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A sarcomere is defined as the segment between two neighbouring Z-lines (or Z-discs). In electron micrographs of cross-striated muscle, the Z-line (from the German "zwischen" meaning between) appears in between the I-bands as a dark line that anchors the actin myofilaments. Surrounding the Z-line is the region of the I-band (for isotropic ).
Contraction band necrosis is a type of uncontrolled cell death unique to cardiac myocytes and thought to arise in reperfusion from hypercontraction, which results in sarcolemmal rupture. [1] It is a characteristic histologic finding of a recent myocardial infarction (heart attack) that was partially reperfused.
Sliding filament theory: A sarcomere in relaxed (above) and contracted (below) positions. The sliding filament theory explains the mechanism of muscle contraction based on muscle proteins that slide past each other to generate movement. [ 1] According to the sliding filament theory, the myosin ( thick filaments) of muscle fibers slide past the ...
Depiction of smooth muscle contraction. Muscle contraction is the activation of tension -generating sites within muscle cells. [ 1][ 2] In physiology, muscle contraction does not necessarily mean muscle shortening because muscle tension can be produced without changes in muscle length, such as when holding something heavy in the same position. [ 1]
Titin[ 2] / ˈtaɪtɪn / (contraction for Tit an prote in) (also called connectin) is a protein that in humans is encoded by the TTN gene. [ 3][ 4] The protein, which is over 1 μm in length, [ 5] functions as a molecular spring that is responsible for the passive elasticity of muscle.
Striated muscle tissue is a muscle tissue that features repeating functional units called sarcomeres. The presence of sarcomeres manifests as a series of bands visible along the muscle fibers, which is responsible for the striated appearance observed in microscopic images of this tissue. There are two types of striated muscle:
During muscle contraction, the I band will shorten, while an A band will maintain its width. The muscle is made up of several myofibrils packed into functional units surrounded by different layers of connective tissues (epimysium, perimysium, and endomysium). The main contractile unit is mainly composed of protein filaments (myofilaments ...
The human musculoskeletal system (also known as the human locomotor system, and previously the activity system) is an organ system that gives humans the ability to move using their muscular and skeletal systems. The musculoskeletal system provides form, support, stability, and movement to the body. It is made up of the bones of the skeleton ...