124 



THE TISSUES 



The striations of heart muscle are less distinct than are those of 

 voluntary muscle, but apparently represent very similar structures. 

 The longitudinal striations indicate fihrillcB lying in the sarcoplasm. 

 From the central mass of sarcoplasm which surrounds the nucleus, 

 strands radiate toward the periphery. These strands, anastomosing, 

 separate the fibrillas into columns, the muscle columns of Kolliker. 

 In cross section these present the appearance described under volun- 

 tary muscle as Cohnlieim^s fields. The disposition of the sarcoplasm, 



■ 



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f?-" 



t 



STi 



t 



Fig. 66. Fig. 67. 



Fig. 66. — Two Muscle Fibres from Upper End of Human Sartorius, to show con- 

 nection of muscle and tendon. X350. (Gage.) m, Muscle fibres; /, tendon fibres. 



Fig. 67. — Muscle Cells from the Human Heart (technic 6, p. 129), showing 4ateral 

 branches and lines of union between cells. X500. 



extending outward from the region of the nucleus like the spokes of a 

 wheel, gives to the cross section a characteristic radiate appearance 

 (Fig. 68), not seen in cross sections of voluntary muscle. The 

 transverse markings represent, as in voluntary muscle, alternate 

 light and dark discs. Through the middle of the light disc can be 

 seen the membrane of Krause. Mc Galium describes Krause's 

 membrane as crossing not only the librillae. but also the sarco- 

 plasm, as in the voluntary muscle fibre. The sarcoplasm he describes 

 as further subdivided by membranes, which are transversely con- 

 tinuous with Krause's membranes, into minute discs. The centre 



