The Mechanism of Urine Formation in Invertebrates

1937 ◽  
Vol 14 (1) ◽  
pp. 20-34 ◽  
Author(s):  
L. E. R. PICKEN
Keyword(s):  
Sodium Chloride ◽  
Hydrostatic Pressure ◽  
Osmotic Pressure ◽  
Vapour Pressure ◽  
Average Rate ◽  
Colloid Osmotic Pressure ◽  
Pericardial Fluid ◽  
Anodonta Cygnea ◽  
Cent Sodium ◽  
Urine Formation

1. In Anodonta cygnea: (a) The blood has a vapour pressure equivalent to that of a solution of ca. 0.10 per cent sodium chloride. (b) The pericardial fluid is isotonic with the blood. (c) The urine has a vapour pressure equivalent to that of a solution of ca. 0.06 per cent sodium chloride. (d) The hydrostatic pressure of the blood is ca. 6 cm. of water. (e) The calculated colloid osmotic pressure is ca. 3.8 mm. of water. (f) The average rate of filtration of fluid into the pericardium is ca. 250 c.c. in 24 hours. (g) The salt uptake from ingested phytoplankton is estimated as equivalent to 0.012. g. sodium chloride in 24 hours. (h) The loss of osmotically active substance in the urine is estimated as equivalent to 0.15 g. sodium chloride in 24 hours. 2. In Limnaea peregra the vapour pressure of the blood is equivalent to that of a solution of ca. 0.43 per cent sodium chloride. The pericardial fluid is isotonic with the blood, and the urine has a concentration equivalent to ca. 0.30 per cent sodium chloride. 3. In Limnaea stagnalis the hydrostatic pressure of the blood is ca. 8 cm. of water. The colloid osmotic pressure of the blood is ca. 2.5 cm. of water (calculated); that of the pericardial fluid is ca. 0.7 cm. of water.

scholarly journals The Mechanism of Urine Formation in Invertebrates

1936 ◽  
Vol 13 (3) ◽  
pp. 309-328
Author(s):  
L. E. R. PICKEN
Keyword(s):  
Hydrostatic Pressure ◽  
Osmotic Pressure ◽  
Body Fluid ◽  
External Medium ◽  
Carcinus Maenas ◽  
Colloid Osmotic Pressure ◽  
Body Fluids ◽  
The Body ◽  
Small Animals ◽  
Urine Formation

1. In Carcinus maenas: (a) The blood may be hypertonic, isotonic or hypotonic to the external medium. (b) The urine may be hypertonic, isotonic or hypotonic to the blood, and its concentration may differ in the two antennary glands. (c) The hydrostatic pressure of the body fluid is c. 13 cm. of water. (d) The colloid osmotic pressure of the blood is c. 11 cm. of water. (e) The urine probably contains protein and has a colloid osmotic pressure of c. 3 cm. of water. 2. In Potamobius fluviatilis: (a) The blood is hypertonic to the external medium. (b) The urine is hypotonic to the blood but hypertonic to the external medium and its concentration may differ in the two antennary glands. (c) The hydrostatic pressure of the body fluid is c. 20 cm. of water. (d) The colloid osmotic pressure of the blood is c. 15 cm. of water. (e) The urine may contain protein and has a colloid osmotic pressure (calculated) of c. 2 cm. of water. 3. In Peripatopsis spp.: (a) The blood is hypertonic to the urine. (b) The hydrostatic pressure of the body fluid is c. 10 cm. of water. (c) The colloid osmotic pressure (calculated) of the blood is c. 5 cm. of water. (d) The urine may contain protein and has a colloid osmotic pressure (calculated) of c. 2.5 cm. of water. 4. It is concluded that filtration is possible and that secretion and resorption almost certainly occur in the formation of the urine. 5. A microthermopile is described. 6. Methods are described for measuring the hydrostatic pressure and the colloid osmotic pressures of the body fluids in small animals.

