Respiration and respiratory adaptations of dolphins
dolphin has a unique respiratory system that can adapt to its breathing mechanism easily, and the following is its mechanism of action
Breathing with the lungs
The dolphin breathes using the lungs and takes approximately 2-3 breaths every minute, and its exhalation and inhalation rarely take more than a fraction of a second,[2] as the lungs of the dolphin contain a number of alveoli or air cells much greater than those in the human lung, as it consists of Two layers of blood capillaries, unlike other mammals whose lungs consist of one layer, and these two layers increase the surface area of the lungs, and thus increase the efficiency of gas exchange and the exchange occurs much faster. [1] The pleural space in the lungs of dolphins is characterized by thickness and flexibility, and there is a large amount of flexible muscle fibers in its lung tissue, in addition to the bronchial tubes lined with muscle tissue, and the alveoli are separated from the rest of the lung by a sphincter muscle and small bronchioles. On the largest possible amount of oxygen, as only 10-20% of the air is exchanged within the human lung, while the air is renewed and exchanged within the dolphin's lung by 80-90%. [1] Dolphins voluntarily control breathing, that is, they make a decision to do so, as They control the amount of nitrogen inside the bloodstream, to avoid exposure to pressure, and prevent its dissolution in the blood because it causes severe pain.[2] And the brain, as it determines its heart rate to pump a small amount of blood into its body.
Breathing through holes in the head
Dolphins breathe through the nostril in the upper part of their head, as they expose only the upper part of their head to inhaling air while swimming or resting under water, then the nostril closes tightly with strong muscles surrounding it to prevent water from reaching their lungs.[3] The dolphin begins the exhalation process before reaching the surface to reduce the time it spends on the surface to breathe, then inhales the air and takes up to 5 breaths within one minute before diving, and the dolphin can hold its breath under water for a period of up to more than 7 minutes.
How much oxygen does the blood and muscles of a dolphin contain?
The reason for the ability of dolphins to dive and hold their breath for long periods is due to the efficiency and ability of their blood and muscles to store a large amount of oxygen, and this helped the dolphin to derive most of the oxygen through it.[1] In humans, which is the main means of transporting oxygen.[1] It is also worth noting that the concentration of hemoglobin inside red blood cells is higher than its concentration in human cells, which increased the desire of red blood cells to merge with oxygen, and increase its quantity inside them.[1] Muscle tissues also have hemoglobin, which is more inclined to combine with oxygen, so when oxygen-laden blood passes next to the muscles, oxygen easily transfers to them, and therefore muscles are one of the main tissues for oxygen storage.
The mechanism of dolphin efficient use of oxygen
The dolphin uses several methods to use oxygen efficiently to enable it to dive for long periods, as follows:
Supplying oxygen to vital organs only
The dolphin supplies the oxygen-laden blood during its diving to the depths only to the vital organs, such as: the brain and the heart, as we mentioned previously. As for the other organs, the blood never flows to them or flows in a very small amount. Thus, these organs convert their respiration to anaerobic respiration to represent their food, and this method does not need oxygen.[1] But the anaerobic metabolism process is a very slow process and produces little energy in addition to its production of lactic acid, which is an acid that causes fatigue, and dolphins need time to convert it into a harmless substance. .
Reducing the dolphin's body temperature
Dolphins use oxygen in a small amount by making a reflex reaction to the pituitary gland that stimulates the heart to beat slowly, and thus the blood flow from the veins to the heart will decrease, then the heart in turn prevents the blood that lacks oxygen from reaching the lungs. On the oxygen inside the lungs and the blood, and after a while the right side of the heart stops beating, while the left side of the heart pumps the re-oxygenated blood to the brain.
The dolphin comes out of the water and constantly rises to the surface to breathe and get air, as when it dives into the water it holds its breath, then returns to the surface to absorb more air when it runs out of it, and the dolphins are distinguished by their ability to travel alone or in groups, and the speed of the dolphin reaches approximately 56 km per hour. The hour, and dolphins feed on flying fish.[4] Dolphins can locate these fish by listening to the sound of these fish echoing, and dolphins are also distinguished by their ability to talk to each other, by whistling and calling.