What are myofibrils?
formerly known as sarkostyly , myofibrils are long, bunches of cytoskeleton that run along the length of striped muscle fibers. Like all cytoskeletons, myofibrils in cellular support, movement and intraling work work. To facilitate this purpose, they consist of long chains of regular recurring units known as sarcomreres . These units are located contractile apparatus cells. Two microfilaments, primarily composed of actin and myosin, interact in sarcomers to create a cell contraction - allowing the movement of cells, muscle and the whole organism. Strong fibers are mainly composed of myosin protein and are located near the center of the sarcomer. Thin fibers consist of three proteins, especially actin, and sit at the outer edges of the sarcomer. The boundary between sarcomers is known as of line , a dark belt of material that acts as a base for thin fibers.
muscle cells themselves are analogous to other cells in many ways, isHowever, the increased size and high degree of specialization lead to the fact that many of their attributes are names that are specific to muscle cells. This usually includes the use of "sarco-" cytoplasm muscle cells therefore becomes sarcoplasm ; Endoplasmic reticulum is known as sarcoplasmic reticulum ; And the cell membrane is often called sarcolemma .
myofibrils are located in sarcoplasm and usually take up most of the space in the muscle cell. Running parallel to myofibrils are infoldings sarolemma known as transverse tubules or t tubules. These internal channels primarily provide a path for neurons. On the same paths as other structures of Within The Cell, a specialized organelle known as sarcoplasmic reticulum running along T tubules. Sarcoplasmic reticulum acts as a storage system for calcium ions.
When t tubul bears an electrical signal knownAs an action potential, to the muscle fiber, sarcoplasmic reticulum reacts by relaxing calcium ions into sarcoplasm. As they move freely by sarcoplasm, calcium ions can bind to specialized structures on actin and myosin proteins in myofibrils. In doing so, they attract thin fibers towards the center of the saromer and effectively shorten the entire unit. This process is known as the model of the sliding fiber of muscle contraction .