Exam IV: Abdomen III Flashcards Preview

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Flashcards in Exam IV: Abdomen III Deck (55):
1

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)

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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

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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

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Lesser Omentum/Sac

Derived from ventral mesentery associated with liver

Connects lesser curvature of stomach and duodenum to liver Specific regions (ligaments):

1. Gastroheptaic- running between the lesser curvature of the stomach and the liver

2. 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

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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

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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):

1. Gastrocolic- stomach to colon

2. Gastrosplenic- stomach to spleen

3. Gastrophrenic- stomach to diaphragm (phrenic innervates diaphragm)

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Mesentery: Transverse Mesocolon

Dorsal mesentery of transverse colon

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Mesentery: Phrenicocolic Ligament

Attaches left colic flexure to diaphragm

Supports spleen

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Mesentery: Mesentery Proper

Fan like fold of peritoneum

Suspends jejunum and ileum (attaches to the small intestine)

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Mesentery: Sigmoid Mesocolon

Attaches sigmoid colon to posterior abdominal wall

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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

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Stomach

1. Cardia- where abdominal esophagus attaches to stomach

2. Fundus sits superior to the cardiac notch where esophagus and stomach meet and form a small curvature; superior to body

3. Body: biggest portion of stomach

4. Pyloric antrum is where the “funnel” spans out to get food into the duodenum; section starts with angular incisures

5. Pyloric canal is the section after the antrum leading into the duodenum

6. Pyloric sphincter: circular muscles that contract to prevent food coming back to stomach from the duodenum

7. Pyloric orifice: directly connects the stomach to the duodenum

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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

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GI Study with Barium Enema: Stomach Structures

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Small Intestine

Divided into duodenum, jejunum, and then ileum

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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

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Clinical Relevance of Duodenal Segments

1. First/Superior segment: duodenal ulcers are located on the posterior wall can interfere with IVC and gallbladder duct

2. 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

3. 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

4. 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

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Duodenal Arteriogram

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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

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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

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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

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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

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Large Intestine Barium Enema

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Compartments and Gutters

Infracolic Compartment: right and left infracolic

Paracolic Gutter: on both sides of large intestine

1. Right: continuous with right subphrenic; flows from lesser omentum area all the way down

2. Left: phrencicocolic ligament separates it from left subphrenic; forms a barrier so can’t get a passage of fluid to the left paracolic gutter, just a small amount

With different appendages and attachments (retro vs. infra) = able to form pathways/passages against posterior wall with peritoneum

If laying down vs. standing up= have different pull of fluid

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Liver and Diaphragmatic Surface

Subphrenic recess- between the liver and diaphragm

Falciform ligament- diaphragm sitting on top, but then falciform ligament divides it into right and left sides of the liver

Hepatorenal recess- space between liver and kidney

Accessory organs: pancreas, liver, and gallbladder = from foregut to get blood supply from celiac artery

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Liver Ventral Surface

Fossa/indentation for the gallbladder to sit in, also portahepatis next to gallbladder

Other organs running next to the liver: esophagus, stomach, duodenum, lesser omentum, gallbladder = ventral surface

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Liver Associated Ligaments

Falciform: former ventral mesentery

Ligamentum teres (round ligament)- stems from portahepatis

Ligamentum venosus (obliterated ductus venosus)- used to run to umbilical cord; stems from portahepatis

Anterior coronary ligament goes to posterior coronary ligament then right triangular ligament the left triangular ligament = all border the bare area where there is no peritoneum covering it

Lesser omentum associated with hepatogastric ligament and hepatoduodenual ligament

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Liver Lobes

Structural lobes: right, left, caudate, quadrate

Functional lobes: Right and left halves: served by right and left hepatic artery, portal vein, and bile passages then further split into four more segments for 8 functional lobes

Segmented: 8

They all get their own vasculature aka bile duct, hepatic artery, and portal vein

Clinically we can isolate these areas to prevent the spread of infection/ cut segments off of liver like you can for the lungs (bronchopulmonary segments)

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Liver: Porta Hepatis

Porta hepatis:

1. Bile passage

2. Hepatic artery

3. Portal vein: ligamentum teres and ligamentum venosum

4. Hepatic vein Area where bile passage, hepatic artery, and portal vein, and hepatic veins are coming out of it

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Gallbladder Location and Structure

