Gill Circulation Research Articles

Vascular and microvascular anatomy of the gill of the southern rock lobster, Jasus novaehollandiae Holthius

The vascular architecture of the gill of J. novaehollandiae was studied by light microscopy, scanning electron microscopy and vascular casting. Before fixation or infusion of the vascular casting medium, haemolymph was flushed from the lobster using 3.5% saline infused into the dorsal aorta. J. novaehollandiae has a complex gill circulation, with three types of gill filament present. The fewer, but larger, inner filaments have a longitudinal septum, from 3 to 8 pm thick, dividing them into afferent and efferent channels. By contrast, the septum in the outer filaments is 11-22�m thick. Middle filaments, found between the inner and outer ones, have two septa dividing them into three channels. The gill axis has four major vessels: an afferent vessel supplying the outer and middle filaments, two lateral canals draining the outer filaments, connecting to the middle filaments and supplying the inner filaments on each side of the gill, and an efferent vessel draining the middle and inner filaments. Thus, most of the haemolymph passes through both outer and inner filaments on its route through the gill. Movement of haemolymph from one channel to another within each filament is via a number of lateral lacunae around the sides of the filament. It is postulated that the relatively thick septum of the outer filament acts as a barner to counter-current loss of oxygen from the efferent to the afferent channels of the filament, whereas the thinner septum of the inner filament may not function in this capacity.

The vascular anatomy of the gills of the smooth toadfishTorquiginer glaber (Teleostei: Tetraodontidae)

The branchial vasculature of the smooth toadfish,Torquiginer glaber, was studied by light microscopic examination of Microfil vascular casts, and scanning electron microscopy of critical point dried tissue and vascular corrosion casts. The anatomy of the respiratory vascular bed was similar to that described for other teleosts. An extensive non-respiratory vascular bed was also present in the gills. In each filament this comprised a series of capillaries arising mainly from the efferent side of the gill circulation (efferent filament artery, efferent lamellar arterioles, branches of the efferent branchial artery), but also from the afferent side (afferent filament artery, afferent lamellar arterioles, lamellar blood channels). The capillaries eventually connected to a system of broadly interconnected sinuses in the filament termed the central canal and the afferent and efferent companion vessels. The sinuses connected with a large subepithelial sinus and a pair of venolymphatic vessels in the gill arch. Connections between the subepithelial sinus of the arch and the anterior venous system were demonstrated. It is suggested that the non-respiratory capillaries serve a nutritive function, while the filament sinuses provide a combined venolymphatic drainage for the filament.

Functional aspects of the morphology and vascular anatomy of the gills of the endeavour dogfish,Centrophoms scalpratus (McCulloch) (Elasmobranchii:Squalidae)

The morphology and vascular anatomy of the gills of the Endeavour dogfish,Centrophorus scalpratus, were studied by light microscopic examination of Microfil vascular casts and scanning electron microscopy of vascular corrosion casts and critical point dried tissue. The anatomy of the respiratory vasculature was similar to that described for other elasmobranchs. How-ever, it was noted that approximately one-fifth of the total respiratory exchange area lay within a ventilatory deadspace, thus providing a potential respiratory by-pass shunt pathway. An extensive non-respiratory vascular bed was also present in the gills. In each gill filament there was a series of non-respiratory capillaries arising both from the afferent and efferent sides of the gill circulation (filament corpus cavernosum and efferent filament artery respectively). These capillaries eventually connected to a system of broadly interconnected sinuses in the filament termed the central canal and the afferent and efferent companion vessels. These sinuses connected with a large subepithelial sinus in the gill arch and a pair of large sinuses in the interbranchial septum. It is suggested that the non-respiratory capillaries serve a nutritive function, while the filament, septal and arch sinuses provide a venous and/or lymphatic drainage for the gills. The non-respiratory vascular bed of the gills would not function as a respiratory by-pass shunt pathway.

A study on the blood vascular system of the lamprey gill filament.

The blood vessels in the gill filaments of lamprey, Lampetra japonica, were studied with an electron microscope. Each gill filament is supplied by an afferent filament artery (afa) flanked by a pair of filament veins (fv), along the outer border of the axial plate, and an efferent filament artery (efa) along the inner, free border. Between these arteries are interposed the cavernous body and the blood lacunae. The marginal channel arises from the cavernous body, which leads to the afa, runs along the free border of the secondary lamella collecting oxygenated blood from the lamellar blood lacunae, and finally joins efa. This channel is considered to play an important role in the gill circulation as a bypass between afa and efa. Pillar cells were found only in the blood lacunae of the axial plate and the secondary lamellae. The basal lamina is generally absent on the vascular wall, but only a small amount of dense material could be seen on the basal surface of endothelial cells of afa and fv: this is regarded as an anchoring device between the cell and connective tissue fibrils. Fenestrations are generally absent in the endothelial layer but numerous gaps were seen in the wall of fv. Arterio-venus anastomoses were found between afa or the cavernous body and fv, and between efa or the collecting arteries of the efferent branchial artery and the peribranchial venous sinus. The anastomosing channel consists of the inner endothelial layer and the outer smooth muscle layer, which is thicker in the intermediate portion of the channel. The endothelial cells called "AVA cells" here are characterized by (1) dense cytoplasms, (2) apical microvilli and (3) basal cytoplasmic processes closely associated with smooth muscle cells.