Influence of hydrostatic pressure gradients on regulation of plasma volume after exercise

1998 ◽  
Vol 85 (2) ◽  
pp. 667-675 ◽  
Author(s):  
Gary W. Mack ◽  
Roger Yang ◽  
Alan R. Hargens ◽  
Kei Nagashima ◽  
Andrew Haskell
Keyword(s):  
Hydrostatic Pressure ◽  
Osmotic Pressure ◽  
Plasma Volume ◽  
Fluid Pressure ◽  
Colloid Osmotic Pressure ◽  
Upright Position ◽  
Upright Posture ◽  
Immediate Recovery ◽  
Before And After ◽  
The Impact

The impact of posture on the immediate recovery of intravascular fluid and protein after intense exercise was determined in 14 volunteers. Forces which govern fluid and protein movement in muscle interstitial fluid pressure (PISF), interstitial colloid osmotic pressure (COPi), and plasma colloid osmotic pressure (COPp) were measured before and after exercise in the supine or upright position. During exercise, plasma volume (PV) decreased by 5.7 ± 0.7 and 7.0 ± 0.5 ml/kg body weight in the supine and upright posture, respectively. During recovery, PV returned to its baseline value within 30 min regardless of posture. PV fell below this level by 60 and 120 min in the supine and upright posture, respectively ( P < 0.05). Maintenance of PV in the upright position was associated with a decrease in systolic blood pressure, an increase in COPp (from 25 ± 1 to 27 ± 1 mmHg; P < 0.05), and an increase in PISF (from 5 ± 1 to 6 ± 2 mmHg), whereas COPi was unchanged. Increased PISFindicates that the hydrostatic pressure gradient favors fluid movement into the vascular space. However, retention of the recaptured fluid in the plasma is promoted only in the upright posture because of increased COPp.

Functional characteristics of the renal interstitium

1981 ◽  
Vol 241 (2) ◽  
pp. F105-F111 ◽  
Author(s):  
M. Wolgast ◽  
M. Larson ◽  
K. Nygren
Keyword(s):  
Hydrostatic Pressure ◽  
Osmotic Pressure ◽  
Plasma Proteins ◽  
Protein Transport ◽  
Fluid Transport ◽  
Colloid Osmotic Pressure ◽  
Capillary Membrane ◽  
Tubular Transport ◽  
Physical Forces ◽  
Capillary Fluid

The renal interstitial space analyzed as "inulin space" comprises about 13% in the rat. The Starling forces of this compartment are governed by the balance between tubular and capillary fluid transport and also by the leakage of plasma proteins from the blood side. Protein transport will occur in a large-pore system in the peritubular capillary membrane. During control antidiuresis, the interstitial hydrostatic pressure is 2-4 mmHg. The colloid osmotic pressure shows a larger variability but is generally about 5 mmHg. During conditions of depressed capillary reabsorption but unchanged tubular reabsorption, as in saline expansion, the interstitial hydrostatic pressure rises 3-4 times, whereas the colloid osmotic pressure will show a steep fall resulting from the increased fluid entry and unchanged protein transport. The interstitial volume increases only slightly, since it is compressed by the expanding tubules. The influence of interstitial physical forces on tubular transport remains unclear, mainly due to the inaccessibility of the lateral interspaces to direct measurement of relevant parameters.

scholarly journals The osmotic pressure of compressible solutions of any degree of concentration

1907 ◽  
Vol 79 (533) ◽  
pp. 519-528 ◽  
Keyword(s):  
Hydrostatic Pressure ◽  
Osmotic Pressure ◽  
Vapour Pressure ◽  
Concentrated Solutions ◽  
Insufficient Attention ◽  
Pure Solvent ◽  
The Subject ◽  
Great Simplicity ◽  
Made In

This paper is an attempt to make more complete the theory of solutions, at the same time maintaining as great simplicity of treatment as is possible without sacrificing precision. Renewed attention has been called to the subject, owing to the success of the experiments of the Earl of Berkeley and Mr. E. J. Hartley on the osmotic pressure of concentrated solutions of sugars. Diversity of opinion has existed in regard to the interpretation of these experiments, insufficient attention having been previously paid to the influence of the hydrostatic pressure of the pure solvent upon the value of the osmotic pressure. The principal advances made in this paper consist in simply demonstrating the influence of pressure upon osmotic pressure for compressible solutions and in including the effect of the variability of vapour pressure with hydrostatic pressure. The influences of accidental properties (such as the effects of gravitation) are excluded. Summary of Notation . The following is the notation employed. All the values are isothermal values. Solution .— Hydrostatic pressure ................................................................ p Vapour pressure corresponding to hydrostatic pressure p .. π p Vapour pressure when solution is in contact with its own vapour alone.............................................. π π Volume at hydrostatic pressure p .......................................... V p Reduction of volume when 1 gramme of solvent escapes....... s p Osmotic pressure for hydrostatic pressure p ........................... P p Osmotic pressure for hydrostatic pressure π π ....................... P π

scholarly journals The Interaction of Ph, Tonicity, and Electrolyte Concentration on the Motility of Fowl Spermatozoa

