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At Science Daily: Why whales don’t get brain damage when they swim


There are many theories as to the exact use of these networks of blood vessels cradling a whale’s brain and spine, known as ‘retia mirabilia’, or ‘wonderful net’, but now UBC zoologists believe they’ve solved the mystery, with computer modeling backing their predictions.

Credit: Todd Cravens

Land mammals such as horses experience ‘pulses’ in their blood when galloping, where blood pressures inside the body go up and down on every stride. In a new study, lead author Dr. Margo Lillie and her team have suggested for the first time that the same phenomenon occurs in marine mammals that swim with dorso-ventral movements; in other words, whales. And, they may have found out just why whales avoid long-term damage to the brain for this.

In all mammals, average blood pressure is higher in arteries, or the blood exiting the heart, than in veins. This difference in pressure drives the blood flow in the body, including through the brain, says Dr. Lillie, a research associate emerita in the UBC department of zoology. However, locomotion can forcefully move blood, causing spikes in pressure, or ‘pulses’ to the brain. The difference in pressure between the blood entering and exiting the brain for these pulses can cause damage.

Long-term damage of this kind can lead to dementia in human beings, says Dr. Lillie. But while horses deal with the pulses by breathing in and out, whales hold their breath when diving and swimming. “So if cetaceans can’t use their respiratory system to moderate pressure pulses, they must have found another way to deal with the problem,” says Dr. Lillie.

Dr. Lillie and colleagues theorized that the retia use a ‘pulse-transfer’ mechanism to ensure there is no difference in blood pressure in the cetacean’s brain during movement, on top of the average difference. Essentially, rather than dampening the pulses that occur in the blood, the retia transfer the pulse in the arterial blood entering the brain to the venous blood exiting, keeping the same ‘amplitude’ or strength of pulse, and so, avoiding any difference in pressure in the brain itself.

The researchers collected biomechanic parameters from 11 cetacean species, including, fluking frequency, and input these data into a computer model.

“Our hypothesis that swimming generates internal pressure pulses is new, and our model supports our prediction that locomotion-generated pressure pulses can be synchronized by a pulse transfer mechanism that reduces the pulsatility of resulting flow by up to 97 per cent,”says senior author Dr. Robert Shadwick, professor emeritus in the UBC department of zoology.

The model could potentially be used to ask questions about other animals and what’s happening with their blood pressure pulses when they move, including humans, says Dr. Shadwick. And while the researchers say the hypothesis still needs to be tested directly by measuring blood pressures and flow in the brain of swimming cetaceans, this is currently not ethically and technically possible, as it would involve putting a probe in a live whale.

“As interesting as they are, they’re essentially inaccessible,” he says. “They are the biggest animals on the planet, possibly ever, and understanding how they manage to survive and live and do what they do is a fascinating piece of basic biology.”

“Understanding how the thorax responds to water pressures at depth and how lungs influence vascular pressures would be an important next step,” says co-author Dr. Wayne Vogl, professor in the UBC department of cellular and physiological sciences. “Of course, direct measurements of blood pressure and flow in the brain would be invaluable, but not technically possible at this time.”

Science Daily

The mechanism that protects a whale’s brain from potentially harmful blood pressure pulses while swimming, ‘retia mirabilia,” could be translated, “miraculous net”. It’s certainly “wonderful” in its unique benefit to whales, but its origin and integration into the whale’s physical being is an example of something consistent with a miraculous instance of intelligent design.

