On 10/12/22 2:13 PM, Trolidan7 wrote:
> On 10/9/22 11:58 AM, John Harshman wrote:
>> On 10/9/22 9:57 AM, Trolidan7 wrote:
>>> On 10/6/22 12:05 PM, Peter Nyikos wrote:
>>>> On Tuesday, October 4, 2022 at 6:45:58 PM UTC-4, John Harshman wrote:
>>>>> On 10/4/22 2:07 PM, Peter Nyikos wrote:
>>>>>
>>>>>> And now, back to Ichthyosaurs. They were the most exclusively
>>>>>> marine reptiles of the Mesozoic,
>>>>>> just as sea snakes in one subfamily are the most exclusively
>>>>>> marine reptiles of the Cenozoic.
>>>>>> So it's a bit suggestive [but no more] that, just as those sea
>>>>>> snakes are ovoviviparous,
>>>>>> so too the ichthyosaurs might have been.
>>>>>>
>>>>>> If either you, Erik, or John shows some interest, I can talk about
>>>>>> a fascinating
>>>>>> example that probably spans Mesozoic and Cenozoic: there are several
>>>>>> lines of evidence that coelacanths are, and have been for a long
>>>>>> time, ovoviviparous.
>>>>
>>>> In fact, *Rhabdoderma*, another candidate for ovoviviparity, is from
>>>> the Paleozoic.
>>>>
>>>>> Sure. What do you have? I presume here that your definition is gas
>>>>> exchange across the shell, but no nutrients.
>>>>
>>>> Yes.
>>>>
>>>> I'm busy in talk.origins and other s.b.p. threads for probably the
>>>> rest of the week,
>>>> but I intend on Monday to go deep into details in a great book on
>>>> *Latimeria,*
>>>> the living coelacanth and AFAIK the only known Cenozoic coelacanth.
>>>> It is by Keith S. Thompson, titled _Living Fossil: The Story of the
>>>> Coelacanth_ .
>>>>
>>>> For now, I'll just quote something about that Paleozoic coelacanth.
>>>>
>>>> "The Carboniferous fossils that Schultze had described as
>>>> free-living yolk sac larvae were from a genus, (*Rhabdoderma*) that
>>>> may have lived in brackish waters rather than the sea. In this case
>>>> (if the water was less saline than the body tissues) it is possible
>>>> that ovoviviparity was not needed, but economy of hypotheses
>>>> suggests the strong likelihood that this genus was ovoviviparous
>>>> also." [p. 199]
>>>>
>>>> The rationale for this "strong likelihood" would seem to be that
>>>> the yolk sac, being still attached to the free-swimming young,
>>>> creates the
>>>> presumption that there had been enough yolk all the way to birth
>>>> to dispense with any maternal nutrients in addition.
>>>>
>>>> The alternative hypothesis, that the yolk sac was only a partial
>>>> source of nutrition, is less economical, as the author puts it.
>>>>
>>>> Peter Nyikos
>>>> Professor, Dept. of Mathematics   -- standard disclaimer--
>>>> University of So. Carolina in Columbia
>>>> http://people.math.sc.edu/nyikos
>>>
>>> Double checking.
>>>
>>> For oviparous reptiles, birds, and monotremes, The shell of
>>> an amniote egg is secreted onto an egg during the process of laying.
>>>
>>> Therefore an egg that is not laid will have no shell?
>>
>> Nope. This "process of laying" can take days, as the egg moves down
>> the oviduct. All that's needed is for the finished egg to skip that
>> last step of leaving the mother's body.
>>
>>> Is it possible for a blood vessel in a closed circulatory
>>> system to be able to exchange oxygen with a tissue outside
>>> of a blood vessel without also being able to exchange nutrients?
>>
>> Yes, totally. Oxygen and CO2 diffuse more easily than most other
>> molecules.
>
> When I look up the words 'closed circulatory system' in Wikipedia
> it gives three examples - annelids, some molluscs, and vertebrates.
>
> Since two are protostomes and one is a deuterostome I am guessing
> that is not based upon phylogenetics.
>
> Now in cephalopods, I am thinking that the copper metalloprotein
> that carries oxygen is not contained within any cells inside a
> cell membrane, rather it is within a blood matrix.  I am not sure
> if the oxygen bound copper diffuses across the blood vessel or not.
>
> Now in vertebrates in general, hemoglobin resides inside red blood
> cells.  For oxygen to get inside the cells in tissues outside of
> blood vessels I am thinking it has to do the following.
>
> Go outside the red blood cell into the extracellular fluid of
> the blood in the vessel.
>
> Travel outside the fluid of the blood vessel into the fluid
> outside of the blood vessel (sometimes called lymph or other
> tissue fluid)
>
> Then go inside of the cells receiving oxygen.  There in some
> circumstances it might bind with myoglobin for storage before
> metabolic use.
>
> During all of this time, both oxygen, nitrogen, and carbon
> dioxide remain dissolved in an aqueous solution.   They never
> go into the gas state.  If something like this happens, this
> is called the 'bends' (or decompression sickness).  This is
> generally suppressed because if it becomes too widespread
> it can lead to problems with circulation.
>
> Basic question.
>
> In the closed circulatory system of vertebrates, how do
> white blood (immune, not red blood) cells go from the
> blood vessels into tissues outside of the blood stream
> when they undergo some form of damage or infection?  Do
> they open up small passages in the walls of the blood
> vessels and then close them afterward?  Are there gaps
> that allow them to go through?
>
> How does oxygen or carbon dioxide pass through a blood
> vessel?  Does it go inside of the cell membranes of the
> cells making up the blood vessel walls themselves and
> pass through the cells to get inside and outside of the
> blood vessels?  Does it go through small gaps between
> the cells of the blood vessels without passing into and
> out of the cells themselves that make up much of the
> blood vessel tissues?
>
> Then after that the oxygen or carbon dioxide when then
> have to pass through the extracellular fluid of the
> tissue before being taken up by the cells in the tissue.

I doubt that small, uncharged molecules notice whether they're going
through a cell membrane or not. I'm pretty sure travel is by passive
diffusion, not active transport.

