scholarly journals Muscular action in Holothuria grisea

1953 ◽  
Vol 18 (18) ◽  
pp. 51 ◽  
Author(s):  
C. F. Pantin ◽  
Paulo Sawaya
Keyword(s):  
Muscular Action

Holothuria grisea é um dos animais comuns nas praias rochosas do sul do Brasil. A forma e a construção do corpo é tal que os seus movimentos dependem das construções de paredes musculares do corpo atuando contra o volume do fluído que se encontra dentro da cavidade do corpo. Êste sistema de ação é característico dos animais com um esqueleto hidrostático - os "hohlorganartige Tiere" de Jordan (1914; 1929). No presente trabalho trataremos da mecânica de ação muscular dêste sistema nêste animal.

scholarly journals FRACTURE OF THREE RIBS FROM MUSCULAR ACTION.

The Lancet ◽  
1884 ◽  
Vol 123 (3174) ◽  
pp. 1162
Author(s):  
T.Edgar Underhill
Keyword(s):  
Muscular Action

scholarly journals I. The Croonian Lecture. On the structure and uses of the membrana tympani of the ear

1800 ◽  
Vol 90 ◽  
pp. 1-21 ◽  
Keyword(s):  
Human Body ◽  
Comparative Anatomy ◽  
Large Field ◽  
The Subject ◽  
Muscular Action ◽  
Satisfactory Manner

The subject of inquiry appointed by the Croonian Institution, has been greatly elucidated at different times by ingenious members of this learned Society. A large field, however, still remains open; and, respecting future investigations, I shall have occasion to offer a fresh proof of the aid to be derived from comparative anatomy, in ascertaining the structure of parts which, from their minuteness and situation in the human body, admit with much difficulty of being explored. The principal object of the present lecture is to communicate a discovery of the structure of the membrana tympani; which, in some respects, affords a new and very curious instance of the application of muscular action, and may conduce to account for certain phaenomena in the sense of hearing, in a more satisfactory manner than has hitherto been proposed.

Dynamic control of cell-cell adhesion and membrane-associated actin during food-induced mouth opening in Beroe

1993 ◽  
Vol 106 (1) ◽  
pp. 355-364
Author(s):  
S.L. Tamm ◽  
S. Tamm
Keyword(s):  
Cell Adhesion ◽  
Actin Cytoskeleton ◽  
Actin Filaments ◽  
Dynamic Control ◽  
Mouth Opening ◽  
Cell Junctions ◽  
Dynamic Changes ◽  
Rhodamine Phalloidin ◽  
Rapid Changes ◽  
Muscular Action

We used rhodamine-phalloidin and ultrastructural methods to follow dynamic changes in adhesive cell junctions and associated actin filaments during reversible epithelial adhesion in the mouth of the ctenophore Beroe. A cruising Beroe keeps its mouth closed by interdigitated actin-coated appositions between paired strips of cells lining the lips. The mouth opens rapidly (in 0.2-0.3 s) by muscular action to engulf prey (other ctenophores), then re-seals after ingestion. We found that the interlocking surface architecture of the adhesive cells, including the actin-coated junctions, rapidly disappears after food-induced opening of the mouth. In contrast, forcible separation of the lips in the absence of food rips the junctions, still intact, from the surfaces of the cells. The prey-stimulated loss of adhesive cell junctions and associated actin cytoskeleton is one of the most rapid changes in actin-based junctions yet observed. This system provides unique experimental advantages for investigating the dynamic control of reversible cell adhesions and membrane-associated actin filaments.

