Editing Sarcoplasm

{{short description|Cytoplasm of a muscle cell, including the sarcoplasmic reticulum}}
{{Infobox cell
| Name        = Sarcoplasm
| Latin       = sarcoplasma
| Image       = Figure_38_04_02.jpg
| Caption     = Sarcoplasm shown with a muscle fiber
| Image2      =
| Caption2    =
| Precursor   =
| System      =
| Location = Cytoplasm of [[muscle cell]]
}}
'''Sarcoplasm''' is the [[cytoplasm]] of a [[muscle cell]]. It is comparable to the cytoplasm of other cells, but it contains unusually large amounts of [[glycogen]] (a polymer of glucose), [[myoglobin]], a red-colored protein necessary for binding oxygen molecules that diffuse into [[myofibril|muscle fiber]]s, and [[mitochondria]].<ref>Douplik, A (2013) The response of tissue to laser light. Woodhead Publishing. pp. 47–109. {{ISBN|978-0-85709-237-3}}.</ref><ref>Toumanidou, Themis (2018). Chapter 9 - Spinal Muscles. Academic Press. pp. 141–166. {{ISBN|978-0-12-812851-0}}.</ref><ref name=":3">Roberts, Michael D.; Haun, Cody T.; Vann, Christopher G.; Osburn, Shelby C.; Young, Kaelin C. (2020). "Sarcoplasmic Hypertrophy in Skeletal Muscle: A Scientific "Unicorn" or Resistance Training Adaptation?". Frontiers in Physiology. 11. {{doi|10.3389/fphys.2020.00816}}. {{ISSN|1664-042X}}. {{PMC|7372125}}. {{PMID|32760293}}.</ref> The [[calcium]] ion concentration in sarcoplasm is also a special element of the muscle fiber; it is the means by which [[muscle contraction]]s take place and are regulated.<ref name=":0">{{Cite book|title=Junqueira's basic histology : text and atlas|last=Mescher, Anthony L.|others=Junqueira, Luiz Carlos Uchôa, 1920-|date=22 February 2013|isbn=978-0-07-180720-3|edition=Thirteenth|location=New York|oclc=854567882}}</ref><ref name=":1">{{Cite book|title=Histology : a text and atlas : with correlated cell and molecular biology|last=Ross, Michael H.|date=2011|publisher=Wolters Kluwer/Lippincott Williams & Wilkins Health|others=Pawlina, Wojciech.|isbn=978-0-7817-7200-6|edition=  6th|location=Philadelphia|oclc=548651322}}</ref> The sarcoplasm plays a critical role in muscle contraction as an increase in Ca<sup>2+</sup> concentration in the sarcoplasm begins the process of filament sliding. The decrease in Ca<sup>2+</sup> in the sarcoplasm subsequently ceases filament sliding.<ref>Shahinpoor, Mohsen (2013). Muscular Biomimicry. Elsevier. pp. 139–160. {{ISBN|978-0-12-415995-2}}.</ref> The sarcoplasm also aids in pH and ion balance within muscle cells.<ref name=":3" />

It contains mostly [[myofibrils]] (which are composed of [[sarcomere]]s), but its contents are otherwise comparable to those of the cytoplasm of other cells. It has a [[Golgi apparatus]] near the [[Cell nucleus|nucleus]], [[mitochondria]] just inside the cell membrane ([[sarcolemma]]), and a [[smooth endoplasmic reticulum]] (specialized for muscle function and called the [[sarcoplasmic reticulum]]).<ref name=":2">{{Cite journal|last1=Trovato|first1=Francesca Maria|last2=Imbesi|first2=Rosa|last3=Conway|first3=Nerys|last4=Castrogiovanni|first4=Paola|date=22 July 2016|title=Morphological and Functional Aspects of Human Skeletal Muscle|journal=Journal of Functional Morphology and Kinesiology|language=en|volume=1|issue=3|pages=289–302|doi=10.3390/jfmk1030289|doi-access=free}}</ref>

While ''sarcoplasm'' and ''myoplasm,'' viewed etymologically, might seem to be synonyms, they are not. Whereas sarcoplasm is a type of cytoplasm, myoplasm is the entire contractile portion of [[muscle tissue]].<ref name=":0" /><ref name=":1" /><ref name=":2" />

While some authors argue that the proteins and other molecules within the [[sarcoplasmic reticulum]] lumen technically belong to the sarcoplasm. These molecules are not part of the [[sarcoplasmic reticulum]] membrane itself but reside within the enclosed sarcoplasmic reticulum space. In that sense, one could say the [[sarcoplasmic reticulum]] has a type of specialized sarcoplasm.{{cn|date=January 2024}}

== References ==
{{Reflist}}

==External links==
* [http://medical.merriam-webster.com/medical/sarcoplasm Merriam-Webster Dictionary]
* [http://www.encyclopedia.com/doc/1O8-sarcoplasm.html Sarcoplasm at Encyclopedia.com]

{{Muscle tissue}}
{{Authority control}}

[[Category:Cell anatomy]]