Talk:Cardiac muscle

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Type of muscle[edit]

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.

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

Googling tells me the high number of mitochondria is the key. 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 "tired." 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.[

--Achapman18 (talk) 16:42, 6 March 2017 (UTC)"ATP per glucose" factoid that gives some numbers measured in vivo, not in isolated mitochondria; or, let's be good encyclopedians and in Wikipedia always say "MAY give up a lot of ATP per glucose" -- you know, throw in a weasel word. All those values of how many moles of ATP you get from a mole of glucose via oxidative phosphorylation are from adding up the maximal --- even rounded-upward -- yield you get from mitochondria doing tricks for us in a reaction chamber. The coupling of oxidation to phosphorylation is anything but stoichiometric. Richard8081 (talk) 05:15, 2 October 2013 (UTC)

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

Striated muscle?[edit]

I have a question about this edit: Some sources do consider cardiac muscle to be striated muscle -- for example, Dorlands, 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.

Forgive my intrusion, recommend further reading of [Arthur Guyton]s Textbook of Physiology regarding the cardiomyocyte. Weblike striation of cardiomyocytes is far more differentiated in cardiac muscle than in skeletal muscle and stretches well into the vascular trees. The myocardial muscle mass responds to a much greater number of endocrine influences than simple skeletal striated mass. Comparing the physiologic demand on these two distinct types of muscle mass is apples and oranges.--Lbeben (talk) 02:04, 17 September 2008 (UTC)

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

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?

Nucleation[edit]

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

Myocardium and Cardiac muscle[edit]

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)

Merging the cardiac muscle article with the myocardium article makes about as much sense as merging the skeletal muscle article with an article about the biceps muscle. Yes, the myocardium is made of skeletal muscle. True, cardiac muscle is found few places outside of the myocardium, but they are far from identical topics. --Medgineer (talk) 02:48, 22 September 2008 (UTC)
I think they probably overlap significantly enough to warrant a merge given the analogy you've proposed. Wisdom89 (T / C) 02:54, 22 September 2008 (UTC)
Since the discussion seems to have stagnated, and it has been that way for a while now, I've gone ahead and redirected myocardium to this article. Wisdom89 (T / C) 20:46, 16 October 2008 (U

TC)

cardiac muscle found in jaw and brain?[edit]

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)

Diseases/disorders of the myocardium[edit]

IMHO there should be some discussion of, or a link to a discussion of, diseases/disorders of the myocardium, call it what you like, myocardosis, myocardial disease, myocardium disorders. Thomas.Hedden (talk) 13:45, 9 December 2008 (UTC)

 Done PeaBrainC (talk) 05:41, 24 November 2017 (UTC)

just ventricular muscle?[edit]

I note that almost all of article is focussed on ventricular muscle with no mention of the differences present in atrial muscle... It also needs a bit of clarification on the calcium cycle re. termination of the calcium release and return to diastole. If any of the previous editors would like to consider this that would be great, if not I'll add some bits later. MarkC (talk) 21:09, 14 April 2009 (UTC)

There isn't any overt mention of ventricular muscle in the article, but if you wish to make any changes feel free to do so. Although, I have never seen anybody or any text distinguish between ventricular and atrial myocytes in the general sense. Wisdom89 (T / C) 19:55, 6 January 2010 (UTC)
 Done I have added a section comparing ventricular with atrial muscle PeaBrainC (talk) 22:02, 29 November 2017 (UTC)

Regeneration of heart muscle cells[edit]

Is it just me thinking DNA can be replaced without the cell actually dividing? When DNA gets damaged due to causes such as background radiation, UV light (probably rare for the heart but alas), viral infections etc, the DNA needs repair which is abundantly applied throughout a cell's lifetime. What do they use for this? Exactly, nucleic acids available from foodstuffs, which has an elevated C14 level. I must admit I haven't read the Science article, coming from a pronounced source it probably is right in some way or another. Redtails (talk) 20:17, 3 May 2010 (UTC)

Introduction[edit]

The intro is terribly written I do not know much about this topic but the first two or three lines are confusing 86.179.152.124 (talk) 12:03, 28 April 2012 (UTC)

 Done I have rewritten the lead in to make it more understandable PeaBrainC (talk) 22:02, 29 November 2017 (UTC)

Gentlemen and ladies, a smallish reminder, if I may.[edit]

I) an infant at birth weighs ohhh, a few pounds. II) They grow III) all organs grow with that. IV) how many cells in the body, do you suppose are renewed untill you reach the age of say 18 — Preceding unsigned comment added by 201.208.167.177 (talk) 00:58, 16 March 2013 (UTC)

Diagrams[edit]

This article is desperately lacking illustrated diagrams

2602:304:CFE4:4939:FC23:49F9:9758:2AB2 (talk) 07:13, 9 August 2013 (UTC)

Proposed merge with Atrial syncytium[edit]

This topic is inherently linked to the topic of cardiac muscle tissue, and it would improve the quality of the overall article to have it merged here. It would also improve the readability, by reducing needless fragmentation of articles and giving the article additional context. LT910001 (talk) 23:23, 29 March 2014 (UTC)

:Disagree - think it would be better if Atrial syncytium was merged to Atrium and likewise for Ventricle syncytium to be merged to Ventricle. Iztwoz (talk) 22:17, 25 July 2014 (UTC)

Second thoughts - agree with merge - items could still be added to atrium and ventricle. Iztwoz (talk) 18:03, 31 July 2014 (UTC)
 Done