Key result
Non-striated muscle from the tunicate Ciona intestinalis exhibits morphological and physiological properties analogous to vertebrate skeletal muscle, including rapid all-or-none Ca action potentials.
Answers are grounded in this paper and cite their sources.
May model vertebrate skeletal muscle in research; extends comparative physiology but leaves clinical translation open.
Non-striated muscle from the longitudinal body wall muscle in an adult ascidian (tunicate) is characterized morphologically and physiologically. These muscles are unique among chordate non-striated (i.e. 'smooth') muscles in that they are composed of discrete bundles of several small diameter (4-10 microns) muscle cells (fibers) arranged in parallel functional units. Each bundle is wrapped by a basal lamina, and at least some appear to be directly innervated at a neuromuscular junction similar to an end plate. In these regards, a bundle of Ciona smooth muscle cells is analogous to a skeletal muscle fiber of a vertebrate. This analogy also extends to physiological properties. Ciona muscle generates a rapid all-or-none Ca action potential which gives rise to a brisk twitch with brief latency. These anatomical and physiological adaptations are discussed in terms of the evolution of vertebrate skeletal muscle.
No takes yet. Share an insight, caveat, or question.
Nevitt et al. (1986) studied Ciona intestinalis muscle physiology. Non-striated muscle from the tunicate Ciona intestinalis exhibits morphological and physiological properties analogous to vertebrate skeletal muscle, including rapid all-or-none Ca action potentials.
Synapse has enriched 10 related papers. Consider them for comparative context: