Tubular GI Flashcards
Most of the alimentary system is contained in the abdominal region of the _____?
abdomino-pelvic cavity
where does the esophagus extend?
between the pharynx and the stomach
where the esophagus begin and end?
in the neck; travels through the thorax and enters the abdomino pelvic cavity connecting to the stomach
what does the stomach join too?
the small intestine
what does the small intestine join too?
the large intestine
where does the large intestine end and what does it join?
pelvic cavity; rectum which is continuous with the anus and so this strucuture has the anal canal that serves as the passageway for feces to exit
how is the GI tract organized? blood supply?
into the foregut, midgut and hindgut; they each have their own
what are the structures of the foregut?
esophagus
stomach
proximal duodenum
(accessory organs: liver, gallbladder, pancreas)
what are the structures of the midgut?
distal duodenum
jejunum/ileum
proximal 2/3 of large intestine
what are the structures of the hindgut?
distal 1/3 of large intestine
sigmoid colon
rectum
what is the arterial supply to the foregut?
celiac trunk
what is the arterial supply to the midgut?
Superior mesenteric artery, comes off aorta and branches wildly
what is the arterial supply to the hindgut?
Inferior mesenteric artery
each of these arteries is an unpaired branch of the _____?
abdominal aorta
HOW DOES FOOD MOVE THROUGH THE GI TRACT?
The abdomen may be divided into 4 quadrants: upper and lower right, upper and lower left.
Food enters the abdomen in the upper left quadrant, moves toward the upper right, then back to the upper left. It then follows the coils of the small intestine that generally moves the food in a direction of upper left to lower right, where it enters the large intestine.
where does digestion begin?
stomach
A valve at the distal end of the stomach prevents food from moving out of the stomach until it has been thoroughly processed. The valve is at the _____ end of the stomach?
pyloric
pyloric antrum is also equal too?
entry way to the pyloric canal.
pyloric canal is also equal too? where does this canal lead?
passageway through the pyloric valve. The canal leads to the duodenum.
what is the membrane attached to the greater curvature of the stomach?
greater omentum
what is the membrane attached to the lesser curvature of the stomach?
lesser omentum
what are the important landmarks of the stomach?
Cardia Body Fundus Pyloric antrum Pyloric canal Greater curvature Lesser curvature
how long is the small intestine?
approximately 6-7 m long
where does the small intestine begin and end?
It begins at the pylorus and ends at the cecum
what does the small intestine contain?
duodenum, jejunum and ileum
what is the shortest segment of the small intestine?
duodenum
where does the jejunum begin?
duodenal jejunal flexure (junction)
T/F, The small intestine occupies all four quadrants of the abdominal cavity?
T
what quadrant is the jejunum located?
upper right and left quadrants whereas the ileum is located in the lower left and right quadrants
where does the lumen of the small intestine begin?
upper left quadrant and moves toward the lower right quadrant
where does the ilieum join the large intestine?
cecum, which is a blind ending pouch that is the initial segment of the large intestine
the opening that joins the ileum to the cecum is also known as the _____?
ileocecal orifice
the cecum is home to this structure?
vermiform appendix. The appendix is attached to the end of the cecum. It is typically 6 – 10 cm in length.
what quadrant is the cecum with the attached appendix located?
the lower right quadrant of the abdomino-pelvic cavity
where does the large intestine extend?
the cecum to the anal canal
what comprises the large intestine?
the ascending, transverse, descending and sigmoid segments.
how is the large intestine characterized?
Haustra (pouch-like sacs)
Omental (epiploic) appendices (fat appendages)
Taenia coli (smooth muscle)
how are the haustra described?
characteristic saccules or pouches; they are normal
what are the taenia coli?
3 bands of longitudinal muscle. These are specializations of the longitudinal smooth muscle layer of the gut wall and serve a motility function.
what are the mental appendices?
accumulations of fat; they are characteristic of the normal colon (even in lean people)
though we know that the distal end of the large intestine is continuous with the rectum and anus what is it lacking?
lacks haustra, omental appendages and teniae coli
what does the wall of the anus include?
muscular sphincters, one of which is under voluntary control
The abdominal cavity is lined by a “serosa”, an epithelial sheet that secretes small amounts of lubricating fluid. This cellular sheet is the _____ ?
parietal peritoneum
The parietal peritoneum reflects off the abdominal wall and extends over the organs of the GI tract. The serosa that covers the organs is the _____ ?
visceral peritoneum
what is the peritoneal cavity? what are the contents?
the space between the parietal and visceral peritoneal layers.
