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> we need a store of calcium to mediate blood pH Blood pH is regulated mainly by dissolved carbon dioxide and bicarbonate [1]. There's an order of magnitude le

> we need a store of calcium to mediate blood pH Blood pH is regulated mainly by dissolved carbon dioxide and bicarbonate [1]. There's an order of magnitude less calcium in the blood, usually in the form of calcium phosphate, than either of those, and the amount is extremely tightly regulated within a very narrow concentration range -- far too narrow to have a notable effect on pH. [1]: https://www.ncbi.nlm.nih.gov/books/NBK482291 https://www.ncbi.nlm.nih.gov/books/NBK482291

DoreenMichele 3y ago
The majority of calcium ions within the cell are bound to intracellular proteins, leaving a minority freely dissociated. When calcium is added to or removed from the cytoplasm by transport across the cell membrane or sarcoplasmic reticulum, calcium buffers minimise the effect on changes in cytoplasmic free calcium concentration by binding calcium to or releasing calcium from intracellular proteins. As a result, 99% of the calcium added to the cytosol of a cardiomyocyte during each cardiac cycle becomes bound to calcium buffers, creating a relatively small change in free calcium. https://en.m.wikipedia.org/wiki/Calcium_buffering https://en.m.wikipedia.org/wiki/Calcium_buffering I raised and homeschooled two kids and watched a lot of when dinosaurs ruled the earth type stuff. That's my source for the idea that a store of calcium was critical for allowing life to leave the ocean and I've tried repeatedly to search for additional info on this and can never find it. I have no problem imagining that calcium is essential for buffering pH in land mammals and that free calcium ions simultaneously are tightly regulated and not directly used to move that number for the blood in short time frames. That actually fits perfectly well with my mental models that cellular acidosis is a more fundamental problem that fuels acidosis of bodily fluids. If anyone has any good sources that might clarify this relationship for me, that would be cool.
- Retric 3y ago
  > calcium is essential for buffering pH Except that’s not what’s going on. The Wikipedia article lays it out. The amount of hydrogen ions someplace is what PH means, so controlling PH is controlling the number of hydrogen ions. The same thing happens with calcium, but rather than doing the buffering it’s the number of calcium ions being controlled. Calcium buffering is controlling the number of calcium ions. > Calcium buffering describes the processes which help stabilise the concentration of free calcium ions within cells, in a similar manner to how pH buffers maintain a stable concentration of hydrogen ions.[1] The majority of calcium ions within the cell are bound to intracellular proteins, leaving a minority freely dissociated.[2] When calcium is added to or removed from the cytoplasm by transport across the cell membrane or sarcoplasmic reticulum, calcium buffers minimise the effect on changes in cytoplasmic free calcium concentration by binding calcium to or releasing calcium from intracellular proteins. As a result, 99% of the calcium added to the cytosol of a cardiomyocyte during each cardiac cycle becomes bound to calcium buffers, creating a relatively small change in free calcium.[2]
  - DoreenMichele 3y ago
    Thank you. In layman's terms, pH is a scale for measuring alkalinity vs acidity. Calcium is supposedly alkaline and high levels of intracellular calcium is associated with cell death (apoptosis). So, for example, some people with CF avoid calcium because they think excess calcium causes cell death. But I think most likely excess calcium -- along with high levels of intracellular glutathione -- are a desperate attempt to buffer against something, including but not limited to excess acid. So that's really what I'm interested in understanding. And also would love to see confirmation that calcium stores helped life leave the ocean and that wasn't something stupid and stated in error. Though people with CF also likely misprocess sodium bicarbonate, in addition to being prone to very early onset osteoporosis (as early as their teens).
    - pdonis 3y ago
      > Calcium is supposedly alkaline More precisely, calcium is an alkali earth metal (second column from the left in the periodic table), and those metals are so named because the compounds in which they were first discovered were alkalis. But that does not mean all calcium compounds are alkalis. For example, calcium citrate, which is a common way to convey calcium in supplements, can be weakly acidic in water solution (because of the citrate ion).
