Download Chapter 23: The Digestive System

The Digestive System
The digestive system is responsible for the food-processing activities of
ingestion, digestion, absorption, and elimination of feces. Because of the
external openings, you will be presented with the unique concept that
food “inside” the alimentary canal (the GI tract) is actually “outside” of
the body. The structural plan of the alimentary canal includes digestive
organs: the mouth, pharynx, esophagus, stomach, small intestine, and
large intestine. In addition, it contains several accessory digestive organs:
the teeth, tongue, gallbladder, major salivary glands, liver, and pancreas.
A clear understanding of the peritoneum, peritoneal cavity, and
associated mesenteries is essential to your study. The general
arrangement, location, gross anatomy, microscopic anatomy, and
functions of all the aforementioned structures are part of your study of
the digestive system.
1: Describe an overview of the digestive system.
__ Identify the anatomical abdominal regions and quadrants, locating the
positions of the abdominopelvic organs.
__ List and describe specific and essential food-processing activities of the
digestive system.
__ Draw a simple diagram distinguishing peristalsis from segmentation.
2: Explain the peritoneum and peritoneal cavity.
__ Define peritoneum, distinguishing among visceral peritoneum, parietal
peritoneum, and the peritoneal cavity.
__ Define mesentery
__ Explain the difference between retroperitoneal organs and
intraperitoneal organs, and give several examples.
__ Name several specific examples of mesenteries, describing their
locations and functions, and indicating whether each example is dorsal
or ventral. (Note: Some mesenteries are called “ligaments”; do not
confuse this terminology with fibrous ligaments that connect bone to
bone.)
3: Describe the general characteristics of the alimentary canal.
__ Describe the histology of the alimentary canal wall, including structure
and function of smooth muscle.
__ Draw a cross section and label the four layers of the alimentary canal
wall at the level of the small intestine.
__ Name the visceral nerve plexuses that occur in the wall of the
alimentary canal, and list the types of fibers and neurons present.
__ Describe the effects of sympathetic and parasympathetic innervation
to the stomach.
4: Describe the mouth (oral cavity) and its associated organs.
.
__ Describe the gross anatomy of the oral cavity.
__ Identify the type of epithelium that lines the oral cavity.
__ Explain the function of lips and cheeks, also explaining why lips are
reddish.
__ Describe the structure and function of the tongue, including papillae
and taste buds.
__ Name and identify locations of major salivary glands.
5: Describe the gross anatomy and histology of the pharynx,
esophagus, and stomach.
__ Explain the role of the pharynx during swallowing.
__ Describe the location and gross anatomy of the pharynx, including
openings.
__ Describe the location, gross structure, and function of the esophagus.
__ Explain how the outer layer of the wall of the esophagus differs from
the rest of the digestive tract.
__ Describe the location, gross anatomy, and functions of the stomach.
__ Compare and contrast the microscopic structure of the esophagus and
stomach.
6: Describe the small intestine and the large intestine and their roles
in
digestion.
__ Describe the location and functions of the small intestine, identifying
its individual segments.
__ Explain why the duodenum is retroperitoneal.
__ Identify major ducts and their contents that empty into the duodenum.
__ Describe the features of the small intestine that increase its surface
area.
__ Describe the location and functions of the large intestine, identifying
its subdivisions.
__ Describe and identify special anatomical features on the external
surface of the colon.
__ Compare the lining of the large intestine to the lining of the small
intestine.
__ Describe defecation.
7: Describe the liver, gallbladder, pancreas, and blood flow through
the liver.
__ Identify the location, and list the functions of the liver.
__ Describe the gross anatomy of the liver, including its lobes,
mesenteries, and vessels.
__ Describe liver lobules, including the components of a portal triad.
__ Outline the flow of blood through the liver. (Reminder: It has two
blood-supply sources.)
__ Explain the functions of hepatocytes.
__ Explain the functions of hepatic macrophages.
__ Identify the location, structure, and function of the gallbladder.
__ Trace the movement of bile from its point of secretion all the way to
the duodenum.
__ Explain the function of bile.
__ Identify the location, structure, and function of the pancreas.
8: Describe diseases and disorders of the digestive system.
__ Discuss the causes and symptoms of peptic ulcer, intestinal
obstruction, inflammatory bowel disease, viral hepatitis, and cystic
fibrosis.
9: Discuss the development of the digestive system and the
consequences of aging to the digestive system.
__ Discuss how aging affects digestive processes and diseases associated
with aging and the digestive system.