Morphometry of the Placental Exchange Area

ISBN-13: 9783540081593 / Angielski / Miękka / 1977 / 65 str.

R. Baur

Opis

Considering the placenta from the functional point of view as an exchange organ be- tween mother and foetus, it is noteworthy that placentas of all types have a common structural principle in that all placentas have structures enlarging the surface area avail- able for exchange, as is also the case with other organs with similar functions, such as the lungs, kidneys and intestine. It may therefore be assumed that a quantitative rela- tionship must exist between the structure of the placenta and its function. Accurate information on this relationship could contribute to better understanding of the pla- centa and of its function. The study of this relationship requires quantitative physio- logical and morphological data. Detailed data on quantitative morphology (morphometry) are available mainly for the human placenta. Even these data, however, are rather sparse as far as the early sta- ges of development are concerned, because most-studies relate to full term placentas (see Aherne, 1975; Bender et al. , 1974; Laga et aI. , 1973; Geissler et aI. , 1972; Baur, 1972; Cattoor, 1967; Aherne and Dunnill, 1966). We know of only a few morphomet- ric studies concerned with placentas of other animal species. These studies relate to in- vestigations on the development of the placenta of sheep (Stegeman, 1974) and of cat- tle (Baur, 1972), and measurements carried out on full term placentas of the guinea- pig (Millier et aI. , 1967) and on full term placentas of various other species (Baur, 1973).

Spis treści

A. Introduction.- B. Materials and Methods.- 1. Materials.- 1.1. Development Stages.- 1.2. Full Term Placentas.- 2. Contributors.- 2.1. Development Stages.- 2.2. Full Term Placentas.- 3. Nomenclature.- 4. Measurement Methods.- 4.1. Macroscopic Data.- 4.2. Histological Preparation Procedure.- 4.3. Microscopic Data.- 4.4. Calculation of the Parameters.- 5. Evaluation.- 5.1. Graphical Presentation.- 5.2. Choice of Smoothing Curves.- 5.3. Calculation of the Smoothing Curves.- 5.4. Biological Interpretation of the Regression Parameters.- 5.5. Assessment of the Significance of Differences.- C. Findings.- 1. Growth of the Total Villous Surface Area.- 2. Transformed Values of Areas and Volumes.- 2.1. Square Root of the Total Villous Surface Area.- 2.2. Cube Root of the Total Volume.- 3. Variation of the Area/ Volume Ratio with Time.- 3.1. Linear Coordinates.- 3.2. Transformed Values.- 3.3. Logarithmic Coordinates.- Slope of the Straight Smoothing Lines.- Size of the Total Villous Surface Area.- 4. Relative Villous Surface Area.- 5. Volume of the Compact Parts of the Placenta.- 6. Surface Density.- 7. Macroscopic Chorionic Surface Area.- 8. Surface Enlargement Factor.- 9. Area/Volume Ratios in Full Term Placentas.- 9.1. Compact Placentas.- 9.2. Diffuse Placentas.- 9.3. Compact Versus Diffuse Placentas.- D. Discussion.- 1. Smoothing Curves and Function Equations.- 1.1. Growth of the Total Villous Surface Area.- 1.2. Growth of the Total Volume.- 1.3. Area/Volume Ratio during Development.- 1.4. Relative Villous Surface Area.- 1.5. Area/Volume Ratios in Full Term Placentas.- 2. Compact Parts of the Placenta and Surface Density.- 3. Macroscopic Chorionic Surface Area and Surface Enlargement Factor.- 4. Model of the Growth of the Total Villous Surface Area and of the Total Volume.- 5. Physiological Implications of the Area/Volume Ratio.- 5.1. Development Stages.- 5.2. Full Term Placentas.- 6. Differences in the Size of the Villous Surface Area in Compact and in Diffuse Placentas.- 6.1. Effects of Shrinkage on the Macroscopic Data.- 6.2. Effects of Shrinkage on the Microscopic Data.- 6.3. Excess Surface Area.- 6.4. Duration of Development.- 6.5. Microvilli.- 6.6. Physiological Differences.- 7. Morphometric Findings and Systematic Classification of Placentas.- E. Summary.- F. References.- G. Subject Index.