A Riddle

[Duncan]

the next part of the riddle . hope this is getting your thinking cap on i think its waisted on the other section but who knows

the picture is the clue comments please what you think is happening here ?

dunc

[StuW]

Are the bones of the lower jaw pivoting to close the gills as the fish is about to eat?
Seems from the diagram that they are all pivoting in sequence as the mouth opens.
Probably totally wrong, as usual

Stuart

[Duncan]

stu

your on ther right lines but its nought to do with eating and more complex than you suggest

[greg]

Duncan,

Been watching with interest even though i'm well out of my comfort zone with physiology of koi.

I would guess it is to do with the actual breathing action and the is a linkage between the mouth and Gill but does the nostril work off this aswell? Maybe looking at the way it all lines up thinking off the cuff is it to do with the gill rakers?

[Gazza]

Hi Dunc,

OK you've got me i am going to have a stab and after you have had a giggle i will get my coat

I am thinking along the lines that there must be (as mother nature and evolution is normally good at this stuff) a way that this operation all works nice and easy each time and is sort of fail safe.So i am thinking that when one is open and the other is shut there is a mechanical type of interlock to make sure that this operation can be carried out spot on each time perhaps even a sort of none return valve or linkage.

Great stuff though is its been getting me thinking............................runs off to get the books out

[Duncan]

hi guys

im gonna let this run a bit more simply because ive lost my favourite photo editor and need to get one as good that worked with win7 64

its nothing to do with the Nares (nose) the nares actually are just "U" tubes the water goes in past the olfactory sensors then back out the other end the sensors ar4e just like weed in a stream flow the "U" tube is the mechanism that creates the flow for sensory detection

regards this bone think about how the fish breaths or more exactly how it pumps if its sinply oopened its mouth without forward motion nothing would happen so being as it can breath while beihng stationary there has to be a pump or several pumps involved

now imj gonna stick my chest out here a bit, all the great book show this bone ( well some of them anyway ) but none of them know what it does in fact one German book says it just joins the to gill plates togethe,r interesting but no cigar you could do that (Join them together) with out evolution creating a bizzar shapds bone like this~~~ as soon as i looked at when doing chris's fish my engineering brain kicked in there had to be a reason for it to have evolloved into this shape it just to strange for it to simply hold something together

its called the basihyal bone and thats me done for a while i'll leave you to it

dunc

[boogatee]

My two p's worth ... looking at that bone and its connection to the others, I'm wondering if it's making the others move from convex to concave .... leading edge open while trailing edge close, sort of sucking then pushing (pumping) .... I can use my hands better to explain - but you can't see me --- uugh frustrating

[greg]

leading edge open while trailing edge close, sort of sucking then pushing (pumping) ....

Chris,

You mean like tghe old film hand pumped train carts you used to see

[Duncan]

Greg /Chris not quite but you remarkably close

look that bone we are discussing the reason for it being that long can only mean one thing its the old fulcrum ideal and i think your all homeing in on at least one half its purpose but while its that long and in the right place why not have it do something else at the same time? a secondary related function

hope your all enjoying this work out and neading the old grey matter like bread dough?

You cant get this elsewhere in forum terms

[greg]

Dunc,

Its not the bone that also controls the "koi teeth" is it?

[Duncan]

colder !

[Jon W]

Hi Duncan

I now know what it is because I cheated by looking it up because I was completely stumped, so I won't give it away for anyone else who wants to make an educated guess. What I don't understand is whether it has a specfic purpose in koi/carp? Function or lack of seems to vary with different classes of fish.

Cheers

Jon W

[Duncan]

Hi Jon

Yes it’s entirely different in different fish and indeed mammals some of these bones don’t even look the same

I’m on the run at the moment but I’ll post these pictures to see what i mean by a pump

if the fish was in still (stationary) water and just simply opens its mouth, all that would happen is the water that’s already in its mouth would simply stay there and no fresh water would replace it , sure there would be a slight very small mix of fresh water with stale water from outside at the peripheral extremes and this may be of some very small benefit but not enough to sustain the biology of the fish.

