What does the esophagus descend and enter?
the esophagus descends the posterior mediastinum and enters the abdominal cavity via the esophageal hiatus of the diaphragm
Define the function of the inferior esophageal sphincter
What artery supplies the abdominal part of the esophagus?
the left gastric artery from the celiac trunk (artery) supplies the abdominal part of the esophagus
What does the left gastric vein drain into?
the left gastric vein drains into the hepatic portal vein.
What do some tributaries of the left gastric vein anastomose with?
What does the azygos vein empty into?
some tributaries of the left gastric vein anastomose with esophageal tributaries of the azygos vein. (can cause esophageal varcies)
the azygos vein empties into the SVC thus creating a portal-systemic anastomosis.
How do esophageal varices form and why are they life-threatening?
• Caused by portal hypertension --> blood backs up from left gastric into submucosal veins in esophagus
• Can rupture and cause severe hemorrhage --> LIFE-THREATENING and difficult to control surgically
Alcoholic cirrhosis common cause
How is pyrosis related to GERD?
• Usually the result of regurgitation of small amounts of food or gastric fluid into the lower esophagus (GERD)
How does the inferior esophageal sphincter contribute to hiatal hernia formation? How do paraesophageal and sliding hiatal hernias differ?
• Due to weakening of muscular part of diaphragm, widening of hiatus w/ age
o Cardia remains in normal position (no regurg)
o Pouch of peritoneum (often containing part of fundus) extends through hiatus
• Sliding --> abd part of esophagus, cardia, parts of fundus slides SUP through hiatus, esp when lying down or bending over
o Some regurg because HCl producing cells are above the hiatus
envision the fundus, body, pylorus, and lesser and greater curvatures of the stomach
Interpret how the pylorus controls discharge of stomach contents into the duodenum
Pyloric part: the funnel-shaped outflow region of the stomach; its wider part, the pyloric antrum, leads into the pyloric canal, its narrower part.
The pylorus is the distal, sphincteric region of the pyloric part. It is a marked thickening of the circular layer of smooth muscle that controls discharge of the stomach contents through the pyloric orifice (inferior opening or outlet of the stomach) into the duodenum. Intermittent emptying of the stomach occurs when intragastric pressure overcomes the resistance of the pylorus. The pylorus is normally tonically contracted so that the pyloric orifice is reduced, except when emitting chyme (semifluid mass). At irregular intervals, gastric peristalsis pushes the chyme through the pyloric canal and orifice into the small intestine for further mixing, digestion, and absorption.
What does the common hepatic artery arise from? What does it bifurcate into?
the common hepatic artery arises from the celiac trunk and bifurcates into the hepatic proper and gastroduodenal arteries
What does the right gastric artery branch from? What does it anastomose with?
the right gastric artery branches from the hepatic proper artery and anastomoses with the left gastric artery on the lesser curvature of the stomach.
What does the right gastroepiploic artery reside on? What does it anastomose with?
the right gastroepiploic artery (gastro-omental), a branch of the gastroduodenal artery, resides on the greater curvature of the stomach where it anastomoses with the left gastroepiploic artery, a branch of the splenic artery
What does the right gastric vein and the right and left gastro-epiploic veins deliver?
the right gastric vein and the right and left gastro-epiploic veins deliver venous blood from the stomach and spleen to the hepatic portal vein
How is Helicobacter pylori infection related to gastric ulcers and why are ulcers that perforate through the posterior wall of the stomach life-threatening?
• Most ulcers are assoc. w/ H. pylori infx
o Stressed individuals secrete more H+, overwhelming duodenal HCO3- protections & reducing effectiveness of mucosa lining --> vulnerable to infx
o HP erode the protective lining of the stomach, inflaming the mucosa and making it vulnerable to the effects of H+ and pepsin
• Stomach supplied by pain afferents that reach T7-T8 spinal ganglia + segments via greater splanchnic nerve --> Pain referred to epigastric region
• Ulcers that perforate through POST wall of stomach
o Expose pancreas to stomach acid + pepsin
o Erode splenic artery --> severe hemorrhage (LIFE-THREATENING!!)
Why is vagotomy performed with chronic or recurring gastric ulcers and how do truncal and selective proximal vagotomy differ?
VAGOTOMY (for chronic or recurring gastric ulcers)
• Vagus nerve stimulates stomach acid secretion --> removing vagus innervation to stomach reduces H+ secretion --> mucosal environment less hospitable for H. pylori.
