1. Unit Thirteen: Metabolism and Temperature Regulation
Chapter 70: The Liver as an Organ
Guyton and Hall, Textbook of Medical Physiology, 12th edition

2. Basic Properties
Physiologic Anatomy of the Liver
Largest organ of the body, contributes about 2% of the
total body weight
Functional unit is the liver lobule; liver contains
50, ,000 individual lobules

3. Physiologic Anatomy of the Liver
Basic Properties
Physiologic Anatomy of the Liver
Fig Basic structure of a liver lobule

4. Basic Properties
Hepatic Vascular and Lymph Systems
Blood flows through the liver from the portal vein
and hepatic artery
Liver has high blood flow and little vascular
resistance
Liver functions as a blood reservoir
Liver has high lymph flow

5. Basic Properties
Regulation of Liver Mass-Regeneration
The liver can restore itself after significant hepatic
tissue loss
Control mechanisms are largely unknown but may
be regulated by hepatocyte growth factor (HGF)
Once the liver has returned to its normal size,
growth is inhibited, possibly by cytokines
(i.e. transformng growth factor-beta)

6. Basic Properties
Hepatic Macrophage System Serves a Blood
Cleansing Function
Kupffer cells- large phagocytic macrophages that
line the hepatic venous sinuses
Removes approximately 99% of the bacteria
entering the portal blood from the intestinal
tract

7. Basic Properties
Metabolic Functions of the Liver
Carbohydrate metabolism
1) storage of large amounts of glycogen
2) conversion of galactose and fructose to glucose
3) gluconeogenesis
4) formation of many chemical compounds from
intermediate products of cbh metabolism
5) important for maintaining a normal blood
glucose concentration

8. Basic Properties
Metabolic Functions of the Liver
Fat metabolism
1) oxidation of fatty acids to supply energy
for other body functions
2) synthesis of large quantities of cholesterol,
phopholipids, and most lipoproteins
3) synthesis of fat from proteins and cbhs

9. Basic Properties
Metabolic Functions of the Liver
c. Protein metabolism
1) deamination of amino acids
2) formation of urea for removal of ammonia
from the body fluids
3) formation of plasma proteins
4) Interconversions of the various amino acids
and synthesis of other compounds from
amino acids

10. Basic Properties
Metabolic Functions of the Liver
d. Other metabolic functions
1) storage site for vitamins
2) stores iron as ferritin
3) forms the blood substances used in coagulation
4) removes or excretes drugs, hormones, and
other substances