The Role of Oesophageal Rhythms in the Behaviour of Arenicola Ecaudata Johnston

1951 ◽  
Vol 28 (1) ◽  
pp. 51-56
Author(s):  
G. P. WELLS ◽  
ELINOR B. ALBRECHT
Keyword(s):  
Body Wall ◽  
The Body ◽  
Rhythmic Contraction ◽  
Back Ground ◽  
Continuous Background ◽  
Mode Of Life ◽  
Nearly Continuous

1. Arenicola ecaudata differs not only in structure, but in mode of life, from A. marina. Our results indicate that there are also great differences in behaviour physiology. 2. The brainless isolated extrovert of ecaudata traces a continuous, or nearly continuous, background of activity, upon which prominent spells of vigorous rhythmic contraction appear at intervals of the order of 30-40 min. Similar spells are sometimes shown by the corresponding preparation from marina, whose characteristic f cycle can be regarded as produced by the organization of the back-ground activity of ecaudata into vigorous and regularly spaced outbursts. 3. There is little evidence of a pacemaker role of the oesophagus in ecaudata. If the movements of the extrovert and body wall are simultaneously recorded, they generally exhibit correlated outbursts of variable and fluctuating pattern, and very unlike the behaviour of the brainless extrovert. Similar outbursts are shown by the body wall after severance of its connexion with the extrovert. They are probably of central nervous origin.

Some Observations on the Role of the Body Wall of Acanthocephalus Ranae in Lipid Uptake

1968 ◽  
Vol 48 (1) ◽  
pp. 217-225
Author(s):  
R. A. HAMMOND
Keyword(s):  
Lipid Droplets ◽  
Body Wall ◽  
The Body ◽  
Lipid Uptake ◽  
Uptake Of Nutrients ◽  
Lipid Excretion

1. Acanthocephalus ranae has been found to take up glyceryl tri[oleate-9,10-3H] solely through the surface of the trunk. The proboscis and lemnisci play no part in the uptake of this material. The large amounts of lipid present in the latter organs may be evidence of their involvement in lipid excretion. 2. Fat-soluble dyes are taken up by the animal and accumulate in lipid droplets in the lemnisci and proboscis wall. It is suggested that such dyes do not enter the animal through the surface of the proboscis, as has been suggested previously, but through the surface of the trunk. 3. The structure of the acanthocephalan body wall is discussed in relation to the uptake of nutrients.

Cnidaria

1989 ◽  
Author(s):  
Heinz A. Lowenstam ◽  
Stephen Weiner
Keyword(s):  
Calcium Sulfate ◽  
Body Wall ◽  
Structural Features ◽  
The Body ◽  
Internal Space ◽  
Gravity Perception ◽  
Sessile Polyp ◽  
Gastrovascular Cavity ◽  
Mode Of Life ◽  
Pass Through

The phylum Cnidaria or Coelenterates includes sea anemones, jellyfish, hydras, sea fans, and, of course, the corals. With few exceptions they are all marine organisms and most are inhabitants of shallow water. In spite of the great variation in shape, size, and mode of life, they all possess the same basic metazoan structural features: an internal space for digestion (gastrovascular cavity or coelenteran), a mouth, and a circle of tentacles, which are really just an extension of the body wall. The body wall in turn is composed of three layers: an outer layer of epidermis, an inner layer of cells lining the gastrovascular cavity, and, sandwiched between them, a so-called mesoglea (Barnes 1980). All these features are present in both of the basic structural types: the sessile polyp and the free-swiming medusa. During their life cycle, some cnidarians exhibit one or the other structural type whereas others pass through both. Most Cnidaria have no mineralized deposits. The ones that, to date, are known to have mineralized deposits are listed in Table 5.1. They are found in both the free-swimming medusae and the sessile polyps. Not surprisingly, these have very different types of mineralized deposits. In the medusae they are located exclusively within the statocyst where they constitute an important part of the organism’s gravity perception apparatus. Interestingly the statoconia of the Hydrozoa, examined to date for their major elemental compositions only, are all composed of amorphous Mg-Ca-phosphate, whereas those of the Scyphozoa and Cubozoa are composed of calcium sulfate. Calcium sulfate minerals (presumably gypsum) are not commonly formed by organisms and the only other known occurrence is in the Gamophyta among the Protoctista. Spangenberg (1976) and her colleagues have expertly documented this phenomenon in the Cnidaria. (For a more detailed discussion of mineralization and gravity perception see Chapter 11.) The predominant mineralized hard part associated with the sessile polyps is skeletal. These can take the form of skeletons composed of individual spicules, spicule aggregates, or massive skeletons. They are composed of aragonite, calcite, or both.

