scholarly journals What Fish Can Teach Us about the Feeding Functions of Postcranial Muscles and Joints

2019 ◽  
Vol 59 (2) ◽  
pp. 383-393 ◽  
Author(s):  
Ariel L Camp
Keyword(s):  
Motor Function ◽  
Muscle Function ◽  
Vertebral Column ◽  
The Body ◽  
Pectoral Girdle ◽  
Suction Feeding ◽  
Feeding Behaviors ◽  
Major Transitions ◽  
Role Changes

Abstract Studies of vertebrate feeding have predominantly focused on the bones and muscles of the head, not the body. Yet, postcranial musculoskeletal structures like the spine and pectoral girdle are anatomically linked to the head, and may also have mechanical connections through which they can contribute to feeding. The feeding roles of postcranial structures have been best studied in ray-finned fishes, where the body muscles, vertebral column, and pectoral girdle attach directly to the head and help expand the mouth during suction feeding. Therefore, I use the anatomy and motion of the head–body interface in these fishes to develop a mechanical framework for studying postcranial functions during feeding. In fish the head and body are linked by the vertebral column, the pectoral girdle, and the body muscles that actuate these skeletal systems. The morphology of the joints and muscles of the cranio-vertebral and hyo-pectoral interfaces may determine the mobility of the head relative to the body, and ultimately the role of these interfaces during feeding. The postcranial interfaces can function as anchors during feeding: the body muscles and joints minimize motion between the head and body to stabilize the head or transmit forces from the body. Alternatively, the postcranial interfaces can be motors: body muscles actuate motion between the head and body to generate power for feeding motions. The motor function is likely important for many suction-feeding fishes, while the anchor function may be key for bite- or ram-feeding fishes. This framework can be used to examine the role of the postcranial interface in other vertebrate groups, and how that role changes (or not) with morphology and feeding behaviors. Such studies can expand our understanding of muscle function, as well as the evolution of vertebrate feeding behaviors across major transitions such as the invasion of land and the emergence of jaws.

scholarly journals Fishes can use axial muscles as anchors or motors for powerful suction feeding

2020 ◽  
Vol 223 (18) ◽  
pp. jeb225649 ◽  
Author(s):  
Ariel L. Camp ◽  
Aaron M. Olsen ◽  
L. Patricia Hernandez ◽  
Elizabeth L. Brainerd
Keyword(s):  
Ictalurus Punctatus ◽  
Micropterus Salmoides ◽  
The Body ◽  
Pectoral Girdle ◽  
Suction Feeding ◽  
Axial Muscles ◽  
X Ray Imaging ◽  
Oral Pressure ◽  
Volume Measurements ◽  
Epaxial Muscles

ABSTRACTSome fishes rely on large regions of the dorsal (epaxial) and ventral (hypaxial) body muscles to power suction feeding. Epaxial and hypaxial muscles are known to act as motors, powering rapid mouth expansion by shortening to elevate the neurocranium and retract the pectoral girdle, respectively. However, some species, like catfishes, use little cranial elevation. Are these fishes instead using the epaxial muscles to forcefully anchor the head, and if so, are they limited to lower-power strikes? We used X-ray imaging to measure epaxial and hypaxial length dynamics (fluoromicrometry) and associated skeletal motions (XROMM) during 24 suction feeding strikes from three channel catfish (Ictalurus punctatus). We also estimated the power required for suction feeding from oral pressure and dynamic endocast volume measurements. Cranial elevation relative to the body was small (<5 deg) and the epaxial muscles did not shorten during peak expansion power. In contrast, the hypaxial muscles consistently shortened by 4–8% to rotate the pectoral girdle 6–11 deg relative to the body. Despite only the hypaxial muscles generating power, catfish strikes were similar in power to those of other species, such as largemouth bass (Micropterus salmoides), that use epaxial and hypaxial muscles to power mouth expansion. These results show that the epaxial muscles are not used as motors in catfish, but suggest they position and stabilize the cranium while the hypaxial muscles power mouth expansion ventrally. Thus, axial muscles can serve fundamentally different mechanical roles in generating and controlling cranial motion during suction feeding in fishes.

