The answer to this question depends on the level of sophistication behind the question. Besides the various types of muscle fibre. There are satellite cells, which are thought to be the main source of myogenic cells for repair of damaged muscle fibres.  There is some evidence of heterogeneity of satellite cells - some being more stem-like than others.  Skeletal muscle is richly vascularized and thee is some debate about the interactions of some of the microvascular cells and satellite cells. There is also some evidence that pericyte cells of the microvasculature can become myogenic.  Recently, an interstitial cell call fibroadipocyes have been shown to interact with myogenic cells during muscle repair.   In addtion to all of the 'resident' cells, lymphocytes and cells of the mononuclear series have been shown to pass through even 'normal' muscle, but it should be remembered that normal muscle is in constant interaction with the environment via the stresses and strains of normal physiological use.

Basically there are 2 types of muscle fibers - Type I, Type IIA and Type IIB. If you need the basics on muscle fiber typing and histology - I suggest you try to get hold of the book entitled "Muscle Biopsy: A Practical Approach, 3rd Edition" by V. Dubowitz.

There are also muscle spindles in the skeletal muscle -- mechanoreceptors arranged in parallel with the rest of the muscle fibers to give feedback information to the neuronal motor system on the rate and degree of stretch of the muscle. They consist of an elongated bundle of muscle fibers surrounded by a capsule derived from perineurium. There are three types of muscle fibers (intrafusal fibers) in spindles: nuclear bag1 fibers, nuclear bag2 fibers and nuclear chain fibers. The fiber types can be distinguished on ATPase reactions. The ultrastructure of regenerated intrafusal fibers is describe in:  Soukup and Novotova (2000), Acta Neuropathol 100: 435-444.

The answer to this question depends on the level of sophistication behind the question. Besides the various types of muscle fibre. There are satellite cells, which are thought to be the main source of myogenic cells for repair of damaged muscle fibres.  There is some evidence of heterogeneity of satellite cells - some being more stem-like than others.  Skeletal muscle is richly vascularized and thee is some debate about the interactions of some of the microvascular cells and satellite cells. There is also some evidence that pericyte cells of the microvasculature can become myogenic.  Recently, an interstitial cell call fibroadipocyes have been shown to interact with myogenic cells during muscle repair.   In addtion to all of the 'resident' cells, lymphocytes and cells of the mononuclear series have been shown to pass through even 'normal' muscle, but it should be remembered that normal muscle is in constant interaction with the environment via the stresses and strains of normal physiological use.

Dear Terry,

I really appreciate your accurate answer. Thank you very much for your time. Recently, was published an interestingly review (attached) talking about the plethora of resident (and non-resident) cells in skeletal muscle.

Best regards,

For muscle fiber type it it is important to note that there are distinctions depending on the species considered.

You will learn a lot when reading Schiaffino S (2010) Fibre types in skeletal muscle: a personal account. Acta Physiol (Oxf) 199:451-463, Schiaffino S, Reggiani C (2011) Fiber types in mammalian skeletal muscles. Physiol Rev 91:1447-1531 or  Soukup T, Jirmanova I (2000) Regulation of myosin expression in developing and regenerating extrafusal and intrafusal muscle fibers with special emphasis on the role of thyroid hormones. Physiol Res 49:617-633. For survey of references you can look at Soukup T, Smerdu V: Effect of altered innervation and thyroid hormones on myosin heavy chain expression and fiber type transitions - a mini-review. Histochem Cell Biol • DOI: 10.1007/s00418-014-1276-0, 2014.

Hi everyone, and thank you all for the great answers above. I've just completed reading the review tirled "Cellular Players in Skeletal Muscle Regeneration' posted by Osvaldo. I'd be grateful for your input on the following:

Upon digesting muscle with collagenase and dispase, both fast adhering fibroblasts and slower adhering myoblasts can be cultured in vitro. Among these populations, the fibroblasts are Desmin and Pax7 negative. The Desmin+ AND Pax7+ populations are activated satellite cells and there is a population of myoblasts which is Desmin+ and Pax7- . Another population of satellite cells which is Pax7+ and desmin-. Am I to understand that all myoblasts that are obtained in in-vitro culture upon muscle digestion are the result of satellite cell activation, and subsequent proliferation as myoblasts? Or is there also an intrinsic myoblast population present in the muscle itself? 

I'd be VERY grateful for any clarifications or publications that might help me understand this better. Thanks!

Dear Sujata

In an adult muscle, in theory the myogenic cells obtained after the enzymatic digestion are satellite cells and the proliferative cells which grow in your cell factory are myoblasts derived from those satellite cells. Intrinsic myoblasts are absent in the adult tissue. Using the Pax7 marker, you see proliferative myoblasts derived from satellite cells but probably also a population of low proliferative or unproliferative cells named reserve cells in mice. Then the desmin marker is not specific of skeletal muscle. However, in a growing muscle satellite cells are activated, a population of myoblasts derived from satellite cells and a population of quiescent satellite cells are probably also present . In my knowledge these population are not well characterized.

I hope it will be helpful for you.

Christophe, thank you! That's very helpful to begin with. I really appreciate your input. 

Hi guys,

Following a couple of years later with this discussion, I would like to share this new paper with you:

https://www.biorxiv.org/content/biorxiv/early/2018/04/19/304683.full.pdf

I found it really interesting! Take a look...

Check this link

https://www.thoughtco.com/types-of-cells-in-the-body-373388

regards