Muscle contraction - Revision history

Prab: CSV import

2025-02-23T21:10:56Z

CSV import

← Older revision		Revision as of 21:10, 23 February 2025
Line 44:		Line 44:

	[[Category:Muscle physiology]]		[[Category:Muscle physiology]]
			== Muscle_contraction ==
			<gallery>
			File:Smooth_muscle_cell_contraction.png\|Smooth muscle cell contraction
			File:1015_Types_of_Contraction_new.jpg\|Types of contraction
			File:Muscle_Tissue_(1).svg\|Muscle tissue
			File:1022_Muscle_Fibers_(small).jpg\|Muscle fibers
			File:1009_Motor_End_Plate_and_Innervation.jpg\|Motor end plate and innervation
			File:Interactions_within_Excitation-contraction_Coupling.jpg\|Interactions within excitation-contraction coupling
			File:Sarcomere.svg\|Sarcomere
			File:1008_Skeletal_Muscle_Contraction.jpg\|Skeletal muscle contraction
			File:1012_Muscle_Twitch_Myogram.jpg\|Muscle twitch myogram
			File:1013_Summation_Tetanus.jpg\|Summation tetanus
			File:Lengthtension.jpg\|Length-tension
			File:Muscle_Force_Velocity_relationship.png\|Muscle force velocity relationship
			</gallery>

Prab: CSV import

2025-02-18T17:44:30Z

CSV import

← Older revision		Revision as of 17:44, 18 February 2025
Line 1:		Line 1:
	~~'''Muscle Contraction''' is a process that occurs when the [[muscle]] fibers generate tension through the action~~ of ~~[[actin]] and [[myosin]] cross-bridge cycling. While under tension, the~~ muscle ~~may lengthen, shorten, or remain the same. Although the term '~~contraction~~' implies shortening, when referring to the muscular system, it means muscle fibers generating tension with the help of motor neuron action potentials.~~		{{Short description\|Overview of muscle contraction}}
			{{Use dmy dates\|date=October 2023}}

	~~== Types~~ of ~~Muscle Contraction ==~~		'''Muscle contraction''' is a complex physiological process that involves the interaction of various cellular components to produce force and movement. This process is essential for all types of [[muscle]]s, including [[skeletal muscle]], [[cardiac muscle]], and [[smooth muscle]].
	~~There are three~~ types of muscle ~~contraction:~~ [[~~isotonic contractions~~]], [[~~isometric contractions~~]], and [[~~isokinetic contractions~~]].

	==~~= Isotonic Contractions =~~==		==Mechanism of Muscle Contraction==
	~~In isotonic contractions~~, the muscle ~~changes length as it contracts~~ and ~~causes movement of a body part. There are two types of isotonic contractions: concentric and eccentric~~.		Muscle contraction occurs through a series of biochemical and mechanical events. The primary mechanism involves the sliding filament theory, which describes how [[actin]] and [[myosin]] filaments within the muscle fiber slide past each other to generate tension and shorten the muscle.

	===~~= Concentric Contractions =~~===		===Sliding Filament Theory===
	~~In a [[concentric contraction]], the muscle tension rises~~ to ~~meet the resistance, then remains stable as the~~ muscle ~~shortens~~.		The sliding filament theory is central to understanding muscle contraction. It involves the following steps:

	~~==== Eccentric Contractions ====~~		# '''Excitation''': A nerve impulse reaches the neuromuscular junction, releasing [[acetylcholine]] into the synaptic cleft.
	~~During an~~ [[~~eccentric contraction~~]], the muscle ~~lengthens as the tension decreases~~.		# '''Coupling''': Acetylcholine binds to receptors on the muscle cell membrane, leading to depolarization and the release of [[calcium ions]] from the [[sarcoplasmic reticulum]].
			# '''Contraction''': Calcium ions bind to [[troponin]], causing a conformational change in [[tropomyosin]] that exposes binding sites on actin filaments. Myosin heads attach to these sites, forming cross-bridges.
			# '''Power Stroke''': The myosin heads pivot, pulling the actin filaments toward the center of the sarcomere, shortening the muscle.
			# '''Detachment''': ATP binds to myosin, causing it to release actin and reset for another cycle.

	=== ~~Isometric Contractions~~ ===		===Role of ATP===
	~~In an~~ [[~~isometric contraction~~]], the ~~muscle does not change length~~ and the ~~joint angle does not change~~.		[[Adenosine triphosphate]] (ATP) is crucial for muscle contraction. It provides the energy required for the power stroke and the detachment of myosin from actin. Without ATP, muscles would remain in a contracted state, a condition known as [[rigor mortis]].

