Talk:Cardiac muscle

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is cardiac muscle be consider as voluntary or involuntary?

cardiac muscle is definitely involuntary


This article states that cardiac muscle is a type of striated muscle, I am unsure as to whether this is the case as skeletal muscle is considered to be striated. Since this is a non-skeletal muscle and is considered as smooth muscle by its very nature it should not be striated should it not?

It would be nice to have a pretty picture.

Contents

[edit] cardiac muscle found in jaw and brain?

I deleted the following: "cardiac muscle is also found in the jaw and around the brain. In the jaw it pumps the blood there also." If anyone thinks this is true, please cite a reference. Thanks. Bmord (talk) 15:10, 2 April 2008 (UTC)

[edit] Isn't the tone of this article a touch presumptous

It reads like a medical text book designed for those already well versed in biological terms. I'm not saying dumb it down but perhaps make it more suitable for a general access encyclopedia?

For example : "There is a cost to lactate recycling, since one NAD+ is reduced to get pyruvate from lacate, but the pyruvate can then be burnt aerobically in the TCA cycle, liberating much more energy." ...eh?

[edit] Why doesn't the heart get tired?

Googling tells me the high number of mitochondria is the key. Can anyone add that to the article, with a citation, please? Thank you. --Kjoonlee 04:34, 26 September 2006 (UTC)

Some other links mention acquiring energy directly from the bloodstream. Hmm... --Kjoonlee 16:30, 26 September 2006 (UTC)
The heart has the highest amount of mitochondria of any muscle. Around 30% of its weight is mitochondria. Its because of this that the heart doesn't "tire." Think about postural muscles like in the spinal chord, or the ones in your neck that hold up your head. Generally, these don't get very tired either, because slow skeletal muscle is made to not tire very easily. One of the main reasons of this is that they get their energy from oxidative phosphorylation, which gives up a lot of ATP per glucose. The heart is made to provide a small amount of energy for extended periods of time. Your biceps are made to give a high amount of intensity, but only for a very short amount of time.Rjkd12 18:04, 18 May 2007 (UTC)


My question is why is cardiac muscle lack multiple nuclei and would you expect to see recruitment in cardiac muscle or notr

[edit] Striated muscle?

I have a question about this edit: Some sources do consider cardiac muscle to be striated muscle -- for example, m_22/12547787 at Dorland's Medical Dictionary, and my physiology textbook ("Medical Physiology", Rhoades and Tanner, p. 138, ISBN 0-7817-1936-4). I do agree that when "striated muscle" is used without qualification, it usually refers to skeletal muscle. --Arcadian 04:53, 19 October 2006 (UTC)

As I understood it, cardiac muscle was a type of striated muscle - 'striated' refers to the presence of bands on the myofibrils in muscle cells, which skeletal and cardiac muscle possess, but smooth muscle does not. Also, the link to an external source at the bottom of the page leads to a page about smooth muscle, is this relevant to the article? Alaeangelorum 19:16, 6 November 2006 (UTC)

This is indeed ambiguous. 'striated muscle' on its own does refer to skeletal muscle only. Rather than say whether cardiac muscle is or is not a 'type' of striated muscle, maybe we could just say "although cardiac muscle has clear striations, the term 'striated muscle' refers exclusively to skeletal muscle." Robotsintrouble 22:42, 6 November 2006 (UTC)


Thats wrong. It's like saying uhm a someone is a human and not short because being short is blah blah blah etc. Cardiac muscle is striated just like skeletal muscle is striated. Whatever connotations to the different types you make is superfluous. It is what it is because thats the way it looks under light microscopy.

I agree also. Doing medicine in the Uk we are taught that cardiac and skeletal are striated muscle. To say it's not is wrong. Also to say 'it's conventionally said that striated refers specifically skeletal' is like saying 'conventionally canabilism is great and practiced by nearly 100% of members in some communities' If that makes no sense i apologise but you get my drift. Whose conventions do we have to use? In the case of stating fact then do it and say cardiac IS striated BECAUSE IT IS.

Ha ha i realise that i just 'agreed' with myself. I think i made both of the above posts. twat —Preceding unsigned comment added by 81.96.196.219 (talk) 16:20, 4 June 2008 (UTC)

[edit] Nucleation

This paragraph needs some tidying up. The sentence structure isn't great. I would propose a change from...

In some animal species, the fetus and post parturition infant most cardiac muscle cells are mononucleated. Shortly after birth (within a few months) most cardiac muscles undergo a change of nucleation from mononucleated to primarily binucleated, and some go on to become multinucleated. Generally among species the cardiac muscle is 90% binucleated cells and 5% both mono gram and multinucleated gram cells, but exact numbers depend upon the species in question.

to...

In some non-human species the foetal and post-parturition cardiac myocytes undergo a change from a mononuclear cell to a binuclear cell. In some cases the myocytes further develop into multinucleated cells. Amongst most species the cardiac myocyte consists of 90% binucleated cells and 5% mono-gram and multinucleated-gram cells. The exact proportions depend upon the species in question.

Some further info is required in defining which 'species' are involved in the final sentence, are these most non-human species? mammals only? vertebrates? Also, what is meant by "mono gram and multinucleated gram cells". Excuse my ignorance but what is a gram cell? Is this referring to 'Gram' staining as in microbiology? Finally, how about a reference for this paragraph? anybody?

I will proceed with the above edit depending on what sort of feedback we get here...


tomc

[edit] Myocardium and Cardiac muscle

These two articles refer to the same thing. I think they should be put together. Kadellar (talk) 00:14, 17 March 2008 (UTC)

I agree, I'll propose a merge. Wisdom89 (T / C) 01:36, 17 March 2008 (UTC)
Definitely needs merge asap. Horus (talk) 18:46, 3 April 2008 (UTC)

Please note however that cardiac muscle tissue is not only located in the myocardium, but also in the superior and inferior vena cavae. —Preceding unsigned comment added by 220.245.232.145 (talk) 06:27, 9 April 2008 (UTC)