scholarly journals Respiratory Physiology of Intestinal Air Breathing in the Teleost Fish Misgurnus Anguillicaudatus

1987 ◽  
Vol 133 (1) ◽  
pp. 371-393 ◽  
Author(s):  
BRIAN R. McMAHON ◽  
WARREN W. BURGGREN
Keyword(s):  
Gas Exchange ◽  
Alimentary Canal ◽  
Co2 Exchange ◽  
Gas Diffusion ◽  
Respiratory Physiology ◽  
Misgurnus Anguillicaudatus ◽  
Air Breathing ◽  
Intestinal Gas ◽  
Partial Pressures ◽  
O2 Extraction

The Japanese weatherloaeh (Misgurnus anguillicaudatus Cantor) can exchange gases both with water, via gills and skin, and with air, via the posterior region of the alimentary canal (intestine). Air breathing occurs by unidirectional ventilation of the alimentary canal with air taken in at the mouth and simultaneous expulsion of intestinal gas from the vent. Although the weatherloaeh is not an obligate air-breather, aerial gas exchange normally occurs even at 10°C in air-saturated water. The alimentary canal was examined histologically to assess differences in capillary density and distribution and the diffusion distance for gases across those regions modified for aerial respiration. A respirometer system specifically designed for 2- to 3-g fish allowed continuous measurement of O2 and CO2 exchange via both aquatic and aerial routes at rest and at various ambient temperatures, and respiratory gas partial pressures. Air ventilation volumes, O2 and CO2 partial pressures of exhaled gas, O2 extraction, and O2 and CO2 exchange via the intestine were also determined, allowing the role of the intestine in total gas exchange in the weatherloaeh to be determined and compared with aerial gas exchange organs in other fishes. The alimentary canal is divided into three zones, an anterior glandular portion separated by a spiral section from the posterior, respiratory zone which has the greatest capillary densities and shortest gas diffusion distances. At rest (20°C), the intestine takes up about 20% of total O2 but accounts for less than 3 % of total CO2 elimination (gas exchange ratio = 0.08 for intestine). O2 extraction averages 50%. Increasing temperature causes only slight increases in total metabolic rate (Q10 for MOO2= 1.5-1.8), but highly significant increases in intestinal gas exchange relative to total gas exchange develop as temperature rises. Intestinal gas exchange also rises with decreasing O2 availability. A strong hypoxic drive and weak hypercapnic drive exist for aerial ventilation of the intestine, but are reduced or absent for aquatic ventilation of the gills. In spite of having to function in respiration, absorption, secretion and buoyancy regulation, the potential effectiveness of intestinal gas exchange is shown to be similar to that of other structures used for aerial gas exchange in facultative air-breathing fish.

scholarly journals The alveolar gas equation: do lessons from WW2 research into high flying pilots provide insights into the adaptation to high altitude flight in birds?

2020 ◽  
Author(s):  
Michael Seear
Keyword(s):  
Gas Exchange ◽  
Partial Pressure ◽  
High Altitude ◽  
Oxygen Transport ◽  
Predictive Accuracy ◽  
Gas Diffusion ◽  
Respiratory Physiology ◽  
Partial Pressures ◽  
Starting Point ◽  
Sequential Addition

AbstractDalton’s law of partial pressures applies equally to birds and mammals so, as gas moves from the nostrils to the smallest gas-diffusion airways, the sequential addition of water vapour and CO2, steadily reduce the partial pressure of O2 (PO2) within the gas mixture. The PO2, at the point of gas exchange, at sea level, will be about 60 mm Hg less than the original PO2 within atmospheric air. As a result, the inspired PO2 is an inaccurate starting point for any model of oxygen transport. In humans, the interactions of gases at the point of diffusion, is described and quantified by the Alveolar Gas Equation (AGE). Its development during WW2, provided valuable insights into human gas exchange and also into the responses to high altitude flight in pilots but, except for an early study of hypoxia in pigeons, the AGE is not mentioned in the avian literature. Even detailed models of oxygen transport in birds omit the effect of CO2 clearance on pulmonary oxygen transfer. This paper develops two related arguments concerning the application of the AGE to birds. The first is that avian blood gas predictions, based on the theory of multicapillary serial arterialization (MSA), are inaccurate because they do not account for the added partial pressure of diffused CO2. The second is that the primary adaptation to hypobaric hypoxia is the same for both classes and consists of defending PaO2 by reducing PaCO2 through increasing hyperventilation. Support for the first is demonstrated by comparing PaO2 predictions made using the AGE, with published values from avian studies and also against values predicted by the theory of MSA. The second is illustrated by comparing the results of high altitude studies of both birds and humans. The application of the AGE to avian respiratory physiology would improve the predictive accuracy of models of the O2 cascade and would also provide better insights into the primary adaptation to high altitude flight.

