Tissue and Other Levels of Organization: Muscle Tissue and Types of Muscle Fibers (For CBSE, ICSE, IAS, NET, NRA 2022)

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A muscle tissue arises from the embryonic mesoderm.

  • Structure: All muscles are made up of elongated and thin cells called muscle fibers. The cytoplasm of muscle fibers is known as sarcoplasm that contains a network of membranes called sarcoplasmic reticulum. A muscle fiber may be bounded by a specialized membrane called sarcolemma. Each muscle fiber may contain one or more nuclei. The position of nuclei is variable in different types of muscle fibers. Each muscle fiber may contain numerous thin myofibrils arranged along the long axis of the fiber.
  • Function: Muscle tissue brings about movements of the body parts and helps the organism in locomotion, also responsible for the passage of food through the alimentary canal, Muscles perform important functions such as in ingesting food, in passing urine and in moving the sense organs such as eyes, nose, pinnae and in the maintenance of equilibrium and in posture and play important role in the facial expression and gesture.

Types of Muscle Fibers

Image Showing Types of Muscle Fibres
Striated/Skeletal muscleUntreated/smooth muscleCardiac muscle
LocationAttached to the bones, in the head, trunk and limb region and also found in the tongue and pharynxLocated in the walls of visceral organs such as intestinal, genital, urinary and respiratory organs and the walls of the blood vesselsFound in the walls of the heart
ShapeElongated, narrow, cylindrical, and unbranched fibers with blunt ends, Myofibrils of striated muscle fiber show alternate dark and light cross bandsSpindle shaped cell, tapering at both ends, round or polygonal in cross section, sarcoplasm contains numerous fine longitudinally arranged thread like myofibrilsElongated, cylindrical, branched. The fibers show faint but regular cross striations due to the presence of myofibrils that contain action and myosin filaments
SarcolemmaThin and tough membrane sarcolemma of the fiber (cell) . Each muscle fiber is bounded by an elastic sheath, the sarcolemmaThin cell membrane, muscle cell lacks definite membrane comparable to sarcolemma of striated muscle.Thin
NucleusMultimutated that are peripheral to their fibersUninucleate at the centerOne nucleus per cell at the center
Blood SupplyRichPoorRich
Intercalate DiscsAbsent

Voluntary controlled

Absent

Involuntary controlled

Present

Involuntary controlled

ResponsibleFor the movement of the skeleton and musclesFor the movement of substances such as food and bloodFor moving blood in the heart
Image Showing Structural Characteristics of Skeletal, Smooth …

The muscle fibers have the following characteristics: Excitability (respond to stimulus) , Extensibility (stretch) , Contractility (contract) and Elasticity (move back to the original position) .

Developed by: