CHAPTER 29 



Exchange of substances through the capillary walls 



E. M. LAND IS 

 J. R. PAPPENHEIMER 1 



Harvard Medical School, Boston, Massachusetts 



CHAPTER CONTENTS 



Filtration and Absorption; General Formulation 

 Capillary Blood Pressure, P c 

 Methods of Measurement 

 Capillary Pressures in Various Tissues; Relation to the 



Osmotic Pressure of the Plasma Proteins 

 Variability of Capillary Blood Pressures Under Control 



Conditions 

 Functional Changes of Capillary Blood Pressure 

 Effects of Venous Pressures and of Venular Constriction on 

 Capillary Pressure 

 Osmotic Pressure of the Plasma Proteins, U p i 

 Methods of Measurement 

 Protein Osmotic Pressure of Human Plasma 

 Species Differences, Fetal Plasma 

 Physiological Significance of the Deviations from van't 



Hoff's Law 

 Physicochemical Aspects of Protein Osmotic Pressure 

 Interstitial Fluid Pressure ('Tissue Pressure'), P, f 

 Proteins in Extracapillary Fluids; n,y 



Capillary Filtrate from Limb Capillaries; Protein Content 

 Interstitial Fluid, Protein Content and n,y 

 Circulation of Interstitial Fluid; Circulation of Protein 

 Filtration Coefficients of Capillaries, k c ; and of Tissues, k, 

 Normal Capillaries 



Effects of Temperature on Filtration Coefficients 

 Adsorbed Plasma Protein and Filtration Coefficients 

 Effects of Injury on Filtration, Absorption, and Filtration 

 Coefficients 

 Capillary stasis 



Filtration coefficients, k c , of injured capillaries 

 Capillary pressure in injury 

 Tissue asphyxia; relation of filtration coefficients to O2, 



CO», and pH 

 Adrenal cortical hormones and filtration coefficients 

 Porosity of the injured capillary wall 

 Diffusion, General Principles 

 Free Diffusion 

 Diffusion Through Porous Membranes, Restricted Diffusion 



Career Investigator, American Heart Association. 



Diffusion and Hydrodynamic Flow, Relation to Pore Di- 

 mensions 

 Diffusion 



Hydrodynamic flow 

 Simultaneous Flow and Restricted Diffusion; Theory of 



Molecular Sieving 

 Distribution of Pore Sizes 



Osmotic Pressure and Osmotic Flow Through Leaky Mem- 

 branes, Osmotic Reflection Coefficients 

 Transcapillary Movement of Lipid-Insoluble Molecules 

 Structure of Muscle Capillaries as Deduced from Permeability 

 Measurements and from Electron Microscopy. Quantita- 

 tive Aspects of Transcapillary Diffusion 

 Molecular Sieving of Large Molecules; Regional Differences 



in Porosity 

 Capillary Permeability to Lipid-Soluble Molecules; Respira- 

 tory Gases 

 Capillary Permeability and Blood Flow in Relation to Exchange 

 of Materials Between Blood and Tissues 

 Blood-Tissue Transport of Oxygen 

 Blood-Tissue Exchange of Small, Nonmetabolized Molecules 



or Ions 

 Nonuniform Distribution of Blood Flow in Relation to 

 Blood-Tissue Exchange 



I . FILTRATION AND ABSORPTION; GENERAL FORMULATION 



"transudation of water and solids" through the 

 walls of blood vessels was proposed by Bartholin 

 (10) in 1653 to explain the flow of lymph. This sug- 

 gestion was largely neglected though a somewhat 

 similar process was expressed vaguely by Hales 

 (140) in 1753 as an "insinuation of liquid" into the 

 wall of the intestine in connection with some of his 

 more prolonged perfusion experiments. Ludwig 

 (223) proposed a definite filtration theory in 1861 

 based largely upon observations made by Noll (263) 



961 