Is there a compromise between nutrient uptake and gas exchange in the gut of Misgurnus anguillicaudatus, an intestinal air-breathing fish?

2007 ◽  
Vol 2 (4) ◽  
pp. 345-355 ◽  
Author(s):  
Ana Filipa Gonçalves ◽  
L. Filipe C. Castro ◽  
Cristina Pereira-Wilson ◽  
João Coimbra ◽  
Jonathan Mark Wilson
Keyword(s):  
Gas Exchange ◽  
Nutrient Uptake ◽  
Misgurnus Anguillicaudatus ◽  
Air Breathing

Histological study of different regions of the skin and gills in the mudskipper, Boleophthalmus boddarti with respect to their respiratory function

1988 ◽  
Vol 68 (3) ◽  
pp. 413-422 ◽  
Author(s):  
N. K. Al-Kadhomiy ◽  
G. M. Hughes
Keyword(s):  
Gas Exchange ◽  
Respiratory Function ◽  
Alimentary Canal ◽  
Histological Study ◽  
Respiratory Organ ◽  
Air Breathing ◽  
Body Regions ◽  
General Importance ◽  
Physiological Adaptations

Gills are the typical respiratory organ of fish in their usual habitat of well-aerated water. The transition from water- to air-breathing required many modifications to the structural and physiological adaptations of the gas-exchange surfaces, i.e. gill, skin, swimbladder and other accessory organs of the alimentary canal. The skin is particularly important among air-breathing fish. This histological study showed varying degrees of adaptation of parts of the skin from different body regions, paying particular attention to the water/blood barrier. The results suggest a general importance in gas exchange in the following order: gill, inner operculum, nasal, body and outer opercular skin, as indicated by increasing thickness of the water/blood barrier.

Vasculature of the Gas-Exchange Organs in Air-Breathing Brachyurans

1990 ◽  
Vol 63 (1) ◽  
pp. 117-139 ◽  
Author(s):  
Peter Greenaway ◽  
Caroline Farrelly
Keyword(s):  
Gas Exchange ◽  
Air Breathing

Acid-base status and spiracular control during discontinuous ventilation in grasshoppers

1995 ◽  
Vol 198 (8) ◽  
pp. 1755-1763 ◽  
Author(s):  
J Harrison ◽  
N Hadley ◽  
M Quinlan
Keyword(s):  
Gas Exchange ◽  
Respiratory Physiology ◽  
Acid Base ◽  
Threshold Levels ◽  
Lubber Grasshopper ◽  
Open Phase ◽  
Internal Co2 ◽  
Acid Base Status

Many insects ventilate discontinuously when quiescent, exhibiting prolonged periods during which little or no gas exchange occurs. We investigated the consequences of discontinuous ventilation (DV) on haemolymph acid­base status and tested whether spiracular opening during DV is due to changes in internal gas tensions in the western lubber grasshopper Taeniopoda eques. At 15 °C, resting T. eques exhibited interburst periods of about 40 min. During the interburst period, haemolymph PCO2 rose from 1.8 to 2.26 kPa, with minimal acidification of haemolymph. Animals in atmospheres in which PCO2 was 2 kPa or below continued to exhibit DV, while atmospheres in which PCO2 was 2.9 kPa or above caused cessation of DV. These data indicate that accumulation of internal CO2 to threshold levels between 2 and 2.9 kPa induces spiracular opening in grasshoppers. In contrast to the situation in lepidopteran pupae, variation in atmospheric PO2 had no effect on interburst duration. Relative to lepidopteran pupae, the internal PCO2 of grasshoppers during DV is threefold lower, the PCO2 required for triggering spiracular opening is also threefold lower, and the open phase spiracular conductance is at least tenfold higher, demonstrating that considerable diversity exists in these aspects of insect respiratory physiology.

Inspiratory Speech as a Management Option for Spastic Dysphonia

1992 ◽  
Vol 101 (5) ◽  
pp. 375-382 ◽  
Author(s):  
Gordon A. Harrison ◽  
Richard H. Troughear ◽  
Pamela J. Davis ◽  
Alison L. Winkworth
Keyword(s):  
Carbon Dioxide ◽  
Gas Exchange ◽  
Voice Quality ◽  
Management Option ◽  
Communication Problems ◽  
Partial Pressures ◽  
The Subject ◽  
And Control ◽  
Laryngeal Resistance