@ CD Corn Dog it’s just that’s been my general experience with it, and I was following you.I I think a lot of people of already have addressed those concern (jerry for instance) so no need to repeat. Again, I sincerely hope everything goes in a better direction for you and your mom. I’m still changing your name though, to show that nothing has changed and I still love you. AaronS1978
God is responsible for all of it or none of it. And that is a major problem for the omnibenevolent God of theism
Absolute nonsense. Anything less than a perfect world according to people who espouse this gobbledygook is an example of a problem. But maybe this is the best of all possible worlds and it is perfect for whatever the creator’s objectives are. One has to just think a little and realize their version of the perfect world would be an horrendous one. One where there would no value in anything we do. We would all be automatons. A great illustration from Netflix’s Dracula
I Knew The Future Would Bring Wonders. I Did Not Know It Would Make Them Ordinary.” Fans of Netflix’s Dracula mini-series (only three episodes) might recognize that quote. It comes from a conversation Dracula has with a modern-day woman as he admires her house. She terms it “a dump” but he is amazed at its marvels: “Kathleen, I’ve been a nobleman for 400 years. I’ve lived in castles and palaces among the richest people of any age. Never….never! Have I stood in greater luxury than surrounds me now. This is a chamber of marvels. There isn’t a king, or queen or emperor that I have ever known or eaten who would step into this room and ever agree to leave it again.” This has always been my own view of the present. As an archaeologist, I’m fascinated with how people lived in the past. As someone with a degree in economics as well, I’m always humbled by the technological progress and sheer plenty that surrounds us today. Our ancestors — not even that long ago — lacked things that all but those of the most mired in poverty have today. Clean water is an obvious one. We do not spend large amounts of our life suffering from diarrhea. Let us not forget bountiful supplies of food — we don’t know how many people were obese in most of human history, but they were undoubtedly well off. Air conditioning and indoor heating that doesn’t poison your lungs with carbon monoxide make us far more comfortable than anyone realizes until they get roped into a family camping trip or actually work outside for a living. All manner of entertainment, both free and purchased, staves off the crushing boredom that was the reward for affluence in the past. Nobility and kings engaged in hunting and warfare and petty politicking in lieu of Netflix and Facebook and movies and books (though I suppose Facebook might be making petty politicking more possible for the average person from what I see every election cycle). As a parent, I’m particularly thankful for the secure knowledge that my children will almost surely bury me, rather than the other way around. That one right there is worth more than all the Oreos, cars, and that newfangled “iced cream” combined. Compare that to the scurvy, siphilis-riddled, lifestyle where King Henry VIII had to paint crosses on all his walls to keep well-mannered nobility from pissing in random corners of the palace. It’s not just physical technology that has come so far. For that same king to get a divorce, he had to start his own religion, setting in motion the deaths, persecutions, and property seizures that was the English Reformation. Pretty much anyone in a Western democracy can get a divorce these days. You don’t even have to burn anyone at the stake. The part of the world any reader of this lives in also has a surprising lack of slaves. Why surprising? Because for most of human history, the taking of captives for labor or sex has been a dark, common stain on every culture that ever met another one and lived to tell the tale. In a way, it makes a depressing amount of sense — in a world with little technological progress, the only way to raise your standard of living was by taking from others. Slavery, serfdom, and the general abuse of the wider population by elites resulted. Granted, we still have the general abuse of the wider population by elites, but it is usually not on the scale of even the recent past. Also, in a democracy, you get to root for your favorite team of evil people every election cycle — but the particular mental disorder known as partisanship is a discussion for another time. I’m sure with a longer discussion, Dracula’s character would also have seen some of the problems that come from modernity. Climate change is probably the one most legitimately worse than any time in the last few thousand years. But even many of the most pressing problems are ones that stem from the world of plenty Westerners live in. Whether to ration the medicine through bankruptcy or dying while waiting in line is a conundrum that could only come about because of the miracles worked by our scientists and researchers. How to not put tiny island countries under water in 50 years is a direct result of first Western and now developing countries (mostly China) finding so much cheap energy that we don’t have to live like it’s the year 1800. I know some of you are still rolling your eyes and thinking this is a far too optimistic view of the world. I like to think the archaeologists amongst you can at least appreciate the material difference between now and any time in the past. But for those still unconvinced, I query: What time and place would you rather be than today? I feel this is an especially important question if you are not a straight white male.
Sorry for the long post. It does make the point that whatever we have, it will never be enough. Aside: according to one religious tradition, there is a future world that eliminates all supposed hardships if one just believes and acts on those beliefs. jerry
AaronS1978/22 While I appreciate your sentiment, I'm not sure you are tracking on my broader point. Perhaps I wasn't clear. Sometimes irony is not the best way to make a point. I don't blame God for my mother's condition, nor am I angry at him/her/it. Since, ala Spinoza, I don't buy the notion of a personal God, those emotions would be wasted. It reminds me of the joke "I'm an atheist because I'm really angry at God." My point was simply that you can't exonerate the God of theism for the ugly and harsh aspects of creation by glossing them over with "miraculous instance(s) of intelligent design." God is responsible for all of it or none of it. And that is a major problem for the omnibenevolent God of theism..... chuckdarwin
Chuck @20 “ But I digress………” No. You don’t. Same tune. Same flute. Belfast
