Abdominal Gastroenterology Flashcards
Esophagus
Muscular tube running from the Laryngopharynx to the stomach
Esophagus reaches the stomach by passing through the:
Esophageal Hiatus of the Thoracic Diaphragm
Phenoesophageal Ligament
Anchors the Esophagus to the Esophageal Hiatus of the Thoracic Diaphragm
Esophagus opens into the the ___ of the stomach around the level of the ___ thoracic vertebrae
- Cardia
- 11th
Thoracic Esophagus
Portion of the esophagus above the thoracic diaphragm
Abdominal Esophagus
- Lower portion of the esophagus, inferior to the diaphragm
- Turns left after passing through the esophageal hiatus and enters the stomach
Esophageal Constrictions
Areas where there is narrowing due to the structures the esophagus is passing by
Cervical Constriction (Upper Esophageal Constriction, Pharyngoesophageal Constriction)
- Most superior constrictor of the esophagus
- Located near the Cricopharyngeus muscle
- Forms the superior esophageal sphincter which is a physiological sphincter (not an actual sphincter)
Middle Esophageal Constriction (Thoracic Constriction)
- Two-part constriction created as the esophagus
- Contacts the aorta and left main bronchus
Diaphragmatic Constriction (Lower Esophageal Constriction, Phrenic Constriction)
- Creates the inferior esophageal sphincter (gastroesophageal sphincter)
- Physiological sphincter, not an actual sphincter
Stomach runs from T___ on the left to L__ on the right
- T10
- L1
Stomach lies behind the:
- Diaphragm
- Liver
- Anterior Abdominal Wall
Stomach lies in front of:
- Posterior Diaphragm
- Spleen
- Left Kidney and Suprarenal Gland
- Pancreas
- Lesser Sac
Cardia of the Stomach
- Superior part of the stomach containing the opening from the esophagus (cardiac orifice)
Cardiac Orifice
Opening for the bolus of food to move from the esophagus into the stomach
Cardiac Notch
Depression that separates the esophagus from the fundus of the stomach (lateral to the cardia)
Fundus of the Stomach
- Superior, dome-shaped portion of the stomach sitting in the left dome of the thoracic diaphragm (gastrophrenic ligament)
- Lateral to the cardia and esophagus
- Most distal to duodenum
Body of the Stomach
Lies between the fundus/cardiac and pyloric parts
Greater Curvature of the Stomach
Large, inferior, convex border of the stomach
Structures associated with the Greater Curvature of the Stomach
- Greater Omentum
- Gastrocolic Ligament
- Gastrosplenic Ligament
- Gastroepiploic Vessels
Lesser Curvature of the Stomach
Superior, smaller, concave curvature of the stomach
Gastric Folds (Gastric Rugae) of the Stomach
- Longitudinal ridges created by the gastric mucosa inside the stomach
- Allows for the expansion of the stomach during the consumption of food and drink
- Helps direct chyme
Pyloric Part of the Stomach
Funnel-shaped distal out-flow area of the stomach located right of the midline, close to the liver
Pyloric Antrum
Widest portion of the pyloric part of the stomach – like the wide, open part of a funnel that collects everything
Pyloric Canal
Narrowing part of the pyloric part of the stomach – like the bottom part of a funnel
Pylorus
- Distal part of the pyloric part of the stomach
- Allows chyme to move from the stomach into the small intestine (duodenum) via the pyloric sphincter
Pyloric Sphincter
- Created by circular smooth muscle in the pylorus
- Controls the movement of chyme into the small intestine
3 Parts of the Small Intestine
(1) Duodenum
(2) Jejunum
(3) Ileum
Location of Small Intestine
Lies between two sphincters/valves – pyloric sphincter and ileocecal valve
Function of Small Intestine
Responsible for absorption of nutrients from food (chyme)
Duodenum
- First and shortest part of the small intestine
- Begins after the pyloric part of the stomach and ends at the duodenojejunal flexure
- Changes course around the Pancreas
The Duodenum is considered _____ although a small portion is _____
- Retroperitoneal (Secondary Retroperitoneal)
- Intraperitoneal
4 Parts of the Duodenum
(1) Superior
(2) Descending
(3) Inferior
(4) Ascending
Superior Duodenum
- First part of duodenum