On 10/12/22 2:33 PM, John Harshman wrote:
> On 10/12/22 2:13 PM, Trolidan7 wrote:
>> On 10/9/22 11:58 AM, John Harshman wrote:
>>> On 10/9/22 9:57 AM, Trolidan7 wrote:
>>>> On 10/6/22 12:05 PM, Peter Nyikos wrote:
>>>>> On Tuesday, October 4, 2022 at 6:45:58 PM UTC-4, John Harshman wrote:
>>>>>> On 10/4/22 2:07 PM, Peter Nyikos wrote:
>>>>>>
>>>>>>> And now, back to Ichthyosaurs. They were the most exclusively
>>>>>>> marine reptiles of the Mesozoic,
>>>>>>> just as sea snakes in one subfamily are the most exclusively
>>>>>>> marine reptiles of the Cenozoic.
>>>>>>> So it's a bit suggestive [but no more] that, just as those sea
>>>>>>> snakes are ovoviviparous,
>>>>>>> so too the ichthyosaurs might have been.
>>>>>>>
>>>>>>> If either you, Erik, or John shows some interest, I can talk
>>>>>>> about a fascinating
>>>>>>> example that probably spans Mesozoic and Cenozoic: there are several
>>>>>>> lines of evidence that coelacanths are, and have been for a long
>>>>>>> time, ovoviviparous.
>>>>>
>>>>> In fact, *Rhabdoderma*, another candidate for ovoviviparity, is
>>>>> from the Paleozoic.
>>>>>
>>>>>> Sure. What do you have? I presume here that your definition is gas
>>>>>> exchange across the shell, but no nutrients.
>>>>>
>>>>> Yes.
>>>>>
>>>>> I'm busy in talk.origins and other s.b.p. threads for probably the
>>>>> rest of the week,
>>>>> but I intend on Monday to go deep into details in a great book on
>>>>> *Latimeria,*
>>>>> the living coelacanth and AFAIK the only known Cenozoic coelacanth.
>>>>> It is by Keith S. Thompson, titled _Living Fossil: The Story of the
>>>>> Coelacanth_ .
>>>>>
>>>>> For now, I'll just quote something about that Paleozoic coelacanth.
>>>>>
>>>>> "The Carboniferous fossils that Schultze had described as
>>>>> free-living yolk sac larvae were from a genus, (*Rhabdoderma*) that
>>>>> may have lived in brackish waters rather than the sea. In this case
>>>>> (if the water was less saline than the body tissues) it is possible
>>>>> that ovoviviparity was not needed, but economy of hypotheses
>>>>> suggests the strong likelihood that this genus was ovoviviparous
>>>>> also." [p. 199]
>>>>>
>>>>> The rationale for this "strong likelihood" would seem to be that
>>>>> the yolk sac, being still attached to the free-swimming young,
>>>>> creates the
>>>>> presumption that there had been enough yolk all the way to birth
>>>>> to dispense with any maternal nutrients in addition.
>>>>>
>>>>> The alternative hypothesis, that the yolk sac was only a partial
>>>>> source of nutrition, is less economical, as the author puts it.
>>>>>
>>>>> Peter Nyikos
>>>>> Professor, Dept. of Mathematics   -- standard disclaimer--
>>>>> University of So. Carolina in Columbia
>>>>> http://people.math.sc.edu/nyikos
>>>>
>>>> Double checking.
>>>>
>>>> For oviparous reptiles, birds, and monotremes, The shell of
>>>> an amniote egg is secreted onto an egg during the process of laying.
>>>>
>>>> Therefore an egg that is not laid will have no shell?
>>>
>>> Nope. This "process of laying" can take days, as the egg moves down
>>> the oviduct. All that's needed is for the finished egg to skip that
>>> last step of leaving the mother's body.
>>>
>>>> Is it possible for a blood vessel in a closed circulatory
>>>> system to be able to exchange oxygen with a tissue outside
>>>> of a blood vessel without also being able to exchange nutrients?
>>>
>>> Yes, totally. Oxygen and CO2 diffuse more easily than most other
>>> molecules.
>>
>> When I look up the words 'closed circulatory system' in Wikipedia
>> it gives three examples - annelids, some molluscs, and vertebrates.
>>
>> Since two are protostomes and one is a deuterostome I am guessing
>> that is not based upon phylogenetics.
>>
>> Now in cephalopods, I am thinking that the copper metalloprotein
>> that carries oxygen is not contained within any cells inside a
>> cell membrane, rather it is within a blood matrix.  I am not sure
>> if the oxygen bound copper diffuses across the blood vessel or not.
>>
>> Now in vertebrates in general, hemoglobin resides inside red blood
>> cells.  For oxygen to get inside the cells in tissues outside of
>> blood vessels I am thinking it has to do the following.
>>
>> Go outside the red blood cell into the extracellular fluid of
>> the blood in the vessel.
>>
>> Travel outside the fluid of the blood vessel into the fluid
>> outside of the blood vessel (sometimes called lymph or other
>> tissue fluid)
>>
>> Then go inside of the cells receiving oxygen.  There in some
>> circumstances it might bind with myoglobin for storage before
>> metabolic use.
>>
>> During all of this time, both oxygen, nitrogen, and carbon
>> dioxide remain dissolved in an aqueous solution.   They never
>> go into the gas state.  If something like this happens, this
>> is called the 'bends' (or decompression sickness).  This is
>> generally suppressed because if it becomes too widespread
>> it can lead to problems with circulation.
>>
>> Basic question.
>>
>> In the closed circulatory system of vertebrates, how do
>> white blood (immune, not red blood) cells go from the
>> blood vessels into tissues outside of the blood stream
>> when they undergo some form of damage or infection?  Do
>> they open up small passages in the walls of the blood
>> vessels and then close them afterward?  Are there gaps
>> that allow them to go through?
>>
>> How does oxygen or carbon dioxide pass through a blood
>> vessel?  Does it go inside of the cell membranes of the
>> cells making up the blood vessel walls themselves and
>> pass through the cells to get inside and outside of the
>> blood vessels?  Does it go through small gaps between
>> the cells of the blood vessels without passing into and
>> out of the cells themselves that make up much of the
>> blood vessel tissues?
>>
>> Then after that the oxygen or carbon dioxide when then
>> have to pass through the extracellular fluid of the
>> tissue before being taken up by the cells in the tissue.
>
> I doubt that small, uncharged molecules notice whether they're going
> through a cell membrane or not. I'm pretty sure travel is by passive
> diffusion, not active transport.

O2 has no polar or non-polar side.

A cell membrane is a bilayer generally composed of lipid molecules
along with glycerols and other materials. The lipid has a non-polar
tail that has affinities for other non-polar materials and a polar
side is attracted toward the aqueous polar inside and outside of the
membrane.

A cell membrane also has a lot of pores in them that open or close
to allow certain substances in or out. The sodium, potassium, and
calcium channels specific for certain types of ions are some examples.

It might be that CO2 could be different from O2, but you are in
essence saying that all of O2 at least passes through the cell membranes
of the cells of the blood vessels on both sides, and when immune cells
exist the bloodstream they in essence open small doors between the
blood vessel cells, and close those doors behind them?

I was thinking there were regular gaps between the blood vessel cells,
and lymph was formed from a persistent regular leakage from the blood
vessels into the intercellular fluid outside of the blood vessels.
Perhaps that was wrong.

adheres to non-polar fats and a polar (carboxylic acid) side.

