The active pumping of ions into the sarcoplasmic reticulum creates a deficiency in the fluid around the myofibrils.
22.
Costameres are sub-sarcolemmal protein assemblies circumferentially aligned in register with the Z-disk of peripheral myofibrils.
23.
However, in electron microscopy relaxed myofibrils, as well as glycogen loss and mitochondrial swelling can be seen.
24.
Biopsies demonstrate more molecular damage and dysfunction within the mitochondria, higher lipid storage, and vibrant red myofibrils.
25.
The sarcoplasmic reticulum surrounds the myofibrils and holds a reserve of the calcium ions needed to cause a muscle contraction.
26.
Each muscle fiber contains myofibrils, which are very long chains of sarcomeres, the contractile units of the cell.
27.
Myofibrils are composed of long proteins including actin, myosin, and titin, and other proteins that hold them together.
28.
The sarcoplasmic reticulum, a specialized type of smooth endoplasmic reticulum, forms a network around each myofibril of the muscle fiber.
29.
The mechanism is not clear but it is thought to involve contraction of tonic myofibrils and transient dilation of choroidal blood vessels.
30.
Postnatal sarcomere disorganization and degeneration occurred rapidly in these mice, indicating the nebulin is essential for maintaining the structural integrity of myofibrils.