Nautilus pompilius: Branchial circulation enhanced by an auxiliary pumping mechanism

Blood pressure recordings from the vena cava, afferent branchial and efferent branchial veins inNautilus showed that a significant increase in pressure of the gill circulation was achieved by the rhythmic contractions of the renal appendages and pericardial glands.

Metabolic heterogeneity of phosphoglyceride classes and subfractions during cell cleavage and early embryogenesis: Model for cell membrane biogenesis

AbstractDuring the early developmental stages of the toad, Bufo arenarum, Hensel. up to the stage of gill circulation (150 hr of development at 20–25°C) the total phospholipids content as well as that of phosphoglycerides of choline and of ethanolamine were found unchanged. The subfraction of both phosphoglycerides were separated according to the number of double bonds on silver‐ion chromatography and were also found to be unchanged up to the tail bud stage. The distribution of non‐polar side chains in the subfractions varied in both phosphoglycerides showing a structural heterogeneity. In the phosphatidylethanolamines predominate the polyenoic containing subfractions.In contrast with the constant concentration of polar lipids, during early embryogenesis a steady increase in 32P incorporation into phospholipids takes place when oocytes labeled during oogenesis are used. These changes were also correlated with the DNA content up to gill circulation stage.It is proposed that most of the nascent membrane polar lipids during early embryogenesis may be derived from a storage site through an active and specific intracellular redistribution process. At the arrival of the polar lipid to the nascent membrane a change in their covalent structure by introduction of a phosphorylbase from a highly labeled pool may explain the raise in specific activity. This change may be necessary to make possible the assembly of the lipid into the membrane structure.

Expression of the paternal genes for glutamate-oxaloacetate transaminase (GOT) during embryogenesis in Xenopus laevis.

AbstractGenetic differences in soluble glutamate‐oxaloacetate transaminase (GOT) electrophoretic mobility have been used to determine the time of expression of paternal genes in Xenopus laevis embryos. Maternal isozymes in unfertilized eggs persist through the first two days of development. Paternal‐type bands appear at three days of development when embryos are Stage 37 (gill circulation). The time of expression of paternal GOT genes appears to occur at the same stage as in R. pipiens ♀ × R. palustris ♂ hybrids. These results are discussed in terms of the genomic control of early amphibian development.

Observations on the behavior of the right ventricular outflow tract, with reference to its developmental origins

The behavior of the mammalian right ventricular outflow tract has been considered, in accordance with its classic position in developmental anatomy, as a derivative of the bulbus cordis, a division of the primitive vertebrate cardiac tube. The outflow tract was studied by high speed cinematography and by strain gauge arches sutured to appropriate segments of the right ventricle in dogs. Cinematographic observations were also made on the bulbus cordis at the epitome of its development in gill-breathers, as represented by a typical elasmobranch; it was similarly observed in its modified form in the turtle, where it has been adapted and modified to the requirements of the newly evolved pulmonary circulation. The observations on the outflow tract in these studies indicate that it is a functionally distinct portion of the right ventricle. It expands in early systole concordantly with the pulmonary artery. Its contraction is delayed both in the cinefilms and in curves from strain gauge arches which measure the onset of tension in the segments of myocardium to which they are sutured. Relaxation and diastolic filling begin in the inflow tract at a time when outflow tract tonus remains at least partially sustained. Cinefilm observations on the bulbus cordis in both the shark and turtle are described. The roles of this structure in the single gill circulation of the shark and of its modified homologue in the incomplete double circulation of the turtle are interpreted. The study suggests that the mammalian right ventricular outflow tract may retain and utilize the inheritance from its parent structure. This is particularly evident in congenital heart disease in which abnormal pressure and flow loads may exist and, in essence, certain of the conditions of a more primitive circulatory organization are present. The manner in which the outflow tract responds to these atavistic circumstances is illustrated by selective examples from cases of human disease. Both the experimental and the clinical data support the view of Sir Arthur Keith that, regardless of the anatomic form it may take and regardless of the stage of vertebrate development, the functional integrity of the bulbus cordis remains, in its essentials, unchanged.

THE TIME-TEMPERATURE RELATION OF DIFFERENT STAGES OF DEVELOPMENT

1. Stages in embryo formation among Amphibia between yolk plug and gill circulation have similar time-temperature relations.2. The time-temperature relation of cleavage, although constant from first to fourth cleavages, differs from that of embryo formation.3. It is suggested that the different time-temperature relations of cleavage and of morphogenesis represent different controlling processes; while the similarity of the time-temperature relations among cleavages and among stages of later development is the expression of a common controlling process in each case. These controlling processes are probably parts of the respiratory metabolism and they prevent temperature from disorganizing development.