On 10/12/22 2:33 PM, John Harshman wrote:
> On 10/12/22 2:13 PM, Trolidan7 wrote:
>> On 10/9/22 11:58 AM, John Harshman wrote:
>>> On 10/9/22 9:57 AM, Trolidan7 wrote:
>>>> On 10/6/22 12:05 PM, Peter Nyikos wrote:
>>>>> On Tuesday, October 4, 2022 at 6:45:58 PM UTC-4, John Harshman wrote:
>>>>>> On 10/4/22 2:07 PM, Peter Nyikos wrote:
>>>>>>
>>>>>>> And now, back to Ichthyosaurs. They were the most exclusively
>>>>>>> marine reptiles of the Mesozoic,
>>>>>>> just as sea snakes in one subfamily are the most exclusively
>>>>>>> marine reptiles of the Cenozoic.
>>>>>>> So it's a bit suggestive [but no more] that, just as those sea
>>>>>>> snakes are ovoviviparous,
>>>>>>> so too the ichthyosaurs might have been.
>>>>>>>
>>>>>>> If either you, Erik, or John shows some interest, I can talk
>>>>>>> about a fascinating
>>>>>>> example that probably spans Mesozoic and Cenozoic: there are several
>>>>>>> lines of evidence that coelacanths are, and have been for a long
>>>>>>> time, ovoviviparous.
>>>>>
>>>>> In fact, *Rhabdoderma*, another candidate for ovoviviparity, is
>>>>> from the Paleozoic.
>>>>>
>>>>>> Sure. What do you have? I presume here that your definition is gas
>>>>>> exchange across the shell, but no nutrients.
>>>>>
>>>>> Yes.
>>>>>
>>>>> I'm busy in talk.origins and other s.b.p. threads for probably the
>>>>> rest of the week,
>>>>> but I intend on Monday to go deep into details in a great book on
>>>>> *Latimeria,*
>>>>> the living coelacanth and AFAIK the only known Cenozoic coelacanth.
>>>>> It is by Keith S. Thompson, titled _Living Fossil: The Story of the
>>>>> Coelacanth_ .
>>>>>
>>>>> For now, I'll just quote something about that Paleozoic coelacanth.
>>>>>
>>>>> "The Carboniferous fossils that Schultze had described as
>>>>> free-living yolk sac larvae were from a genus, (*Rhabdoderma*) that
>>>>> may have lived in brackish waters rather than the sea. In this case
>>>>> (if the water was less saline than the body tissues) it is possible
>>>>> that ovoviviparity was not needed, but economy of hypotheses
>>>>> suggests the strong likelihood that this genus was ovoviviparous
>>>>> also." [p. 199]
>>>>>
>>>>> The rationale for this "strong likelihood" would seem to be that
>>>>> the yolk sac, being still attached to the free-swimming young,
>>>>> creates the
>>>>> presumption that there had been enough yolk all the way to birth
>>>>> to dispense with any maternal nutrients in addition.
>>>>>
>>>>> The alternative hypothesis, that the yolk sac was only a partial
>>>>> source of nutrition, is less economical, as the author puts it.
>>>>>
>>>>> Peter Nyikos
>>>>> Professor, Dept. of Mathematics   -- standard disclaimer--
>>>>> University of So. Carolina in Columbia
>>>>> http://people.math.sc.edu/nyikos
>>>>
>>>> Double checking.
>>>>
>>>> For oviparous reptiles, birds, and monotremes, The shell of
>>>> an amniote egg is secreted onto an egg during the process of laying.
>>>>
>>>> Therefore an egg that is not laid will have no shell?
>>>
>>> Nope. This "process of laying" can take days, as the egg moves down
>>> the oviduct. All that's needed is for the finished egg to skip that
>>> last step of leaving the mother's body.
>>>
>>>> Is it possible for a blood vessel in a closed circulatory
>>>> system to be able to exchange oxygen with a tissue outside
>>>> of a blood vessel without also being able to exchange nutrients?
>>>
>>> Yes, totally. Oxygen and CO2 diffuse more easily than most other
>>> molecules.
>>
>> When I look up the words 'closed circulatory system' in Wikipedia
>> it gives three examples - annelids, some molluscs, and vertebrates.
>>
>> Since two are protostomes and one is a deuterostome I am guessing
>> that is not based upon phylogenetics.
>>
>> Now in cephalopods, I am thinking that the copper metalloprotein
>> that carries oxygen is not contained within any cells inside a
>> cell membrane, rather it is within a blood matrix.  I am not sure
>> if the oxygen bound copper diffuses across the blood vessel or not.
>>
>> Now in vertebrates in general, hemoglobin resides inside red blood
>> cells.  For oxygen to get inside the cells in tissues outside of
>> blood vessels I am thinking it has to do the following.
>>
>> Go outside the red blood cell into the extracellular fluid of
>> the blood in the vessel.
>>
>> Travel outside the fluid of the blood vessel into the fluid
>> outside of the blood vessel (sometimes called lymph or other
>> tissue fluid)
>>
>> Then go inside of the cells receiving oxygen.  There in some
>> circumstances it might bind with myoglobin for storage before
>> metabolic use.
>>
>> During all of this time, both oxygen, nitrogen, and carbon
>> dioxide remain dissolved in an aqueous solution.   They never
>> go into the gas state.  If something like this happens, this
>> is called the 'bends' (or decompression sickness).  This is
>> generally suppressed because if it becomes too widespread
>> it can lead to problems with circulation.
>>
>> Basic question.
>>
>> In the closed circulatory system of vertebrates, how do
>> white blood (immune, not red blood) cells go from the
>> blood vessels into tissues outside of the blood stream
>> when they undergo some form of damage or infection?  Do
>> they open up small passages in the walls of the blood
>> vessels and then close them afterward?  Are there gaps
>> that allow them to go through?
>>
>> How does oxygen or carbon dioxide pass through a blood
>> vessel?  Does it go inside of the cell membranes of the
>> cells making up the blood vessel walls themselves and
>> pass through the cells to get inside and outside of the
>> blood vessels?  Does it go through small gaps between
>> the cells of the blood vessels without passing into and
>> out of the cells themselves that make up much of the
>> blood vessel tissues?
>>
>> Then after that the oxygen or carbon dioxide when then
>> have to pass through the extracellular fluid of the
>> tissue before being taken up by the cells in the tissue.
>
> I doubt that small, uncharged molecules notice whether they're going
> through a cell membrane or not. I'm pretty sure travel is by passive
> diffusion, not active transport.

I have several more questions about the lymphatic versus the
regular blood circulatory systems that I may have been mistaken
about before.

1, The direction of flow of the lymphatic system is opposite
the flow of the blood circulatory system. Is that correct?

That means that when lymph empties into the regular blood system
at the exit to the lymphatic system, possible backflow of blood
into the lymphatic ducts is stopped by the valves in the lymphatic
system. Since there are many valves in the lymph system, just like
in the blood vessels, failure of one valve will not mean that the
lymph system is not filled because there are many valves within it?

2. I read that in some reptiles there are 'lymph hearts'. Is that
in only some reptiles? Which ones? How about birds? How about
monotremes or marsupials? I am thinking that in mammals it is all
skeletal muscles and the fact that the lymph vessels have valves
that make the lymph flow only one way. It does not need to flow
very fast.

3. I remember reading once that mammals have mature red blood cells
with no nucleus. Other vertebrates do not and will retain a nucleus
in mature red blood cells. Why would you think that is so? Small
blood vessels in small animals in the Mesozoic? Resistance to virus
infections of the blood? Something else?

