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Blood volume of the ascidian Pyura praeputialis
Author(s) -
GODDARD C. K.
Publication year - 1975
Publication title -
journal of zoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.915
H-Index - 96
eISSN - 1469-7998
pISSN - 0952-8369
DOI - 10.1111/j.1469-7998.1975.tb03208.x
Subject(s) - extracellular fluid , blood volume , volume (thermodynamics) , biology , dilution , interstitial fluid , albumin , indicator dilution , extracellular , body weight , anatomy , medicine , endocrinology , cardiac output , biochemistry , thermodynamics , blood pressure , physics
Blood dilution curves have been obtained by injecting 125 I labelled albumin and 125 I labelled gamma‐globulin into the blood of Pyura praeputialis . After mixing is complete the dilution curve shows a two‐stepped pattern. There is some question as to how the two steps of the curve should be interpreted. The first step has been extrapolated to give blood volume s.s. , i.e. volume of the vessels, sinuses and lacunae of the vascular system. Values for this range from 30% to 45 % of body weight, with a mean value of 35%. The second step has been extrapolated to give total extracellular fluid volume, i.e. blood volume plus interstitial fluid volume. Values for this range from 21 % to 52 % of body weight, the average being 38 %. The interstitial space ranges from 15 % to 32 % of the weight of the visceral mass, the average being 23 %. The rationale for the above interpretation of the dilution curve is stated and discussed. Most reliable is extracellular fluid volume which probably corresponds to the blood volume of other invertebrates with open systems. An attempt was made to assess the relative importance of (a) the visceral circuit and (b) the tunic circuit, by comparing the specific activities of the visceral mass and the tunic. The specific activities indicate little or no blood in the tunic circuit: this result is suspect.