scholarly journals Pulmonary Mechanics and the Work of Breathing in the Semi-Aquatic Turtle, Pseudemys Scripta

1986 ◽  
Vol 125 (1) ◽  
pp. 137-155 ◽  
Author(s):  
Timothy Z. Vitalis ◽  
William K. Milsom
Keyword(s):  
Body Wall ◽  
Striated Muscle ◽  
Work Of Breathing ◽  
Body Cavity ◽  
The Body ◽  
Mechanical Work ◽  
Pulmonary Mechanics ◽  
Pump Frequency ◽  
Elastic Forces ◽  
Pseudemys Scripta

Measurements of pulmonary mechanics on anaesthetized specimens of the aquatic turtle Pseudemys scripta (Schoepff) indicate that the static pulmonary mechanics of the total respiratory system are determined primarily by the mechanics of the body wall rather than those of the lungs. This is also true under the dynamic conditions of pump ventilation at low pump frequencies. As pump frequency increases, the work required to inflate the multicameral lungs of the turtle begins to contribute an increasing portion to the total mechanical work required to produce each breath as measured from pressure volume loops. The rise in the work performed on the lungs results from an increase in the non-elastic, flow-resistive forces which must be overcome during ventilation. The primary bronchus to each lung is the most likely site of flow resistance. There is also a small elastic component to the work required to ventilate the lungs associated with movement of the intrapulmonary septa and the striated muscle surrounding the lungs. The contribution of the work required to distend the body cavity as a percentage of the total mechanical work required to generate each breath remains relatively unchanged with increasing ventilation frequency, indicating that the majority of the forces to be overcome in the body wall are elastic in nature. For a constant rate of minute pump ventilation, as frequency increases, the work done per minute to overcome elastic forces decreases, while that done to overcome non-elastic forces begins to rise. These opposing trends produce an optimum combination of pump volume and frequency at which the rate of mechanical work is minimum.

scholarly journals Pulmonary Mechanics and the Work of Breathing in the Lizard, Gekko Gecko

1984 ◽  
Vol 113 (1) ◽  
pp. 187-202 ◽  
Author(s):  
WILLIAM K. MILSOM ◽  
TIMOTHY Z. VITALIS
Keyword(s):  
Tidal Volume ◽  
Chest Wall ◽  
Minute Ventilation ◽  
Work Of Breathing ◽  
Body Cavity ◽  
The Body ◽  
Pulmonary Mechanics ◽  
Lung Inflation ◽  
Gekko Gecko ◽  
Tokay Gecko

Measurements of pulmonary mechanics made on anaesthetized specimens of the Tokay gecko Gekkogecko (Linné), indicate that both static and dynamic pulmonary mechanics are dominated by the mechanics of the body cavity and chest wall. The lungs are relatively large and compliant and offer little resistance to air flow at any of the ventilation frequencies (f) used in this study. The body wall is relatively stiff and becomes less compliant with increasing ventilation frequency and with increasing tidal volume (VT) at the higher frequencies. The vast majority of the work performed in breathing is used to overcome elastic forces in the chest wall resisting lung inflation. This work increases exponentially with increases in volume. As a consequence, in terms of total ventilation, the most economic breathing pattern is a high frequency, low tidal volume pattern in which changes in minute ventilation (VE) are most economically produced solely by changes in f. Because reductions in tidal volume drastically reduce alveolar ventilation volume while dead space remains constant, the same arguments do not apply to alveolar minute ventilation (VA). In terms of alveolar minute ventilation, there is an optimum combination of f and VT for each level of VA, with changes in VA being most economically produced by almost equal changes in both f and VT

scholarly journals The influence of the post-pulmonary septum and submersion on the pulmonary mechanics of Trachemys scripta (Cryptodira: Emydidae)

2021 ◽  
Author(s):  
Ray Brasil Bueno de Souza ◽  
Wilfried Klein
Keyword(s):  
Hydrostatic Pressure ◽  
Respiratory System ◽  
Intact Animal ◽  
Work Of Breathing ◽  
Dynamic Compliance ◽  
Body Cavity ◽  
Trachemys Scripta ◽  
Pulmonary Mechanics ◽  
Static Compliance ◽  
Breathing Mechanics