The only contents of the peritoneal cavity is peritoneal fluid, which serves as a lubricant.
what important for the the parietal and visceral peritoneum?
“slippery” surfaces that enable portions of the GI tract to move against itself and also against the abdominal wall. Injury to the peritoneal lining can result in “adhesions” (formed from scar tissue).
The peritoneum first forms a double-layered sheet called _____ ?
mesentery
The mesentery extends to the organ (a segment of the GI tract) and surrounds it. The portion of the mesentery that surrounds the organ is called _____ ?
visceral peritoneum.
the location of the stomach, small intestine, and transverse portion of the large intestine is called the _____?
intraperitoneal
Some GI organs do not display a “mesentery”. Instead, the parietal peritoneum extends directly from the abdominal wall to cover the sides and anterior surface of the organ.
The location of such organs is said to be _____ ?
retroperitoneal
Examples of GI segments that are retroperitoneal include portions of the duodenum, ascending and descending colon and rectum.
what is the peritoneal cavity divided into? how do they communicate?
Greater sac Lesser sac (also known as the omental bursa)
omental foramen (epiploic foramen of Winslow)
The greater omentum and lesser omentum are specializations of the _____?
mesentery (visceral peritoneum)
what is the significance of the mesentery?
affords a passageway for vessels (blood and lymph) and nerves to reach these parts of the GI tract.
T/F, The ascending colon is not suspended by a mesentery?
T
where is the ascending colon?
This segment is “retroperitoneal”, meaning that it is attached directly to the posterior abdominal wall. Peritoneum covers its anterior surface.
T/F, The transverse colon is intraperitoneal?
T
T/F, The ascending (and the descending) colon are (secondarily) retroperitoneal.
T
T/F, The sigmoid colon is also intraperitoneal, if not, describe why?
it is suspended from the posterior abdominal wall by the sigmoid mesocolon, which has a mesentery
The appendix also has a mesentery associated with its entire length called the _____?
mesoappendix, and all mesenteries, provide a pathway by which vessels and nerves reach the GI tract.
this artery is removed in addition to the appendix during an appendectomy?
appendicular artery
the entire GI tract receives arterial blood from branches of this aorta?
abdominal aorta
what are the arteries that supply the entire abdominal region of the GI tract?
Celiac trunk
Superior mesenteric artery
Inferior mesenteric artery
what does the celiac trunk supply?
supplies foregut derived structures, which include stomach, proximal duodenum, (and accessory glands)
what does the superior mesenteric artery supply?
supplies midgut-derived structures including distal duodenum, jejunum, ileum, cecum, appendix, ascending colon and proximal 2/3 of transverse colon.
what does the inferior mesenteric artery supply?
supplies hindgut derived structures including distal 1/3 of transverse colon, descending colon, sigmoid colon, and rectum.
what are the terminal branches of the celiac trunk?
Splenic artery
Left gastric artery
Common hepatic artery
Further branching of these vessels will give rise to arteries that supply stomach and proximal duodenum (foregut derivatives)
where does the superior mesenteric artery originate?
originates from the anterior surface of the abdominal aorta
supplies vessels to part of the duodenum, all of the jejunum and ileum and part of the large intestine (midgut derivatives).
what branches are formed from the superior mesenteric artery and what do they supply?
forms many jejunal and ileal branches that travel through the mesentery to supply the jejunum and ileum and as they approach the GI tract, they form anastomotic networks called arcades and then straight arteries to the wall of the gut
what are the vessels that supply the cecum and the appendix?
Ileal colic – distal ileum, cecum and appendix
Right colic – ascending colon
Middle colic – transverse colon
the portal vein is formed from the confluence of the _____?
splenic and superior mesenteric vein
T/F, The nerves that supply the GI tract are from the autonomic nervous system and include both sympathetic and parasympathetic fibers.
T
what are the parasympathetic fibers that innervate the GI tract?
CN X
what are the sympathetic fibers that innervate the GI tract?
Sympathetic fibers originate in the spinal cord and extend through the sympathetic chain and then into splanchnic nerves to reach celiac, superior and inferior mesenteric ganglia
