ISSN:
1432-0878
Keywords:
Heart ultrastructure
;
Lepidurus arcticus (Branchiopoda)
;
Myofibrils
;
T-system
;
Sarcoplasmic reticulum
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary The heart of Lepidurus arcticus consists of an epicardium and a single layer of strongly polarized myocardial cells, 10–50 μm thick, with the myofibrillar part facing the epicardium. The Z-bands are diffuse and some Z-material forms attachment plaques. Relaxed sarcomeres show a hexagonal arrangement of thick filaments and 6 thin filaments in orbit, but filaments often diverge in their orientation. The sarcolemma invaginates from both the epicardial and the endocardial side of the cell, forming clefts and T-tubules. The sarcoplasmic reticulum is loosely reticular, cisternae associate with sarcolemma to form large and typical peripheral and interior couplings. The latter are of the “button-to-button” type and they tend to be located at the A-I level.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00233955
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