On Wednesday, October 12, 2022 at 2:33:58 PM UTC-7, John Harshman wrote:
> On 10/12/22 2:13 PM, Trolidan7 wrote:
> > On 10/9/22 11:58 AM, John Harshman wrote:
> >> On 10/9/22 9:57 AM, Trolidan7 wrote:
> >>> On 10/6/22 12:05 PM, Peter Nyikos wrote:
> >>>> On Tuesday, October 4, 2022 at 6:45:58 PM UTC-4, John Harshman wrote:
> >>>>> On 10/4/22 2:07 PM, Peter Nyikos wrote:
> >>>>>
> >>>>>> And now, back to Ichthyosaurs. They were the most exclusively
> >>>>>> marine reptiles of the Mesozoic,
> >>>>>> just as sea snakes in one subfamily are the most exclusively
> >>>>>> marine reptiles of the Cenozoic.
> >>>>>> So it's a bit suggestive [but no more] that, just as those sea
> >>>>>> snakes are ovoviviparous,
> >>>>>> so too the ichthyosaurs might have been.
> >>>>>>
> >>>>>> If either you, Erik, or John shows some interest, I can talk about
> >>>>>> a fascinating
> >>>>>> example that probably spans Mesozoic and Cenozoic: there are several
> >>>>>> lines of evidence that coelacanths are, and have been for a long
> >>>>>> time, ovoviviparous.
> >>>>
> >>>> In fact, *Rhabdoderma*, another candidate for ovoviviparity, is from
> >>>> the Paleozoic.
> >>>>
> >>>>> Sure. What do you have? I presume here that your definition is gas
> >>>>> exchange across the shell, but no nutrients.
> >>>>
> >>>> Yes.
> >>>>
> >>>> I'm busy in talk.origins and other s.b.p. threads for probably the
> >>>> rest of the week,
> >>>> but I intend on Monday to go deep into details in a great book on
> >>>> *Latimeria,*
> >>>> the living coelacanth and AFAIK the only known Cenozoic coelacanth.
> >>>> It is by Keith S. Thompson, titled _Living Fossil: The Story of the
> >>>> Coelacanth_ .
> >>>>
> >>>> For now, I'll just quote something about that Paleozoic coelacanth.
> >>>>
> >>>> "The Carboniferous fossils that Schultze had described as
> >>>> free-living yolk sac larvae were from a genus, (*Rhabdoderma*) that
> >>>> may have lived in brackish waters rather than the sea. In this case
> >>>> (if the water was less saline than the body tissues) it is possible
> >>>> that ovoviviparity was not needed, but economy of hypotheses
> >>>> suggests the strong likelihood that this genus was ovoviviparous
> >>>> also." [p. 199]
> >>>>
> >>>> The rationale for this "strong likelihood" would seem to be that
> >>>> the yolk sac, being still attached to the free-swimming young,
> >>>> creates the
> >>>> presumption that there had been enough yolk all the way to birth
> >>>> to dispense with any maternal nutrients in addition.
> >>>>
> >>>> The alternative hypothesis, that the yolk sac was only a partial
> >>>> source of nutrition, is less economical, as the author puts it.
> >>>>
> >>>> Peter Nyikos
> >>>> Professor, Dept. of Mathematics -- standard disclaimer--
> >>>> University of So. Carolina in Columbia
> >>>> http://people.math.sc.edu/nyikos
> >>>
> >>> Double checking.
> >>>
> >>> For oviparous reptiles, birds, and monotremes, The shell of
> >>> an amniote egg is secreted onto an egg during the process of laying.
> >>>
> >>> Therefore an egg that is not laid will have no shell?
> >>
> >> Nope. This "process of laying" can take days, as the egg moves down
> >> the oviduct. All that's needed is for the finished egg to skip that
> >> last step of leaving the mother's body.
> >>
> >>> Is it possible for a blood vessel in a closed circulatory
> >>> system to be able to exchange oxygen with a tissue outside
> >>> of a blood vessel without also being able to exchange nutrients?
> >>
> >> Yes, totally. Oxygen and CO2 diffuse more easily than most other
> >> molecules.
> >
> > When I look up the words 'closed circulatory system' in Wikipedia
> > it gives three examples - annelids, some molluscs, and vertebrates.
> >
> > Since two are protostomes and one is a deuterostome I am guessing
> > that is not based upon phylogenetics.
> >
> > Now in cephalopods, I am thinking that the copper metalloprotein
> > that carries oxygen is not contained within any cells inside a
> > cell membrane, rather it is within a blood matrix. I am not sure
> > if the oxygen bound copper diffuses across the blood vessel or not.
> >
> > Now in vertebrates in general, hemoglobin resides inside red blood
> > cells. For oxygen to get inside the cells in tissues outside of
> > blood vessels I am thinking it has to do the following.
> >
> > Go outside the red blood cell into the extracellular fluid of
> > the blood in the vessel.
> >
> > Travel outside the fluid of the blood vessel into the fluid
> > outside of the blood vessel (sometimes called lymph or other
> > tissue fluid)
> >
> > Then go inside of the cells receiving oxygen. There in some
> > circumstances it might bind with myoglobin for storage before
> > metabolic use.
> >
> > During all of this time, both oxygen, nitrogen, and carbon
> > dioxide remain dissolved in an aqueous solution. They never
> > go into the gas state. If something like this happens, this
> > is called the 'bends' (or decompression sickness). This is
> > generally suppressed because if it becomes too widespread
> > it can lead to problems with circulation.
> >
> > Basic question.
> >
> > In the closed circulatory system of vertebrates, how do
> > white blood (immune, not red blood) cells go from the
> > blood vessels into tissues outside of the blood stream
> > when they undergo some form of damage or infection? Do
> > they open up small passages in the walls of the blood
> > vessels and then close them afterward? Are there gaps
> > that allow them to go through?
> >
> > How does oxygen or carbon dioxide pass through a blood
> > vessel?

"Inside the air sacs, oxygen moves across paper-thin walls to tiny blood vessels called capillaries and into your blood. A protein called haemoglobin in the red blood cells then carries the oxygen around your body. At the same time, carbon dioxide that is dissolved in the blood comes out of the capillaries back into the air sacs, ready to be breathed out."

https://www.blf.org.uk/support-for-you/how-your-lungs-work/oxygen-and-blood
> >Does it go inside of the cell membranes of the
> > cells making up the blood vessel walls themselves and
> > pass through the cells to get inside and outside of the
> > blood vessels? Does it go through small gaps between
> > the cells of the blood vessels without passing into and
> > out of the cells themselves that make up much of the
> > blood vessel tissues?
> >
> > Then after that the oxygen or carbon dioxide when then
> > have to pass through the extracellular fluid of the
> > tissue before being taken up by the cells in the tissue.
> I doubt that small, uncharged molecules notice whether they're going
> through a cell membrane or not. I'm pretty sure travel is by passive
> diffusion, not active transport.

You doubt? Or you're pretty sure? Which is it?