On certain Semi-carnivorous Anthomyid Larvae

Parasitology ◽  
1930 ◽  
Vol 22 (2) ◽  
pp. 168-181 ◽  
Author(s):  
D. Keilin ◽  
P. Tate
Keyword(s):  
Alimentary Canal ◽  
Body Wall ◽  
Anatomical Structure ◽  
The Body ◽  
Sensory Organs ◽  
Ventral Region ◽  
Anatomical Features ◽  
Mode Of Life ◽  
Ventral Wall

In previous papers one of us (Keilin, 1915, 1917) has shown that among cyclorrhaphous dipterous larvae there is a remarkable correlation between the anatomical structure of the larvae and their mode of life. Although the mode of life of the larvae is in correlation with such anatomical features as thickness and hardness of the body-wall, the development of sensory organs on the head, and the structure of the alimentary canal, it is in the bucco-pharyngeal armature that the most obvious and important adaptations are to be found. The most important of these adaptations may be mentioned briefly. In certain cyclorrhaphous dipterous larvae the ventral wall of the basal sclerite of the bucco-pharyngeal armature has a number of longitudinal ridges projecting into the lumen of the pharynx. These ridges are usually Y-shaped at their free borders, and form a series of longitudinal channels in the ventral region of the pharynx. In other cyclorrhaphous dipterous larvae such ridges are absent and the ventral wall of the pharynx is smooth. This character allows the larvae to be divided into two groups—“all cyclorrhaphous dipterous larvae parasitic on the most diverse animals or on plants, as well as carnivorous larvae, and larvae which suck the blood of mammals, never have ridges in their pharynx; on the contrary, ridges are always present in saprophagous larvae” (Keilin, 1915). All the larvae which are devoid of ridges and are either parasitic, carnivorous, pass their whole life in the uterus of the female, or are phytophagous, may be united into the group of biontophagous; all larvae which have ridges are saprophagous.

scholarly journals Preliminary observations on the role of the coelomic cells in food storage and transport in certain polychaetes

1957 ◽  
Vol 36 (1) ◽  
pp. 91-110 ◽  
Author(s):  
R. Phillips Dales
Keyword(s):  
Body Wall ◽  
The Body ◽  
Food Storage ◽  
Coelomic Cells ◽  
Different Parts

Determinations of the concentration of fat and glycogen in the body wall, in different parts of the gut and in the coelomic cells are described in Amphitrite and Arenicola. It is suggested that the trephocyte system constitutes a store of fat and glycogen derived from a primary store in the absorptive parts of the gut itself. In Arenicola and Nereis surplus fat is removed from the gut itself through the blood or directly by amoebocytes; the fat deposited in the epidermis and the glycogen in the peritoneum. In these worms the coelomic trephocytes are solely concerned with the maturation of the gametes. No relationship can be established between these cells and the chloragocytes. In Amphitrite and Terebella fat is stored also in the coelomic trephocytes which may derive their contents directly from the gut or from the body wall. Glycogen is stored in the trephocytes in Amphitrite, and in Arenicola in the peritoneum. Thus while large amounts of fat and glycogen are found in the trephocytes in Amphitrite, the total amount present in the body is no more than in Arenicola which lacks a well-developed trephocyte system, and in this species a larger proportion of fat and glycogen is found in the body wall.

THE ETHOLOGY OF THE SYNAPTID HOLOTHURIAN, OPHEODESOMA SPECTABILIS

1966 ◽  
Vol 44 (3) ◽  
pp. 457-482 ◽  
Author(s):  
Michael Berrill
Keyword(s):  
Body Wall ◽  
The Body ◽  
Tactile Sensitivity ◽  
Sensory Receptors ◽  
Rhythmic Contraction ◽  
Anterior Portion ◽  
Nervous Control ◽  
Strong Light ◽  
Activity Peak ◽  
Early Evening

Opheodesoma spectabilis commonly occurs in aggregations in the alga Sargassum echinocarpus, a source of shade from which it scrapes adhering detritus, and which allows the dense populations necessary for efficient spawning. The animal is photonegative and moves away from a strong light source. Ocelli provide information on the direction and intensity of sunlight. Statocysts, aided by tactile sensitivity, maintain dorsoventral equilibrium."They may also inhibit unwarranted rapid locomotion. The animal shows no gravity orientation. All sensory receptors are most concentrated in the region of the tentacle crown, and their interaction in controlling the animal's reactions implies considerable central integration of stimuli. The three primary muscular activities are the rhythmic contraction and extension of the tentacles, used in feeding and for slow locomotion; peristalsis of the body wall, involved in rapid locomotion; and the contraction, bending, and reextension of the anterior portion of the body. These activities may vary in rate and amplitude and occur independently or in any combinations. Their initiation and coordination are under central nervous control. Opheodesoma spectabilis has a diurnal rhythm of behavior, reaching an activity peak during the early evening hours and apparently directly dependent on changes in light intensity. Spawning occurs during the summer months.

scholarly journals The rôle of the body fluid in relation to movement in soft-bodied invertebrates I. The burrowing of Arenicola

