Stomach, Liver, and Gallbladder Flashcards
Define the stomach:
It is the portion of the alimentary system that is positioned between the esophagus and duodenum
The digestion of food is by 2 mechanisms:
Chemical and mechanical
What are the functions of the stomach?
- Stomach mucosa secretes HCl to maintain a pH of 2.0 and gastric enzymes (mainly PEPSIN) aiding in the reduction of solid foods to a pulp-like liquid - chyme
- Peristaltic action of muscle fibers mixes food with digestive juices, facilitating reduction to chyme
- Acts as a reservoir, empty volume is 50-75 mL, capable of holding up to 2-3 liters
- Site of LIMITED absorption
What are the 5 regions of the stomach?
- Cardiac portion
- Fundus
- Body
- Pyloric antrum
- Pyloric canal
What is the cardiac portion of the stomach?
It connects the esophagus to the body of the stomach
What is the fundus of the stomach?
It is usually filled with gas and in contact with the thoracic diaphragm
What is the body of the stomach?
It is the largest region of the 5 and responsible for the secretory part of the stomach
What is the pyloric antrum?
Transition from the body to the pyloric canal?
What is the pyloric canal?
The terminal part of the stomach, that connects the duodenum and ends as the pyloric sphincter
What is the location of the lesser curvature?
Along the SUPERIOR margin of the stomach and it is associated with the lesser omentum
Where is the greater curvature located?
Along the inferior/lateral margin of the stomach and it is associated with the greater omentum and …..
What ligament is the greater curvature of the stomach associated with?
The gastrosplenic ligament
Where is the cardiac notch located?
Between the junction of the cardiac portion and the fundus of the stomach
Where is the angular notch located?
Along the lesser curvature, defines the border between the body and the pyloric region
What is the gastro-esophageal junction?
The transition from the esophagus to cardiac portion of the stomach occurs at T10 and is where the esophagus passes thru the thoracic diaphragm.
What is the gastro-esophageal junction strengthened by?
The ascending and descending phrenoesophageal ligaments and the thickening of fascia around the esophageal opening.
The esophageal/stomach junction lacks:
A muscular valve
What is the pyloric/duodenal junction?
It marks the location of a true smooth muscle valve called the pyloric sphincter. This valve is regulated by autonomics (sympathetics and parasympathetics) and controls the flow of digested food/liquid from the stomach into the duodenum
What is in contact with the fundus region?
The diaphragm
What is superior to the body and pylorus?
The liver (mostly the left lobe)
What is to the left of the body of the stomach?
The spleen
What is located inferior and posterior to the body of the stomach?
The transverse colon and left colic flexure (aka splenic flexure)
What is anterior to the stomach?
The anterior abdominal wall
What is the bed of the stomach formed by?
It is posterior to the stomach and is formed by the posterior wall of the omental bursa (lesser sac)
Retroperitoneal structures within the bed of the stomach include:
The pancreas, left kidney, left adrenal gland, diaphragm, celiac artery *trunk and proximal branches), splenic artery and vein, terminal part of the superior mesenteric artery and vein.
Which peritoneal structures make up part of the bed of the stomach?
Spleen and transverse colon
Is the stomach freely moving or anchored to something?
Although it is motile and extensible, it is firmly anchored to the diaphragm and posterior abdominal wall in the fundus and superior lacteal aspect of the greater curvature by the peritoneal ligaments derived from the dorsal mesogasrtrum
Describe the gastrophrenic ligament:
Attaches to the lateral (left) surface of the cardiac portion of the stomach and follows the posterior-superior and lateral margin of the fundus and inserts onto the left diaphragm
Describe the gastrosplenic ligament:
The same two sheets of peritoneum then course along the posterior-lateral margin of the greater curvature of the corresponding to the proximal region of the body of the stomach just medial to the spleen. This is the ligament from the spleen to the greater curvature of the stomach
Describe the splenorenal ligament:
The same two sheets of peritoneum making up the gastrosplenic ligament continues to the posterior body wall and attaches to it immediately anterior to the left kidney. The splenorenal ligament contains the terminal branches of the splenic a. and the tail of the pancreas
What is the role of the hepaticduodenal ligament?
