CHAPTER 41 



The hepatic circulation 1 



STANLEY E. BRADLEY 



Department of Medicine, Columbia University College of Physicians 

 and Surgeons, and Presbyterian Hospital, New York City 



CHAPTER CONTENTS 



Anatomy 

 Methodology 

 Direct Methods 



I lepatic and splanchnic blood Hows 



Hepatic and splanchnic blood volumes 



Hepatic and splanchnic blood pressures 

 Indirect Methods 



Hepatic blood flow 



Splanchnic blood volume and transit time 

 Normal Parameters of the Hepatic Circulation 

 Hepatic Blood Flow 



Splanchnic Vascular Pressures and Resistances 

 Splanchnic Blood Volume 

 Primary Determinants of Hepatic Blood Flow and Volume 

 Cross Section 



Path Length and Distributional Pattern 

 Viscosity 



Volume and Distensibility 

 Secondary Determinants of Hepatic Hemodynamic Adjust- 

 ments 

 Neural Determinants 

 Neurohumoral Determinants 



Epinephrine and norepinephrine 



Acetylcholine 



Autonomic blockade 

 Local Biochemical Determinants 



Oxygen 



Carbon dioxide 



Histamine 

 Physical Determinants 



Intra-abdominal pressure 



Gravity 



Respiration 



Exercise 



1 The preparation of this report was aided by a grant from 

 The Heart and Lung Foundation, New York City. It is sub- 

 mitted in honor of Chester S. Keefer and the Golden Anni- 

 versary of the Evans Memorial Department of Clinical Re- 

 search, Boston Massachusetts. 



Hepatic Circulatory Integration and Dysfunction 

 Hepatosystemic Interrelationships 

 Hepatosplanchnic Interrelationships 



a voluminous literature testifies convincingly, 

 and sometimes eloquently, to the importance of the 

 hepatic circulation in the body economy of verte- 

 brates. The volume and composition of the blood 

 perfusing the liver are undoubtedly major deter- 

 minants of hepatocellular function. The maintenance 

 of the hepatic parenchymal "milieu interieur" with 

 essential nutrients and the delivery of raw materials 

 from the gut and other parts of the body to the liver 

 for processing depends directly upon the blood 

 supply. In even the lowest vertebrates the liver lies 

 in the path of all the vessels draining the splanchnic 

 viscera, thus potentially controlling the total splanch- 

 nic venous outflow (85). The splanchnic vasculature 

 as a whole must be considered therefore an integral 

 part of the hepatic circulatory system. The liver is 

 influential in affecting general cellular metabolism 

 and homeostasis only to the extent to which it can 

 modify the chemical structure of the blood coming to 

 it. A copious flow of blood is required for this purpose 

 and the resultant anatomical arrangements and 

 size of the hepatic vasculature appear to confer upon 

 the liver an important place in cardiovascular dy- 

 namics. 



Quantitative evaluation of the circulatory physiol- 

 ogy of the liver and the other splanchnic viscera has 

 proved extremely difficult owing to the inadequacies 

 of the methods available, to uncertainties arising 

 from species differences, and to the lack of data ob- 

 tained simultaneously to provide information regard- 

 ing the behavior of the remainder of the circulatory 



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