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2025-02-20T01:41:42Z

CSV import

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	[[Category:Soft tissue]]		[[Category:Soft tissue]]
	[[Category:Tissues (biology)]]		[[Category:Tissues (biology)]]
			== Muscle ==
			<gallery>
			File:Types Of Muscle.jpg\|Types Of Muscle
			File:Muskelreiz-glatt.svg\|Smooth Muscle Stimulation
			File:Muskelreiz-herz.svg\|Heart Muscle Stimulation
			File:Muskelreiz-skelett.svg\|Skeletal Muscle Stimulation
			File:Skeletal Muscle Tissue.jpg\|Skeletal Muscle Tissue
			File:Gray18.png\|Muscle Anatomy
			</gallery>

Prab at 22:09, 17 April 2020

2020-04-17T22:09:20Z

New page

Muscle is part of the [[muscular system]] or [[musculoskeletal system]] that is composed of specialized [[cells]] called [[muscle fibers]].
[[File:Intrinsic Muscles of the Hand Superficial sin.png|alt=Muscles of the hands|thumb|Muscles of the hands]]
== Function ==
Their predominant function is [[contractibility]]. Muscles, attached to [[bones]] or [[internal organs]] and [[blood vessels]], are responsible for [[movement]].

== Movement and muscle action ==
* Nearly all movement in the body is the result of muscle contraction.
* Exceptions to this are the action of [[cilia]], the [[flagellum]] on [[sperm cells]], and [[amoeboid]] movement of some [[white blood cells]].
* The integrated action of [[joints]], [[bones]], and [[skeletal muscles]] produces obvious movements such as walking and running.
[[File:Skeletal muscle.png|alt=Muscle fiber|thumb|Muscle fiber]]
== Facial expressions ==
Skeletal muscles also produce more subtle movements that result in various facial expressions, eye movements, and respiration.

== Posture and stability ==
* In addition to movement, muscle contraction also fulfills some other important functions in the body, such as [[posture]], [[joint stability]], and [[heat production]].
* Posture, such as sitting and standing, is maintained as a result of muscle contraction.
* The skeletal muscles are continually making fine adjustments that hold the body in stationary positions.
* The tendons of many muscles extend over joints and in this way contribute to joint stability.
* This is particularly evident in the knee and shoulder joints, where muscle tendons are a major factor in stabilizing the joint.
[[File:Diagram of muscle cells CRUK 035.svg|alt=Muscle fiber cells|thumb|Muscle fiber cells]]
== Thermal actions of muscles ==
* Heat production, to maintain body temperature, is an important by-product of muscle metabolism.
* Nearly 85 percent of the heat produced in the body is the result of muscle contraction.
* The [[brown adipose tissue]] in the skin helps regulate body heat at times of cold climate.

== Structure of skeletal muscles ==
* A whole skeletal muscle is considered an organ of the muscular system.
* Each organ or muscle consists of skeletal muscle tissue, connective tissue, nerve tissue, and blood or vascular tissue.
* Skeletal muscles vary considerably in size, shape, and arrangement of fibers.
* They range from extremely tiny strands such as the stapedium muscle of the middle ear to large masses such as the muscles of the thigh.
* Some skeletal muscles are broad in shape and some narrow.
* In some muscles the fibers are parallel to the long axis of the muscle; in some they converge to a narrow attachment; and in some they are oblique.

== Types of muscles ==

There are three types of muscle: skeletal (striated), smooth, and cardiac.

==== Skeletal Muscle ====
[[File:Illu lower extremity muscles.jpg|alt=Muscles of the lower extremity|thumb|Muscles of the lower extremity]]
* Skeletal muscle, attached to bones, is responsible for skeletal movements.
* The peripheral portion of the central nervous system (CNS) controls the skeletal muscles.
* Thus, these muscles are under conscious, or voluntary, control.
* The basic unit is the muscle fiber with many nuclei. These muscle fibers are striated (having transverse streaks) and each acts independently of neighboring muscle fibers.

=== Smooth Muscle ===

* Smooth muscle, found in the walls of the hollow internal organs such as blood vessels, the gastrointestinal tract, bladder, and uterus, is under control of the autonomic nervous system.
* Smooth muscle cannot be controlled consciously and thus acts involuntarily.
* The non-striated (smooth) muscle cell is spindle-shaped and has one central nucleus. Smooth muscle contracts slowly and rhythmically.

=== Cardiac Muscle ===

* Cardiac muscle, found in the walls of the heart, is also under control of the autonomic nervous system.
* The cardiac muscle cell has one central nucleus, like smooth muscle, but it also is striated, like skeletal muscle.
* The cardiac muscle cell is rectangular in shape. The contraction of cardiac muscle is involuntary, strong, and rhythmical.

== Muscle groups ==
* There are more than 600 muscles in the body, which together account for about 40 percent of a person's weight.

== External links ==
{{Wiktionary|muscle}}
* {{Commons category-inline|Muscles|lcfirst=yes}}
* [https://web.archive.org/web/20060107094530/http://www.dundee.ac.uk/medther/StrokeSSM/ClinExamNeuro.htm University of Dundee] article on performing neurological examinations (Quadriceps "strongest")
* [https://web.archive.org/web/20051201203913/http://www.coachesinfo.com/category/rowing/77/ Muscle efficiency in rowing]
* [http://www.scholarpedia.org/article/Muscle_Physiology_and_Modeling Muscle Physiology and Modeling] [[Scholarpedia]] Tsianos and Loeb (2013)
* [https://web.archive.org/web/19980221073751/http://www.gwc.maricopa.edu/class/bio201/muscle/mustut.htm Human Muscle Tutorial] (clear pictures of main human muscles and their Latin names, good for orientation)
* Microscopic stains of [http://www.ii.bham.ac.uk/clinicalimmunology/Neuroimmunology/images/skm02.32706.jpg skeletal] and [http://www.ii.bham.ac.uk/clinicalimmunology/CISimagelibrary/images/mycard-positive.jpg cardiac] muscular fibers to show striations. Note the differences in myofibrilar arrangements.
{{Muscular system}}
{{Muscle tissue}}
{{Muscles of head}}
{{Muscles of neck}}
{{Muscles of thorax and back}}
{{Muscles of trunk}}
{{Muscles of upper limb}}
{{Muscles of lower limb}}
{{Use dmy dates|date=July 2011}}
{{stb}}
[[Category:Exercise physiology]]
[[Category:Muscular system]]
[[Category:Soft tissue]]
[[Category:Tissues (biology)]]

Muscle - Revision history

Prab: CSV import

Prab at 22:09, 17 April 2020