On 10/12/22 3:01 PM, Trolidan7 wrote:
> On 10/12/22 2:33 PM, John Harshman wrote:
>> On 10/12/22 2:13 PM, Trolidan7 wrote:
>>> On 10/9/22 11:58 AM, John Harshman wrote:
>>>> On 10/9/22 9:57 AM, Trolidan7 wrote:
>>>>> On 10/6/22 12:05 PM, Peter Nyikos wrote:
>>>>>> On Tuesday, October 4, 2022 at 6:45:58 PM UTC-4, John Harshman wrote:
>>>>>>> On 10/4/22 2:07 PM, Peter Nyikos wrote:
>>>>>>>
>>>>>>>> And now, back to Ichthyosaurs. They were the most exclusively
>>>>>>>> marine reptiles of the Mesozoic,
>>>>>>>> just as sea snakes in one subfamily are the most exclusively
>>>>>>>> marine reptiles of the Cenozoic.
>>>>>>>> So it's a bit suggestive [but no more] that, just as those sea
>>>>>>>> snakes are ovoviviparous,
>>>>>>>> so too the ichthyosaurs might have been.
>>>>>>>>
>>>>>>>> If either you, Erik, or John shows some interest, I can talk
>>>>>>>> about a fascinating
>>>>>>>> example that probably spans Mesozoic and Cenozoic: there are
>>>>>>>> several
>>>>>>>> lines of evidence that coelacanths are, and have been for a long
>>>>>>>> time, ovoviviparous.
>>>>>>
>>>>>> In fact, *Rhabdoderma*, another candidate for ovoviviparity, is
>>>>>> from the Paleozoic.
>>>>>>
>>>>>>> Sure. What do you have? I presume here that your definition is gas
>>>>>>> exchange across the shell, but no nutrients.
>>>>>>
>>>>>> Yes.
>>>>>>
>>>>>> I'm busy in talk.origins and other s.b.p. threads for probably the
>>>>>> rest of the week,
>>>>>> but I intend on Monday to go deep into details in a great book on
>>>>>> *Latimeria,*
>>>>>> the living coelacanth and AFAIK the only known Cenozoic coelacanth.
>>>>>> It is by Keith S. Thompson, titled _Living Fossil: The Story of
>>>>>> the Coelacanth_ .
>>>>>>
>>>>>> For now, I'll just quote something about that Paleozoic coelacanth.
>>>>>>
>>>>>> "The Carboniferous fossils that Schultze had described as
>>>>>> free-living yolk sac larvae were from a genus, (*Rhabdoderma*)
>>>>>> that may have lived in brackish waters rather than the sea. In
>>>>>> this case (if the water was less saline than the body tissues) it
>>>>>> is possible that ovoviviparity was not needed, but economy of
>>>>>> hypotheses suggests the strong likelihood that this genus was
>>>>>> ovoviviparous also." [p. 199]
>>>>>>
>>>>>> The rationale for this "strong likelihood" would seem to be that
>>>>>> the yolk sac, being still attached to the free-swimming young,
>>>>>> creates the
>>>>>> presumption that there had been enough yolk all the way to birth
>>>>>> to dispense with any maternal nutrients in addition.
>>>>>>
>>>>>> The alternative hypothesis, that the yolk sac was only a partial
>>>>>> source of nutrition, is less economical, as the author puts it.
>>>>>>
>>>>>> Peter Nyikos
>>>>>> Professor, Dept. of Mathematics   -- standard disclaimer--
>>>>>> University of So. Carolina in Columbia
>>>>>> http://people.math.sc.edu/nyikos
>>>>>
>>>>> Double checking.
>>>>>
>>>>> For oviparous reptiles, birds, and monotremes, The shell of
>>>>> an amniote egg is secreted onto an egg during the process of laying.
>>>>>
>>>>> Therefore an egg that is not laid will have no shell?
>>>>
>>>> Nope. This "process of laying" can take days, as the egg moves down
>>>> the oviduct. All that's needed is for the finished egg to skip that
>>>> last step of leaving the mother's body.
>>>>
>>>>> Is it possible for a blood vessel in a closed circulatory
>>>>> system to be able to exchange oxygen with a tissue outside
>>>>> of a blood vessel without also being able to exchange nutrients?
>>>>
>>>> Yes, totally. Oxygen and CO2 diffuse more easily than most other
>>>> molecules.
>>>
>>> When I look up the words 'closed circulatory system' in Wikipedia
>>> it gives three examples - annelids, some molluscs, and vertebrates.
>>>
>>> Since two are protostomes and one is a deuterostome I am guessing
>>> that is not based upon phylogenetics.
>>>
>>> Now in cephalopods, I am thinking that the copper metalloprotein
>>> that carries oxygen is not contained within any cells inside a
>>> cell membrane, rather it is within a blood matrix.  I am not sure
>>> if the oxygen bound copper diffuses across the blood vessel or not.
>>>
>>> Now in vertebrates in general, hemoglobin resides inside red blood
>>> cells.  For oxygen to get inside the cells in tissues outside of
>>> blood vessels I am thinking it has to do the following.
>>>
>>> Go outside the red blood cell into the extracellular fluid of
>>> the blood in the vessel.
>>>
>>> Travel outside the fluid of the blood vessel into the fluid
>>> outside of the blood vessel (sometimes called lymph or other
>>> tissue fluid)
>>>
>>> Then go inside of the cells receiving oxygen.  There in some
>>> circumstances it might bind with myoglobin for storage before
>>> metabolic use.
>>>
>>> During all of this time, both oxygen, nitrogen, and carbon
>>> dioxide remain dissolved in an aqueous solution.   They never
>>> go into the gas state.  If something like this happens, this
>>> is called the 'bends' (or decompression sickness).  This is
>>> generally suppressed because if it becomes too widespread
>>> it can lead to problems with circulation.
>>>
>>> Basic question.
>>>
>>> In the closed circulatory system of vertebrates, how do
>>> white blood (immune, not red blood) cells go from the
>>> blood vessels into tissues outside of the blood stream
>>> when they undergo some form of damage or infection?  Do
>>> they open up small passages in the walls of the blood
>>> vessels and then close them afterward?  Are there gaps
>>> that allow them to go through?
>>>
>>> How does oxygen or carbon dioxide pass through a blood
>>> vessel?  Does it go inside of the cell membranes of the
>>> cells making up the blood vessel walls themselves and
>>> pass through the cells to get inside and outside of the
>>> blood vessels?  Does it go through small gaps between
>>> the cells of the blood vessels without passing into and
>>> out of the cells themselves that make up much of the
>>> blood vessel tissues?
>>>
>>> Then after that the oxygen or carbon dioxide when then
>>> have to pass through the extracellular fluid of the
>>> tissue before being taken up by the cells in the tissue.
>>
>> I doubt that small, uncharged molecules notice whether they're going
>> through a cell membrane or not. I'm pretty sure travel is by passive
>> diffusion, not active transport.
>
> O2 has no polar or non-polar side.

Actually, O2 is a polar molecule, but not very polar.

> A cell membrane is a bilayer generally composed of lipid molecules
> along with glycerols and other materials.  The lipid has a non-polar
> tail that has affinities for other non-polar materials and a polar
> side is attracted toward the aqueous polar inside and outside of the
> membrane.
>
> A cell membrane also has a lot of pores in them that open or close
> to allow certain substances in or out.  The sodium, potassium, and
> calcium channels specific for certain types of ions are some examples.
>
> It might be that CO2 could be different from O2, but you are in
> essence saying that all of O2 at least passes through the cell membranes
> of the cells of the blood vessels on both sides, and when immune cells
> exist the bloodstream they in essence open small doors between the
> blood vessel cells, and close those doors behind them?

