278 ANATOMY FOR NURSES [Chap. XIV 



the centre of each lobule, they unite, and all the blood sup])lied 

 to the liver is carried away from it by the one set of \eins de- 

 scribed under head of portal vein. 



Lymphatics. — There is a deep and a superficial set. They 

 begin in irregular spaces in the lobules, form networks around 

 the lobules, and run always from the centre outward. They drain 

 off waste j)roducts and unconsumed nutritious substances. 



Glisson's capsule. — The whole liver is invested in an outer 

 capsule of areolar connective tissue, which is reflected inward 

 at the portal fissure and encloses the vessels and ducts passing 

 through this opening. 



Serous membrane. — With the exception of a few small areas, 

 the liver is enclosed in a serous tunic derived from the jjeritoneum. 



Nerves. — Nerves are derived from the left pneumogastric and 

 the solar plexus.^ 



Functions. — The liver may be compared to a wonderful 

 laboratory, the most wonderful in the body. It has three im- 

 portant functions : — 



1. Bile secreting. — The cells of the liver manufacture bile 

 from the blood brought to them by the i)ortal vein. The function 

 of bile is considered in the next chapter. 



2. Glycogenic. — The cells of the liver take from the blood 

 brought to them by the portal vein a substance called glucose, 

 which is derived from the carbohydrates eaten. This is stored 

 in the liver in the form of glycogen until such time as the body 

 needs more glucose than the food eaten furnishes. When such 

 demand is made, the liver cells reconvert the glycogen into glucose 

 and pour it into the circulation, 



3. Higher chemical actitities. — i\Iany of the end products of pro- 

 tein digestion are toxic substances. Some of these substances are 

 acted upon by the liver and rendered less harmful. Others are 

 changed into urea, and in the form of urea it is possible for the 

 kidneys to eliminate them from the blood. 



The gall-bladder. — The gall-bladder is a pear-shaped sac, lodged 

 in the gall-bladder fissure on the under surface of the liver, where it 

 is held in place by a fold of the peritoneum. It is about four inches 

 (10 cm.) long, one inch (25 mm.) wide, and holds about ten drachms 

 (25 gms.). It is composed of three coats: (1) the inner one is 



' See page 376. 