- Connected to the stomach and is one inch in length
- Intraperiotneal at beginning (ampulla or bulb here) and becomes Retroperitoneal
Structure Associated with the Superior Part of the Duodenum:
Hepatoduodenal Ligament (Lesser Omentum)
Structures that are Anterior to the Superior Part of the Duodenum:
- Liver
- Gallbladder
Structures that are Posterior to the Superior Part of the Duodenum:
- Hepatic Portal Triad
- Pancreas
Descending Part of the Duodenum
- Second part of duodenum
- Travels inferiorly around the head of the pancreas
- Retroperitoneal
- Connects to the superior and inferior portions of the duodenum
Structure that is Anterior to the Descending Part of the Duodenum:
Transverse Colon (Mesocolon)
Structures that are Posterior to the Descending Part of the Duodenum:
- Right Kidney
- Psoas Major M
Descending Part of the Duodenum marks the transition between:
Foregut and Midgut
Hepatopancreatic Ampulla (Ampulla of Vater)
- Area where the bile duct from the biliary system and the main pancreatic duct combine
- Located medial to the descending part of the duodenum
Major Duodenal Papilla
- Opening of the hepatopancreatic ampulla
- Allows the bile and pancreatic juices into the descending duodenum
The Major Duodenal Papilla is controlled by the ___ ___ ____ which is made of ___ muscle
- Sphincter of Oddi
- Smooth Muscle
Minor Duodenal Papilla
Opening to the accessory pancreatic duct within the pancreas
Inferior Part of the Duodenum (Horizontal Part, Third Part)
- Runs horizontally along the bottom of the pancreas towards the left; located at L3 vertebral level
- Connects to the descending portion and the distal ascending portion of the duodenum
- Part of Midgut
- Retroperitoneal
Structures that are anterior to the Inferior Part of the Duodenum:
- Superior Mesenteric Artery and Vein
Structures that are posterior to the Inferior Part of the Duodenum:
- IVC
- Aorta
- Posas Major M
Structure that is superior to the Inferior Part of the Duodenum:
Pancreas
Structure that is inferior to the Inferior Part of the Duodenum:
Ileum
Ascending Part of the Duodenum
- Fourth part of the duodenum
- Runs superiorly in front of the abdominal aorta
- Turns anteriorly at lower edge of the body of the pancreas then joins with the Jejunum
Dudodenojejunal Flexure
Point where the duodenum turns anteriorly and changes from the duodenum into the jejunum
Suspensory Ligament of the Duodenum (Ligament of Treitz)
- Ligament that contains peritoneum and muscle fibers that contract to aid in the movement of the intestinal contents along the GI path
- Runs from the right crus of the diaphragm and the celiac trunk to the duodenojejunal flexure
Jejunum
- Second part of small intestine
- Intraperitoneal
- Starts at the duodenojejunal flexure and ends at the ileum
Jejunum: Distinction- Vascular Supply
- Fewer arterial arcades
- Longer vasa recta in mesentery
Jejunum: Distinction - Internal Structures
- Circular folds (plicae circulares) are larger and closely packed
- Tends to be less fat within the mesentery
Ileum
- Last and longest part of the small intestine
- Releases its product into the larger intestine
- Intraperitoneal
- Neurovascular supply comes from the posterior aspect of the abdominal wall via the mesentery
Ileum releases the its products into the ____ via the ___ ___
- Cecum
- Ileocecal Valve
Ileum: Distinction - Vascular Supply
- More arterial arcades
- Shorter vasa recta within mesentery
Ileum: Distinction - Internal Structures
- Circular folds (plicae circulares) are less distinct or absent
Large Intestine (Colon)
- Final segment of the GI Tract
- Water is removed from the chyme to produce feces here
7 Segments of the Colon:
(1) Cecum
(2) Ascending Colon
(3) Transverse Colon
(4) Descending Colon
(5) Sigmoid Colon
(6) Rectum
(7) Anal Canal
Omental Appendices (Epiploic Appendices)
- Small, fat blobs that hang off the large intestione
Teniae Coli
- Give the appearance of stripes along the large intestine
- Made of smooth muscle (external longitudinal layer)
- Play a part in movement within the large intestine
What attaches to the Mesocolic Tenia?
Mesocolon
What attaches to the Omental Tenia?