A case study is reported of a subject who has used inspiratory speech (IS) for 6 years as a means of overcoming the communication problems of long-standing adductor spastic dysphonia (ASD). The subject was studied to confirm his use of IS, determine the mechanisms of its production, investigate its effects on ventilatory gas exchange, and confirm that it was perceptually preferable to ASD expiratory speech (ES). Results showed that the production and control of a high laryngeal resistance to airflow were necessary for usable IS. Voice quality was quantitatively and perceptually poor; however, the improved fluency and absence of phonatory spasm made IS the preferred speaking mode for both the listener and the speaker. Transcutaneous measurements of the partial pressures of oxygen and carbon dioxide in the subject's blood were made during extended speaking periods. These measurements indicated that ventilation was unchanged during IS, and that ventilation during ES was similar to the “hyperventilation” state of normal speakers. The reasons for the absence of phonatory spasm during IS are discussed, and the possibility of its use as a noninvasive management option for other ASD sufferers is addressed.

Gas diffusion from ascending gas bubbles

1969 ◽  
Vol 35 (4) ◽  
pp. 711-719 ◽  
Author(s):  
Paul H. Leblond
Keyword(s):  
Surface Tension ◽  
Gas Exchange ◽  
Gas Bubbles ◽  
Gas Diffusion ◽  
Gas Pressure ◽  
Pressure Balance ◽  
Spherical Bubble ◽  
Gas Leakage ◽  
Quantitative Results ◽  
Ascent Velocity

General qualitative rules are derived for the behaviour of the volume of an ascending spherical bubble and of the gas pressure within it. Three modes of behaviour are discerned, corresponding to as many possible orderings of the relative influences of ascent velocity, gas leakage and surface tension on the volume and the pressure balance. These general results are nearly independent of the particular forms of the ascent velocity and gas exchange functions. Quantitative results are presented for the Stokes law régime.

Respiration in the African Lungfish Protopterus Aethiopicus

1968 ◽  
Vol 49 (2) ◽  
pp. 437-452 ◽  
Author(s):  
CLAUDE LENFANT ◽  
KJELL JOHANSEN
Keyword(s):  
Gas Exchange ◽  
Haemoglobin Concentration ◽  
Temperature Shift ◽  
Mean Value ◽  
Gas Analysis ◽  
Air Exposure ◽  
Air Breathing ◽  
African Lungfish ◽  
High Degree ◽  
Protopterus Aethiopicus

1. Respiratory properties of blood and pattern of aerial and aquatic breathing and gas exchange have been studied in the African lungfish, Protopterus aethiopicus. 2. The mean value for haematocrit was 25%. Haemoglobin concentration was 6.2 g% and O2 capacity 6.8 vol. %. 3. The affinity of haemoglobin for O2 was high. P50 was 10 mm. Hg at PCOCO2, 6 mm. Hg and 25 °C. The Bohr effect was smaller than for the Australian lungfish, Neoceratodus, but exceeded that for the South American lungfish, Lepidosiren. The O2 affinity showed a larger temperature shift in Protopterus than Neoceratodus. 4. The CO2 combining power and the over-all buffering capacity of the blood exceeded values for the other lungfishes. 5. Both aerial and aquatic breathing showed a labile frequency. Air exposure elicited a marked increase in the rate of air breathing. 6. When resting in aerated water, air breathing accounted for about 90% of the O2 absorption. Aquatic gas exchange with gills and skin was 2.5 times more effective than pulmonary gas exchange in removing CO2. The low gas-exchange ratio for the lung diminished further in the interval between breaths. 7. Protopterus showed respiratory independence and a maintained O2 uptake until the ambient O2 and CO2 tensions were 85 and 35 mm. Hg respectively. A further reduction in O2 tension caused an abrupt fall in the oxygen uptake. 8. Gas analysis of blood samples drawn from unanaesthetized, free-swimming fishes attested to the important role of the lung in gas exchange and the high degree of functional separation in the circulation of oxygenated and deoxygenated blood.

A primer on respiratory physiology

2019 ◽  
pp. 9-22
Author(s):  
Steven F. Perry ◽  
Markus Lambertz ◽  
Anke Schmitz
Keyword(s):  
Gas Exchange ◽  
Respiratory Physiology ◽  
Gas Laws ◽  
The Core ◽  
Ventilatory Mechanics

According to the principle ‘before you can do what you want to do, you always have to do something else’, this chapter first delves into the basics of respiratory physiology. It begins with summarizing the physical gas laws and their physiological applications to the core process of respiration: diffusion. The chapter finally arrives at introducing the different gas exchange models that can be observed in the various lineages of animals and the basics of ventilatory mechanics. Equipped with this knowledge, it is hoped that the reader will better understand the functional and evolutionary discussions of the respiratory faculties in the following chapters.

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