Let’s put it this way if you open your mouth this will not be enough to put oxygen in your lungs where it’s needed there has to be a pump involved and this is the muscle in your chest opening and closing your lungs to draw and expel oxygen this is a pumping action although it’s not working on or with fluid

So the fish has to actively pump oxygenated water over its gills and the function must be very, very efficient and is therefore a very complex process. Remember a litre of air contains 210 cc of oxygen, but a litre of water will contain a max of 11cc of oxygen and can be as low as 5cc and lower

Getting back to the main subject there are 9 bones that make up each gill operculum plus the main plates so it must make you wonder what these bone doe exactly


dunc

[Duncan]

the drawing did not do it for you so lets start drawing this to a close

Ok, before we go into what this bone does we need to explain how the fish QED the carp breathe

Just like us if the fish merely opens its mouth nothing much happens the air inside or in this case the water holding oxygen remains stationary that’s not desirable, So what happens?

There are three components at work here that make breathing possible for carp maybe four but you will see what I mean later. For us to breathe the organ where the oxygen is needed to enable this is a long way away from the mouth the source of O2, this is of course our lungs, which are a muscle as well that expand and contract drawing air and pumping air. This is our pump This presents a whole lot of other difficulties to the human that the fish does not have to deal with ( I.E the mixing of fresh and stale air ).

The koi’s lungs if you want to put it that way are right by the source of O2 but it’s still not as easy as you would think

A lot of the functions I’m about to relay to you happen at the same time as one another sometimes over lapping it took me quite some time to gather this information and understand the mechanics of it what appears to be a very simply process is in fact very complex in its choreography.

There are three/four pieces of anatomy at work here to list them starting with the mouth. The gill plate (operculum) there is a wide membrane on the trailing edge of the operculum and there is the buccal valve and cavity. The buccal cavity is the portion of the mouth where your tongue normally lies. in the carp it’s a pillow like pad that rises and falls when needed.

Right as a starting point, let’s assume the mouth is closed the mouth cavity is at its smallest volume/capacity in effect its empty

To start out the fish begins opening its mouth, as we have discovered this does not achieve any of the much needed drawing in of fresh water so what happens is the buccal valve/pad in the cavity starts to drop/fall. This action of the buccal valve puts a draw or negative pressure on the cavity and the mouth and begins sucking in fresh water. At the same time the gill plate the main big operculum starts to expand outward this put further negative pressure on the oral cavity. because of this high negative pressure the membrane around the edge of the big gill plate sucks down and forms a tight seal on the koi’s body at the gill edge this further drops pressure in the cavity. Because now the only relief for all this negative pressure is the mouth entrance the mouth fills to capacity with fresh oxygenated water at which point the mouth closes.

So what happens next?

With the mouth shut the buccal cavity begins to rise this starts to displace the water, this in effect puts positive pressure on the oral cavity this positive pressure lifts the membrane off its seat on the edge of the gill plate and water starts to move across the gill filaments. Next the buccal valve starts to move back down into its fully retracted position this action starts the gill plates to contract inward and apply the last piece of positive pressure on the water and the gill membrane flaps outward as the water drafts past it and finally the oral cavity is empty once more, but before this is achieved the mouth has already begun to open.

This is a suck-squeeze-blow action but the suck and blow overlap at the extreme ends of their respective cycles

I heard the term “caterpillar drive” don’t know where but this describes this this process perfectly it performs exactly how a caterpillar moves or one of this metal spring toys the slinky. And remember all these actions overlap one another to the naked eye you won’t be able to differentiate between process cuz some act simultaneous

So if you have grasped this you should start to see what this bone does now

I hope I have explained this well enough if any of you are struggling just shout up

To the next part, the bone ! what your should be thinking now is how does this bone tie into all this?

Clue for those that have fully sedated a fish should have noted the gill cover when a koi is fully sedated is always shut this should imply something to you?

[tomy2ponds]

Does this bone flex or move to keep the gill covers held tight to the body and as the other bones etc move it allows them to open but then flexes back to its original position to close the gill cover tight again.Probably got it arse about face