Diving a kilometre down and not getting 'the bends' — how dolphins do it | CBC Radio
“In his second study, the hypothesis was that the Bermudian population must have extra squishy lungs to prevent damage from compression, but that's not what they found. This suggests the dolphins might use other means to avoid the bends. So they came up with a new hypothesis: the dolphin is able to control gas exchange between their lungs and blood to manipulate the amount of nitrogen that enters their bloodstream to avoid diving-related problems.”
“The interesting thing about dolphins and some other marine mammals is that their lung architecture is different from humans'. Once they dive past the five meter point, the bottom half of each of the two lobes of the Bermudian dolphin's lungs naturally collapses due to pressure and their lung architecture. This is very useful during deep dives because it prevents nitrogen from getting into their bloodstream, as there's no air in the bottom half of the lungs.”
“These adaptable dolphins are also able to manipulate their body to send blood to different regions of the lungs. "There's been evidence that they can select the heart rate, and basically the volume of blood that is pumped out from the blood per minute," said Fahlman.”
“As a result, blood only goes to the compressed regions of their lungs, and not the gas-filled regions, thereby preventing gas exchange.”
“But how do they get oxygen? According to Fahlman, they do it by sending tiny amounts of blood to the gas-filled regions of their lungs to exchange a little bit of oxygen and carbon dioxide. But they're able to make sure that nitrogen doesn't get into the blood during the gas exchange by varying the rate of air flow and blood flow. “
“When the dolphins manipulate this perfectly they're able to avoid getting nitrogen into their bloodstream, says Fahlman. Fahlman calls them the elite dolphins of the species, similar to elite human athletes who can manipulate their heart rate and physiology to achieve mind-blowing feats.”
“In his second study, the hypothesis was that the Bermudian population must have extra squishy lungs to prevent damage from compression, but that's not what they found. This suggests the dolphins might use other means to avoid the bends. So they came up with a new hypothesis: the dolphin is able to control gas exchange between their lungs and blood to manipulate the amount of nitrogen that enters their bloodstream to avoid diving-related problems.”
“The interesting thing about dolphins and some other marine mammals is that their lung architecture is different from humans'. Once they dive past the five meter point, the bottom half of each of the two lobes of the Bermudian dolphin's lungs naturally collapses due to pressure and their lung architecture. This is very useful during deep dives because it prevents nitrogen from getting into their bloodstream, as there's no air in the bottom half of the lungs.”
“These adaptable dolphins are also able to manipulate their body to send blood to different regions of the lungs. "There's been evidence that they can select the heart rate, and basically the volume of blood that is pumped out from the blood per minute," said Fahlman.”
“As a result, blood only goes to the compressed regions of their lungs, and not the gas-filled regions, thereby preventing gas exchange.”
“But how do they get oxygen? According to Fahlman, they do it by sending tiny amounts of blood to the gas-filled regions of their lungs to exchange a little bit of oxygen and carbon dioxide. But they're able to make sure that nitrogen doesn't get into the blood during the gas exchange by varying the rate of air flow and blood flow. “
“When the dolphins manipulate this perfectly they're able to avoid getting nitrogen into their bloodstream, says Fahlman. Fahlman calls them the elite dolphins of the species, similar to elite human athletes who can manipulate their heart rate and physiology to achieve mind-blowing feats.”
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