    - hansvm 3y ago
      > Calcium is supposedly alkaline Most reliable sources of information describing calcium as alkaline stem from PRAL (potential renal acid load) and other kidney literature. Combined with the right chemicals (as you find in the kidneys), calcium does reduce acidity (contrasted with a buffering agent, the formulae are more linear, and a linear amount of other shit requires a linear amount of calcium or other alkalizing compounds to compensate) in the kidneys. As something of a fun aside, most "alkaline diets" recommend a diet of weakly to strongly acidic foods which have an alkalizing effect on the kidneys and nearly no pH impact anywhere else in the body. No comment on the rest. I just want to reiterate that acid/alkaline in one context (most commonly a description of the hydrogen concentration or other related ions) absolutely does not translate without extra effort and math and chemistry to other contexts (like anything describing calcium as alkaline). When those two ideas are mixed in presentation, a correct interpretation absolutely requires you to understand the details of what/where/why an author means when they refer to pH as something other than hydrogen/hydroxide concentration.
- levischoen 3y ago
  How refreshing. A non defensive critically thoughtful reply to feedback during a public discourse
  - DoreenMichele 3y ago
    It used to be somewhat common on HN. Then it got bigger and covid introduced the entire internet to Eternal September on steroids.
    - eru 3y ago
      Even early Reddit used to be like this. Back when HN wasn't even opened yet.
      - DoreenMichele 3y ago
        YC was founded in March 2005 and Reddit in June 2005. Reddit is a YC company.
        eru 3y ago
        I know. And HN is younger than Reddit. HN != YC.
        DoreenMichele 3y ago
        Paul Graham substantially shaped both cultures from what I gather. So hardly shocking if something once common here was also common there.
        eru 3y ago
        It's possible, but I suspect demographics are more likely to be the main reason here. 'Eternal September on steroids' as you say.
- leplen 3y ago
  It looks like there is a theory that dermal bone in early tetrapods was used this way, but it's still fairly speculative. https://www.nbcnews.com/id/wbna47176272 https://www.nbcnews.com/id/wbna47176272
  - DoreenMichele 3y ago
    Thank you: Breathing air came with challenges, though. A major one was getting rid of the air's carbon dioxide, which, when it builds up, reacts with water in the body and forms an acid.
- eru 3y ago
  > I raised and homeschooled two kids and watched a lot of when dinosaurs ruled the earth type stuff. That's my source for the idea that a store of calcium was critical for allowing life to leave the ocean and I've tried repeatedly to search for additional info on this and can never find it. Insects and friends manage to live on land just fine without any calcium bones.
  - DoreenMichele 3y ago
    Dragonflies used to get to a two-foot wingspan. They don't anymore. The atmosphere was thicker and contained more oxygen. What works once life is established on land can be different from what it took to transition to land and that's what I'm asking about.
    - eru 3y ago
      There was more oxygen in the air when the dinosaurs roamed, but not when insects (and other critters) first came on land. https://forces.si.edu/atmosphere/02_02_06.html https://forces.si.edu/atmosphere/02_02_06.html says > As plants became firmly established on land, life once again had a major effect on Earth’s atmosphere during the Carboniferous Period. Oxygen made up 20 percent of the atmosphere—about today’s level—around 350 million years ago, and it rose to as much as 35 percent over the next 50 million years.
      - DoreenMichele 3y ago
        Irrelevant.
        deleted 3y ago
        [deleted]
        eru 3y ago
        Huh? The high oxygen levels you mentioned occurred long after life had successfully made its way on land.
- mykowebhn 3y ago
  The Wikipedia article you linked as a reference makes no mention about bones, but it does mention intracellular proteins as the location of where the majority of calcium ions are found. I'll take wikipedia as a reference (with reservations), but children's television shows?

