ABSTRACT
Figure 8.8 Propose d assembl y o f keratin polypeptide chain s t o for m kerati n filaments . (Reproduced b y permissio n fro m Eichne r R , Re w P , Enge l A , Aeb i U . H u m an epiderma l keratin filaments : studies on thei r structure an d assembl y A n n NY Acad Sc i 455:381-401, 1985.)
system. A myofibri l consist s o f tw o type s o f fibril s o r filaments , th e thic k (10-1 5
n m diameter ) an d th e thi n (5-7 nm ) fibril s o r filaments . Latera l microscopi c
examination o f myofibril s furthe r show s a bande d structur e (Figur e 8.9) . Th e
repeating uni t ( Z lin e t o Z line ) o f a myofibri l i s calle d a sarcomere . I t i s abou t
2300 n m long . A s th e muscl e contracts , th e sarcomer e become s smaller , largel y
at th e expens e o f th e I bands (isotropi c bands) .