You know, reading Chuck’s commentary really explains everything about him and his position and I’m not surprised Chuck, I’m really sorry about your mother then. I’m not gonna try to minimize your issues as my mother is going through things as well and I dread the day I’m going to lose her However, I don’t blame God for a lot of terrible things that take place on earth( although I have when I was pissed) but when I really think about it, it does boil down to just a combination of chance, or people making poor decisions. These things also don’t truly determine whether God exists or not I don’t believe God or the designer sits there and makes everything happen. God gives its creation freedom, which is what I think we do have, and that freedom is a two-way street for better or for worse Again, I’m sorry for your mom and I can only hope for things to change for the better for you two and there have been some recent developments on the topic of Alzheimer’s that look promising. AaronS1978
"It’s a bit like Bhuddism, you can believe whatever you want and still wear the label." Yeah, just like the late 1960s. Some celebrities got pulled into Eastern beliefs. I recall that bookstore on the edge of my college campus. One wall, filled floor to ceiling, with books about Eastern beliefs. Who put them there? But, at the time, there was a push to replace Christianity with this. relatd
Relatd/18 Well now that you've fulfilled your obligation to tell me "The Good News," we can both breathe easier. BTW, I have never in my posts on this blog claimed to be an atheist. I find atheists just as insufferable as Christians. I've expressed some affinities regarding deism, but not in any "hey look at me, I'm a deist" kind of way. Because deism is kind of old and confused. But some of its tenets are interesting, for example, the rejection of revealed truth. It's a bit like Bhuddism, you can believe whatever you want and still wear the label. In the end, religion, and particularly Christianity, is, as it has always been, nothing but economic charlatanism. Pay to play. But I digress......... chuckdarwin
CD at 17, The same old same old. Where do you get your ideas? Who told you that you become worm food? It may surprise you to learn that ideas like yours are old and I've seen them before. Cremation? Yeah, so what? Matthew 10:28 "And do not fear those who kill the body but cannot kill the soul. Rather fear him who can destroy both soul and body in hell." relatd
CD again, "You are flying blind, just like the rest of us…." How can you be so sure? As you no doubt realize, here the conflict is between atheism and religious belief. Between nothing and something. A real something. You may be quick to ignore the idea that someone made you and that after you die, you will be judged by God. I have an obligation to tell you this. relatd
Relatd/16 What is it with you? Do you get your theology off the back of a cereal box? "Every life will end. Sooner or later." That is truly deep. I don't have any "beliefs" as to what happens to us after we die, other than we become worm food. I'm pretty certain of that, as far as it goes. But then there's cremation. What can you say? chuckdarwin
CD at 15, Every life will end. Sooner or later. Believing that dying is followed by nothing does not consider the following. Hebrews 9:27 "And just as it is appointed for man to die once, and after that comes judgment," From a billboard sponsored by a group of nuns. "Life is short. Eternity isn't." relatd
Caspian/13 Actually, it is a singularly human problem. It is estimated that Alzheimer's will see a threefold increase in the American elderly population by 2050. 50% of all baby boomers over 85 will be diagnosed with the disease. I see the "marvels in God's design" every time I visit my mother who, after ten grueling years, is in the final stages of Alzheimer's. I will spare you the details and merely note that it is truly, as you put it, a "marvel" to behold. Sometime, when you are alone with your thoughts, seriously reflect on whether you have actually thought through the ramifications of an "eternal life" with the God that you so cavalierly endorse. I submit that the human mind cannot even grasp such a notion, let alone claim to know any of the particulars which it would bring. You are flying blind, just like the rest of us.... chuckdarwin
AF @3: “What is God’s plan?” This is a question that has a well-developed answer, as told in the Bible. The invitation to eternal life is one-sided; God paid it all in Christ; we say, that sounds good; He says, “Welcome home.
Do you have a reference?
Alan Fox
CD @1: It's not the case that humans are "so singularly susceptible to dementia". Rather than seeing flaws in God's design, consider the marvels in God's designs. AF @3: "What is God's plan?" This is a question that has a well-developed answer, as told in the Bible. The invitation to eternal life is one-sided; God paid it all in Christ; we say, that sounds good; He says, "Welcome home." Caspian
The Niche can do anything. Just like evolution, which can do anything. It explains nothing.
Doesn't it bother you to be so triumphantly and doggedly wrong about evolution? If I didn't allow for the distinct possibility of ignorance (eminently curable with a little effort), I'd have to conclude dishonesty. Alan Fox
Andrew at 8, The Niche can do anything. Just like evolution, which can do anything. It explains nothing. And remember, the pro-Evolution troops are stationed here forever. relatd
But you think The Niche has creative abilities, right? Makes the lump of clay into a chimp?
Nope. Alan Fox
What is God’s plan?
Follow the evidence. Then use logic. It cannot be obvious because that has negative implications. But lots of things can be ruled out. ID only gets you part way there. Aside: people want certainty but fail to realize certainty is their enemy. It leads to a meaningless existence. Aside2: certainly not natural evolution. That is nonsense and one of the things that can be ruled out. But what does that point to? jerry
"they don’t plan." AF, But you think The Niche has creative abilities, right? Makes the lump of clay into a chimp? Andrew asauber
What’s The Niche’s plan?
Niche environments are not sentient (well, sentient organisms are a factor in the niche they inhabit but I doubt you are interested in nuance) so they don't plan. I've heard some deists suggest God constructs niches to a plan with an intended result but I guess that's another example of thinking there's a plan but not knowing what it is. Alan Fox
"What is God’s plan?" AF, What's The Niche's plan? Andrew asauber
No idea. Ask Chuck.
Well, I get the impression Chuck is agnostic, so I doubt he could tell me. But do folks here who think there's a God also think there's a plan? I regularly hear (the Christian version of) God described with attributes: omniscience, omnipresence, omnipotence and that he is also ineffable. I guess people could say both yes, there's a plan and no, we have no idea what it is. Alan Fox
No idea. Ask Chuck. Belfast
It’s no longer surprises that so many people think they spot flaws in God’s plan and believe that they, personally, could have done it better.
What is God's plan? Alan Fox
It’s no longer surprises that so many people think they spot flaws in God’s plan and believe that they, personally, could have done it better. What is surprising is that after 1,000,000 takedowns of this wearisome, long-decayed, argument they try it for a million and first time. Belfast
It’s curious that God left humans so singularly susceptible to dementia while “miraculously” benefiting the lesser creatures of the land and the sea…. chuckdarwin

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