Chapter 7 Stomach & Intestines Flashcards
What is the stomach?
the dilated portion in the digestive system that acts as a food reservoir and is responsible for the early stages of digestion
What are the four major functions of the stomach?
- storage of food
- mechanical breakdown of food
- dissolution of chemical bonds via acids and enzymes
- production of intrinsic factor, which is necessary for the absorption of B_12
Where is the stomach located?
under the left dome of the diaphragm, with the superior portion joining the esophagus at the cardiac orifice creating and cardiac sphincter, creating the gastroesophageal junction
What are the two borders of the stomach?
- lesser curvature
2. greater curvature
What is the largest potion of the stomach called?
the body
What is the fundus of the stomach?
the superior surface of the body
What does the posterior surface of the stomach contact?
the pyloric antrum empties into the duodenum via the pyloric sphincter
What does in the anterior surface of the stomach contact?
the diaphragm, anterior abdominal wall, and left lobe of the liver
How is blood supplied to the stomach?
via the gastric, splenic, and gastroduodenal arteries; venous drainage corresponds to the arterial supply and drains into the portal system
What is located posterior to the stomach?
the spleen, left adrenal gland, kidney, and body and tail of the pancreas
What are rugae?
the prominent folds the stomach creates when the stomach is empty which allows it to expand with the ingestion of food
How long is the small intestine?
6-7 m long
What are the 3 subdivisions of the small intestine?
- duodenum
- jejunum
- ileum
Where is the small intestine located as a general?
between the pylorus and ileocecal valve
What is the duodenum?
the most proximal portion of the small intestine
What does the structure of the duodenum look like?
it begins at the gastric pylorus and curves around the head of the pancreas to create the letter “C”
Is the duodenum peritoneal or retroperitoneal?
mostly retroperitoneal
Describe the first portion of the duodenum
located in the anterior pararenal space and is formed by the first 2 inches of the duodenum; suspended in the abdomen by the hepatoduodenal ligament
Describe the second portion of the duodenum
the descending 4 inches of the duodenum that follow the right side of the vertebral column just anterior to the right renal hilum. it contains the ampulla of Vater and receives pancreatic and biliary drainage
Describe the third portion of the duodenum
the 10cm of horizontal duodenum that runs horizontally in front of the third lumbar vertebrae. it runs anterior to the IVC, aorta, and IMA and posterior to the SMA
Describe the fourth portion of the duodenum
a second section of ascending duodenum that is 2.5 cm long, it ascends on the left side of the aorta to the level of the L2 vertebrae, where it meets up with the jejunum at the duodenojejunal flexure
What is the duodenojejunal flexure?
where the duodenum and jejunal connect, it is fixed in place by the ligament of Treitz
How long is the jejunum?
2.5 m long
How much of the small intestine is jejunum?
40%
Where is the jejunum located?
it occupies the left upper abdomen or umbilical region of the abdomen
What are characteristics of jejunum tissue?
it is thicker and more vascular than the wall of the ileum
How long is the ileum?
3.5m long
How much of the small intestine is ileum?
60%
Where is the ileum located?
in the right lower abdomen. the loops of the ileum terminate at the ileocecal valve
What is the ileocecal valve?
the sphincter that controls the flow of material from the ileum to cecum of the large intestine
What is so important about the ileum?
it is the place where vitamin B_12 can be absorbed
Why is vitamin B_12 so important?
it is essential for normal RBC formation and nervous system function
How do the segments of the small intestine receive blood?
by the branches of the SMA
Where is the large intestine located?
it lies inferior to the stomach and liver and almost completely frames the small intestines
How long is the large intestine?
1.5 m long with a large diameter and thin walls
Where do the two ends of the large intestine connect to?
starts; ileocecal junction
ends: anus
What are taeniae coli?
the three thickened bands of longitudinal muscle on the outer layer of the large intestine
What are epiploic appendages?
the small fat-filled sac of omentum on the outer surface of the large intestine
What are the 3 main divisions of the large intestine?
- cecum
- colon
- rectum
What is the cecum?
the pouchlike section of the proximal portion of the large intestine that is 7 cm in length. it is the location of the ileocecal valve and the slender vermiform appendix
What is the colon?
the longest portion of the large intestine
What are the four subdivisions of the colon?
- ascending
- transverse
- descending
- sigmoid
What is the ascending colon?
a retroperitoneal portion of the colon that commences at the cecum, ascends the right lateral wall of the abdomen to the level of the liver. it then curves sharply to the left to form the hepatic fixture
What is the hepatic flexure?
the sharp left corner of the colon that marks the beginning of the transverse colon
What is the transverse colon?
the portion of the colon that travels horizontally across the anterior abdomen toward the spleen until it bends sharply downward; creating the splenic flexure. located with the peritoneal cavity and is the largest and most mobile portion of the large intestine
What is the splenic flexure?
the sharp right corner of the colon that marks the beginning of the descending colon?
What is the descending colon?
a retroperitoneal portion that continues inferiorly along the left abdominal wall to the iliac fossa, where it curves to become the S-shaped sigmoid colon posterior to the bladder
What is the sigmoid colon?
the terminal portion of the colon that joins to the rectum
What is the rectum?
a pelvic organ responsible for defecation
What are the two major functions of the large intestine?
- reabsorption of water
2. storage and elimination of fecal material
How is the large intestine supplied with blood?
via the superior and inferior mesenteric arteries and veins supply and drain blood from the large intestine
