into the blood and as this happens carbon dioxide from the blood diffuses into the alveoli. Mucus in the trachea and the bronchioles help to keep them moist and clean and to stop unwanted particles getting into the gas exchange system. It is important the alveoli stays moist in order for the oxygen to dissolve and diffuse into the blood. Because the lungs are deep inside the body they are kept moist as it is harder for it to