The Site of Formation of Hypotonic Urine in the Nephridium of Lumbricus

1949 ◽  
Vol 26 (1) ◽  
pp. 65-75 ◽  
Author(s):  
J. A. RAMSAY
Keyword(s):  
Osmotic Pressure ◽  
Freezing Point ◽  
Freezing Point Depression ◽  
Narrow Tube ◽  
Wide Tube ◽  
Different Parts

1. Methods for the collection of samples of urine from different parts of the nephridium of Lumbricus are described. 2. The osmotic pressures of these samples have been measured by determination of freezing-point depression and have been compared with the osmotic pressure of the medium surrounding the nephridium. 3. The results of this comparison indicate that the ability to form hypotonic urine is certainly present in the wide tube, is possibly present in the middle tube and is probably not present in the narrow tube. 4. The analogy between the nephridium and the vertebrate nephron is discussed.

Ideal Solutions and Colligative Properties

2021 ◽  
pp. 214-227
Author(s):  
Christopher O. Oriakhi
Keyword(s):  
Osmotic Pressure ◽  
Vapour Pressure ◽  
Boiling Point ◽  
Freezing Point ◽  
Freezing Point Depression ◽  
Pure Solvent ◽  
Ideal Solutions ◽  
Pressure Lowering ◽  
Colligative Properties

Ideal Solutions and Colligative Properties deals with the properties of solutions that depend on the concentration, but not the identity, of solute particles. The discussion examines the solution properties of vapour pressure depression, boiling point elevation, freezing point depression and osmotic pressure for an ideal solution, and how they differ from the properties of the pure solvent. Raoult’s law is used to quantify the magnitude of vapour pressure lowering. This is followed by illustrations of boiling point elevation and freezing point depression as well as the determination of boiling and freezing points of a solution. Calculation of osmotic pressure and its use to determine the molar mass of a solute is discussed.

Colloid osmotic pressure changes of dog's blood exposed to different mixtures of CO2 and air

1978 ◽  
Vol 44 (2) ◽  
pp. 254-257 ◽  
Author(s):  
Y. Kakiuchi ◽  
A. B. DuBois ◽  
D. Gorenberg
Keyword(s):  
Red Blood Cells ◽  
Osmotic Pressure ◽  
Cell Volume ◽  
Blood Cells ◽  
Freezing Point ◽  
Colloid Osmotic Pressure ◽  
Red Cell ◽  
Freezing Point Depression ◽  
Pressure Changes ◽  
Different Levels

Hansen's membrane manometer method for measuring plasma colloid osmotic pressure was used to obtain the osmolality changes of dogs breathing different levels of CO2. Osmotic pressure was converted to osmolality by calibration of the manometer with saline and plasma, using freezing point depression osmometry. The addition of 10 vol% of CO2 to tonometered blood caused about a 2.0 mosmol/kg H2O increase of osmolality, or 1.2% increase of red blood cell volume. The swelling of the red blood cells was probably due to osmosis caused by Cl- exchanged for the HCO3- which was produced rapidly by carbonic anhydrase present in the red blood cells. The change in colloid osmotic pressure accompanying a change in co2 tension was measured on blood obtained from dogs breathing different CO2 mixtures. It was approximately 0.14 mosmol/kg H2O per Torr Pco2. The corresponding change in red cell volume could not be calculated from this because water can exchange between the plasma and tissues.

Physiological studies on trematodes: the osmotic activity of Gastrothylax crumenifer

Parasitology ◽  
1966 ◽  
Vol 56 (1) ◽  
pp. 101-104 ◽  
Author(s):  
Madan M. Goil
Keyword(s):  
Sodium Chloride ◽  
Osmotic Pressure ◽  
Freezing Point ◽  
Percentage Change ◽  
Freezing Point Depression ◽  
Gastrothylax Crumenifer ◽  
Physiological Studies ◽  
Osmotic Activity

The percentage change in weight, at 38·2 °C, in different concentrations of sodium chloride at different intervals, of a trematode, Gastrothylax crumenifer, from the reticulum of buffaloes has been recorded.A state of approximate isotonicity is reached between 0·4 and 0·5% sodium chloride.The osmotic pressure has also been expressed in terms of freezing-point depression.

Freezing point depression of rat kidney slices during water diuresis and antidiuresis

1960 ◽  
Vol 199 (5) ◽  
pp. 915-918 ◽  
Author(s):  
George A. Bray
Keyword(s):  
Pressure Gradient ◽  
Osmotic Pressure ◽  
Freezing Point ◽  
Rat Kidney ◽  
Freezing Point Depression ◽  
Water Diuresis ◽  
Outer Medulla ◽  
Kidney Slices ◽  
Outer Stripe ◽  
Osmotic Pressure Gradient

The freezing point depression of slices of rat kidney removed during water diuresis or antidiuresis has been investigated with a microcryoscopic method. The osmotic pressure gradient in the inner medulla first demonstrated by Wirz has been confirmed. The inner medulla was found to be hypertonic to plasma during water diuresis. Hypotonic tubules were present throughout the cortex and outer stripe of the outer medulla.

Correction for loss of CO2 from blood during measurement of osmotic pressure

1978 ◽  
Vol 44 (3) ◽  
pp. 474-478 ◽  
Author(s):  
S. S. Khosla ◽  
A. B. DuBois
Keyword(s):  
Vapor Pressure ◽  
Blood Sample ◽  
Osmotic Pressure ◽  
Freezing Point ◽  
Gas Mixture ◽  
Sample Holder ◽  
Freezing Point Depression ◽  
Pressure Method ◽  
Sample Chamber

During osmolality measurement by the vapor pressure method, exposure of the blood sample to air lowers the blood CO2 content and hence osmolality. A modification of the sample holder of a vapor pressure osmometer is described allowing exposure of the blood sample to a gas mixture with known concentration of CO2 and O2 while inside the closed sample chamber. This restores its CO2 content and hence osmolality. Data are presented comparing the unmodified and modified vapor pressure method with the freezing point depression method. A table was prepared for further correction of osmolality in case the blood's PCO2 differs from that of the gas mixture.

FREEZING POINT VALUES AND MILK SOLIDS-NOT-FAT CONTENT OF RETAIL MILK1

1961 ◽  
Vol 24 (2) ◽  
pp. 48-52 ◽  
Author(s):  
R. W. Henningson
Keyword(s):  
Freezing Point ◽  
Fat Content ◽  
Freezing Point Depression ◽  
Processing Plants ◽  
Added Water ◽  
Milk Solids ◽  
Area Data

Observed freezing point and milk solids-not-fat values were determined for approximately 400 retail samples. Most of these samples were systematically collected at monthly intervals over a calendar year from designated processing plants. The average observed freezing point value found was −0.529°C. The average MSNF value found was 8.88%. No relationship was expected, or found, between the observed freezing point value and the MSNF value of milks. The MSNF value did not assist in explaining high freezing point values or in confirming the presence of added water. It did prevent suspicion which could not be easily confirmed. A minimum freezing point depression standard, based on area data and administered in a manner similar to a minimum butterfat standard, appears to be the most feasible way of utilizing the cryoscopic method for the determination of added water in milk.

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