Card Set Information
Chapter 25 The digestive system
Name the major regions & organs of the digetive system.
Oral cavity, pharnyx, esophagus, stomach, small intestines, & large intestines.
Name the accessory organs of the digestive system.
Salivary glands, liver, pancreas & gall bladder
Name the layers of the digestive tract (beginning with the innermost layer).
Mucosa, submocusa, musculari extrena, serosa & adventitia
What are the regions of the small intestines, what are their appromixal lengths?
Duodenum (10-12 inches)
Jejunum (8 feet)
Ileum (12 feet)
Name the regions of the large intestines.
Cecum, ascending colon, transverse colon, descending colon, sigmoid colon, & rectum.
Where are the gastric pits located?
At the opening (superficial) to the gastric glands.
Where are the gastric glands located?
They extend deep into the lamina propria.
Name the structures of the stomach.
Cardia, fundus, body, pylorus/pyloric sphincter, & rugae.
What controls the shape of lumen?
What type of function is this?
The ANS does the controlling
This is an example of an involuntary function
What type of tissue makes up the submucosa?
Dense irregular connective tissue.
What structures are found within the submucosa?
Large blood, lymph vessels & glands. Brunners glands, peyers patches & parasympathetic ganglion.
How are the two muscle layers of the muscularis externa arranged?
These muscles are arranged in two thin concentric layers; circularis and longitudinal.
What is the primary function of the serosa layer?
What areas of the digestive system do not have a layer of serosa?
Esophagus, oral cavity, pharnyx, & rectum.
What layer does the serosa cover?
The muscularis externa.
What is the function of the adventitia layer?
Holds structures in place.
What type of tissue makes up the adventitia?
Dense connective tissue
Name the valves of the small intestines.
Pyloric, & ileo-cecum.
What is the function of the stomach?
Mechanical break down of food.
What is the function of the small intestines?
Digestion, & absorption of 90% of nutrients.
What is considered the major digestive organ?
What is the function of the large intestines?
Reabsorption of water, electrolytes & vitamins. Compaction of contents into feces, & storage & defection.
Name the salivary glands.
Parotid, sublingual, & submandibular
How many salivary glands are there?
3 pairs, 6 total
What is the function of the salivary glands?
Dissolves carbohydrates, flushes mouth, & moisture/lubrication.
Name the digestive enzyme of the parotid salivary glands.
Name the largest visceral organ.
What is the basic functional unit of the liver?
The liver lobule
What are mucosa folds called?
What is the function of Plicae?
Increases surface area
Where is rugae located?
In the mucosa layer of the stomach
What is the function of the rugae?
Allows for expansion of the gastric lumen.
What is chyme?
A soupy mixture, which is the result of ingested substances mixing with acids & enzymes.
What two areas of the digestive system does the pylorus connect?
The body of the stomach & duodenum.
What muscle regulates the release of chyme into the duodenum?
The visceral peritoneum covering the outer surface of the stomach is continous with what?
The greater omentum.
What does the greater omentum form?
A large pouch that hangs like an apron.
What is the function of the greater omentum?
Provides protection & insulation that reduces heat loss to the abdomen.
What tissue lines all regions of the stomach?
Simple columnar epithelium.
What does the mucous layer in the stomach protect?
Protects the epithelium against the acids & enzymes in the gastric lumen.
What does the epithelium in the stomach produce?
A carpet of mucus that covers the luminal surfaces of the stomach.
What does the mucosa of the small intestines form?
What is each villus covered with?
Simple columnar epithelium.
What are the apical surfaces of the epithelial cells in the small intestines carpeted with?
What sits at the base of the villus in the small intestines?
Entrances to the intestinal crypts.
What structure of the small intestines encloses the pancreas?
Which area of the small intestines is considered the mixing bowl?
Almost all essential digestive enzymes enter the small intestines from which accessory digestive organ?
Where does the ileum end?
The ileocecal valve/sphincter
Each villus of the small intestines contains what terminal lymphatic?
What materials do the lacteals transport?
Large lipids & protein complexes
What is another name for Brunners glands?
Duodenal submucosa glands
Brunners glands produce what?
Large quantites of mucus.
What is the purpose of mucus in the duodenum?
Mucus contains buffers that help to elevate the PH of the chyme.
What structures meet at the duodenal ampulla?
The common bile duct from the liver & gall bladder & the pancreatic duct from the pancreas.
What is the duodenal ampulla?
A muscular chamber
Where are peyers patches located?
In the termianl portion of the ileum, near the entrance to the large intestines.
Where is the appendix located?
Attached to the posteromedial surface of the cecum.
Where is the Haustra located?
Wall of the colon.
What is the Haustra?
A series of pouches.
What is the function of the Haustra?
They permit distention & elongation.
What is the taeniae coli?
3 longitudinal ribbons of smooth muscle.
Where is the taeniae coli located?
On the outer surfaces of the colon just beneathe the serosa.
What are hepatocytes?
Name the two blood vessels that deliver blood to the liver.
Hepatic artery proper & hepatic portal vein.
How much blood arrives from the hepatic artery?
Roughly 1/3 while the remainder 2/3 arrives via the hepatic portal vein.
From the liver how does blood return to the systemic circuit?
Through the hepatic vein that opens into the inferior vena cava.
Name the three functions of the liver?
Metabolic, hematological, & digestive.
Where are kupffer cells located?
Within the sunusoidal lining of the liver lobule.
What type of cells are kupffer cells?
Where does blood enter the liver sinusoids?
From the small branches of the portal vein & hepatic artery.
Where is the the triad located?
One at each of the six corners of the liver lobule.
What three structures does the triad consist of?
A branch of the hepatic portal vein, a branch of the hepatic artery proper & a small branch of the bile duct.
Where/how does blood exit the sinusoids?
It enters the central vein of the lobule. The central vein merges to form the hepatic veins that empty into the inferior vena cava.
What two structures unite to create the common bile duct?
The common hepatic duct & the cystic duct.
Where is the sphincter of oddi located?
What does the contraction of the sphincter of oddi prevent?
Seals off the passageway from the common bile duct to the duodenum. Preventing bile from entering the small intestines.
Where/how do the pancreatic enzymes enter the duodenum ampulla?
Via the large pancreatic duct.
What does the pancreatic acini release into the duodenum?
A mixture of water, ions & pancreatic digestive enzymes.
Name the four pancreatic enzymes.
Lipases, carobhydrases, nucleases & proteolytic enzymes.
Lipases digest what materials?
What do carbohydrases digest?
Sugar & starches
Nucleases digest what?
Proteolytic enzymes digest what materials?
Breaks apart proteins.