1958 ◽  
Vol 11 (2) ◽  
pp. 177 ◽  
Author(s):  
RG Wales ◽  
IG White
Keyword(s):  
Sodium Chloride ◽  
Citric Acid ◽  
Chemical Composition ◽  
Osmotic Pressure ◽  
Sodium Carbonate ◽  
Electrolyte Concentration ◽  
Chloride Content ◽  
Cent Sodium ◽  
Sodium Phosphates

The motility of fowl spermatozoa has been studied in vitro under various modifications of pH, osmotic pressure, and chemical composition of diluents. The glucose and sodium chloride content of the diluents has been varied to give tonicities ranging between that of 0�45 and 1�8 per cent. sodium chloride. Tliese diluents were buffered with citric acid-disodium phosphate, sodium phosphates, or sodium carbonate-bicarbonate mixtures which were equally innocuous.

scholarly journals On the vapour-pressure and osmotic pressure of a volatile solute

1908 ◽  
Vol 81 (548) ◽  
pp. 336-336 ◽  
Keyword(s):  
Liquid Phase ◽  
Hydrostatic Pressure ◽  
Osmotic Pressure ◽  
Vapour Pressure ◽  
Specific Volume ◽  
Vapour Phase ◽  
The Other ◽  
Other Hand ◽  
Specific Volumes

It follows by a method given in a recent paper by the author that if the osmotic membrane be assumed to be impermeable to the solute, the formula for the change of vapour-pressure of a volatile solute with hydrostatic pressure, and also the formula for the osmotic pressure which is deduced from it, must be the same as the formula for a non-volatile solute, and should not contain any terms depending on the vapour-pressure of the solute, except in so far as it may affect the hydrostatic pressure of the solution. If, on the other hand, an osmotic membrane is regarded as a vapour-sieve permeable to the vapour of the solution but not to the liquid phase, the equation takes a different form, depending on the concentration of the constituents in the vapour-phase. If c 1 , c 2 , etc., be the concentrations of the constituents in grammes per gramme of the vapour, and if U 1 , U 2 , etc., be the specific volumes of the constituents in the solution, the change of total vapour-pressure dp of the solution for a change of hydrostatic pressure d P is given by the relation, ∑ c U d P = v dp , where v is the specific volume of the whole vapour-phase. If only on constituent is volatile, this relation reduces to the form U d P = v dp for that constituent.

Effect of end-expiratory airway pressure on accumulation of extravascular lung water

1975 ◽  
Vol 38 (5) ◽  
pp. 907-912 ◽  
Author(s):  
R. H. Demling ◽  
N. C. Staub ◽  
L. H. Edmunds
Keyword(s):  
Hydrostatic Pressure ◽  
Arterial Pressure ◽  
Osmotic Pressure ◽  
Extravascular Lung Water ◽  
Airway Pressure ◽  
Pulmonary Arterial Pressure ◽  
Venous Occlusion ◽  
Colloid Osmotic Pressure ◽  
Lung Water ◽  
Pulmonary Arterial

The effect of end-expiratory airway pressure on the accumulation of extravascular lung water during lobar venous occlusion for 2 h was studied in closed-chest artifically ventilated dogs. Dogs were divided into two groups by end-expiratory airway pressures of 0 or 10 cmH2O. High-pressure lobar pulmonary edema was produced by lobar venous occlusion, which elevated microvascular hydrostatic pressure. After occlusion of the lobar pulmonary vein, lobar venous pressure (and microvascular hydrostatic pressure) rapidly became identical to pulmonary arterial pressure. We measured extravascular lung water (post mortem) and pulmonary arterial pressure and calculated plasma colloid osmotic pressure to determine the relationship between the accumulation of lung water and the difference between pulmonary microvascular pressure and plasma colloid osmotic pressure (net intravascular filtration pressure). At comparable net intravascular filtration pressures, dogs ventilated at the higher end-expiratory airway pressure accumulated more extravascular lung water. This study indicates that increasing end-expiratory airway pressure from zero to 10 cmH2O increases the accumulation of extravascular lung water when microvascular hydrostatic pressure is raised.