Attaches to the superior region of the first part of the duodenum to the liver, maintaining positioning of the pyloric region of the stomach. The heparticduodenal ligament is continuous with the peritoneal sheets making up the lesser omentum and is located laterally (to the right) and contains the hepatic portal vein, the hepatic, cystic and common bile ducts along with the proper hepatic artery including the right and left hepatic arteries
What is the primary source of arterial flow to the stomach?
Provided by the celiac trunk (one of 3 single midline abdominal arteries that supply the viscera)
Where is the celiac trunk located?
Just inferior to the crura of the diaphragm at the level of T12 and it gives rise to 3 primary branches, all of which provide direct supply to the stomach
What are the 3 primary branches of the celiac trunk?
- Left gastric a
- Splenic a
- Common hepatic aa
What does the left gastric artery supply?
The left half of the lesser curvature of the stomach. In the lesser curvature, it forms an anastomosis with the right gastric artery (a branch off of the proper hepatic artery) within the lesser omentum
What does the left gastric artery give rise to?
The ascending esophageal branch which anastomose with the thoracic esophageal arteries to supply the CARDIAC REGION of the stomach
Where is the splenic artery located and what does it supply?
It is a very torturous artery that can be found embedded in the posterior abdominal wall just superior to the superior margin of the body of the pancreas. It gives rise to 3 branches to the pancreas en route to the spleen.
Approaching the spleen, the splenic artery enters the _________ and then does what?
Splenorenal ligament and branches into 5-7 splenic branches that go directly into the spleen and provides 2-3 branches - the short gastric arteries which supply the fundus of the stomach
What single artery does the splenic artery give off at the end?
The gastro-omental artery (aka left gastroepiploic), which follows the greater curvature of the stomach and travels within the greater omentum on the left side. The left gastro-omental artery forms an anastomosis with the right gastro-omental artery
Where is the common hepatic artery located?
It is positioned to the right of the left gastric and splenic arteries and gives rise to two branches
What are the two major branches that the common hepatic artery gives off?
The proper hepatic and the gastroduodenal arteries
What is the first branch that the proper hepatic artery gives off?
The right gastric artery (as the first branch) which supplies the right half of the lesser curvature of the stomach and the pyloric region. It forms an anastomotic connection with the left gastric artery
What does the proper hepatic artery supply?
The liver and gallbladder
What is the second branch that the common hepatic artery gives off?
The gastroduodenal artery, it descends posterior to the junction of the pylorus and the duodenum and gives rise to 2 major branches
What are the 2 branches of the gastroduodenal artery?
- Right gastro-omental (aka R gastroepiploic)
2. Superior pancreaticoduodenal artery
What does the right gastro-omental artery supply?
The right half of the greater curvature of the stomach and it forms an anastomosis with the left gastro-omental artery (a branch of the splenic artery) within the greater omentum
What is the hepatic portal vein?
Venous return from all organs associated with the digestive track (distal to the esophagus and proximal to the anal canal) is directed to the liver via the hepatic portal vein
What is the portal vein formed by?
The junction of the splenic vein and the superior mesenteric vein. It travels within the hepatoduodenal ligament in route to the liver
Which veins drain directly into the splenic vein?
The left gastro-omental vein and the short gastric veins
Which veins drain into the portal vein?
The right and left gastric veins
Which veins drain into the superior mesenteric vein
The right gastro-omental vein
What path do the lymph nodes follow?
They follow the arterial pathways to the stomach and are named by the corresponding artery
Where do all lymph nodes drain?
Directly into the celiac lymph nodes, which cluster around the celiac trunk and then drain into the thoracic duct
What provides motor and secretory input to the stomach?
Autonomics
Describe the parasympathetic input to the stomach:
It is provided by the vagus n (X) primarily by the anterior vagal trunk. These PREGANGLIONIC fibers act locally to increase glandular secretions (HCl and pepsinogen) and to stimulate the peristalsis of the stomach
Describe the sympathetic input to the stomach:
Primarily provided by POSTGANGLIONIC fibers from the celiac ganglion (paired). Preganglionic fibers are from the greater splanchnic nerve (T5-9). Sympathetic innervation reduces peristalsis, glandular secretion and constricts the pyloric sphincter
Describe the pain and stretch sensory fibers to the stomach:
They use the sympathetic pathway by way of the greater splanchnic nerve to transmit their signals from the stomach to dermatome levels corresponding to T7-T8. The cell bodies of these sensory neurons are housed in the dorsal root ganglion at these thoracic leveles
What is the enteric nervous system?