Position – between right and quadrate lobes of the liver Structure – divisions of fundus, head, and neck

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Pancreas Location and Structure

Position – retroperitoneal Structures – divisions of head with uncinated process, neck, body, tail

Pancreas is sitting in the “C” of the duodenum

The pancreas is very long almost to the spleen

Head: tiny portion that projects down called the uncinated process

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Pancreatic Duct System

1. Main: major duodenal papilla

2. Accessory: minor duodenal papilla

3. Hepatopancreatic ampulla/ Sphincter of ampulla (Sphincter of Oddi)

Duct system of pancreas: single long duct/ main pancreatic duct and smaller accessory duct

Developed as a dorsal and ventral bud that fuses during embryonic development so that is why you have one main one and sometimes have the accessory duct

Bile duct is coming down and the main duct of pancreas comes down and they both come together to form the hepatopancreatic ampulla contain the sphincter of ampulla/Oddi that controls when we release bile and pancreatic secretions into the duodenum

Pain in the abdomen with jaundice (something wrong with liver) and can’t get bile out… pancreatitis and jaundice together because stone is stuck in major duodenal papilla so cannot drain pancreas or bile

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Bile Duct System

Right and left hepatic ducts

Common hepatic duct

Cystic duct

Bile duct Hepatic duct (right and left): come to a common hepatic duct and then fuses with cystic duct and comes down to the bile duct Inject dye through major duodenal papilla and it shoots upwards to see these structures

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Bile Duct System Radiograph

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Spleen

Splenic hilum- has a lot of blood going to it, so if damaged it bleeds a lot

Location landmarks:

1. Rib IX to rib X

2. Greater curvature of the stomach- gastrosplenic ligament

3. Left kidney- splenorenal ligament; sits on lower spleen

Not that useful Ligaments above connect the mesenteries

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Arterial Supply: Abdominal Aorta

Major branches coming off the abdominal aorta (superior to inferior): celiac trunk, superior mesenteric artery, inferior mesenteric artery, then bifurcation at L4 to the left and right common iliac artery

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Arterial Supply: Foregut, Midgut, and Hindgut

Foregut is supplied by the celiac artery

Midgut is supplied by the superior mesenteric artery

Hindgut is supplied by the inferior mesenteric artery

*All these branches stem from the abdominal aorta

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Celiac Trunk

3 main branches off of the celiac trunk:

1. Left Gastric

2. Splenic

3. Common hepatic artery

**Come off L1 superior border

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Celiac Trunk Angiogram

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Left Gastric Artery

Stems from Celiac Trunk

Along lesser curvature of stomach and supplies esophagus and stomach lesser curvature

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Common Hepatic Artery

Common hepatic branches into (stems from celiac trunk):

1. Hepatic proper heading towards the liver

2. Gastroduodenal artery

Hepatic proper: branches into right and left hepatic arteries and supplies liver, cystic artery that supplies gallbladder, and right gastric artery anastomoses with hepatic proper

Gastroduodenal: on some people have supraduodenal artery that goes over duodenal cap, right gastro-omental (gastroepiploic) artery, posterior superior pancreaticoduodenal, and anterior superior pancreaticoduodenal artery

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Splenic Artery

Stems from the Celiac Trunk

Squiggly one posterior to stomach

Has short gastric arteries, dorsal pancreatic artery, great pancreatic artery, and left gastro-omental (gastroepiploic) artery

Left gastro-omental (gastroepiploic) runs into the greater omentum since it is near the greater curvature of the stomach

Cut left gastromental from common hepatic artery branch of celiac trunk: comes from right greater omental on greater curvature of the stomach; still have blood to back through the splenic artery

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Superior Mesenteric Artery

Second main branch coming from abdominal aorta (inferior to celiac trunk and superior to inferior mesenteric artery)

Jejunal and Ileal (intestinal)

1st Branch: Inferior pancreaticoduodenal artery- divides into anterior and posterior pancreaticoduodenal arteries

2nd Branch: Middle Colic

3rd Branch: Right Colic

4th Branch: Ileocolic- divides into colic arerty and ileal artery; the ileal artery further divides into the anterior and posterior cecal artery, and appendicular artery

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Breakdown of Superior Mesenteric Artery Branches

1st branch: Inferior pancreaticoduodenal artery- divides into:

