b. Other lymphoid aggregations are found in the walls of the small intestines.
c. The vermiform appendix, attached to the cecum of the large intestine, is also
a mass of lymphoid tissue. It is the "tonsil" of the intestines.
Section VII. ACCESSORY STRUCTURES OF THE DIGESTIVE SYSTEM
1-15. THE LIVER
The liver is a massive glandular organ. In fact, the liver is the largest gland in the
body. The major function of the liver, as far as digestion is concerned, is the production
of bile, a substance that aids in the digestion of lipids (fats). There are salts contained
in the bile (bile salts) that help to emulsify fat globules so that they can be digested by
intestinal lipases. Bile also aids in making the end products of fat digestion more
soluble so that they are absorbed through the intestinal mucosa. Bile is continuously
being made and excreted by the liver. Bile is stored in the gallbladder until it is needed.
The function of the gallbladder is to store bile and release it when it is needed in the
small intestine. The liver also has functions that are not related to the digestive system.
a. Glycogen Storage. When carbohydrates are digested and the end product
sugars are not immediately utilized by the body, they are made into a substance called
glycogen and stored in the liver in that form until needed.
b. Hematopoiesis. The liver is an important organ in the hematopoietic system.
It functions as a blood reservoir during venous pooling and it polices up iron from
destroyed red cells so that it can be used for synthesis of new red cells by the bone
c. Phagocytosis. The liver has phagocytic cells called Kupffer's cells that can
remove bacteria and foreign particles from the blood.
d. Detoxification. This is not the most accurate word to describe this function,
but the liver is responsible for metabolizing many drugs and other substances in the
blood from an active to an inactive form. For example, alcohol is active and is
metabolized by the liver to an inactive substance and the drink wears off.
e. Vitamin Storage and Synthesis. The liver can store large quantities of
Vitamins A and B12. It also functions in the synthesis of Vitamin D from precursors in
the body, a very important vitamin affecting bone structure and function, and blood
f. Blood Coagulation. The liver is the organ responsible for the production of
fibrinogen, prothrombin, and other factors important in the blood clotting mechanism.
Impairment could result in inhibition of the clotting process.