DoreenMichele 3y ago

The majority of calcium ions within the cell are bound to intracellular proteins, leaving a minority freely dissociated. When calcium is added to or removed from the cytoplasm by transport across the cell membrane or sarcoplasmic reticulum, calcium buffers minimise the effect on changes in cytoplasmic free calcium concentration by binding calcium to or releasing calcium from intracellular proteins. As a result, 99% of the calcium added to the cytosol of a cardiomyocyte during each cardiac cycle becomes bound to calcium buffers, creating a relatively small change in free calcium. https://en.m.wikipedia.org/wiki/Calcium_buffering https://en.m.wikipedia.org/wiki/Calcium_buffering I raised and homeschooled two kids and watched a lot of when dinosaurs ruled the earth type stuff. That's my source for the idea that a store of calcium was critical for allowing life to leave the ocean and I've tried repeatedly to search for additional info on this and can never find it. I have no problem imagining that calcium is essential for buffering pH in land mammals and that free calcium ions simultaneously are tightly regulated and not directly used to move that number for the blood in short time frames. That actually fits perfectly well with my mental models that cellular acidosis is a more fundamental problem that fuels acidosis of bodily fluids. If anyone has any good sources that might clarify this relationship for me, that would be cool.

Retric 3y ago
> calcium is essential for buffering pH Except that’s not what’s going on. The Wikipedia article lays it out. The amount of hydrogen ions someplace is what PH means, so controlling PH is controlling the number of hydrogen ions. The same thing happens with calcium, but rather than doing the buffering it’s the number of calcium ions being controlled. Calcium buffering is controlling the number of calcium ions. > Calcium buffering describes the processes which help stabilise the concentration of free calcium ions within cells, in a similar manner to how pH buffers maintain a stable concentration of hydrogen ions.[1] The majority of calcium ions within the cell are bound to intracellular proteins, leaving a minority freely dissociated.[2] When calcium is added to or removed from the cytoplasm by transport across the cell membrane or sarcoplasmic reticulum, calcium buffers minimise the effect on changes in cytoplasmic free calcium concentration by binding calcium to or releasing calcium from intracellular proteins. As a result, 99% of the calcium added to the cytosol of a cardiomyocyte during each cardiac cycle becomes bound to calcium buffers, creating a relatively small change in free calcium.[2]
- DoreenMichele 3y ago
  Thank you. In layman's terms, pH is a scale for measuring alkalinity vs acidity. Calcium is supposedly alkaline and high levels of intracellular calcium is associated with cell death (apoptosis). So, for example, some people with CF avoid calcium because they think excess calcium causes cell death. But I think most likely excess calcium -- along with high levels of intracellular glutathione -- are a desperate attempt to buffer against something, including but not limited to excess acid. So that's really what I'm interested in understanding. And also would love to see confirmation that calcium stores helped life leave the ocean and that wasn't something stupid and stated in error. Though people with CF also likely misprocess sodium bicarbonate, in addition to being prone to very early onset osteoporosis (as early as their teens).
  - pdonis 3y ago
    > Calcium is supposedly alkaline More precisely, calcium is an alkali earth metal (second column from the left in the periodic table), and those metals are so named because the compounds in which they were first discovered were alkalis. But that does not mean all calcium compounds are alkalis. For example, calcium citrate, which is a common way to convey calcium in supplements, can be weakly acidic in water solution (because of the citrate ion).
  - hansvm 3y ago
    > Calcium is supposedly alkaline Most reliable sources of information describing calcium as alkaline stem from PRAL (potential renal acid load) and other kidney literature. Combined with the right chemicals (as you find in the kidneys), calcium does reduce acidity (contrasted with a buffering agent, the formulae are more linear, and a linear amount of other shit requires a linear amount of calcium or other alkalizing compounds to compensate) in the kidneys. As something of a fun aside, most "alkaline diets" recommend a diet of weakly to strongly acidic foods which have an alkalizing effect on the kidneys and nearly no pH impact anywhere else in the body. No comment on the rest. I just want to reiterate that acid/alkaline in one context (most commonly a description of the hydrogen concentration or other related ions) absolutely does not translate without extra effort and math and chemistry to other contexts (like anything describing calcium as alkaline). When those two ideas are mixed in presentation, a correct interpretation absolutely requires you to understand the details of what/where/why an author means when they refer to pH as something other than hydrogen/hydroxide concentration.
levischoen 3y ago
How refreshing. A non defensive critically thoughtful reply to feedback during a public discourse
- DoreenMichele 3y ago
  It used to be somewhat common on HN. Then it got bigger and covid introduced the entire internet to Eternal September on steroids.
  - eru 3y ago
    Even early Reddit used to be like this. Back when HN wasn't even opened yet.
    - DoreenMichele 3y ago
      YC was founded in March 2005 and Reddit in June 2005. Reddit is a YC company.
      - eru 3y ago
        I know. And HN is younger than Reddit. HN != YC.
        DoreenMichele 3y ago
        Paul Graham substantially shaped both cultures from what I gather. So hardly shocking if something once common here was also common there.
        eru 3y ago
        It's possible, but I suspect demographics are more likely to be the main reason here. 'Eternal September on steroids' as you say.
leplen 3y ago
It looks like there is a theory that dermal bone in early tetrapods was used this way, but it's still fairly speculative. https://www.nbcnews.com/id/wbna47176272 https://www.nbcnews.com/id/wbna47176272
- DoreenMichele 3y ago
  Thank you: Breathing air came with challenges, though. A major one was getting rid of the air's carbon dioxide, which, when it builds up, reacts with water in the body and forms an acid.
eru 3y ago
> I raised and homeschooled two kids and watched a lot of when dinosaurs ruled the earth type stuff. That's my source for the idea that a store of calcium was critical for allowing life to leave the ocean and I've tried repeatedly to search for additional info on this and can never find it. Insects and friends manage to live on land just fine without any calcium bones.
- DoreenMichele 3y ago
  Dragonflies used to get to a two-foot wingspan. They don't anymore. The atmosphere was thicker and contained more oxygen. What works once life is established on land can be different from what it took to transition to land and that's what I'm asking about.
  - eru 3y ago
    There was more oxygen in the air when the dinosaurs roamed, but not when insects (and other critters) first came on land. https://forces.si.edu/atmosphere/02_02_06.html https://forces.si.edu/atmosphere/02_02_06.html says > As plants became firmly established on land, life once again had a major effect on Earth’s atmosphere during the Carboniferous Period. Oxygen made up 20 percent of the atmosphere—about today’s level—around 350 million years ago, and it rose to as much as 35 percent over the next 50 million years.
    - DoreenMichele 3y ago
      Irrelevant.
      - deleted 3y ago
        [deleted]
      - eru 3y ago
        Huh? The high oxygen levels you mentioned occurred long after life had successfully made its way on land.
mykowebhn 3y ago
The Wikipedia article you linked as a reference makes no mention about bones, but it does mention intracellular proteins as the location of where the majority of calcium ions are found. I'll take wikipedia as a reference (with reservations), but children's television shows?