scholarly journals The Enigmatic Reissner’s Fiber and the Origin of Chordates

2021 ◽  
Vol 15 ◽  
Author(s):  
Francisco Aboitiz ◽  
Juan F. Montiel
Keyword(s):  
Vertebral Column ◽  
The Body ◽  
Reissner's Fiber ◽  
Reissner’S Fiber ◽  
Clinical Observations ◽  
Neural Canal ◽  
History Of ◽  
Shed Light ◽  
Origin Of Chordates

Reissner’s fiber (RF) is a secreted filament that floats in the neural canal of chordates. Since its discovery in 1860, there has been no agreement on its primary function, and its strong conservation across chordate species has remained a mystery for comparative neuroanatomists. Several findings, including the chemical composition and the phylogenetic history of RF, clinical observations associating RF with the development of the neural canal, and more recent studies suggesting that RF is needed to develop a straight vertebral column, may shed light on the functions of this structure across chordates. In this article, we will briefly review the evidence mentioned above to suggest a role of RF in the origin of fundamental innovations of the chordate body plan, especially the elongation of the neural tube and maintenance of the body axis. We will also mention the relevance of RF for medical conditions like hydrocephalus, scoliosis of the vertebral spine and possibly regeneration of the spinal cord.

scholarly journals The Role of Water Homeostasis in Muscle Function and Frailty: A Review

Nutrients ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1857 ◽  
Author(s):  
Lorenzo ◽  
Serra-Prat ◽  
Yébenes
Keyword(s):  
Muscle Strength ◽  
Muscle Mass ◽  
Functional Capacity ◽  
Muscle Function ◽  
The Body ◽  
Hyperosmotic Stress ◽  
Muscle Quality ◽  
Cell Swelling ◽  
Cell Dehydration

Water, the main component of the body, is distributed in the extracellular and intracellular compartments. Water exchange between these compartments is mainly governed by osmotic pressure. Extracellular water osmolarity must remain within very narrow limits to be compatible with life. Older adults lose the thirst sensation and the ability to concentrate urine, and this favours increased extracellular osmolarity (hyperosmotic stress). This situation, in turn, leads to cell dehydration, which has severe consequences for the intracellular protein structure and function and, ultimately, results in cell damage. Moreover, the fact that water determines cell volume may act as a metabolic signal, with cell swelling acting as an anabolic signal and cell shrinkage acting as a catabolic signal. Ageing also leads to a progressive loss in muscle mass and strength. Muscle strength is the main determinant of functional capacity, and, in elderly people, depends more on muscle quality than on muscle quantity (or muscle mass). Intracellular water content in lean mass has been related to muscle strength, functional capacity, and frailty risk, and has been proposed as an indicator of muscle quality and cell hydration. This review aims to assess the role of hyperosmotic stress and cell dehydration on muscle function and frailty.

Gallbladder motor function in gallstone patients: sonographic and in vitro studies on the role of gallstones, smooth muscle function and gallbladder wall inflammation

1994 ◽  
Vol 21 (3) ◽  
pp. 430-440 ◽  
Author(s):  
Piero Portincasa ◽  
Agostino Di Ciaula ◽  
Giuseppe Baldassarre ◽  
Vincenzo Palmieri ◽  
Antonia Gentile ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Motor Function ◽  
Muscle Function ◽  
Gallbladder Wall ◽  
In Vitro Studies ◽  
Smooth Muscle Function

The Role of Polyphenols in the Modulation of Plasma Non-Enzymatic Antioxidant Capacity (NEAC)

2012 ◽  
Vol 82 (3) ◽  
pp. 228-232 ◽  
Author(s):  
Mauro Serafini ◽  
Giuseppa Morabito
Keyword(s):  
Antioxidant Capacity ◽  
Dietary Intervention ◽  
Ex Vivo ◽  
The Body ◽  
Dietary Polyphenols ◽  
Enzymatic Antioxidant ◽  
Endogenous Antioxidant

Dietary polyphenols have been shown to scavenge free radicals, modulating cellular redox transcription factors in different in vitro and ex vivo models. Dietary intervention studies have shown that consumption of plant foods modulates plasma Non-Enzymatic Antioxidant Capacity (NEAC), a biomarker of the endogenous antioxidant network, in human subjects. However, the identification of the molecules responsible for this effect are yet to be obtained and evidences of an antioxidant in vivo action of polyphenols are conflicting. There is a clear discrepancy between polyphenols (PP) concentration in body fluids and the extent of increase of plasma NEAC. The low degree of absorption and the extensive metabolism of PP within the body have raised questions about their contribution to the endogenous antioxidant network. This work will discuss the role of polyphenols from galenic preparation, food extracts, and selected dietary sources as modulators of plasma NEAC in humans.