• Truncal vagotomy (rare)
o Surgical section of vagal trunks
o Affects innervation of other abdominal structure
• Selective proximal vagotomy
o Only denervate stomach region w/ H+ producing parietal cells
o Stomach motility spared
What kind of course does the duodenum take around the pancreas?
the C-shaped course taken by the duodenum around the head of the pancreas.
Which parts of the duodenum are intraperitoneal foregut derivatives?
Which parts are retroperitoneal midgut derivatives?
The superior (1st) part of the duodenum and the proximal portion of its descending (2nd) part are intraperitoneal foregut derivatives.
the distal portion of its 2nd part and the horizontal (3rd) and ascending (4th) parts are retroperitoneal midgut derivatives.
What is the anterior and posterior surface of the 1st, 2nd, and 3rd part of the duodenum?
What artery supplies the duodenum?
What is this artery supplied by/anastamose with?
the superior pancreaticoduodenal artery, a branch of the gastroduodenal artery, supplies the duodenum
it is supplied by the inferior pancreaticoduodenal artery from the SMA
What does venous blood from the duodenum drain into?
venous blood from the duodenum drains into the hepatic portal vein
Where are celiac lymph nodes? What are they for?
celiac lymph nodes surround the celiac trunk and are primary sites of lymph drainage from viscera supplied by branches of the ciliac artery i.e., the abdominal esophagus, stomach, and proximal duodenum
Where are the celiac ganglion and plexus? What synapses in this prevertebral ganglion?
What do postsynaptic sympathetic fibers with accompanying sensory fibers from the DRG at T5-T9 form?
the presynaptic greater splanchnic nerves (T5-T9) synapse in this prevertebral ganglion.
postsynaptic sympathetic fibers with accompanying sensory fibers from the DRG at T5-T9 form periarterial plexuses on the aforementioned branches of the celiac trunk.
What do DRG at T5-T9 convey?
DRG at T5-T9 convey visceral pain sensations from foregut derivatives to the spinal cord and brain.
the brain correlates the sensations with dermatomes whose somatic sensory fibers enter spinal cord segments T5-T9 i.e., the epigastric region.
What plexus does the vagus nerve contribute to and what do branches of the vagus nerve join?
the vagus nerve contributes to the esophageal nerve plexus and branches of the vagus nerve also join the periarterial plexuses.
When do duodenal ulcers cause peritonitis, which organs can become inflamed, and why can life-threatening hemorrhage occur?
DUODENAL ULCERS (peptic ulcer)
• When ulcers perforate posterior duodenal wall ---> intestinal contents can enter peritoneal cavity --> peritonitis
o Inflamed organs near the SUP part of the duodenum: liver, gallbladder, pancreas
• Erosion of the gastroduodenal artery --> severe hemorrhage into peritoneal cavity --> LIFE-THREATENING!!!
Why is visceral pain from duodenal and gastric ulcers referred to the epigastric region?
they are foregut derivatives so are innervated by T5-T9
Where is the spleen positioned?
Where is the left kidney and the splenic hilum?
the spleen, the largest lymphatic organ, is positioned posteriorly in the left upper quadrant; thus it is protected by the left 9th, 10th and 11th ribs.
the left kidney is posteroinferior to the spleen and the splenic hilum is adjacent to the tail of the pancreas.
What is the splenic artery a branch of? Where does it course?
the splenic artery is a tortuous branch of the celiac trunk that courses adjacent to the superior border of the pancreas toward the splenic hilum.
What does the splenic vein follow?
What vein does the splenic vein receive?
the splenic vein follows the reverse course of the artery
the splenic vein typically receives the IMV before joining the SMV to form the hepatic portal vein.
What artery is the periarterial plexus on?
What do the postsynaptic sympathetic fibers from the celiac ganglion provide?
the periarterial plexus on the splenic artery
postsynaptic sympathetic fibers from the celiac ganglion provide vasoconstrictor regulation of blood flow into the spleen.
Why is the spleen the most frequently injured abdominal organ?
Spleen = most freq injured abdominal organ; often secondary to the following injuries:
o Fracture of Left 9th-12th ribs
o Blunt trauma to other region of abdomen
Why does splenic rupture usually require splenectomy?
splenectomy is done for splenic rupture because repair of a ruptured spleen is difficult
o it is the removal of the spleen to prevent person from bleeding to death
What is splenomegaly, where is it palpated, and where is the resulting visceral pain referred?
splenomegaly = enlarged spleen
• If lower edge can be palpated below the L costal margin at the end of inspiration --> approx. 3x normal size spleen
The visceral pain is referred to the left shoulder