Omental appendices
Haustra
- Sac-like structures along the length of the intestines
- Help with the movement of chyme through the large intestine
Haustra are created by the:
Tenia Coli
Cecum
- First part of large intestine
- Pouch lying in the lower right quadrant
- Begins at the Ileocecal junction and runs into the ascending colon
- Intraperitoneal
Ileocecal Valve
- Structure in the Cecum that controls the passage of chyme from the ileum into the Cecum via the ileocecal orifice
Vermiform Appendix
- Pouch like structure (diverticulum) that contains lymphatic tissue
- Attaches to the posteromedial aspect of the cecum
The ___ supports the Vermiform Appendix
Mesoappendix
Ascending Colon
- Part of large intestine that runs along the right side of the abdominal cavity
- Secondarily Retroperitoneal (originally suspended in mesentery but lost the mesentery when it adhered to the abdominal wall)
What gutter is located between the Ascending Colon and the Abdominal Wall?
Paracolic Gutter
Right Colic Flexure (Hepatic Flexure)
- The curve the GI Tract takes once the large intestine reaches the right lobe of the liver
- Located between the Ascending Colon and the Transverse Colon
Transverse Colon
- Superior part of the large intestine
- Intraperitoneal
- Transitions from midgut (proximal 2/3) to hindgut (distal 1/3)
Transverse Mesocolon
- Meso-fold of peritoneum that connects the transverse colon to the posterior wall of the abdomen
- Provides the pathway for the neurovascular supply to reach the transverse colon
Left Colic Flexure (Splenic Flexure)
- The curve the GI Tract takes once the transverse colon reaches the spleen
- Located higher than the right colic flexure and turns more sharply
Phrenicocolic Ligament
Runs from the Left Colic Flexure to the Diaphragm
The Left Colic Flexure is a transition between ___ and ____ as well as a change in _____ innervation (changes from ____ innervation to ____ ______ innervation)
- Midgut
- Hindgut
- Autonomic
- Vagus
- Pelvic Splanchnic
Descending Colon
- Part of the GI Tract that runs along the left side of the abdominal cavity
- Secondarily Retroperitoneal
- Located between the transverse colon (left colic flexure) and the sigmoid colon
What gutter is located between the abdominal wall and descending colon?
Left Paracolic Gutter
Sigmoid Colon
- Part of GI Tract that takes on an S-shaped appearance
- Intraperitoneal
- Neurovascular supply runs through the sigmoid mesocolon
- Sits within the pelvis (iliac fossa); found between the descending colon and rectum
Rectosigmoid Junction
- Point where sigmoid colon transitions into the rectum
- Located around S3
Rectum
- Distal part of the GI Tract
- Continuous with the sigmoid colon
- Located within the pelvis
- Follows the curvature of the sacrum and coccyx, and ends with the anal canal
- Retroperitoneal and subperitoneal
Function of the Rectum
Storage of feces
3 Arterial sources of the Rectum:
(1) Superior Rectal A
(2) Middle Rectal A
(3) Inferior Rectal A
Transverse Rectal Folds
- Thickened parts of circular muscle within the rectal wall
- 3 rectal folds: superior, intermediate, inferior
Ampulla of the Rectum
- End of the rectum that is dilated and has a pouch-like appearance
- Stores feces until defecation occurs
What two structures support the Ampulla of the Rectum?
