Cytoplasm of a muscle cell, including the sarcoplasmic reticulum
Sarcoplasm
Sarcoplasm shown with a muscle fiber
Details
Location
Cytoplasm of muscle cell
Identifiers
Latin
sarcoplasma
TH
H2.00.05.0.00004
Anatomical terms of microanatomy
[edit on Wikidata]
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 muscle fibers, and mitochondria.[1][2][3] The calcium ion concentration in sarcoplasma is also a special element of the muscle fiber; it is the means by which muscle contractions take place and are regulated.[4][5] The sarcoplasm plays a critical role in muscle contraction as an increase in Ca2+ concentration in the sarcoplasm begins the process of filament sliding. The decrease in Ca2+ in the sarcoplasm subsequently ceases filament sliding.[6] The sarcoplasm also aids in pH and ion balance within muscle cells.[3]
It contains mostly myofibrils (which are composed of sarcomeres), but its contents are otherwise comparable to those of the cytoplasm of other cells. It has a Golgi apparatus near the nucleus, mitochondria just inside the cell membrane (sarcolemma), and a smooth endoplasmic reticulum (specialized for muscle function and called the sarcoplasmic reticulum).[7]
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.[4][5][7]
While some authors argue that the proteins and other molecules within the sarcoplasmic reticulum lumen technically belong to the sarcoplasm. These molecules aren't 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.[citation needed]
^Douplik, A (2013) The response of tissue to laser light. Woodhead Publishing. pp. 47–109. ISBN 978-0-85709-237-3.
^Toumanidou, Themis (2018). Chapter 9 - Spinal Muscles. Academic Press. pp. 141–166. ISBN 978-0-12-812851-0.
^ abRoberts, 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.
^ abMescher, Anthony L. (22 February 2013). Junqueira's basic histology : text and atlas. Junqueira, Luiz Carlos Uchôa, 1920- (Thirteenth ed.). New York. ISBN 978-0-07-180720-3. OCLC 854567882.{{cite book}}: CS1 maint: location missing publisher (link)
^ abRoss, Michael H. (2011). Histology : a text and atlas : with correlated cell and molecular biology. Pawlina, Wojciech. (6th ed.). Philadelphia: Wolters Kluwer/Lippincott Williams & Wilkins Health. ISBN 978-0-7817-7200-6. OCLC 548651322.
^Shahinpoor, Mohsen (2013). Muscular Biomimicry. Elsevier. pp. 139–160. ISBN 978-0-12-415995-2.
^ abTrovato, Francesca Maria; Imbesi, Rosa; Conway, Nerys; Castrogiovanni, Paola (22 July 2016). "Morphological and Functional Aspects of Human Skeletal Muscle". Journal of Functional Morphology and Kinesiology. 1 (3): 289–302. doi:10.3390/jfmk1030289.
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...
sarcoplasmic reticulum, a unique form of endoplasmic reticulum in the sarcoplasm. Muscle cells are stimulated when a motor neuron releases the neurotransmitter...
to cell signaling events and ion channels. These invaginations in the sarcoplasm contain a host of receptors (prostacyclin, endothelin, serotonin, muscarinic...
A special feature of the sarcolemma is that it invaginates into the sarcoplasm of the muscle cell, forming membranous tubules radially and longitudinally...
cell membrane to open and allow calcium ions to pass through into the sarcoplasm (cytoplasm) of cardiac muscle cells. Calcium ions bind to molecular receptors...
Muscle hypertrophy or muscle building involves a hypertrophy or increase in size of skeletal muscle through a growth in size of its component cells. Two...
rise to its terminology. The cytoplasm in a muscle cell is termed the sarcoplasm; the smooth endoplasmic reticulum of a muscle cell is termed the sarcoplasmic...
and endomysium, into fascicles. Each muscle fiber contains sarcolemma, sarcoplasm, and sarcoplasmic reticulum. The functional unit of a muscle fiber is...
sarcoplasmic reticulum stores calcium ions and pumps them out into the sarcoplasm when the muscle fiber is stimulated. After their release from the sarcoplasmic...
leave the troponin molecule to maintain the Ca2+ ion concentration in the sarcoplasm. The active pumping of Ca2+ ions into the sarcoplasmic reticulum creates...
removal from sarcoplasm. Along with Ca2+ pumps, PV contributes to Ca2+ removal from cytoplasm: PV binds to Ca2+ ions in the sarcoplasm, and then shuttles...
as isotropic bands in striated muscle fiber that consist of disks of sarcoplasm and connect the individual fibrils. Also known as Z-Disc or Dobie's line...
stiffening of muscles after death. An increase in calcium concentration in the sarcoplasm can also cause muscle stiffness. Bronner, F. (2003) ‘Extracellular and...
channels open in the sarcoplasmic membrane and release calcium into the sarcoplasm. Some of this calcium attaches to troponin, which causes it to change...
cell via the Na+/Ca++ antiporter. Increase the amount of calcium in the sarcoplasm. More calcium available for Troponin to use will increase the force developed...
membrane is called the sarcolemma with the cytoplasm known as the sarcoplasm. In the sarcoplasm are the myofibrils. The myofibrils are long protein bundles...
Ca2+-activated K+ channels, which are activated by build-up of Ca2+ in the sarcoplasm, while the Ca2+ channels close, ends the plateau. This leads to repolarization...
Calcium ions are then released from the sarcoplasmic reticulum into the sarcoplasm and subsequently bind to troponin. Troponin and the associated tropomyosin...
effluxes for the repolarization phase. Cl− ions also diffuse into the sarcoplasm to aid the repolarization phase. During intense muscle contraction, the...
also has an extended hydrophobic core. Apomyoglobin is produced in the sarcoplasm and is stated as being a hydrophilic protein. This means that the protein...
system (ATP-PCr) occurs in the cytosol (a gel-like substance) of the sarcoplasm of skeletal muscle, and in the myocyte's cytosolic compartment of the...
by ryanodine channels to the cytoplasm of muscle fibers/cells (called sarcoplasm), the process responsible for contractions of the myofibers. Under PSE...
System (ATP-PCr) occurs in the cytosol (a gel-like substance) of the sarcoplasm of skeletal muscle, and in the myocyte's cytosolic compartment of the...
sarcoplasmic reticulum of cardiac muscle cells, and its increased release into sarcoplasm.[citation needed] One of the explanations for an increase in the intracellular...
oxygen is available. Lipids, and glycogen are also stored within the sarcoplasm and these are broken down by mitochondria to release ATP. The cells undergo...
mathematician Francesco Severi and Bottazzi. For his studies on the role of sarcoplasm in muscle contraction, and in the regulation of osmotic pressure in marine...
region, the sarcolemmal membrane, and in the reticular pattern of the sarcoplasm. However, localization assays predict it to also be found in the cytoplasm...
hypovitaminosis, especially in the work "Das Wesen der Avitaminose"" "Role of the sarcoplasm in muscle contraction. Osmotic pressure regulation by marine animals"...