Digestivo SOI II

What is the peritoneum?

A serous membrane lining the abdominal wall and viscera.

What are the two layers of the peritoneum?

Parietal and visceral layers.

Which layer of the peritoneum lines the abdominal wall?

(MOST EXTERIOR)

The parietal peritoneum.

Which layer of the peritoneum covers the abdominal organs?

(MOST INTERIOR)

The visceral peritoneum.

From which embryonic layer does the peritoneum derive?

The lateral mesoderm.

Into what two layers does the lateral mesoderm split during development?

Parietal and visceral layers.

What cavity forms during the split of the lateral mesoderm?

The intraembryonic cavity.

Which other serous membranes share the same origin as the peritoneum?

The pleura and pericardium.

What separates the abdominal cavity from the thoracic cavities during development?

The diaphragm and pleuroperitoneal membranes.

What is the peritoneal cavity?

The potential space between parietal and visceral peritoneum.

What does the peritoneal cavity contain?

A small amount of fluid for support and protection of organs.

How many subdivisions does the peritoneal cavity have?

Two: greater sac and lesser sac.

What is the greater sac?

The main part of the peritoneal cavity.

What is the lesser sac also called?

The omental bursa.

Where is the lesser sac located?

Posterior to the stomach.

What connects the greater and lesser sacs?

The omental foramen.

What defines an intraperitoneal organ?

It is almost completely covered by visceral peritoneum.

Are intraperitoneal organs free to move?

Yes, they can move freely within the peritoneal cavity.

Name 7 intraperitoneal structures.

Stomach, 1st and 4th duodenum, jejunum, ileum, cecum, transverse colon, sigmoid colon, rectum.

Is the liver intraperitoneal?

Yes, but it's fixed by ligaments, so it's less mobile.

Is the spleen intraperitoneal?

Yes, although not derived from the gut tube.

Why is the spleen studied with foregut derivatives?

Because of its close anatomical relationship.

What ligaments fix the liver to the abdominal wall and diaphragm?

The falciform ligament and the coronary ligaments (and triangular ligaments).

Why is the liver less mobile than other intraperitoneal organs?

Because it's fixed by its ligaments.

What is a primary retroperitoneal organ?

An organ that develops behind the peritoneal cavity and remains fixed.

Name 3 primary retroperitoneal organs.

Kidneys, suprarenal glands, ureters.

What is a secondary retroperitoneal organ?

An organ that was initially intraperitoneal but lost its mesentery and became fixed.

Name the secondary retroperitoneal organs.

Pancreas, 2nd and 3rd parts of the duodenum, ascending colon, descending colon.

Into what two sacs is the intraperitoneal cavity divided?

Greater sac and lesser sac.

What is another name for the greater sac?

The peritoneal cavity.

What is another name for the lesser sac?

The omental bursa.

Where is the lesser sac located?

Posterior to the stomach.

What connects the greater sac and lesser sac?

The omental foramen (foramen of Winslow).

Where is the omental foramen located?

Posterior to the hepatic pedicle.

What structures are found in the hepatic pedicle?

Hepatic artery, portal vein, and bile duct.

What is the lesser omentum?

A two-layered peritoneal fold.

From where to where does the lesser omentum extend?

From the lesser curvature of the stomach and first part of the duodenum to the inferior liver.

What does the lesser omentum become in the adult?

Ligamentous structures.

What are the two ligaments formed from the lesser omentum?

Hepatoduodenal ligament and hepatogastric ligament.

What does the hepatoduodenal ligament connect?

The liver and the duodenum.

What important structures are contained in the hepatoduodenal ligament?

The portal triad: hepatic artery, portal vein, bile duct.

What does the hepatogastric ligament connect?

The liver and the stomach.

What are peritoneal reflections?

Folds of peritoneum where it connects viscera to the posterior abdominal wall.

What do peritoneal reflections form?

Mesenteries.

What is the root of the mesentery?

The reflection that connects the jejunum and ileum to the posterior wall.

What does the root of the transverse mesocolon connect?

The transverse colon to the posterior abdominal wall.

What does the root of the sigmoid mesocolon connect?

The sigmoid colon to the posterior abdominal wall.

What is the mesentery made of?

A double layer of peritoneum.

What does the mesentery suspend?

The small intestine (jejunum and ileum).