- Pelvic Diaphragm (Levator Ani)
- Anococcygeal Ligament
Anorectal Flexure (Anorectal Junction)
- Sharp turn between the rectum and anal canal as it passes through the pelvic wall (levator ani muscles)
- Helps with continence
- Marks the transition between the distal rectum and anal canal
Anal Canal
- Runs between the rectum and the anus within the pelvic diaphragm
- About 3-5cm long
- Begins at the anorectal flexure
Internal Anal Sphincter
Involuntary layer of muscle surrounding the upper aspect (2/3) of the anal canal (modification of the circular muscle layer)
Internal Anal Sphincter remains _____ by the ___ ___ plexus
- Contracted
- Inferior Hypogastric Plexus (sympathetic innervation)
External Anal Sphincter
Voluntary, skeletal muscle sphincter surrounding the lower portion of the anal canal
External Anal Sphincter is anchored by the ___ ___ and ____ ____
- Perineal Body
- Anococcygeal Ligament
External Anal Sphincter: Innervation
Inferior Rectal N – branch of the Pudendal N
Anal Column (Columns of Morgagni)
- Folds of the mucus membrane running longitudinally within the anal canal
- Surround the branches of the superior rectal artery and vein
Anal Valve
- Folds within the anal mucosa at the inferior end of the anal columns
- Pouch-like structures that surround the anal sinus
Anal Sinus (Anal Crypt)
Spaces that end in glands
Anal Glands
Produce mucus when compressed that helps with fecal movements
Pectinate Line (Dentate Line, Anorectal Line)
- Found at the inferior aspect of the anal valves
- Demarcates the embryological origins of the anal canal
Superior to the Pectinate Line, the anal canal derives from the embryological ____ while the inferior aspect comes from the ____
- Hindgut
- Proctodeum
*these two parts have different innervation, vascularization, histology and lymphatic drainage
Anus (External Anal Orifice)
Opening of the GI Tract in the Anal Triangle, posterior to the perineum
Liver
- Largest internal gland in the body
- Secretes bile which helps emulsify fat
- Located in the upper right quadrant immediately underneath the thoracic diaphragm (top of liver around the Xiphisternal Joint)
The GI Tract venous flow goes to the ___ before entering the circulatory system (___ ____ ___) to process the blood and store glycogen.
- Liver
- Portal Venous System
Diaphragmatic Surface of the Liver
Superior convex portion of the liver
Bare Area of the Liver
- Located on the superoposterior aspect of the liver, to the right of the IVC
- Part of the liver that is not covered by the peritoneum which allows the liver to directly contact the diaphragm
Coronary Ligament of the Liver
- Reflection of the peritoneum from the superior surface of the liver to the diaphragm
The ___ and ___ ___ ligaments stem from the Coronary Ligament of the Liver; created by the fusion of the coronary ligaments around the bare area
Right and Left Triangular Ligaments
Left Triangular Ligament is associated with the ___ of the liver (___ lobe)
- Apex
- Left
Visceral Surface of the Liver
- Inferior portion of the liver
- Covered by the visceral peritoneum
- Associated with the lesser omentum and the gallbladder (fossa of the gallbladder)
Porta Hepatis
- Fissure on the inferior surface of the liver
- Houses the Hepatic Portal Vein, Hepatic Artery, lymph, Hepatic Nerve Plexus, and Hepatic Ducts
The Portal Triad contains:
- Bile Duct
- Hepatic Artery
- Hepatic Portal Vein
What structures pass through the Hepatoduodenal Ligament (lesser omentum) to reach the liver?
- Bile Duct
- Hepatic Artery
- Hepatic Portal Vein
Round Ligament of the Liver (Ligamentum Teres Hepatis) forms from the:
Left umbilical vein
During development, the left umbilical vein travels from the ___ to the ___ _____
- Umbilicus
- Portal Vein
Round Ligament of the Liver (Ligamentum Teres Hepatis): Location
Inferior aspect of the Falciform Ligament
Ductus Venosus
Shunts blood from the left portal vein to the left hepatic vein, bypassing hepatic circulation
- After birth it degrates
Ligamentum Venosum
- Remnant of the embryonic structure Ductus Venosus
- Runs from the portal vein to the IVC
- Helps in separating the Left Lobe of the Liver from the Caudate Lobe
How many functional segments of the liver are there? What are these segments based on?
- 8
- Blood supply
Falciform Ligament
- Reflection of the peritoneum
- Connects the liver to the anterior abdominal wall
- Located superior to the umbilicus
- Runs from the superior abdominal wall to the anterior and superior aspects of the liver
- Helps separate the liver into two main lobes
Falciform Ligament covers the ___ ___ of the liver and ___-____ veins
- Round Ligament
- Para-umbilical
Near the diaphragm, the Falciform Ligament fuses with the ___ ____ __ and the ___ ___ on the right.
- Left Triangular Ligament
- Coronary Ligament
Which Lobe of the Liver is larger, Right or Left?
Right
The ____ sits on the inferior surface of the right lobe of the liver, in the ___ ___.
- Gallbladder
- Gallbladder Fossa
Quadrate Lobe of the Liver
- Located on the R side of the anterior liver
- Located between the gallbladder and the porta hepatis
Caudate Lobe of the Liver
- Located on the R side of the posterior liver
- Surrounded by the Lesser Omentum, IVC and Porta Hepatis
Left Lobe of the Liver
Smaller lobe to the left of the falciform ligament