The respiratory system of chelonians needs to function within a mostly solid carapace, with ventilation depending on movements of the flanks. When submerged, inspiration has to work against a hydrostatic pressure and we examined breathing mechanics in Trachemys scripta while underwater. Furthermore, the respiratory system of T. scripta possesses a well-developed post-pulmonary septum (PPS), and we investigated its role on breathing mechanics of lungs with and without their PPS attached. Static compliance was significantly increased in submerged animals and in animals with and without their PPS, while the removal of the PPS did not result in a significantly different static compliance. Dynamic compliance was significantly affected by changes in volume and frequency in every treatment, with submergence significantly decreasing dynamic compliance. The presence of the PPS significantly increased dynamic compliance. Submersion did not alter significantly work per ventilation, but caused minute work of breathing to be much greater at any frequency and ventilation level analyzed. Lungs with or without their PPS did not show significantly different work per ventilation when compared to intact animal. Our results demonstrate that submersion results in significantly altered breathing mechanics, increasing minute work of breathing greatly. The PPS was shown to maintain a constant volume within the animal's body cavity, wherein the lungs can be ventilated more easily, highlighting the importance of this coelomic subdivision in the chelonian body cavity.

scholarly journals I. The Croonian lecture. —“ Observations on the locomotor system of echinodermata

1881 ◽  
Vol 32 (212-215) ◽  
pp. 1-11 ◽  
Keyword(s):  
Short Distance ◽  
Body Wall ◽  
Body Cavity ◽  
The Body ◽  
Considerable Time ◽  
Tube System ◽  
Radial Canal ◽  
Locomotor System ◽  
Direct Pressure ◽  
Stone Canal

In Holothuria the polian vesicle opens freely into a wide circular canal a short distance from the termination of the stone canal. From this circular canal five lozenge-shaped sinuses project forwards, and from each of these two large oval sinuses run forward parallel with each other─the ten oval sinuses becoming continuous with the hollow stems of the tentacles. Injection of the polian vesicle shows that it forms one continuous tube system with the circular canal and its sinuses, oval sinuses and tentacles, ampullæ and pedicels. Unless the pressure is kept up for a considerable time there is no penetration of the injected fluid into the stone canal, and either the ring, the vesicle, or a sinus gives way before the fluid reaches the madreporic plate. Specimens injected with a gelatine mass show that each canal sinus opens into a cæcal tube, which runs forwards internal to the sinuses of the tentacles as far as a wide circum-oral space. This space communicates by well-defined apertures with that portion of the body cavity which lies between the sinuses and the œsophagus, and which is reached through the circular apertures between the sinuses of the circular canal. Each canal sinus has three other apertures in its walls. It opens by a small round aperture into a radial canal, and the two other apertures occur as minute slits, one at each side of the orifice of the radial canal leading into the adjacent tentacle sinuses. When the tentacle into which the sinus opens is protruded, there is no constriction between the sinus and the tentacle ; but when the ten­tacle is retracted, there is a well-marked constriction at the junction of the sinus with the tentacle. The eversion of the perisome and the protrusion of the tentacles are effected chiefly by the shortening of the polian vesicle and the constriction of the longitudinal muscular bands, which run from the inner surface of the body wall between each two adjacent tentacle-sinuses ; but the circular fibres of the body wall also assist in the process by contracting immediately behind the group of sinuses, so as to act on them by direct pressure, and also indirectly by forcing the body fluid against them.

Observations on the anatomy of mammary glands in two species of conilurine rodent (Muridae: Hydromyinae) and in an opossum (Marsupialia: Didelphidae).

1993 ◽  
Vol 16 (1) ◽  
pp. 9
Author(s):  
M. Griffiths ◽  
N.G. Simms
Keyword(s):  
Connective Tissue ◽  
Body Wall ◽  
Striated Muscle ◽  
Mammary Glands ◽  
Monodelphis Domestica ◽  
The Body ◽  
Rodent Species ◽  
Voluntary Muscle ◽  
The Subject

The pups of Pseudomys nanus and P. australis are attached to their mothers' teats for extended periods of time, analogous to the situation encountered in pouchless marsupials. The structures in the mammary glands involved in facilitating prolonged attachment are different in the two rodent species and both kinds are different from those in marsupial glands including those of Monodelphis domestica, the subject of the present study. In P. nanus, the teats are anchored to postero-ventrally directed, tubular diverticula of the body wall. In P. australis there are no diverticula. However, support for the mammary glands and teats is afforded by the body wall, in the form of two well-developed fan-shaped muscles dorsal to the mammary glands in conjunction with a broad lamina of connective tissue, smooth and striated muscle situated between the skin of the belly and the mammary glands. In M. domestica, the teats are anchored to swathes of striated voluntary muscle, derived from the ilio-marsupialis muscles which pass ventrally through the secretory parenchyma to be inserted onto the bases of the teats. Since this musculature has not been observed in the mammary glands of any eutherians so far studied, nor in those of Monotremata, it is put that it is a character unique to the Marsupialia.