1947 ◽  
Vol 134 (877) ◽  
pp. 431-455 ◽  
Keyword(s):  
Body Fluid ◽  
Body Wall ◽  
The Body ◽  
Coelomic Fluid ◽  
Simple Condition ◽  
Muddy Sand ◽  
Fluid System ◽  
Quantitative Results ◽  
Pressure Changes

This investigation is an attempt to obtain quantitative results on the method of functioning of the body-wall muscle-coelomic fluid system of the lugworm which was chosen as an example of a worm having this system in a relatively simple condition. Measurements of the hydrostatic pressure developed in the coelomic fluid during various phases of activity, particularly during burrowing, were recorded, and the mechanism by which pressure is differentially distributed throughout the body is discussed. The relation of pressure changes to burrowing movements is described and some calculations of the thrust which can be exerted by the worms are given. It is shown that the forces available to the worms are insufficient to allow of straight­-forward burrowing and that the ability to burrow depends on the thixotropic properties of the muddy sand in which the animals live.

scholarly journals Role of Ca(2+) in excitation-contraction coupling in echinoderm muscle: comparison with role in other tissues

2001 ◽  
Vol 204 (5) ◽  
pp. 897-908 ◽  
Author(s):  
R.B. Hill
Keyword(s):  
Control Systems ◽  
Body Wall ◽  
Longitudinal Muscle ◽  
The Body ◽  
Excitation Contraction Coupling ◽  
Contraction Coupling ◽  
Collagenous Tissue

The longitudinal muscle of the body wall of Isostichopus badionotus may be considered a model for excitation-contraction coupling in echinoderm muscle. Other echinoderm muscles are reviewed by comparison with the model. Echinoderm muscle is also of interest as a model for ‘mutable collagenous tissue’; however, in that tissue, Ca(2+) has been proposed to function both in living control systems and in regulation of non-living interstitial substance.

scholarly journals The Contractile Mechanism in Obliquely Striated Body Wall Muscle of the Earthworm, Lumbricus Terrestris

1971 ◽  
Vol 8 (2) ◽  
pp. 413-425 ◽  
Author(s):  
M. F. KNAPP ◽  
P. J. MILL
Keyword(s):  
Body Wall ◽  
Striated Muscle ◽  
Lumbricus Terrestris ◽  
The Body ◽  
Band Width ◽  
Physiological Data ◽  
Muscle Fibres ◽  
Contraction Mechanism ◽  
Cross Links

Obliquely striated muscle fibres from the longitudinal and circular layers of the body wall of the earthworm were prepared in extended and contracted states for study in the electron microscope. Contracted fibres differ from extended ones in the following respects: (i) the I-bands are narrower, (ii) the A-bands are wider, and (iii) there are more rows of thick myofilaments in each A-band. The arrangement of the thick and thin myofilaments in interdigitating arrays and the occurrence of cross-links between the 2 types of myofilament indicate a classical sliding-filament mechanism of contraction as in cross-striated muscle, resulting in a reduction in the I-band width. The increase in the A-band width could be due to a moving apart of the myofilaments during contraction to preserve constant volume of the lattice. The third change, the increase in the number of rows of thick myofilaments in the A-band, can be explained only by a shearing of these filaments past one another in such a way as to increase the amount of their overlap. The role of the sliding-filament and shearing contraction mechanisms in bringing about the changes observed in earthworm muscle fibres is considered and the possible correlation of these mechanisms with certain physiological data is discussed. The function of the sarcoplasmic reticulum in the transmission of impulses to the interior of the fibre and/or in the control of the contraction mechanism is also discussed.

scholarly journals Rhythms of the Body, Rhythms of the Brain: Respiration, Neural Oscillations, and Embodied Cognition

2017 ◽  
Author(s):  
Somogy Varga ◽  
Detlef H. Heck
Keyword(s):  
Embodied Cognition ◽  
Cognitive Processes ◽  
Cognitive Activity ◽  
The Body ◽  
General Mechanism ◽  
Rhythmic Contraction ◽  
Contraction And Relaxation ◽  
Epistemic Role ◽  
The Brain

AbstractIn spite of its importance as a life-defining rhythmic movement and its constant rhythmic contraction and relaxation of the body, respiration has not received attention in Embodied Cognition (EC) literature. Our paper aims to show that (1) respiration exerts significant and unexpected bottom-up influence on cognitive processes, and (2) it does so by modulating neural synchronization that underlies specific cognitive processes. Then, (3) we suggest that the particular example of respiration may function as a model for a general mechanism through which the body influences cognitive functioning. Finally, (4) we work out the implications for embodied cognition, draw a parallel to the role of gesture, and argue that respiration sometimes plays a double, pragmatic and epistemic, role, which reduces the cognitive load. In such cases, consistent with EC, the overall cognitive activity includes a loop-like interaction between neural and non-neural elements. (141 words)

Sign in / Sign up

Export Citation Format

Share Document