	==~~= Isokinetic Contractions =~~==		==Types of Muscle Contraction==
	~~In an [[isokinetic contraction]], the muscle changes length while~~ the ~~contraction speed remains constant.~~		Muscle contractions can be classified into different types based on the movement and force generated:

	~~== Mechanism of~~ Muscle Contraction ==		* '''Isotonic Contraction''': Muscle changes length while the tension remains constant. It includes:
	~~The mechanism of muscle contraction involves several steps~~, ~~including the [[neuromuscular junction]], [[excitation-contraction coupling]]~~, ~~and [[cross-bridge cycling]]~~.		* '''Concentric Contraction''': Muscle shortens as it contracts, such as lifting a weight.
			* '''Eccentric Contraction''': Muscle lengthens while maintaining tension, such as lowering a weight.
			* '''Isometric Contraction''': Muscle generates force without changing length, such as holding a weight steady.

	==~~= Neuromuscular Junction =~~==		==Regulation of Muscle Contraction==
	~~The [[neuromuscular junction]]~~ is ~~the synapse between a motor neuron and a skeletal muscle fiber. It transmits signals from the neuron to the muscle fiber.~~		Muscle contraction is regulated by several factors, including:

	~~=== Excitation-Contraction Coupling ===~~		* '''Neural Control''': The [[central nervous system]] coordinates muscle contraction through motor neurons.
	[[~~Excitation-contraction coupling~~]] is ~~the process by which an electrical stimulus triggers~~ a ~~myocyte to contract~~.		* '''Hormonal Influence''': Hormones like [[adrenaline]] can enhance muscle contraction.
			* '''Calcium Ion Concentration''': The availability of calcium ions in the muscle cell is a key regulator of contraction.

	==~~= Cross-Bridge Cycling =~~==		==Clinical Significance==
	[[~~Cross-bridge cycling~~]] ~~is the mechanism by which muscles contract. It involves the sliding of actin~~ and ~~myosin filaments past each other~~.		Understanding muscle contraction is vital for diagnosing and treating various muscular disorders. Conditions such as [[muscular dystrophy]], [[myasthenia gravis]], and [[muscle cramps]] involve disruptions in normal muscle contraction processes.

	== ~~See Also~~ ==		==Related Pages==
	* [[Muscle]]		* [[Muscle fiber]]
	* [[~~Actin~~]]		* [[Neuromuscular junction]]
	* [[~~Myosin~~]]		* [[Sarcoplasmic reticulum]]
	* [[~~Motor neuron~~]]		* [[Myofibril]]

	[[Category:~~Physiology~~]]		[[Category:Muscle physiology]]
	~~[[Category:Muscular system]]~~

	~~{{stub}}~~
	~~{{dictionary-stub1}}~~
	~~<gallery>~~
	~~File:Smooth_muscle_cell_contraction.png\|Muscle_contraction~~
	~~File:1015_Types_of_Contraction_new.jpg\|Muscle_contraction~~
	~~File:Muscle_Tissue_(1).svg\|Muscle_contraction~~
	~~File:1022_Muscle_Fibers_(small).jpg\|Muscle_contraction~~
	~~File:1009_Motor_End_Plate_and_Innervation.jpg\|Muscle_contraction~~
	~~File:Interactions_within_Excitation-contraction_Coupling.jpg\|Muscle_contraction~~
	~~File:Sarcomere.svg\|Muscle_contraction~~
	~~File:1008_Skeletal_Muscle_Contraction.jpg\|Muscle_contraction~~
	~~File:1012_Muscle_Twitch_Myogram.jpg\|Muscle_contraction~~
	~~File:1013_Summation_Tetanus.jpg\|Muscle_contraction~~
	~~File:Lengthtension.jpg\|Muscle_contraction~~
	~~File:Muscle_Force_Velocity_relationship.png\|Muscle_contraction~~
	~~</gallery>~~

Prab: CSV import

2025-02-18T12:15:44Z

CSV import

← Older revision		Revision as of 12:15, 18 February 2025
Line 42:		Line 42:
	{{stub}}		{{stub}}
	{{dictionary-stub1}}		{{dictionary-stub1}}
			<gallery>
			File:Smooth_muscle_cell_contraction.png\|Muscle_contraction
			File:1015_Types_of_Contraction_new.jpg\|Muscle_contraction
			File:Muscle_Tissue_(1).svg\|Muscle_contraction
			File:1022_Muscle_Fibers_(small).jpg\|Muscle_contraction
			File:1009_Motor_End_Plate_and_Innervation.jpg\|Muscle_contraction
			File:Interactions_within_Excitation-contraction_Coupling.jpg\|Muscle_contraction
			File:Sarcomere.svg\|Muscle_contraction
			File:1008_Skeletal_Muscle_Contraction.jpg\|Muscle_contraction
			File:1012_Muscle_Twitch_Myogram.jpg\|Muscle_contraction
			File:1013_Summation_Tetanus.jpg\|Muscle_contraction
			File:Lengthtension.jpg\|Muscle_contraction
			File:Muscle_Force_Velocity_relationship.png\|Muscle_contraction
			</gallery>

Prab: CSV import

2024-02-24T18:59:57Z

CSV import

New page

'''Muscle Contraction''' is a process that occurs when the [[muscle]] fibers generate tension through the action of [[actin]] and [[myosin]] cross-bridge cycling. While under tension, the muscle may lengthen, shorten, or remain the same. Although the term 'contraction' implies shortening, when referring to the muscular system, it means muscle fibers generating tension with the help of motor neuron action potentials.