The bionomics and parasitic development of Tripius sciarae (Bovien) (Sphaerulariidae: Aphelenchoidea), a nematode parasite of sciarid flies (Sciaridae: Diptera)

Parasitology ◽  
1965 ◽  
Vol 55 (3) ◽  
pp. 559-569 ◽  
Author(s):  
George O. Poinar
Keyword(s):  
Adult Female ◽  
Body Wall ◽  
Pupal Stage ◽  
Body Cavity ◽  
The Body ◽  
National Institutes Of Health ◽  
New Host ◽  
Experimental Station ◽  
Rothamsted Experimental Station ◽  
Fat Bodies

After penetrating through the body wall into the haemocoel of Bradysia paupera, the fertilized female of Tipius sciarae increased in size and slowly expelled the enlarging uterine cells through the vulva.Within 7 days of penetration, the females were mature and began laying eggs into the haemocoel of the host. The eggs hatched in 3 days and, within 2 weeks, the host–s body was swarming with juvenile nematodes. The juveniles moulted three times in the body cavity of the host and 4th-stage forms emerged through ruptures in the intestine or body wall (in larval hosts) or were deposited on the surface of the soil (by adult female flies). They then moulted to adult forms while remaining ensheathed in their last juvenile cuticle, mated, and the fertilized infective females were ready to enter a new host.Most parasitized fly larvae died before reaching the pupal stage but some emerged as adults, still carrying the nematodes within them. All parasitized adult flies were sterile. Infested larvae had smaller fat bodies and adult histoblasts than normal larvae and took twice as long to develop.Preliminary tests suggested that this nematode may be useful in controlling sciarid gnats in glasshouses.T. sciarae (Bovien) and T. gibbosus (Leuckart) were compared.This work was done at Rothamsted Experimental Station, Harpenden, Herts, England, while the author held a postdoctoral grant from the National Institutes of Health, Bethesda, Maryland. I thank Mr F. G. W. Jones for a place in the Nematology Department, Dr Audrey Shepherd for supplying the New Blue R stain, Dr J. B. Goodey for advice, and Dr K. Lindhardt, Denmark, for the loaning of the late Dr Bovien–s slides of T. sciarae.

Memoirs: The Genital Organs of Stylaria lacustris, with an account of thier Development

1924 ◽  
Vol s2-68 (269) ◽  
pp. 147-186
Author(s):  
H. R. MEHRA
Keyword(s):  
Body Wall ◽  
Vas Deferens ◽  
Ejaculatory Duct ◽  
Body Cavity ◽  
The Body ◽  
Yolk Mass ◽  
Sperm Duct ◽  
Prostate Cells ◽  
Stylaria Lacustris ◽  
Columnar Cells

1. The genital organs of Stylaria lacustris are described in detail. The vas deferens opens into the atrium on the anterior face near the opening of the ejaculatory duct and not at the top as described by all the previous authors. The prostate surrounds not only the atrium but also the vas deferens in segment 6. 2. The prostate secretion passes through the atrial epithelium, which consequently hypertrophies and disappears 3. The development of the genital organs proceeds with great rapidity when the sexual phase appears, which occurs only once a, year from the end of September to the beginning of December. There is no long intervening period between the development of the gonads, and other genital organs. 4. The order of development seems to be connected with the time or order of their functioning. 5. The gonads are peritoneal in origin. The sperm-sac and orisac are large portions of the body-cavity enclosed by the extension backwards of septa ⅚ and 6/7 respectively. The yolk-mass is formed by a process of metabolic change in the cytoplasm of some of the ova. 6. The sperm-duct is partly peritoneal in origin and partly an ectodermal invagination. The funnel and the vas deferens rudiments arise by a proliferation of the peritoneal cells on the anterior face of septum ⅚, which assumes the form of a deeply shining plate of columnar cells with prominent nuclei. This after the funnel rudiment becomes the sperm-cord and penetrates the septum in front of the ovary, reaching near the body-wall the atrial rudiment, which is soon formed as an ec todermal invagination. The prostate cells arise from the peritoneum near the rentral body-wal1 of the sixth segment in the neighbourhood of the atrial rudiment. 7. The rudimentary female funnel, which opens ont at the female opening, arises as, an outgrowth from the peritoneum at the base of septum 6/7. 8. The spermatheca srises as an invagination from the ectoderm. I agree with Bergh that the sperm, zthecae are to be considered as new structures, and not phylogenetically connected with the genital ducts as Gatenby supposes to be the case in Tubifex rivulorum. 9. A fern stages obtained showing the development of these organs in Nais e1inguis confirm the above observntions.

