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Skeletal Musde: Sarcoplasmic Rełiculum

MUSCLE PHYSIOLOGY

Segment ot musde fiber greatly enlarged to show sarcoplasmic slructures and indusions

Sarcoplasmic

Nudeus Gdgi apparatus

Sarcoplasm

Glycoger

Lipid

Collagenous basement membrano

Myofilaments

Figurę 3.2 Sarcoplasmic Reticulum

Ihe sarcoplasmic reticulum forms an claborate network within the celi and is Ilu? storage sile lor intracellular Ca²*. The sarcoplasmic reticulum contains Ca-' channels, Ca-¹ -ATPasę, and the low-affinity Ca-''-binding protein cal$eque$trin. Transverse tubules <T tubules) invaginate from ihe sarcolemma (plasma membranę) and associale with two terminal cistemae of ihe sarcoplasmic reticulum (triad). Depolarization of the musde sarcolemma travels down the T tubules and causes Ca²* release trom the sarcoplasmic reticulum (see Figurę 3.3).

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