The Role of Computer Modeling in Electrocardiography

1990 ◽  
Vol 29 (04) ◽  
pp. 282-288 ◽  
Author(s):  
A. van Oosterom
Keyword(s):  
Electrical Activity ◽  
Computer Modeling ◽  
Body Surface ◽  
Electrical Current ◽  
The Body ◽  
Volume Conductor ◽  
Current Generator ◽  
Cardiac Electrical Activity ◽  
Source Models

AbstractThis paper introduces some levels at which the computer has been incorporated in the research into the basis of electrocardiography. The emphasis lies on the modeling of the heart as an electrical current generator and of the properties of the body as a volume conductor, both playing a major role in the shaping of the electrocardiographic waveforms recorded at the body surface. It is claimed that the Forward-Problem of electrocardiography is no longer a problem. Several source models of cardiac electrical activity are considered, one of which can be directly interpreted in terms of the underlying electrophysiology (the depolarization sequence of the ventricles). The importance of using tailored rather than textbook geometry in inverse procedures is stressed.

Questions on the role of biofilms for the adaptation of microorganisms to unfavorable environmental factors by the example of P. aeruginosa

2020 ◽  
Vol 99 (4) ◽  
pp. 379-383
Author(s):  
Vasily N. Afonyushkin ◽  
N. A. Donchenko ◽  
Ju. N. Kozlova ◽  
N. A. Davidova ◽  
V. Yu. Koptev ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Environmental Factors ◽  
Barrier Function ◽  
Infectious Agent ◽  
Antagonistic Activity ◽  
The Body ◽  
Main Function ◽  
Pathogenic Potential ◽  
The Face

Pseudomonas aeruginosa is a widely represented species of bacteria possessing of a pathogenic potential. This infectious agent is causing wound infections, fibrotic cystitis, fibrosing pneumonia, bacterial sepsis, etc. The microorganism is highly resistant to antiseptics, disinfectants, immune system responses of the body. The responses of a quorum sense of this kind of bacteria ensure the inclusion of many pathogenicity factors. The analysis of the scientific literature made it possible to formulate four questions concerning the role of biofilms for the adaptation of P. aeruginosa to adverse environmental factors: Is another person appears to be predominantly of a source an etiological agent or the source of P. aeruginosa infection in the environment? Does the formation of biofilms influence on the antibiotic resistance? How the antagonistic activity of microorganisms is realized in biofilm form? What is the main function of biofilms in the functioning of bacteria? A hypothesis has been put forward the effect of biofilms on the increase of antibiotic resistance of bacteria and, in particular, P. aeruginosa to be secondary in charcter. It is more likely a biofilmboth to fulfill the function of storing nutrients and provide topical competition in the face of food scarcity. In connection with the incompatibility of the molecular radii of most antibiotics and pores in biofilm, biofilm is doubtful to be capable of performing a barrier function for protecting against antibiotics. However, with respect to antibodies and immunocompetent cells, the barrier function is beyond doubt. The biofilm is more likely to fulfill the function of storing nutrients and providing topical competition in conditions of scarcity of food resources.

Receptions of the Past: Commemoration, Racism, Desire

Somatechnics ◽  
2017 ◽  
Vol 7 (2) ◽  
pp. 288-303
Author(s):  
Michael Connors Jackman
Keyword(s):  
Critical Point ◽  
Social Relations ◽  
White Privilege ◽  
Body Politic ◽  
The Body ◽  
Race And Racism ◽  
Lesbian And Gay ◽  
The Past ◽  
History Of

This article investigates the ways in which the work of The Body Politic (TBP), the first major lesbian and gay newspaper in Canada, comes to be commemorated in queer publics and how it figures in the memories of those who were involved in producing the paper. In revisiting a critical point in the history of TBP from 1985 when controversy erupted over race and racism within the editorial collective, this discussion considers the role of memory in the reproduction of whiteness and in the rupture of standard narratives about the past. As the controversy continues to haunt contemporary queer activism in Canada, the productive work of memory must be considered an essential aspect of how, when and for what reasons the work of TBP comes to be commemorated. By revisiting the events of 1985 and by sifting through interviews with individuals who contributed to the work of TBP, this article complicates the narrative of TBP as a bluntly racist endeavour whilst questioning the white privilege and racially-charged demands that undergird its commemoration. The work of producing and preserving queer history is a vital means of challenging the intentional and strategic erasure of queer existence, but those who engage in such efforts must remain attentive to the unequal terrain of social relations within which remembering forms its objects.