Functional bursting by the dracunculoid nematode Philonema oncorhynchi

Parasitology ◽  
1974 ◽  
Vol 69 (3) ◽  
pp. 417-427 ◽  
Author(s):  
J. W. Lewis ◽  
D. R. Jones ◽  
J. R. Adams
Keyword(s):  
Sodium Chloride ◽  
Hydrostatic Pressure ◽  
Sockeye Salmon ◽  
Body Wall ◽  
Body Cavity ◽  
The Body ◽  
Absolute Pressure ◽  
Unit Surface Area ◽  
Ionic Exchange ◽  
Rate Of Increase

Using biomedical techniques experimental determinations of the hydrostatic pressure in the pseudocoel of adult female Philonema oncorhynchi indicated that the rate of increase in pressure (dP/dT) and absolute pressure values (cm/H2O) shown by bursting worms in distilled water are correlated with the diameter of the nematode. At bursting pressures, wall tension in a wide size range of worms was virtually identical, indicating that the bursting process is independent of muscular contraction. That the generation of the hydrostatic pressure was an osmotic phenomenon was confirmed by measuring dP/dT in prelarvigerous and larvigerous female worms subjected to different concentrations of sodium chloride, ranging from 89 to 800 m-osmol/kg, and also to a variety of solutions of similar osmolarity (155–175 m-osmol/kg), e.g. magnesium sulphate, urea, potassium chloride, sodium chloride and sucrose. The overall rate of uptake was faster in the larger worms but, per unit surface area, small worms had an uptake rate three times that of the large individuals.The prediction that the body wall of female P. oncorhynchi is permeable to ions such as Na+ was confirmed using radiolabelled 22Na and by bringing about changes in the osmolarity of worms subjected, for 5 min periods, to hyperosmotic solutions of sodium chloride and sucrose. The survival of P. oncorhynchi in the body cavity of sockeye salmon, Oncorhynchus nerka, is dependent upon the permeable nature of the body wall of P. oncorhynchi allowing the worm to function as an ‘osmometer', because as the anadromous O. nerka enters fresh water, the osmolarity of its blood plasma is known to decrease by about 15%. At the time of spawning in Cultus Lake, British Columbia, the body fluids of both female P. oncorhynchi and O. nerka are isosmotic, indicating that the worms are able to equilibrate to the above changes and at the same time preventing premature bursting in the body cavity of its host. However, osmotic invasion of water must occur far quicker than ionic exchange since complete release of larvae does take place when female worms pass out into the redd along with the eggs of the fish and burst.

Evolutionary Waves: Patterns in the Origins of Animal Phyla.

1985 ◽  
Vol 33 (2) ◽  
pp. 153 ◽  
Author(s):  
WG Inglis
Keyword(s):  
Body Wall ◽  
Functional Anatomy ◽  
Distinct Group ◽  
Body Cavity ◽  
The Body ◽  
Animal Groups ◽  
Structural Modifications ◽  
Hydrostatic Skeleton ◽  
Animal Phyla ◽  
Common Ancestors

