CHAPTER 16
Digestive Glands and Associated Organs
307
Figure 16-1.
Overview of the digestive glands and associated organs.
The
major digestive glands
include the
salivary glands
,
pancreas
, and
liver
. Although the
gallbladder
is not a gland, it is closely
associated
with the liver and digestive system. The digestive glands and gallbladder are located outside of the digestive tract. Their ducts carry
their products (
saliva
) into the oral cavity or into the lumen of the duodenum of the small intestine (
pancreatic secretions
and
bile
). The
salivary glands
include the
major salivary glands
and the
minor salivary glands
. The
parotid
,
submandibular
, and
sublingual glands
are
the three major salivary glands. These glands are either serous glands or mixed glands (both serous and mucous). Most of the minor
salivary glands are mucous or mixed glands, with only von Ebner glands being entirely serous glands (see Fig. 14-6A). For details of clas-
si± cation of the glands see Chapter 3, “Epithelium and Glands.” The
pancreas
includes an
endocrine portion
(islets of Langerhans) and
an
exocrine portion
. The
endocrine portion
secretes hormones into the bloodstream (see Chapter 17, “Endocrine System”), whereas the
exocrine portion
has ducts that carry enzyme products into the lumen of the duodenum (see Figs. 16-9A to 16-10B). The
liver
produces
bile
, which is carried by the bile duct system into the gallbladder (see Figs. 16-11 and 16-15A). The liver also aids in the metabolism of
lipids, carbohydrates, and proteins; stores iron, glycogen, triglycerides, and vitamins A, D, and B12; and detoxi± es certain toxic sub-
stances in the blood. The
gallbladder
stores, concentrates, and releases bile into the duodenum (see Fig. 16-15A,B).
Parotid
gland
Liver
Liver
Gallbladder
Gallbladder
Pancreas
Main duct of
parotid gland
Submandibular
gland
Sublingual
gland
Main duct of
submandibular
gland
Digestive Glands and Associated Organs
I. Major Salivary Glands
A. Parotid glands (serous)
B. Submandibular glands (mixed, predominately serous)
C. Sublingual glands (mixed, predominately mucous)
II. Pancreas
A. Exocrine portion
B. Endocrine (islets of Langerhans) portion
III. Liver
A. Central artery
B. Portal triad
C. Liver lobules
1. Classic lobule
2. Portal lobule
3. Hepatic acinus
IV. Gallbladder
A. Mucosa
B. Muscularis
C. Serosa
previous page 322 Dongmei Cui -  Atlas of Histology with Functional and Clinical Correlations 2011 read online next page 324 Dongmei Cui -  Atlas of Histology with Functional and Clinical Correlations 2011 read online Home Toggle text on/off