7. Abdominal Contents I Flashcards
Abdominopelvic Cavity
Abdominal + pelvic
Continuous
Peritoneum
Serous membrane lining walls and organs
2 continuous parts:
Parietal + Visceral
Parietal Peritoneum
Lines internal aspect of abdominopelvic cavity
Somatic sensory innervation
- supplied by nerves of ab wall
- pain, temp, touch
- acute localized pain
Visceral Peritoneum
Invests organs
Visceral sensory innervation
-stretch, ischemia
Peritoneal Cavity
Potential space between parietal and visceral peritoneum
Contains thin layer of fluid
WHAT DOES THIS MEAN
Ascites
Excess fluid in peritoneal cavity (between visceral and parietal layers)
Peritoneal Cavity (M/F)
Males: closed
Females: open
Retroperitoneal Space
Between parietal peritoneum and muscles of posterior ab wall
Contains:
- fat
- vessels
- some organs
Primary Retroperitoneal Organs
Deep to parietal peritoneum in retroperitoneal space
WHICH ONES?
Ontogeny of Gut Tube
Developing organs become invested in visceral peritoneum
Intraperitoneal Organs
Completely covered by visceral peritoneum
Mobile
Ex: stomach
Secondarily Retroperitoneal Organs
Pressed against posterior body wall in early development - mesentery fuses to ab wall
Loss of mobility
Mesenteries
Two layers of peritoneum suspending organs
Pathway for blood vessels and nerves to get to and from ab organs
Lesser Omentum
Connect stomach and duodenum to liver
Extends from lesser curvature of stomach/proximal duodenum to liver
Composed of 2 peritoneal ligaments (hepatogastric and hepatoduodenal ligaments)
Contains portal triad
Greater Omentum
Connect stomach to large intestine
Extends from greater curvature of stomach/proximal duodenum to transverse colon
LARGE
Forms adhesions to wall off inflamed organs (protects adjacent viscera)
Greater Sac
Potential space
Larger sac
Extends from diaphragm to pelvic region
Lesser Sac
Omental bursa
Smaller sac
Posterior to stomach and lesser omentum
Omental (Epiploic) Foramen
Opening deep to hepatoduodenal ligament
Allows for communication between greater and lesser sacs
Embryonic Gut Tube
Foregut
Midgut
Hindgut
Common bloody supply, venous and lymphatic drainage, innervation
Foregut (derivatives)
Esophagus Stomach Proximal duodenum Liver Gallbladder Pancreas
Foregut (blood supply, venous drainage, lymphatics)
Blood supply: celiac trunk
Venous grainage: gastric veins, splenic vein
Lymphatics: celiac lymph nodes
Spleen
Not foregut/digestive organ
Lymphatic organ
LUQ
Deep to ribs 9-11
Esophagus
Abdominal portion: intraperitoneal
Esophagus (hiatal hernias)
Part of esophagus or other part of gut pushes up through hiatus
Stomach
Intraperitoneal
LUQ
Transpyloric plane
Stomach (curvatures)
Look and Label Image
Lesser: superior concave margin
Greater: inferior convex margin
Stomach: Cardia
Narrow proximal region
Where esophagus enters stomach
Stomach: Fundus
Dome of stomach
Inferior to L dome of diaphragm
Gas bubble on xray
Stomach: Body
Largest part of stomach
Between fundus and pyloric antrum
Stomach: Pyloric Portion
Pyloric antrum
Pyloric canal
Stomach: Pyloric Sphincter
Circular smooth muscle
Regulates flow of food from stomach to duodenum
Stomach: Rugae
Internal folds of gastric mucosa
Adaption to allow stomach to expand
Duodenum
RUQ
4 Parts:
- 1st and 2nd: foregut
- 3rd and 4th: midgut
First part of small intestine
C shaped
Superior (1st Part) of Duodenum
Intraperitoneal
Lies on transpyloric plane (L1)
Descending (2nd Part) of Duodenum
Secondarily retroperitoneal (helps anchor stomach to small intestine)
Parallel to IVC
Curves around head of pancreas
Pancreas
Secondarily retroperitoneal
RUQ
Posterior to stomach
Between duodenum and spleen
Anterior to IVC
Head+Body+Tail
Tail in contact with spleen
Liver
Intraperitoneal
Covered w/ visceral peritoneum (except at bare area)
Mostly RUQ, partially LUQ
Deep to ribs 7-11
Liver: Falciform Ligament
Attaches liver to anterior ab wall
Liver: Hepatoduodenal Ligament of Lesser Omentum
Contains portal triad
Portal Triad
Portal vein
Proper hepatic artery
Bile duct
Lobes of Liver
R lobe
L lobe
Caudate lobe
Quadrate lobe
Segments of Liver
8 segments
Each segment:
- L or R hepatic artery
- portal vein
- L or R hepatic duct
hepatic veins are intersegmental
Bile Duct
Smooth muscle sphincter
Sphincter forces bile into cystic duct and gall bladder
L and R hepatic ducts drain into common hepatic duct –> joins cystic duct –> forms bile duct
Gallbladder