== Types of Muscle Contraction ==
There are three types of muscle contraction: [[isotonic contractions]], [[isometric contractions]], and [[isokinetic contractions]].

=== Isotonic Contractions ===
In isotonic contractions, the muscle changes length as it contracts and causes movement of a body part. There are two types of isotonic contractions: concentric and eccentric.

==== Concentric Contractions ====
In a [[concentric contraction]], the muscle tension rises to meet the resistance, then remains stable as the muscle shortens.

==== Eccentric Contractions ====
During an [[eccentric contraction]], the muscle lengthens as the tension decreases.

=== Isometric Contractions ===
In an [[isometric contraction]], the muscle does not change length and the joint angle does not change.

=== Isokinetic Contractions ===
In an [[isokinetic contraction]], the muscle changes length while the contraction speed remains constant.

== Mechanism of Muscle Contraction ==
The mechanism of muscle contraction involves several steps, including the [[neuromuscular junction]], [[excitation-contraction coupling]], and [[cross-bridge cycling]].

=== Neuromuscular Junction ===
The [[neuromuscular junction]] is the synapse between a motor neuron and a skeletal muscle fiber. It transmits signals from the neuron to the muscle fiber.

=== Excitation-Contraction Coupling ===
[[Excitation-contraction coupling]] is the process by which an electrical stimulus triggers a myocyte to contract.

=== Cross-Bridge Cycling ===
[[Cross-bridge cycling]] is the mechanism by which muscles contract. It involves the sliding of actin and myosin filaments past each other.

== See Also ==
* [[Muscle]]
* [[Actin]]
* [[Myosin]]
* [[Motor neuron]]

[[Category:Physiology]]
[[Category:Muscular system]]

{{stub}}
{{dictionary-stub1}}

← Older revision		Revision as of 21:10, 23 February 2025
Line 44:		Line 44:

	[[Category:Muscle physiology]]		[[Category:Muscle physiology]]
			== Muscle_contraction ==
			<gallery>
			File:Smooth_muscle_cell_contraction.png\|Smooth muscle cell contraction
			File:1015_Types_of_Contraction_new.jpg\|Types of contraction
			File:Muscle_Tissue_(1).svg\|Muscle tissue
			File:1022_Muscle_Fibers_(small).jpg\|Muscle fibers
			File:1009_Motor_End_Plate_and_Innervation.jpg\|Motor end plate and innervation
			File:Interactions_within_Excitation-contraction_Coupling.jpg\|Interactions within excitation-contraction coupling
			File:Sarcomere.svg\|Sarcomere
			File:1008_Skeletal_Muscle_Contraction.jpg\|Skeletal muscle contraction
			File:1012_Muscle_Twitch_Myogram.jpg\|Muscle twitch myogram
			File:1013_Summation_Tetanus.jpg\|Summation tetanus
			File:Lengthtension.jpg\|Length-tension
			File:Muscle_Force_Velocity_relationship.png\|Muscle force velocity relationship
			</gallery>

← Older revision		Revision as of 12:15, 18 February 2025
Line 42:		Line 42:
	{{stub}}		{{stub}}
	{{dictionary-stub1}}		{{dictionary-stub1}}
			<gallery>
			File:Smooth_muscle_cell_contraction.png\|Muscle_contraction
			File:1015_Types_of_Contraction_new.jpg\|Muscle_contraction
			File:Muscle_Tissue_(1).svg\|Muscle_contraction
			File:1022_Muscle_Fibers_(small).jpg\|Muscle_contraction
			File:1009_Motor_End_Plate_and_Innervation.jpg\|Muscle_contraction
			File:Interactions_within_Excitation-contraction_Coupling.jpg\|Muscle_contraction
			File:Sarcomere.svg\|Muscle_contraction
			File:1008_Skeletal_Muscle_Contraction.jpg\|Muscle_contraction
			File:1012_Muscle_Twitch_Myogram.jpg\|Muscle_contraction
			File:1013_Summation_Tetanus.jpg\|Muscle_contraction
			File:Lengthtension.jpg\|Muscle_contraction
			File:Muscle_Force_Velocity_relationship.png\|Muscle_contraction
			</gallery>