out of the blue

[monty]

thanks Monty for the very clear answers. They are very useful. Soon you'll all be writing my books for me
They are in fact two books, i am writing the easiest one now, to get me warmed up for the difficult work. you certainly deserve a copy by now, though it will be Dutch to you, I'm afraid!
got another one: three hearts, any idea why?

Why not?

The role of the 3 hearts is actually pretty similar to the two halves of our own hearts. In humans, the left side pumps blood to the body, while the right cycles blood through the lungs to pick up oxygen. In cephs, the main "systemic" heart pumps blood to the body, while the smaller "brachial" heart at each of the two gills pumps through the gills to get oxygen into the blood. So in some sense, it's just moving things around a bit, but essentially working the same way as many other animals that have an active lifestyle that needs to be able to extract oxygen quickly and efficiently.

 

[monty]

p.s. answering questions is fun, except when end up getting chastised by Steve for my presumptuousness.

I guess I'll have to learn some Dutch, or have Olaf read it to me as a translated bedtime story next time he's in town!

 

[Taollan]

got another one: three hearts, any idea why?

It goes a bit farther than just being the same as our two halves of our hearts (I don't mean to disagree with you too much Monty...). In water, the total oxygen content is much lower than in air. This means that, in order to get enough oxygen, the membranes separating blood from the outside oxygen must be thinner in the gills of aquatic organism than they are in the lungs of land animals. But this creates a problem: blood as high of pressure as ours would damage the gills of essentially any aquatic organism. Fish solve this problem by just having low pressure blood throughout the whole circulatory system. This, however, limits how efficient circulatory system is at delivering oxygen to their tissues (higher blood pressure equals a more efficient delivery system).
Cephs solve this problem by having a "high pressure system" through their body and a separate "low pressure system" through their gills. This is why octopuses have a heart pumping blood at low pressure into each gill (the branchial hearts that Monty mentioned) after the blood leaves the gills they enter the systemic heart, which significantly raises the pressure going to the body, making the ceph circulatory system much more efficient the most other aquatic animals.
Our heart does somewhat the same thing in that the pressure of blood going to our lung from our heart to our lungs is lower than that going to the body, but the differential isn't nearly as great as it is in cephs. This is why it would be difficult for cephs to have a single heart handling both the high pressure and low pressure circulatory systems. They would endanger having one side blow-out into the other because of the great differential in pressure, especially as they increased their activity.

Anyhow, that may be more complicated than you were looking for..

 

[monty]

Thanks for the details... this thread is great for drawing out a lot of good info, even if it involves calling me out for oversimplifications a lot... which is probably good for me.

 

[octokidwriter]

Anyhow, that may be more complicated than you were looking for

..

it's interesting to see how complicated exactly, and i do like having something that is just a little too difficult for me to ponder on. never one boring moment, that way. so: thanks.

 

[Steve O'Shea]

If you'd like to scroll to the bottom of this page you'll find a few images of the tentacles, and how they differ from the arms (they don't just 'grow' from the head with the rest of the arms). Scroll up and down this thread (beginning to end) and you'll find out a lot more info.

 

[DWhatley]

Taolloan,
While you were doing your master's work, did you see any signs of heart attack or stroke? Two of my mercs seemed to have suffered something akin to this in one of their branchial hearts (not both) or in close proximity, several days before they died. I compared it to a heart attack in that only the one side seemed to quit being under the control of the octo (possibly more like a stroke). (PDF?)

 

[Taollan]

I haven't ever encountered anything quite like that. Although, please tell me some more. Approx. age of the octopuses, how long between the symptoms and death, relevant behavior.... You have perked my interest.

 

[DWhatley]

I haven't ever encountered anything quite like that. Although, please tell me some more. Approx. age of the octopuses, how long between the symptoms and death, relevant behavior.... You have perked my interest.

Here is my post when Sisty showed the symptoms. I did not go back and reread it but I felt that the first hand recording would be better than my memory

Here are my notes about his brother sometime later

 

[Jean]

There are papers on heart defects in Sepia officinalis

Schipp, R; Von Boletzky, S. (1998) Congenital malformation of the systemic heart of Sepia officinalis I.: Morphological, phylogenetic and ecotoxicological aspects. South African Journal of Marine Science Vol. 20, pp. 25-27.

Abstract

Numerous preparations of the circulatory system of Sepia officinalis L. caught from the Bay of Arcachon (Atlantic Coast of France) in 1989 and 1996 showed an obvious congenital malformation of the systemic heart complex. The malformation consisted of a cord- or truncus-like structure at the left cranio-apical ventricle. It is interpreted as an atypical second root of the cephalic aorta reflecting an originally paired anlage of the heart in ancestral cephalopods. In considering possible causes of this atavistic abnormality, the high tributyltin (TBT) contamination recorded in the Bay at the time should not be overlooked.

Schipp, R; Boletzky, Svon; Jakobs, P; Labourg, PJ. (1998) A congenital malformation of the systemic heart complex in Sepia officinalis L. (Cephalopoda). Helgol. Meeresunters. Vol. 52, no. 1, pp. 29-40.

Abstract.

In semi-adult Sepia officinalis (Cephalopoda) from the Bay of Arcachon (France) a congenital malformation of the systemic heart is described by macro- and microscopical methods. It concerns an atypical doubling of the site of insertion at the cephalic aorta at the apical ventricle. Its comparison with the paired anlagen of the systemic heart complex in normal embryogenesis and the central circulatory system of Nautilus gives rise to interpret it as a form of atavism. The possible causal role of mutagenic antifoulings is discussed.

J

 

[DWhatley]

Jean,
I have seen a number of posts where octos have "extras" and keep my fingers crossed that these are the oddity and not going to be the norm as we see our oceans change. My little guys were at or near their natural lifespan when I observed the malfunctions and am curious to know if this is a typical end of life sign leading to potential changes in captivity that might extend their lives.

 

[octokidwriter]

Back again!

In fact I have been doing some writing for a change...

In the link below, the working of the mouth/beak of the octopus is described. is it correct?

How Octopuses Work

his beak is useful for breaking open clam shells and tearing apart flesh. Next to the beak is the radula, a barbed tongue the octopus uses to scrape an animal out of its shell once the shell is opened. And if these tools don't do the trick, it also has a tooth-covered organ called the salivary papilla that it can use to drill into shells. The papilla's bodily secretion also erodes the shell and then weakens the prey so it can be consumed.

Especially the passage in italics: this is the only site which mentions "a tooth covered organ" next to the radula???

 

[monty]

I'll leave most of the anatomy to the anatomists, but I can at least say the radula is in the beak more than next to it.

 

[Steve O'Shea]

Check this article out (it's one of the TONMO articles)

The salivary papilla is not 'tooth-covered', but it can have a tooth (or teeth) within that is/are (likely) used to assist in drilling. Not all species have a tooth (or teeth) within this papilla, and those that don't I believe also don't drill (not all octopus drill). The salivary papilla itself is a fleshy structure within the buccal bulb (the musculature that operates the beaks, and encloses all of radula, salivary papilla and lateral (or palatine) palps).

 

[octokidwriter]

thanks steve and monty

reading your answers before bed-time here in europe

have a nice day