Bile storage
Intraperitoneal
RUQ
Major Duodenal Papilla
Pancreatic duct and Bile duct converge to form the hepatopancreatic ampulla
Opens to duodenum via major duodenal papilla
Splenomegaly
Enlargement of spleen
Cause: Sickle cells clog spleen
Spleen: Hilum
Where vessels and nerves enter and exit
Medial surface of spleen
Abdominal Aorta
Extends from aortic hiatus to bifurcation into L and R common iliac arteries (T12-L4)
Paired Branches
Supply primarily retroperitoneal organs (eg: kidneys, gonads)
Unpaired Branches
Supply ab organs
Foregut: celiac trunk (T12)
Midgut: superior mesenteric artery (SMA) (L1)
Hindgut: inferior mesenteric artery (IMA) (L3)
Celiac Trunk Branches
Supply abdominal foregut derivatives and spleen
Branches
- L gastric artery
- splenic artery
- common hepatic artery
Left Gastric Artery
Courses along lesser curvature
In lesser omentum
Branch:
-Esophageal (supplies ab esophagus)
Splenic Artery
Tortuous course
Goes off to pancreas
Branches:
- Short gastric arteries (go to fundus
- L gastro omental artery (aka: gastro epiploic artery)(courses along greater curvature, in greater omentum)
Common Hepatic Artery: Proper Hepatic Artery
Courses in hepatoduodenal ligament
Branches
-R gastric artery (anastomoses w/ L gastric artery)(courses along lesser curvature, in lesser omentum)
-R and L hepatic arteries (supply liver)
Celiac Trunk Branches
Look and Label Image
Cystic Artery
Usually arises from R hepatic artery
Goes to gallbladder
Common Hepatic Artery: Gastroduodenal Artery
Branch:
-R gastro omental artery (R gastro epoploic artery) (courses along R R side of greater curvature, in greater omentum)(anastomoses w/ L gastro omental artery)
-Anterior and posterior superior pancreaticoduodenal Arteries (supply duodenum and pancreas )
Pancreaticoduodenal Arteries
Anterior and Posterior Superior Pancreaticoduodenal arteries (branch off gastroduodenal artery)
Anastomose
Anterior and Posterior Inferior Pancreaticoduodenal arteries (branch off SMA)
Caval (Systemic) System (venous system 1)
Parallel paired aortic branches
Drain contents of the retroperitoneal space
Drain into IVC
Portal System (venous system 2)
O poor/nutrient rich blood from ab organs –> portal vein –> liver (detoxifies/processes blood) –> hepatic veins –> IVC
Portal System
3 main tributaries:
- splenic vein (foregut)
- superior mesenteric vein (midgut)
- inferior mesenteric vein (hindgut)
All 3 converge on portal vein
Capillaries on either end
Minor Duodenal Papilla
Accessory pancreatic duct enters dudodenum at minor duodenal papilla
Portal Caval Anastomoses
Vessels in portal system do not have valves - blood can flow in either direction
Locations:
- umbilicus
- distal esophagus
- colon
- rectum/anus
Portal Caval Anastomoses: Esophageal Varices
Around the distal esophagus, esophageal veins drain into either the azygos system (caval) or left gastric vein (portal); dilated esophageal varices can rupture, resulting in potentially fatal bleeding
Portal Vein Tributaries
Cystic veins R and L gastric veins Splenic vein -Short gastric -L gastro omental vein Superior mesenteric vein -R gastro omental vein -anterior and posterior superior pancreaticoduodenal vein
Fetal Circulation in the Abdomen
O rich blood enters fetus via umbilical vein
-Adult remnant: round ligament of liver (ligamentum teres) located in inferior margin of falciform ligament
O rich blood bypasses liver via ductus venosus
-Adult remnant: ligamentum venosum
O poor blood leaves fetus via umbilical arteries
-Adult remnants: medial umbilical ligaments
Foregut Lymphatics
Lymph - celiac lymph nodes - chyle cistern - thoracic duct
Foregut Innervation: Parasymathetic
Stimulates peristalsis, secretion
Vagus nerve
Preganglionic cell bodies: brain
Preganglionic cell fiber: vagus nerve
Postganglionic cell body: wall of foregut organs
Postganglionic fiber: wall of foregut organs
Foregut Innervation: Sympathetic
Inhibits peristalsis, constricts GI blood vessels
Preganglionic cell bodies: lateral horn of thoracic spinal cord
Preganglionic fibers: ventral root - spinal nerve - ventral ramus - white ramus communicans - sympathetic trunk - greater thoracic splanchnic nerve (T5 -T9)
Postganglionic cell bodies: celiac ganglion (prevertebral ganglion)
Postganglionic fiber: follow arterial branches to target organs
Referred Pain
Foregut visceral pain is typically referred to area at and inferior to costal margin
