muscle
(mŭs′ĕl)
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[L. musculus, diminutive of mus, mouse]
A type of tissue composed of contractile cells. Each muscle cell is filled with parallel actin and myosin filaments. When activated by an internal release of calcium, the filaments use the energy in adenosine triphosphate to crawl along each other in opposite directions. This movement shortens the length of the cell, which then contracts.
The three classes of myocytes (muscle cells) are skeletal (striated), cardiac (striated), and smooth; most human muscle is skeletal. A typical muscle has a central portion (the belly) and two or more attachment ends with tendons. The more stationary of the attachments is called the origin; the more movable attachment is called the insertion.
SELECTED MUSCLES OF THE BODY
MUSCLE FIBER
MORPHOLOGICAL FORMS OF MUSCLE
Comparison of Properties of Three Types of Muscle
Smooth | Cardiac | Striated | |
Synonyms | Involuntary | Myocardial | Voluntary |
Nonstriated | Skeletal | ||
Visceral | |||
Fibers | |||
Length (in/m) | 50-200 | 25,000 | |
Thickness (in/m) | 4-8 | 75 | |
Shape | Spindles | Cylinders | |
Markings | No striation | Striation | Marked striation |
Nuclei | Single | Single | Multiple |
Effects of cutting related nerve | Slight | Regulation of heart rate is lost | Complete paralysis |
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Citation
Venes, Donald, editor. "Muscle." Taber's Medical Dictionary, 24th ed., F.A. Davis Company, 2021. Nursing Central, nursing.unboundmedicine.com/nursingcentral/view/Tabers-Dictionary/765961/all/muscle.
Muscle. In: Venes DD, ed. Taber's Medical Dictionary. F.A. Davis Company; 2021. https://nursing.unboundmedicine.com/nursingcentral/view/Tabers-Dictionary/765961/all/muscle. Accessed December 13, 2024.
Muscle. (2021). In Venes, D. (Ed.), Taber's Medical Dictionary (24th ed.). F.A. Davis Company. https://nursing.unboundmedicine.com/nursingcentral/view/Tabers-Dictionary/765961/all/muscle
Muscle [Internet]. In: Venes DD, editors. Taber's Medical Dictionary. F.A. Davis Company; 2021. [cited 2024 December 13]. Available from: https://nursing.unboundmedicine.com/nursingcentral/view/Tabers-Dictionary/765961/all/muscle.
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