![]() ![]() Muscle - encased by epimysium = layer of dense collagen connective tissue.\).The perimysium is ductile, allowing the bundles to move relative to each other during muscle activity. Between the bundles are vascular and nerve networks. Bundles of fibres - surrounded by perimysium = connective tissue layer reinforced by networks of collagen fibres. ![]() The resulting force acts in the direction of the axis of the tendon attachment. The forces exerted by the contraction of individual fibres are added together. Fiber network embedded in lamina structures → mediator of transmission of forces generated during contraction to the ligamentous structures of the muscle. Muscle fibre - surrounded by endomysium ( lamina basalis network of ret.Through their contractions they provide movement = active component of the musculoskeletal system. Muscles are attached to skeletal components via ligamentous structures. Skeletal muscle tissue is arranged into muscles. Intermediate filaments - intermediate type They are subdivided into subtypes A (fast, moderately fatiguable), B and C (very fast, rapidly fatiguable). They are bulkier, capable of rapid contraction but not persistent. White fibers have low myoglobin, cytochrome, few mitochondria. They contract more slowly but persistently. Energy by oxidative phosphorylation → many mitochondria. Fibers work continuously for long periods of time. Red fibers contain many myoglobin = oxygen-binding protein (similarity to hemoglobins), cytochrome → red color of muscle. The end of the muscle fibre is conical.Īt the transition into the tendon, the sarcolemma forms deep invaginations ← ingrowth of bundles of collagen fibers of the tendon anchoring into the basement membrane. These are important in the process of coupling excitation and contraction. Close relationship between the sarcoplasmic reticulum and the T-tubule membrane → formation of specialized precincts - couplings. To each T-tubule 2 cisternae (one on each side) insist = the complex structure (cisterna-T-tubule-cisterna) forms a triad. ![]() The cisterna inserts on the side away from the reticulum tubule insertion towards the perpendicular T-tubule of the sarcolemma. At the interface of the A and I strips of myofibrils, the tubules terminate in a wide terminal cisterna (a hoop encircling the entire myofibril). The tubules form a network around the myofibrils. It represents a reservoir of calcium ions that are crucial for the initiation and progression of myofibril contraction. The smooth endoplasmic reticulum - sarcoplasmic reticulum - is highly developed. They form a meshwork, the meshes surrounding each myofibril. Perpendicular to the interface between the light (I) and dark (A) stripes of the myofibrils, the T-tubules of the sarcolemma protrude. In the sarcoplasm we also find polysomes, gER, GK, glycogen stores. Mitochondria are located between myofibrils (long axes parallel), are rod-shaped and bulky.
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