From where does the mesentery suspend the small intestine?

From the posterior abdominal wall.

What structures are carried within the mesentery?

Blood vessels, lymphatics, and nerves.

What type of innervation does the parietal peritoneum have?

Somatic innervation.

Which nerves supply the parietal peritoneum?

Phrenic nerve and spinal nerves T6-L2.

Is pain from the parietal peritoneum well localized or diffuse?

Well localized.

Give an example of pain from the parietal peritoneum.

Localized pain in late-stage appendicitis.

What type of innervation does the visceral peritoneum have?

Autonomic (visceral afferent) innervation.

Which autonomic fibers carry pain sensations from the visceral peritoneum?

Sympathetic fibers (thoracic or lumbar splanchnic nerves).

Which autonomic fibers carry distension and reflex sensations?

Parasympathetic fibers (vagus nerve or pelvic splanchnic nerves).

Is pain from the visceral peritoneum well localized or diffuse?

Diffuse and poorly localized.

Give an example of pain from the visceral peritoneum.

Diffuse abdominal pain in early appendicitis.

Does the peritoneum have motor innervation? Why or why not?

No, because it is a serous membrane and not a muscle.

What is the abdominal esophagus?

The short terminal portion of the esophagus that lies below the diaphragm.

Where does the abdominal esophagus lie in relation to the diaphragm?

Just below it, after passing through the esophageal hiatus.

What does the abdominal esophagus connect?

The thoracic esophagus to the cardia of the stomach.

From which two main arteries does the abdominal esophagus receive blood?

Left gastric artery and inferior phrenic arteries.

Where does the left gastric artery originate from?

The celiac trunk.

What branches does the left gastric artery give to the abdominal esophagus?

Esophageal branches.

Where do the inferior phrenic arteries originate from?

The abdominal aorta.

What do the inferior phrenic arteries give off to supply the abdominal esophagus?

Esophageal branches.

What other structure do the inferior phrenic arteries supply?

The diaphragm.

What is the first major visceral branch of the abdominal aorta?

The celiac trunk.

At what vertebral level does the celiac trunk arise?

T12.

What region of the gut does the celiac trunk supply?

The foregut.

What are the three main branches of the celiac trunk?

Left gastric artery, common hepatic artery, and splenic artery.

What does the left gastric artery supply?

The stomach and esophagus.

What two branches arise from the common hepatic artery?

Proper hepatic artery and gastroduodenal artery.

What does the splenic artery supply?

The spleen and pancreas.

Do branches of the celiac trunk supply the abdominal esophagus?

Yes, especially through the left gastric artery.

Does venous drainage of the abdominal esophagus follow the arterial pattern?

Yes.

Into which veins do the esophageal veins drain?

Left gastric vein and phrenic veins.

Do these veins drain into the portal or systemic circulation?

Both.

Why is venous drainage of the abdominal esophagus clinically important?

Because it can lead to esophageal varices in portal hypertension.

What is the cardia of the stomach?

The entry point of the stomach where the esophagus joins.

What structure controls food passage at the cardia?

The cardiac sphincter (lower esophageal sphincter).

What is the fundus of the stomach?

The dome-shaped portion above the level of the cardia.

How is the fundus distinguished?

By drawing a horizontal line at the level of the cardia.

What often fills the fundus on radiographs?

Gas.

What is the body of the stomach?

The central, largest region below the fundus.

What is the main function of the stomach body?

Mixing and digestion of food.

What is the pyloric antrum?

The portion of the stomach leading into the pyloric canal.

What is the pyloric canal?

A narrow tube that leads to the pyloric sphincter.

What is the pyloric sphincter?

A muscular valve that controls passage of chyme into the duodenum.

Which four main arteries supply the stomach?

Right and left gastric arteries, right and left gastro-omental arteries.

Do these arteries all come from the same parent artery?

No, they come from different branches of the celiac trunk system.

Where does the left gastric artery originate?

From the celiac trunk.

What does the left gastric artery supply?

The left side of the lesser curvature of the stomach.

What additional branches does the left gastric artery give?

Esophageal branches.

Where does the right gastric artery originate?

From the proper hepatic artery.

What does the right gastric artery supply?

The right side of the lesser curvature of the stomach.

With which artery does the right gastric artery anastomose?

The left gastric artery.