1. Anterior pancreaticoduodenal artery

2. Posterior pancreaticoduodenal artery surround the pancreas on given side

2nd branch: Middle Colic supplies the transverse colon

3rd branch: Right Colic supplies the ascending colon

4th branch: Ileocolic divides into:

1. Colic artery

2. Ileal branches that supply the ileum, and they further divide into anterior and posterior cecal to supply the cecum as well as the appendicular artery that supplies the appendix

All of the arties go to the edge that runs all the way around= marginal artery that runs the entire length

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Superior Mesenteric Angiogram

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Inferior Mesenteric Artery

Inferior mesenteric: supplies hindgut derivatives

Comes off L3 Left colic- divides into the descending and ascending branches of left colic artery

Sigmoidal- several sigmoid vessels coming over

Superior rectal- supplies the rectum

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Portal Vein

Splenic, superior, and inferior mesenteric from portal vein, which is part of the portal triad

Portal system: capillaries to veins to capillaries to liver to heart

Hepatic portal vein direct tributaries:

1. Right and left gastric veins

2. Cystic vein

3. Paraumbilical veins

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Inferior Mesenteric Angiogram

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Splenic, Superior, and Inferior Mesenteric Tributaries to the Portal Vein

Splenic Vein: stems from celiac trunk

1. Inferior mesenteric vein goes to the splenic

2. Short gastric veins drain to left gastro-omental vein drain to splenic vein

3. Pancreatic vein from pancreas empties into splenic vein

 

Superior Mesenteric Vein tributaries:

1. Colic veins

2. Jejunal and ileal veins

3. Right gastro-omental vein

4. Anterior and posterior inferior pancreaticoduodenal veins

 

Inferior Mesenteric Vein:

1. Superior rectal vein

2. Left colic vein

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Lymphatics

Pre-aortic lymph nodes:

1. Celiac nodes→ Cisterna chyli

2. Superior mesenteric nodes → Celiac nodes

3. Inferior mesenteric nodes → Superior mesenteric nodes

Inferior flows into superior which flows into the celiac noes to the cisterna chyli which goes into the thoracic duct

These are JUST digestive nodes

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Splanchnic Nerves: Sympathetics

Sympathetic innervation:

1. Thoracic splanchnic nerves: GVE, GVA fibers Greater splanchnic (T5-9) → celiac ganglion by celiac trunk where it synpases to go from pre to post ganglionic

Lesser splanchnic (T10-11) → aorticorenal ganglion

Least splanchnic (T12) → renal plexus; no ganglia that it goes to

 

2. Lumbar and sacral splanchnics:

Lumbar splanchnic (L1-2or 4) → pre vertebral plexus (no specific ganglia it is associated with)

Sacral splanchnic → inferior hypograstric plexus; for pelvis

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Parasympathetics

Parasympathetic innervation:

1. Pelvic splanchinics (S2-4) → inferior hypogastric plexus

2. Anterior and posterior vagal trunks → abdominal pre vertebral plexus

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Innervation: Pre-Vertebral Plexus

1. Celiac plexus- between celiac trunk and renal arteries

2. Aortic plexus: intermesenteric plexus; on aorta

3. Superior hypogastric plexus: hypogastric nerve and inferior hypogastric plexus

Bifurcation of right and left common iliacs into external and internal iliac, form two cord like structures= superior hypogastric nerves leading into the superior hypogastric plexus

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Innervation: Pre-Vertebral Nerves Recieved

Nerves received:

1. Vagus nerve- enters abdomen associated with esophagus to provide parasympathic innervation to the foregut and midgut; anterior and posterior vagal trunks send branches to the pre-vertebral plexus containing pre-ganglionic parasympathetic fibers (GVA)

2. Thoracic, lumbar, sacral splanchnic nerves- carry pre-ganglionic sympathetic fibers from the sympathetic trunk/chain to the pre-vertebral plexus and GVAs

3. Pelvic splanchnic- carry pre-ganglionic parasympathetic fibers from S2-4, enter the inferior hypogastric plexus in the pelvis; some fibers move upwards into the inferior mesenteric part of the pre-vertebral plexus to provide innervation to the hindgut

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Innervation: Enteric System

Motor and sensory neurons in the wall of the GI tract

“Brain of the gut”

Controls: GI blood flow, contractions (peristalsis), and gastric secretion Input from sympathetic and parasympathetic to control (only for modification of activity), but if they are cut the enteric system will work without them aka independent of CNS