On 10/12/22 3:46 PM, Trolidan7 wrote:
> On 10/12/22 2:33 PM, John Harshman wrote:
>> On 10/12/22 2:13 PM, Trolidan7 wrote:
>>> On 10/9/22 11:58 AM, John Harshman wrote:
>>>> On 10/9/22 9:57 AM, Trolidan7 wrote:
>>>>> On 10/6/22 12:05 PM, Peter Nyikos wrote:
>>>>>> On Tuesday, October 4, 2022 at 6:45:58 PM UTC-4, John Harshman wrote:
>>>>>>> On 10/4/22 2:07 PM, Peter Nyikos wrote:
>>>>>>>
>>>>>>>> And now, back to Ichthyosaurs. They were the most exclusively
>>>>>>>> marine reptiles of the Mesozoic,
>>>>>>>> just as sea snakes in one subfamily are the most exclusively
>>>>>>>> marine reptiles of the Cenozoic.
>>>>>>>> So it's a bit suggestive [but no more] that, just as those sea
>>>>>>>> snakes are ovoviviparous,
>>>>>>>> so too the ichthyosaurs might have been.
>>>>>>>>
>>>>>>>> If either you, Erik, or John shows some interest, I can talk
>>>>>>>> about a fascinating
>>>>>>>> example that probably spans Mesozoic and Cenozoic: there are
>>>>>>>> several
>>>>>>>> lines of evidence that coelacanths are, and have been for a long
>>>>>>>> time, ovoviviparous.
>>>>>>
>>>>>> In fact, *Rhabdoderma*, another candidate for ovoviviparity, is
>>>>>> from the Paleozoic.
>>>>>>
>>>>>>> Sure. What do you have? I presume here that your definition is gas
>>>>>>> exchange across the shell, but no nutrients.
>>>>>>
>>>>>> Yes.
>>>>>>
>>>>>> I'm busy in talk.origins and other s.b.p. threads for probably the
>>>>>> rest of the week,
>>>>>> but I intend on Monday to go deep into details in a great book on
>>>>>> *Latimeria,*
>>>>>> the living coelacanth and AFAIK the only known Cenozoic coelacanth.
>>>>>> It is by Keith S. Thompson, titled _Living Fossil: The Story of
>>>>>> the Coelacanth_ .
>>>>>>
>>>>>> For now, I'll just quote something about that Paleozoic coelacanth.
>>>>>>
>>>>>> "The Carboniferous fossils that Schultze had described as
>>>>>> free-living yolk sac larvae were from a genus, (*Rhabdoderma*)
>>>>>> that may have lived in brackish waters rather than the sea. In
>>>>>> this case (if the water was less saline than the body tissues) it
>>>>>> is possible that ovoviviparity was not needed, but economy of
>>>>>> hypotheses suggests the strong likelihood that this genus was
>>>>>> ovoviviparous also." [p. 199]
>>>>>>
>>>>>> The rationale for this "strong likelihood" would seem to be that
>>>>>> the yolk sac, being still attached to the free-swimming young,
>>>>>> creates the
>>>>>> presumption that there had been enough yolk all the way to birth
>>>>>> to dispense with any maternal nutrients in addition.
>>>>>>
>>>>>> The alternative hypothesis, that the yolk sac was only a partial
>>>>>> source of nutrition, is less economical, as the author puts it.
>>>>>>
>>>>>> Peter Nyikos
>>>>>> Professor, Dept. of Mathematics   -- standard disclaimer--
>>>>>> University of So. Carolina in Columbia
>>>>>> http://people.math.sc.edu/nyikos
>>>>>
>>>>> Double checking.
>>>>>
>>>>> For oviparous reptiles, birds, and monotremes, The shell of
>>>>> an amniote egg is secreted onto an egg during the process of laying.
>>>>>
>>>>> Therefore an egg that is not laid will have no shell?
>>>>
>>>> Nope. This "process of laying" can take days, as the egg moves down
>>>> the oviduct. All that's needed is for the finished egg to skip that
>>>> last step of leaving the mother's body.
>>>>
>>>>> Is it possible for a blood vessel in a closed circulatory
>>>>> system to be able to exchange oxygen with a tissue outside
>>>>> of a blood vessel without also being able to exchange nutrients?
>>>>
>>>> Yes, totally. Oxygen and CO2 diffuse more easily than most other
>>>> molecules.
>>>
>>> When I look up the words 'closed circulatory system' in Wikipedia
>>> it gives three examples - annelids, some molluscs, and vertebrates.
>>>
>>> Since two are protostomes and one is a deuterostome I am guessing
>>> that is not based upon phylogenetics.
>>>
>>> Now in cephalopods, I am thinking that the copper metalloprotein
>>> that carries oxygen is not contained within any cells inside a
>>> cell membrane, rather it is within a blood matrix.  I am not sure
>>> if the oxygen bound copper diffuses across the blood vessel or not.
>>>
>>> Now in vertebrates in general, hemoglobin resides inside red blood
>>> cells.  For oxygen to get inside the cells in tissues outside of
>>> blood vessels I am thinking it has to do the following.
>>>
>>> Go outside the red blood cell into the extracellular fluid of
>>> the blood in the vessel.
>>>
>>> Travel outside the fluid of the blood vessel into the fluid
>>> outside of the blood vessel (sometimes called lymph or other
>>> tissue fluid)
>>>
>>> Then go inside of the cells receiving oxygen.  There in some
>>> circumstances it might bind with myoglobin for storage before
>>> metabolic use.
>>>
>>> During all of this time, both oxygen, nitrogen, and carbon
>>> dioxide remain dissolved in an aqueous solution.   They never
>>> go into the gas state.  If something like this happens, this
>>> is called the 'bends' (or decompression sickness).  This is
>>> generally suppressed because if it becomes too widespread
>>> it can lead to problems with circulation.
>>>
>>> Basic question.
>>>
>>> In the closed circulatory system of vertebrates, how do
>>> white blood (immune, not red blood) cells go from the
>>> blood vessels into tissues outside of the blood stream
>>> when they undergo some form of damage or infection?  Do
>>> they open up small passages in the walls of the blood
>>> vessels and then close them afterward?  Are there gaps
>>> that allow them to go through?
>>>
>>> How does oxygen or carbon dioxide pass through a blood
>>> vessel?  Does it go inside of the cell membranes of the
>>> cells making up the blood vessel walls themselves and
>>> pass through the cells to get inside and outside of the
>>> blood vessels?  Does it go through small gaps between
>>> the cells of the blood vessels without passing into and
>>> out of the cells themselves that make up much of the
>>> blood vessel tissues?
>>>
>>> Then after that the oxygen or carbon dioxide when then
>>> have to pass through the extracellular fluid of the
>>> tissue before being taken up by the cells in the tissue.
>>
>> I doubt that small, uncharged molecules notice whether they're going
>> through a cell membrane or not. I'm pretty sure travel is by passive
>> diffusion, not active transport.
>
> I have several more questions about the lymphatic versus the
> regular blood circulatory systems that I may have been mistaken
> about before.
>
> 1, The direction of flow of the lymphatic system is opposite
> the flow of the blood circulatory system.  Is that correct?

No idea.