The Ecology and Digestive System of the Struthiolariidae (Gastropoda)

1951 ◽  
Vol s3-92 (17) ◽  
pp. 1-25
Author(s):  
J. E. MORTON
Keyword(s):  
Digestive System ◽  
Structure And Function ◽  
Crystalline Style ◽  
Intracellular Digestion ◽  
Mud Flat ◽  
Food Particles ◽  
Gill Filaments ◽  
And Function ◽  
Deposit Feeding ◽  
Muscular Action

The two neozelanic species Struthiolaria papulosa and Pelicaria vermis have been studied as regards ecology, feeding mechanism, and structure and function of the digestive system. They are dwellers on sand or sand-mud-flat, wit h a feeding position just below the surface, where they construct paired siphonal tubes with the rostrum. A ciliary mode of feeding has been acquired by the modification of the gill filaments and the pallial rejection system. The alimentary canal isadapted for deposit feeding and has developed a crystalline style. Food particles are conducted to the stomach by a functionally reduced mucus-secreting oesophagus, where they are subjected to the action of the rotating style, and a complex system of ciliary currents. Digestible par-ticles are passed into paired diverticula, where absorption and intracellular digestion, takes place, while faecal material is surrounded with mucus and formed into firm pellets by the ciliary and muscular action of the intestine. The relationships of the Struthiolariidae are discussed, and their origin from the Aporrhaidae is postulated.

Effect of various stressors on muscular contraction induced by NaH2PO4 and NaClO4

1959 ◽  
Vol 196 (3) ◽  
pp. 681-684 ◽  
Author(s):  
Hans Selye ◽  
Eörs Bajusz
Keyword(s):  
Muscular Contraction ◽  
The Other ◽  
Muscle Dysfunction ◽  
Biochemical Processes ◽  
Muscular Work ◽  
Electric Shocks ◽  
Threshold Doses ◽  
Clonic Convulsions ◽  
Motor Disturbances ◽  
Muscular Action

Experiments in the rat indicate that the motor disturbances elicited by sudden overdosage with NaH2PO4 and NaClO4 are qualitatively different. NaH2PO4 produces a tetany-like condition, with generalized continuous tremor and occasional fits of generalized clonic convulsions. NaClO4, on the other hand, induces no tremor, but rather persistent, tonic extensor cramps, predominantly in the hind legs. Among a great variety of stressors, only those associated with increased muscular work (exercise in a revolving drum, forced restraint, electric shocks) enhanced the susceptibility to acute NaH2PO4 intoxication, while all the stressors that were examined elicited marked muscular contractions following treatment with threshold doses of NaClO4. These effects of NaH2PO4 and NaClO4 are not due to the Na-ion as such, since equimolecular amounts of NaCl were totally ineffective in producing muscular contractions. It appears that an excess of NaH2PO4 and NaClO4 interferes rather selectively with the biochemical processes responsible for muscular contraction; hence, these salts induce fatigue and muscle dysfunction, following comparatively brief periods of exercise. In addition, the muscular action of NaClO4 (unlike that of NaH2PO4) is greatly enhanced even by stressors which do not act preponderantly upon muscle.

A perspective of respiratory mechanics

1983 ◽  
Vol 54 (5) ◽  
pp. 1183-1187 ◽  
Author(s):  
A. B. Otis
Keyword(s):  
Smooth Muscle ◽  
Experimental Approach ◽  
Respiratory Mechanics ◽  
Bronchial Smooth Muscle ◽  
Pharmacological Agents ◽  
Early 19Th Century ◽  
Willem Einthoven ◽  
Normal Physiological Function ◽  
Accessory Muscles ◽  
Muscular Action

Breathing was recognized very early to be a muscular action. The participation of the diaphragm, intercostals, and accessory muscles was appreciated by Galen. Consideration of a possible role for smooth muscle in breathing did not occur until much later. Even today smooth muscle is seldom included as a topic in discussions of “respiratory mechanics.” Bronchial smooth muscle was first described in the classic study of Reisseisen in the early 19th century, although the presence of contractile elements in lungs had been demonstrated a few decades previously. An important comprehensive investigation of the action of bronchial smooth muscle was published in 1892 by Willem Einthoven. His experimental approach became a paradigm. On the other hand, his analysis of dynamic collapse of the airways received little attention and was independently arrived at half a century later. Although we now have a considerable understanding of the mechanics of bronchial smooth muscle and of the effects of numerous physiological and pharmacological agents on its behavior, the exact role it plays in normal physiological function is unclear. Numerous plausible suggestions have been made, but none has been convincingly demonstrated.

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