Concordant patterns of embryology, morphology and functional anatomy delimit grades of animal phyla, each of which contains a 'Major Phylum': PARACOELOMATA (nom.nov.) = acoelomates + pseudocoelomates, flexible hydrostatic skeleton, Nematoda; DEUTEROSTOMIA (including lophophorates) = enterocoelic coelom, rigid internal skeleton, Chordata; and PROTOSTOMIA with two subgrades, MONOMERIC P. = unsegmented, single coelom, molluscan blastular cross, partial rigid exoskeleton, Molluscs; and POLYMERIC P. = segmented, multiple coelom, annelid cross, rigid exoskeleton, Uniramia. Such groups are usually treated as arbitrary stages in mono- and limited-branch phylogenies, but recent studies show them to be real and significant because the only phylogenetic links are from each Paracoelomata and Protostomia Phylum to Turbellaria; and each Deuterostomia Phylum to Cnidaria-Ctenophora and/or enteropneust Hemichordata. Similar grades have often been explained by hypothetical common ancestors, which are unnecessary if the phyla arose during 'evolutionary waves'. These attribute the origin of each grade to the likelihood that its constituent phyla arose independently, about the same time, from the same ciliary powered ancestral stock which was preadapted to enabling a potential body cavity to be actualized while evolving a cylindrical, wholly muscle-powered, body with a hydrostatic skeleton. Because such a skeleton is functionally dependent upon other structural modifications, particularly of the body wall, it could appear only when these were also available. If the latter could be supplied in a number of ways, all opportunities would be exploited and a body cavity would appear several times. The morphology suggests that this did happen, so that a pseudocoelom and coelom evolved independently in each phylum where they occur. Because of evidence that Protostomia and Deuterostomia were never linked during evolution, the origin of the coeloms in the former are explained by the Gonocoelic Theory and in the latter by the Enterocoelic. This, with the recognition of the monomeric protostomes as a distinct group, establishes that segmentation arose at the same time as the coeloms, so that their origins are one problem and not two as usually thought. Finally, protistan data suggest that Turbellaria, and so Paracoelomata and Protostomia, arose from 'close mitosis' flagellates, as did Fungi; while Cnidaria, and so Deuterostomia, arose from 'open mitosis' flagellates. as did Plantae. Thus, the classic Animalia division into Protostomia and Deuterostomia may represent a Protista division such that the animal groups are closer to fungi and plants respectively than they are to each other.

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.

The Fine Structure of Obliquely Striated Body Wall Muscles in the Earthworm, Lumbricus Terrestris LINN

1970 ◽  
Vol 7 (1) ◽  
pp. 233-261
Author(s):  
P. J. MILL ◽  
M. F. KNAPP
Keyword(s):  
Fine Structure ◽  
Body Wall ◽  
Striated Muscle ◽  
Thin Sheet ◽  
Lumbricus Terrestris ◽  
Acute Angle ◽  
The Body ◽  
Fibre Axis ◽  
Muscle Fibres ◽  
Longitudinal Fibre

The fine structure of obliquely striated muscle fibres from the body wall of the earthworm has been investigated. Certain details of the structure have been confirmed by cutting serial sections. The fibres contain both thick and thin myofilaments. The latter are attached to Z-material and the 2 types of myofilament are arranged in interdigitating arrays to give rise to A- and I-bands and an H-zone similar to those in cross-striated muscle. The A-bands contain both thick and thin myofilaments and the I-bands only thin myofilaments. The Z-material is rod-shaped and these Z-rods, oriented perpendicular to the sarcolemma, are arranged in numerous parallel rows which run obliquely along the length of the fibre A line drawn parallel to the longitudinal fibre axis through a Z-rod in one row passes through a Z-rod in the next row. A thin, sheet-like array of myofilaments lies between 2 such Z-rods, forming a single sarcomere containing an A-band and 2 I-bands. The flat surfaces of neighbouring sarcomeres are directly apposed to one another but, since the rows of Z-rods run diagonally along the length of the fibre, each sarcomere is displaced longitudinally with respect to the next, so that the A- and I-bands follow an oblique course, instead of a transverse course as in cross-striated muscle. Because of the regular stagger of the sarcomeres A- and I-bands are cut alternately in transverse sections. Also the sarcomeres are very narrow and are seen as bands lying perpendicular to the sarcolemma. In the A-band a variable number of thin myofilaments (up to 12) surrounds each thick one. Cross-links have been seen between the 2 types of filaments. In longitudinal sections an appearance similar to that seen in cross-striated muscle is obtained in one plane (perpendicular to the sarcolemma). In the plane at right angles to this (parallel to the sarcolemma) the A- and I-bands are at an acute angle to the longitudinal fibre axis. The thick myofilaments exhibit a banding of about 15 nm. There is a system of transversely oriented tubules and peripheral vesicles with dyad-like structures occurring at the juxtaposition between the penpheral vesicles and the sarcolemma. It is concluded that this system is sarcoplasmic reticulam, and it is compared with tubular systems in other muscles. Other cellular constituents are described, including a peripheral skeleton of fibrillar bundles.

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