> That means that when lymph empties into the regular blood system
> at the exit to the lymphatic system, possible backflow of blood
> into the lymphatic ducts is stopped by the valves in the lymphatic
> system.  Since there are many valves in the lymph system, just like
> in the blood vessels, failure of one valve will not mean that the
> lymph system is not filled because there are many valves within it?

Again, no idea.

> 2. I read that in some reptiles there are 'lymph hearts'.  Is that
> in only some reptiles?  Which ones?  How about birds?  How about
> monotremes or marsupials?  I am thinking that in mammals it is all
> skeletal muscles and the fact that the lymph vessels have valves
> that make the lymph flow only one way.  It does not need to flow
> very fast.

On 10/12/22 4:45 PM, John Harshman wrote:
> On 10/12/22 3:01 PM, Trolidan7 wrote:
>> On 10/12/22 2:33 PM, John Harshman wrote:
>>> On 10/12/22 2:13 PM, Trolidan7 wrote:
>>>> On 10/9/22 11:58 AM, John Harshman wrote:
>>>>> On 10/9/22 9:57 AM, Trolidan7 wrote:
>>>>>> On 10/6/22 12:05 PM, Peter Nyikos wrote:
>>>>>>> On Tuesday, October 4, 2022 at 6:45:58 PM UTC-4, John Harshman
>>>>>>> wrote:
>>>>>>>> On 10/4/22 2:07 PM, Peter Nyikos wrote:
>>>>>>>>
>>>>>>>>> And now, back to Ichthyosaurs. They were the most exclusively
>>>>>>>>> marine reptiles of the Mesozoic,
>>>>>>>>> just as sea snakes in one subfamily are the most exclusively
>>>>>>>>> marine reptiles of the Cenozoic.
>>>>>>>>> So it's a bit suggestive [but no more] that, just as those sea
>>>>>>>>> snakes are ovoviviparous,
>>>>>>>>> so too the ichthyosaurs might have been.
>>>>>>>>>
>>>>>>>>> If either you, Erik, or John shows some interest, I can talk
>>>>>>>>> about a fascinating
>>>>>>>>> example that probably spans Mesozoic and Cenozoic: there are
>>>>>>>>> several
>>>>>>>>> lines of evidence that coelacanths are, and have been for a
>>>>>>>>> long time, ovoviviparous.
>>>>>>>
>>>>>>> In fact, *Rhabdoderma*, another candidate for ovoviviparity, is
>>>>>>> from the Paleozoic.
>>>>>>>
>>>>>>>> Sure. What do you have? I presume here that your definition is gas
>>>>>>>> exchange across the shell, but no nutrients.
>>>>>>>
>>>>>>> Yes.
>>>>>>>
>>>>>>> I'm busy in talk.origins and other s.b.p. threads for probably
>>>>>>> the rest of the week,
>>>>>>> but I intend on Monday to go deep into details in a great book on
>>>>>>> *Latimeria,*
>>>>>>> the living coelacanth and AFAIK the only known Cenozoic coelacanth.
>>>>>>> It is by Keith S. Thompson, titled _Living Fossil: The Story of
>>>>>>> the Coelacanth_ .
>>>>>>>
>>>>>>> For now, I'll just quote something about that Paleozoic coelacanth.
>>>>>>>
>>>>>>> "The Carboniferous fossils that Schultze had described as
>>>>>>> free-living yolk sac larvae were from a genus, (*Rhabdoderma*)
>>>>>>> that may have lived in brackish waters rather than the sea. In
>>>>>>> this case (if the water was less saline than the body tissues) it
>>>>>>> is possible that ovoviviparity was not needed, but economy of
>>>>>>> hypotheses suggests the strong likelihood that this genus was
>>>>>>> ovoviviparous also." [p. 199]
>>>>>>>
>>>>>>> The rationale for this "strong likelihood" would seem to be that
>>>>>>> the yolk sac, being still attached to the free-swimming young,
>>>>>>> creates the
>>>>>>> presumption that there had been enough yolk all the way to birth
>>>>>>> to dispense with any maternal nutrients in addition.
>>>>>>>
>>>>>>> The alternative hypothesis, that the yolk sac was only a partial
>>>>>>> source of nutrition, is less economical, as the author puts it.
>>>>>>>
>>>>>>> Peter Nyikos
>>>>>>> Professor, Dept. of Mathematics   -- standard disclaimer--
>>>>>>> University of So. Carolina in Columbia
>>>>>>> http://people.math.sc.edu/nyikos
>>>>>>
>>>>>> Double checking.
>>>>>>
>>>>>> For oviparous reptiles, birds, and monotremes, The shell of
>>>>>> an amniote egg is secreted onto an egg during the process of laying.
>>>>>>
>>>>>> Therefore an egg that is not laid will have no shell?
>>>>>
>>>>> Nope. This "process of laying" can take days, as the egg moves down
>>>>> the oviduct. All that's needed is for the finished egg to skip that
>>>>> last step of leaving the mother's body.
>>>>>
>>>>>> Is it possible for a blood vessel in a closed circulatory
>>>>>> system to be able to exchange oxygen with a tissue outside
>>>>>> of a blood vessel without also being able to exchange nutrients?
>>>>>
>>>>> Yes, totally. Oxygen and CO2 diffuse more easily than most other
>>>>> molecules.
>>>>
>>>> When I look up the words 'closed circulatory system' in Wikipedia
>>>> it gives three examples - annelids, some molluscs, and vertebrates.
>>>>
>>>> Since two are protostomes and one is a deuterostome I am guessing
>>>> that is not based upon phylogenetics.
>>>>
>>>> Now in cephalopods, I am thinking that the copper metalloprotein
>>>> that carries oxygen is not contained within any cells inside a
>>>> cell membrane, rather it is within a blood matrix.  I am not sure
>>>> if the oxygen bound copper diffuses across the blood vessel or not.
>>>>
>>>> Now in vertebrates in general, hemoglobin resides inside red blood
>>>> cells.  For oxygen to get inside the cells in tissues outside of
>>>> blood vessels I am thinking it has to do the following.
>>>>
>>>> Go outside the red blood cell into the extracellular fluid of
>>>> the blood in the vessel.
>>>>
>>>> Travel outside the fluid of the blood vessel into the fluid
>>>> outside of the blood vessel (sometimes called lymph or other
>>>> tissue fluid)
>>>>
>>>> Then go inside of the cells receiving oxygen.  There in some
>>>> circumstances it might bind with myoglobin for storage before
>>>> metabolic use.
>>>>
>>>> During all of this time, both oxygen, nitrogen, and carbon
>>>> dioxide remain dissolved in an aqueous solution.   They never
>>>> go into the gas state.  If something like this happens, this
>>>> is called the 'bends' (or decompression sickness).  This is
>>>> generally suppressed because if it becomes too widespread
>>>> it can lead to problems with circulation.
>>>>
>>>> Basic question.
>>>>
>>>> In the closed circulatory system of vertebrates, how do
>>>> white blood (immune, not red blood) cells go from the
>>>> blood vessels into tissues outside of the blood stream
>>>> when they undergo some form of damage or infection?  Do
>>>> they open up small passages in the walls of the blood
>>>> vessels and then close them afterward?  Are there gaps
>>>> that allow them to go through?
>>>>
>>>> How does oxygen or carbon dioxide pass through a blood
>>>> vessel?  Does it go inside of the cell membranes of the
>>>> cells making up the blood vessel walls themselves and
>>>> pass through the cells to get inside and outside of the
>>>> blood vessels?  Does it go through small gaps between
>>>> the cells of the blood vessels without passing into and
>>>> out of the cells themselves that make up much of the
>>>> blood vessel tissues?
>>>>
>>>> Then after that the oxygen or carbon dioxide when then
>>>> have to pass through the extracellular fluid of the
>>>> tissue before being taken up by the cells in the tissue.
>>>
>>> I doubt that small, uncharged molecules notice whether they're going
>>> through a cell membrane or not. I'm pretty sure travel is by passive
>>> diffusion, not active transport.
>>
>> O2 has no polar or non-polar side.
>
> Actually, O2 is a polar molecule, but not very polar.
>
>> A cell membrane is a bilayer generally composed of lipid molecules
>> along with glycerols and other materials.  The lipid has a non-polar
>> tail that has affinities for other non-polar materials and a polar
>> side is attracted toward the aqueous polar inside and outside of the
>> membrane.
>>
>> A cell membrane also has a lot of pores in them that open or close
>> to allow certain substances in or out.  The sodium, potassium, and
>> calcium channels specific for certain types of ions are some examples.
>>
>> It might be that CO2 could be different from O2, but you are in
>> essence saying that all of O2 at least passes through the cell membranes
>> of the cells of the blood vessels on both sides, and when immune cells
>> exist the bloodstream they in essence open small doors between the
>> blood vessel cells, and close those doors behind them?
>
> I don't know how the immune cells get around, but presumably they don't
> go through the epithelial cells but around them.
>
> CO2 is a non-polar molecule, and in fact it's known to diffuse somewhat
> more easily than O2.
>
>> I was thinking there were regular gaps between the blood vessel cells,
>> and lymph was formed from a persistent regular leakage from the blood
>> vessels into the intercellular fluid outside of the blood vessels.
>> Perhaps that was wrong.
>
> It's been a while since I thought about cellular physiology, and you
> might more profitably consult a text.