Measurements of intrafollicular pressures in the rabbit ovary

1963 ◽  
Vol 205 (6) ◽  
pp. 1067-1072 ◽  
Author(s):  
Lawrence L. Espey ◽  
Harry Lipner
Keyword(s):  
Blood Pressure ◽  
Hydrostatic Pressure ◽  
Osmotic Pressure ◽  
Structural Changes ◽  
Colloid Osmotic Pressure ◽  
Average Pressure ◽  
Steady Pressure ◽  
Pressure Changes ◽  
Direct Proportionality

Pressures within rabbit Graafian follicles have been determined by direct cannulation with micro-pipettes. The average pressure in the antrum of 60 maturing follicles was slightly over 17 mm Hg. There was no difference in the pressures in precoital and postcoital follicles. The average pressure of 15 blood follicles (preatretic) was 50 mm Hg. A direct proportionality was observed between the blood pressure and follicle pressure, suggesting that colloid osmotic pressure contributes little to the total hydrostatic pressure in the follicle. Blebbing preceded the appearance of the ovulation cone. In six measurements made during ovulation, intrafollicular pressure dropped instantly from about 15 to 5 mm Hg at the time of rupture. Visible muscle-like contractions of the follicle, concomitant with recorded pressure changes, were seen in two of six ovulating follicles. A hypothesis explaining the mechanism of ovulation includes the concept that structural changes in the thecal wall result in ballooning and the appearance of an ovulation cone. Rupture of the ovulation cone occurs under the force of a steady pressure in the antrum.

Pulmonary oedema

2010 ◽  
pp. 2992-3001
Author(s):  
Nicholas W. Morrell ◽  
John D. Firth
Keyword(s):  
Hydrostatic Pressure ◽  
Pulmonary Oedema ◽  
Osmotic Pressure ◽  
Interstitial Fluid ◽  
Endothelial Permeability ◽  
Lymphatic Drainage ◽  
Colloid Osmotic Pressure ◽  
Interstitial Tissue ◽  
Tissue Pressure ◽  
Lymphatic Function

The formation of pulmonary oedema depends on the balance between capillary hydrostatic pressure, interstitial tissue pressure, plasma colloid osmotic pressure, endothelial permeability, and lymphatic function. The efficiency of lymphatic drainage of interstitial fluid (which can increase >10-fold) is critical in determining the onset and extent of hydrostatic oedema....

An intravascular protein osmometer

1983 ◽  
Vol 244 (5) ◽  
pp. H726-H729
Author(s):  
J. W. Henson ◽  
R. A. Brace
Keyword(s):  
Hydrostatic Pressure ◽  
Osmotic Pressure ◽  
Hollow Fiber ◽  
Continuous Measurement ◽  
Colloid Osmotic Pressure ◽  
Artificial Kidney ◽  
Albumin Concentration ◽  
Simple Method ◽  
On Line ◽  
Polyethylene Tubing

Our purpose was to develop an intravascular osmometer for measuring the colloid (i.e., protein) osmotic pressure (COP) of circulating blood. A semipermeable hollow fiber from a Cordis Dow artificial kidney (C-DAK 4000) was attached to polyethylene tubing on one end, filled with saline, and sealed at the other end. This was small enough to be inserted into the vasculature of research animals. Protein osmotic pressure plus hydrostatic pressure was measured by a Statham pressure transducer attached to the hollow fiber. Simultaneously, a second catheter and transducer was used to measure hydrostatic pressure, which was subtracted from the pressure measured from the fiber with an on-line computer. The system was documented by a variety of tests. The colloid osmotic pressure vs. albumin concentration curve determined with the fiber is identical to the curve determined by standard membrane osmometry. The time constant for 2- and 8-cm fibers was 2.6 +/- 0.6 and 1.5 +/- 0.5 (+/- SD) min, respectively. The reflection coefficient (+/- SD) of the fiber for NaCl is 0.042 +/- 0.019 (n = 38); COP measured at varying temperatures (absolute scale) changed linearly as expected from COP = nCRT (i.e., van't Hoff's law). Finally, hollow-fiber osmometers were inserted into femoral veins of dogs and sheep, and blood COP was continuously recorded during osmotic manipulations. In conclusion, we attempted to develop and document a simple method for continuous measurement of intravascular colloid osmotic pressure.

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