Respiratory System
In this section we will be looking at the respiratory system of Blue whales. From similarities to other modern day mammals to unique adaptations.
How they Breath
So blue whales respoiratoryb system has some key similarities to other modern day land mamals such as having nostrils that lead to the larynx that leads to a trachea where the air is split into two lungs , then exhaled through the nostrils again.
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But the differences between modern land mammals and blue whales (and all other baleen whales) starts at the first point of contact, the nostrils.
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In baleen whales the nostril have evloved to move to the top of the head as opposed to the tip of the snout, to help when coming to the surface of the water to breath by not having to lif their wholke head out of the water.
But the first difference between the two systems starts here the mouth and the respiraqtory system in blue whales are completley sepreate. As all other mammals can breath through either their nose or mouth whales can only breath through their blowholes (nose).
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Another differnce found on ballen whales is that they have the ability to close their nostrils through the use of specialized muscles talked about more in depth in the Muscular System portion of this sight. This a evolutionary trait that allows them to completely close off their airways when underwater.
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They also have a structure called the laryngeal sac, which is a structure at the top of the larynx that can hold a pocket of air to be used if needed during deep dives.
The Lungs
While the lungs of the blue whale do function exactly the same as all other mammals lungs with O2 defusing into the blood stream and the CO2 in the blood diffusing into the lungs to get exhaled. There are some unique features of the blue whale that have evolved to allow a animal to live underwater at huge depths.
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The first thing is that for the size of a blue whale its lungs are not as large as one might think, even though they are the largest lungs on the planet, but they are efficient and powerful. They can expand to hold around 5 thousand liters of oxygen and exhale the CO2 at a speed of 600 km/h.
The relative small size of the whale allows the whale to dive at deeper depths then it would be able to if the lungs where any larger. Compared to the relative proportional volume of the lungs of land mammals the proportional volume of blue whales is actually less.
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One feature to the lungs that are unique to the blue whale is that they are able to collapse their lungs at deeper depths. This relives the stress on the lungs caused by the pressure exerted on them by the pressure of the deep water.