I've been busy on other threads last week and am trying
to catch up on this one.

On Wednesday, October 12, 2022 at 5:13:40 PM UTC-4, Trolidan7 wrote:
> On 10/9/22 11:58 AM, John Harshman wrote:
> > On 10/9/22 9:57 AM, Trolidan7 wrote:

> >> Is it possible for a blood vessel in a closed circulatory
> >> system to be able to exchange oxygen with a tissue outside
> >> of a blood vessel without also being able to exchange nutrients?
> >
> > Yes, totally. Oxygen and CO2 diffuse more easily than most other molecules.

> When I look up the words 'closed circulatory system' in Wikipedia
> it gives three examples - annelids, some molluscs, and vertebrates.
>
> Since two are protostomes and one is a deuterostome I am guessing
> that is not based upon phylogenetics.

That is a very safe bet.

> Now in cephalopods, I am thinking that the copper metalloprotein
> that carries oxygen is not contained within any cells inside a
> cell membrane, rather it is within a blood matrix.

What is your source for this? The Wikipedia comment on this looks
like a case of too many cooks spoiling the broth:

"Unlike the hemoglobin in red blood cells found in vertebrates, hemocyanins are not confined in blood cells but are instead suspended directly in the hemolymph."
https://en.wikipedia.org/wiki/Hemocyanin

However, the link to hemolymph takes one to a page where one sees:
"Hemolymph, or haemolymph, is a fluid, analogous to the blood in vertebrates, that circulates in the interior of the arthropod (invertebrate) body, remaining in direct contact with the animal's tissues."

This leaves me up in the air as to where the hemocyanin in cephalopods is confined.
On the other hand, some mollusks and some annelids have true hemglobin.
Most annelids have the hemoglobin in the plasma, but a few species,
including *Glycera*, contain it in red blood cells.

>I am not sure
> if the oxygen bound copper diffuses across the blood vessel or not.

I doubt it: if you look at the picture in the one wikipedia link I gave,
hemocyanins are quite complicated, unlike the gases you talked about below.

> Now in vertebrates in general, hemoglobin resides inside red blood
> cells. For oxygen to get inside the cells in tissues outside of
> blood vessels I am thinking it has to do the following.
>
> Go outside the red blood cell into the extracellular fluid of
> the blood in the vessel.

The plasma, in other words. There is an interplay between the
oxygen and carbon dioxide that influences the red blood
cells to give up their bound oxygen. Strangely, one of the best
biology textbooks (_Biology_, by Campbell, Reece et al)
spends a lot of time on the technical details of this but says
essentially nothing about how the oxygen is then delivered
to the cells.

>
> Travel outside the fluid of the blood vessel into the fluid
> outside of the blood vessel (sometimes called lymph or other
> tissue fluid)
>
> Then go inside of the cells receiving oxygen. There in some
> circumstances it might bind with myoglobin for storage before
> metabolic use.
>
> During all of this time, both oxygen, nitrogen, and carbon
> dioxide remain dissolved in an aqueous solution.

Yes, but the red blood cells need to take up about 90% of the oxygen for
there to be enough stored oxygen in the blood vessels.

> They never go into the gas state. If something like this happens, this
> is called the 'bends' (or decompression sickness). This is
> generally suppressed because if it becomes too widespread
> it can lead to problems with circulation.
>
> Basic question.
>
> In the closed circulatory system of vertebrates, how do
> white blood (immune, not red blood) cells go from the
> blood vessels into tissues outside of the blood stream
> when they undergo some form of damage or infection? Do
> they open up small passages in the walls of the blood
> vessels and then close them afterward? Are there gaps
> that allow them to go through?

White blood cells are like amoebas: they can greatly
change their shapes to squeeze between cells in the capillaries.
Red blood cells are comparatively rigid.

However, they do drastically change their shape in people with
the sickle cell trait. In the altered sickle cell form, the cell
can no longer take in oxygen. In heterozygous individuals,
the change to this form usually happens only when a malaria parasite invades the cell.
Then the parasite dies due to oxygen starvation.

In homozygous individuals, the change can be stimulated a lot
more easily, and the result is sickle cell anemia.

I mention all this because this shows how diffusion of oxygen
across cell membranes needs to be supplemented by the hemoglobin
molecule being in the right location for easy takeup.

> How does oxygen or carbon dioxide pass through a blood
> vessel? Does it go inside of the cell membranes of the
> cells making up the blood vessel walls themselves and
> pass through the cells to get inside and outside of the
> blood vessels? Does it go through small gaps between
> the cells of the blood vessels without passing into and
> out of the cells themselves that make up much of the
> blood vessel tissues?

I think the latter process contributes a lot more,
but I am not sure.

Peter Nyikos
Professor, Dept. of Mathematics -- standard disclaimer--
Univ. of So. Carolina in Columbia
http://people.math.sc.edu/nyikos

> Then after that the oxygen or carbon dioxide when then
> have to pass through the extracellular fluid of the
> tissue before being taken up by the cells in the tissue.