Exam IV: Abdomen III Flashcards
Abdominal Viscera
Peritoneum: continuous, transparent, serous membrane consisting of simple squamous epithelium
Parietal peritoneum: lines walls and cavities and supplies innervation
Visceral peritoneum: covers viscera and innervation
Intraperitoneal: structures almost completely covered with visceral peritoneum
Retroperitoneal: structures located behind the peritoneum; primary vs. secondary (depends on development)
Peritoneal Cavity
Located within abdominal cavity; potential space between parietal and visceral peritoneum
Contains peritoneal fluid
Closed except for uterine tubes
Greater sac/omentum: main part of peritoneal cavity; subdivided to above (supracolic) and below (infracolic) transverse colon
Lesser Sac (omental bursa): epiploic foramen (omental foramen), which is a passageway from greater to lesser sac
Mesentery and Omentum
Mesentery: double layer of peritoneum that results when organ invaginates; nerves and vessels run between layers
Omentum: double layered fold of peritoneum
Lesser Omentum/Sac
Derived from ventral mesentery associated with liver
Connects lesser curvature of stomach and duodenum to liver Specific regions (ligaments):
- Gastroheptaic- running between the lesser curvature of the stomach and the liver
- Hepatoduodenal- between the liver and the first small segment of the duodenum; contains hepatic artery, portal vein, and bile duct (portal triad); anterior boundary of epipolic foramen
Omentum Foramen
Place finger in omentum foramen and pinch it off stopping blood flow to the liver
Superiorly touch the portal triad structures Inferiorly touch the IVC
Greater Omentum
Derived from dorsal mesentery: suspended from the greater curvature of the stomach goes down the abdomen, then comes back up to attach to the duodenum
“Abdominal Policemen”: If you have inflammation somewhere the great omentum will “police” and go over to cover that area for extra cushioning… example: appendicitis, the greater omentum will move over that area and protect it
Specific regions (ligaments):
- Gastrocolic- stomach to colon
- Gastrosplenic- stomach to spleen
- Gastrophrenic- stomach to diaphragm (phrenic innervates diaphragm)
Mesentery: Transverse Mesocolon
Dorsal mesentery of transverse colon
Mesentery: Phrenicocolic Ligament
Attaches left colic flexure to diaphragm
Supports spleen
Mesentery: Mesentery Proper
Fan like fold of peritoneum
Suspends jejunum and ileum (attaches to the small intestine)
Mesentery: Sigmoid Mesocolon
Attaches sigmoid colon to posterior abdominal wall
Esophagus
Abdominal esophagus: it pierces through the diaphragm and joins with the stomach
As it comes through the esophageal hiatus, right and left vagus comes with the esophagus to form a plexus then goes into anterior and posterior vagal trunks as they enter the abdomen
Stomach
- Cardia- where abdominal esophagus attaches to stomach
- Fundus sits superior to the cardiac notch where esophagus and stomach meet and form a small curvature; superior to body
- Body: biggest portion of stomach
- Pyloric antrum is where the “funnel” spans out to get food into the duodenum; section starts with angular incisures
- Pyloric canal is the section after the antrum leading into the duodenum
- Pyloric sphincter: circular muscles that contract to prevent food coming back to stomach from the duodenum
- Pyloric orifice: directly connects the stomach to the duodenum
Pyloric Sphincter Constriction in Infants
Sometimes too closed off in infants/children
Get projectile vomiting because food/milk can’t get through the pyloric sphincter
Sometimes will get to bile then comes back and will have a green tint to it
GI Study with Barium Enema: Stomach Structures
Small Intestine
Divided into duodenum, jejunum, and then ileum
Duodenum Segments
Duodenum: 4 segments; 1 and 2 from foregut and 3 and 4 from midgut
Transpyloric line: L1
1: superior duodenum at L1
2: descending duodenum- major and minor duodenal papilla
3: inferior duodenum- aorta, vertebral column, superior mesenteric artery, and IVC
4: ascending duodenum- has duodenal flexure called the suspensory ligament/ligament of Treitz
Clinical Relevance of Duodenal Segments
- First/Superior segment: duodenal ulcers are located on the posterior wall can interfere with IVC and gallbladder duct
- Second/Descending segment: surrounded by kidney and kidney hilum with all the blood vessels; if had ulcer could spill into that Major and minor duodenal papilla: where pancreas drains into the duodenum
- Third/Inferior Segment: IVC, superior mesentery artery = blood vessel sandwich; vertebral column and aorta; if ulcer there it would be by some major blood vessels
- Fourth part: suspensory ligament/muscle that has the ability to contract = Ligament of Treitz
Forms boundary from last part of duodenum and jejum
Anatomical Function: if this muscle contracts it would straighten out for food to pass through
Clinical Function = if you have bleeding in intestine, it is the dividing line between upper and lower GI bleed
When the stomach rotated during embryonic development, caused segments 2 and 3 to be retroperitoneal and segments 1 and 4 to be infraperitoneal
Duodenal Arteriogram
Duodenum: Jejunum vs. Ileum
Jejunum plicae circulares are more numerous and prominent, whereas in the ileum they are more smooth
Arterial arcades: in jejunum they are shorter, but ileum is longer
Vasa recta: jejunum are longer and the ileum are shorter
Ileocecal Junction
Ileocecal fold serves as a valve to prevent backflow of food
Cecum is associated with the appendix
Mesoappendix: mesentery that suspends onto the appendix with small blood vessels running to the appendix
Characteristics of the Large Intestine
Haustra: subdivision pockets are unique to the large intestine
Teniae coli: strip of smooth muscle runs the entire length and comes down through the sigmoid colon
Omental appendicies: fat deposits/droplets that hang off the large intestine
Segments of the Large Intestine
Cecum will ascend from the right side, bend/turn is the right colic flexure (because underneath the liver called the hepatic flexure), then come across from right to left for transverse colon and next bend is left colic flexure/splenic flexure, then descend on left side of the body for the descending colon, then S shape is sigmoid colon and as is passes posterior it forms the rectum and anal canal which are in the pelvis
No haustra, tenaie coli, or appendicies at rectum and anal canal
Ascending, descending, rectum, and anal canal = retroperitoneal
Transverse and sigmoid = infraperitoneal