It is an endogenous neuronal network that travels the full extent of the alimentary tract. Although regulated by both the parasympathetic and sympathetic input, the enteric nervous system can function independently to provide low-level glandular secretion and auto-peristalsis
What are the functions of the liver?
It is the largest and most vascularized organ in the body.
- Primary site of detoxification and intermediary metabolism
- Major storage site for glycogen and is responsible for synthesis of bile, proteins, and cholesterol.
- Involved with the process of retiring senescent blood cells by reclaiming iron
- Major lymph-producing organ (produces over half of the lymph entering the thoracic duct)
Where is the liver located?
In the upper right quadrant of the abdominal cavity and is completely hidden by the thoracic cage and diaphragm. It is found deep to the ribs (7-10) and its sharp inferior border follows the controur of the right costal margin
What are the 2 surfaces of the liver?
Diaphragmatic and Visceral
Describe the diaphragmatic surface of the liver:
It has a smooth-contoured surface that is directly related to the thoracic diaphragm. It is divided at midline by the falciform ligament (on its ventral surface) into right and left anatomical lobes.
How is the liver suspended?
Superiorly from the thoracic diaphragm by the anterior and posterior coronary ligaments, and the right and left triangular ligaments.
The anterior and posterior coronary ligaments are continuous with:
The falciform ligament and are all derived from the ventral mesogastrum. Due to rapid growth of the liver during development, the mesentary seheets that make up the ventral mesogastrum were separated and pulled away from a portion of the liver and diaphragm to create the anterior and posterior coronary ligaments
The sharp transitions between the anterior and posterior ligaments are called the:
Right and left triangular ligaments. Together, all 4 ligaments suspend the liver from the thoracic diaphragm
What is the bare area of the liver and diaphragm?
The separation of the coronary ligaments by the growth of the liver creates an area on the superior diaphragmatic surface of the liver and corresponding region of the inferior surface of the thoracic diaphragm which is void of mesothelial covering.
What is the bare area of the liver/diaphragm bound by?
By the right and left triangular and anterior and posterior coronary ligaments. It is the site where the hepatic veins of the liver (usually 2-3) empty into the inferior vena cava
The attachment of the liver to the diaphragm via the coronary and triangular ligaments creates:
2 peritoneal recesses that are potential sites for fluid accumulation
Where is the subphrenic recess?
Ventral to the anterior coronary ligament
Where is the hepatorenal recess?
Dorsal and inferior to the posterior coronary ligament
Describe the visceral surface of the liver:
It is located on the inferior aspect of the liver, and is related to the gallbladder, stomach, and duodenum.. Ligaments subdivide the liver into 4 lobes on the visceral surface which are referred to the right, left, caudate, and quadrate lobes
The right anatomical lobe is formed by:
The right visceral lobe, quadrate, and caudate lobes
The left anatomical lobe is formed by:
The left visceral lobe
What makes up the porta hepatis?
The falciform ligament and the ligamentum venosum, together with the positioning of the gallbladder and the inferior vena cava forms the 2 vertical arms of the “H” and the porta hepatis
Define the porta hepatis:
The site where the right and left portal veins, -hepatic arteries, and -hepatic ducts enter and leave the liver, and it forms the horizontal bar of the H
What is the ligamentum teres and what role does it play?
It is the embryological remnant of the umbilical vein that is embedded in the free margin of the falciform ligament, together with the ligamentum venosum (embryo. remnant of ductus venosus) it separates the left visceral lobe from caudate and quadrate lobes
What does the porta hepatis separate?
The quadrate lobe (ventral to the porta hepatis) from the caudate lobe (dorsal to the porta hepatis)\
What separates the right lobe from the quadrate and caudate lobes on the visceral surface?
The gallbladder (its corresponding fossa) and the cystic duct, together with the inferior vena cava
Describe the functional divisions of the liver:
There are 8 functional lobes in the liver as determined by arterial, portal, and hepatic duct systems (bile) as well as by its venous drainage, by the hepatic veins, which are not part of the triad
Blood supply to the liver is provided primarily by:
The portal vein, as it is rich in nutrients, via uptake by the small intestines, while still maintaining a relatively high oxygen tension compared to blood returning via the systemic system (ie vena cava)
The portal vein divides into a right and left hepatic portal branch at the:
Porta hepatis
What is the oxygen-rich blood supplied by?