A Good Sentencing Precedent is Hard to Find

2020 ◽  
Vol 32 (3) ◽  
pp. 138-144
Author(s):  
Brian A. Jacobs
Keyword(s):  
United States ◽  
Significant Role ◽  
College Admissions ◽  
The Body ◽  
Federal Law ◽  
Criminal Cases ◽  
Federal Sentencing

In federal criminal cases, federal law requires that judges consider the sentences other courts have imposed in factually similar matters. Courts and parties, however, face significant challenges in finding applicable sentencing precedents because judges do not typically issue written sentencing opinions, and transcripts of sentencings are not readily available in advanced searchable databases. At the same time, particularly since the Supreme Court’s 2005 decision in United States v. Booker, sentencing precedent has come to play a significant role in federal sentencing proceedings. By way of example, this article discusses recent cases involving defendants with gambling addictions, and recent cases involving college admissions or testing fraud. The article explores the ways the parties in those cases have used sentencing precedent in their advocacy, as well as the ways the courts involved have used sentencing precedent to justify their decisions. Given the important role of sentencing precedent in federal criminal cases, the article finally looks at ways in which the body of sentencing law could be made more readily available to parties and courts alike.

Putting the Madhyamaka Trick in Context: A Contextualist Reading of Huntington’s Interpretation of Madhyamaka

2014 ◽  
Vol 31 (1) ◽  
pp. 91-124
Author(s):  
Michael Dorfman
Keyword(s):  
Fifteenth Century ◽  
Common Ground ◽  
Correspondence Theory ◽  
The Body ◽  
Rational Analysis ◽  
At Command ◽  
Rational Argumentation ◽  
Logical Fallacies ◽  
Key Terms

In a series of works published over a period of twenty five years, C.W. Huntington, Jr. has developed a provocative and radical reading of Madhyamaka (particularly Early Indian Madhyamaka) inspired by ‘the insights of post- Wittgensteinian pragmatism and deconstruction’ (1993, 9). This article examines the body of Huntington’s work through the filter of his seminal 2007 publication, ‘The Nature of the M?dhyamika Trick’, a polemic aimed at a quartet of other recent commentators on Madhyamaka (Robinson, Hayes, Tillemans and Garfield) who attempt ‘to read N?g?rjuna through the lens of modern symbolic logic’ (2007, 103), a project which is the ‘end result of a long and complex scholastic enterprise … [which] can be traced backwards from contemporary academic discourse to fifteenth century Tibet, and from there into India’ (2007, 111) and which Huntington sees as distorting the Madhyamaka project which was not aimed at ‘command[ing] assent to a set of rationally grounded doctrines, tenets, or true conclusions’ (2007, 129). This article begins by explicating some disparate strands found in Huntington’s work, which I connect under a radicalized notion of ‘context’. These strands consist of a contextualist/pragmatic theory of truth (as opposed to a correspondence theory of truth), a contextualist epistemology (as opposed to one relying on foundationalist epistemic warrants), and a contextualist ontology where entities are viewed as necessarily relational (as opposed to possessing a context-independent essence.) I then use these linked theories to find fault with Huntington’s own readings of Candrak?rti and N?g?rjuna, arguing that Huntington misreads the semantic context of certain key terms (tarka, d???i, pak?a and pratijñ?) and fails to follow the implications of N?g?rjuna and Candrak?rti’s reliance on the role of the pram??as in constituting conventional reality. Thus, I find that Huntington’s imputation of a rejection of logic and rational argumentation to N?g?rjuna and Candrak?rti is unwarranted. Finally, I offer alternate readings of the four contemporary commentators selected by Huntington, using the conceptual apparatus developed earlier to dismiss Robinson’s and Hayes’s view of N?g?rjuna as a charlatan relying on logical fallacies, and to find common ground between Huntington’s project and the view of N?g?rjuna developed by Tillemans and Garfield as a thinker committed using reason to reach, through rational analysis, ‘the limits of thought.’

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