Fine structure of the cardiac muscle cells in the orb-web spider Nephila clavata
Autor: | Hyo-Jeong Kim, Yan Sun, Myung-Jin Moon |
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Jazyk: | angličtina |
Rok vydání: | 2020 |
Předmět: |
0106 biological sciences
01 natural sciences Cell junction Sarcomere 03 medical and health sciences medicine Cardiac muscle Spider Terminal cisternae Nephila clavata 030304 developmental biology Microscopy 0303 health sciences biology Research QH201-278.5 Gap junction General Medicine biology.organism_classification musculoskeletal system 010602 entomology medicine.anatomical_structure Biophysics Fascia adherens Fine structure Myofibril |
Zdroj: | Applied Microscopy Applied Microscopy, Vol 50, Iss 1, Pp 1-8 (2020) |
ISSN: | 2287-4445 2287-5123 |
Popis: | The fine structural characteristics of cardiac muscle cells and its myofibril organization in the orb web spider N. clavata were examined by transmission electron microscopy. Although myofibril striations are not remarkable as those of skeletal muscles, muscle fibers contain multiple myofibrils, abundant mitochondria, extensive sarcoplasmic reticulum and transverse tubules (T-tubules). Myofibrils are divided into distinct sarcomeres defined by Z-lines with average length of 2.0 μm, but the distinction between the A-band and the I-bands is not clear due to uniform striations over the length of the sarcomeres. Dyadic junction which consisted of a single T-tubule paired with a terminal cisterna of the sarcoplasmic reticulum is found mainly at the A-I level of sarcomere. Each cell is arranged to form multiple connections with neighboring cells through the intercalated discs. These specialized junctions include three types of intercellular junctions: gap junctions, fascia adherens and desmosomes for heart function. Our transmission electron microscopy (TEM) observations clearly show that spider’s cardiac muscle contraction is controlled by neurogenic rather than myogenic mechanism since each cardiac muscle fiber is innervated by a branch of motor neuron through neuromuscular junctions. |
Databáze: | OpenAIRE |
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