The smaller proper hepatic artery, which is a branch of the common hepatic artery of the celiac trunk, which like the portal vein, divides into a right and left proper hepatic artery at the porta hepatis
What is the portal triad?
The portal vein, the proper hepatic artery, and the hepatic duct travel together and form the portal triad
What is NOT part of the portal triad and does not exit the liver via the porta hepatis?
The hepatic veins
The venous return of the liver empties directly into:
The inferior vena cava by 2-3 hepatic veins. This occurs in the BARE AREA of the liver
What is the function of the gallbladder?
It is a smooth muscular sac that is responsible for the concentration and storage of bile. It contracts and injects bile into the 2nd part of the duodenum, via the common bile duct
What does the gallbladder eject bile in response to?
Cholecystokinin which is released by the stomach following fatty food intake. The duct is located in the gallbladder fossa on the visceral surface of the liver between the right and quadrate lobes
The fundus of the gallbladder rests directly on the:
1st part of the duodenum and the anterior abdominal wall (at the costal margin)
What makes up the gallbladder?
A fundus, body, and neck that empties into the cystic duct. The internal surface of the cystic duct forms a spiral path, and although it is called the spiral valve, it is NOT a functional valve
What forms the common bile duct?
The cystic duct joins the comon hepatic duct and forms the common bile duct, which travels superior to the portal vein, in the hepatoduodenal ligament, en route to the descending part of the duodenum (2nd part)
The common bile duct passes _________ to the first part of the duodenum.
Posterior
Where is the bile duct sphincter and what is its purpose?
It is located at the distal end of the common bile duct, prior to the junction of the pancreatic duct, is the bile duct sphincter, which is normally closed until ingestion of fatty foods. Bile produced by the liver is relatively dilute. The closed bile sphincter allows the flow of the dilute bile to back up into the gallbladder, where it is then concentrated by reabsorption of water and essential metabolites by the mucosa of the gallbladder. Upon contraction, the concentrated bile mixes with the release of pancreatic enzymes, via the pancreatic duct in the ampulla (where 2 ducts meet) and then passes through the sphincter of hepatopancreatic ampulla in the medial wall of the 2nd part of the duodenum
What is the blood supply to the gallbladder?
By the cystic artery, which is usually given off by the right proper hepatic artery.
The cystic artery passes _______ to the common hepatic duct, within the hepatoduodenal ligament, en route to the neck of the gallbladder.
Posterior
What is the cystohepatic triangle?
of surgical importance, defined by the common hepatic duct, the cystic duct, and the liver.
The contents of the cystohepatic triangle include:
The cystic artery and the right hepatic artery
What is the medial border of the cystohepatic triangle ?
The common hepatic duct
What is the lateral border of the cystohepatic triangle ?
The cystic duct
What is the superior border of the cystohepatic triangle?
The liver
Describe sympathetic innervation of the gallbladder:
Sympathetic fibers are supplied by POSTGANGLIONIC fibers from the celiac ganglion which receives preganglionic input from the greater splanchnic nerve T5-9
Describe parasympathetic innervation of the gallbladder:
Fibers derived from the vagus n (X)
Describe visceral sensory innervation of the gallbladder:
Relayed via the greater splanchnic nerve AND the phrenic nerve (C3,4,5) –> pain in the upper R shoulder
Clinical relevance of the stomach:
Site of carcinomas, peptic ulcers, and hiatal hernias
What is an hiatal hernia?
Where the portion of the stomach is pulled thru the esophageal hiatus and displaced into the thoracic cavity
What can go wrong in the liver?
- Rupture results in intraperitoneal bleeding
- A major site of metastatic carcinoma
- Cirrhosis results in progressive destruction of hepatocytes and liver failure
- Hepatitis is inflammation of liver that is usually caused by viral infection or from chemical toxins
- Jaundice is an elevated level of bile pigment found in the blood stream that causes a yellow appearance in the skin and conjunctiva of the eyes.
What is a possible cause of jaundice?
Blockage of the bile duct system by a gallstone. This blockage causes bile to back up into the liver and prevents further processing of the bile pigment (bilirubin) from the blood
What can go wrong in the gallbladder?
Gallstones can produce blockage of bile and can be found throughout the bile-duct system. The most coomon site of blockage occurs in the hepatic-pancreatic ampulla (terminal part of the common bile and the pancreatic duct)
