Abdomen - Lecture 2 Flashcards
Other names for Digestive Tract
- Alimentary Canal
2. Gut Tube
What is the largest lumen (open space organ) of the Digestive Tract?
Stomach
What are the Digestive Tract Organs?
- Abdominal Esophagus
- Stomach
- Small Intestine
- Large Intestine
- Rectum
- Anal Canal
What are the sections of the Small Intestine?
- Duodenum
- Jejunum
- Ileum
What are the sections of the Large Intestine?
- Cecum
- Colon
A. Ascending
B. Transverse
C. Descending
D. Sigmoid
What are the Accessory Digestive Organs? (Don’t aid in digestion)
- Liver
- Gall Bladder
- Pancreas
- Appendix
What are the organs inside of the Abdominal Cavity that have nothing to do with Digestion?
- Spleen
- Kidneys
- Aorta/IVC
- Thoracic Duct
What are the 3 Embryonic Divisions that the Gut develops from?
- Foregut
- Midgut
- Hindgut
What does the Foregut consist of?
- Esophagus
- First half of the Duodenum (until Major Duodenal Papilla)
- Liver
- Pancreas
- Gallbladder
- Spleen
What does the Midgut consist of?
- Second half of Duodenum
- Jejunum
- Ileum
- Large Intestine (up until 2/3 of the transverse line)
What does the Hindgut consist of?
- Large Intestine (starting with distal 1/3 of Transverse colon)
- Superior Portion of Rectum
What are the 3 main UNPAIRED Branches that come off of the Abdominal Aorta to supply the digestive tract?
- Celiac Trunk
- Superior Mesenteric Artery
- Inferior Mesenteric Artery
Celiac Trunk
Artery that branches off of the Abdominal Aorta to supply the Foregut (Esophagus-1/2 Duodenum, Liver, Pancreas, Gallbladder, Spleen)
Superior Mesenteric Artery
Travels in the Mesentery to supply Midgut (1/2 Duodenum, Jejunum, Ileum, up to 2/3 Transverse Colon, Pancreas)
Inferior Mesentery Artery
“Smallest”; Travels in Mesentery to supply Hindgut (Distal 1/3 of Transverse Colon to Superior portion of Rectum)
What is the only organ that receives blood from both the Celiac Trunk and the Superior Mesenteric Artery?
Pancreas
Where is the Esophagus Located?
- Mostly in the Thorax
2. Small portion in the Abdomen
Where is the Esophageal Hiatus of the Diaphragm?
T10 - think “EVN 10” because it crosses the diaphragm with the Vagus Nerve
Innervation of the Esophagus
Branches of the Vagus Nerve
Left and Right Vagus Nerves change course and become…
Left > Anterior Vagal Trunk
Right > Posterior Vagal Trunk
(think L.A.R.P)
Arterial Supply of the Esophagus
Esophageal Branches from the:
- Celiac Trunk
- Left Inferior Phrenic Artery (supplies tiny part)
Regions of the Stomach
- Cardia
- Fundus
- Body
- Pyloric
Fundus
Most superior region of the stomach; “Closet Space”
Body
Middle part of the stomach; The majority
Pyloric
- Pyloric Antrum
- Pyloric Canal (slows down chyme)
- Pylorus (Constriction, Sphincter, and Orifice)
Rugae
Ridges of the stomach that allow it to stretch and help the churning of the stomach
Pyloric Constriction
Size of the Pyloric Orifice (opening in the center) is regulated by the Pyloric Sphincter
Angular Incisure
Angle created at the beginning of the Pyloric Canal
Arteries that Blood Supply to the Stomach
- Left Gastric Artery
- Right Gastric Artery
- Right Gastro-omental
- Left Gastro-omental
- Short Gastric Arteries
Which Arteries Supply the Lesser Curvature of the Stomach?
Left and Right Gastric Arteries (Meet and merge with no clear designation)
3 MAJOR sources of Blood Supply to the Stomach
- Celiac Trunk
- Splenic Artery
- Common Hepatic Artery
Which Arteries Supply the Greater Curvature of the Stomach?
Left and Right Gastro-Omental Arteries (meet and merge with no clear designation)
What are the 3 Major Branches that come off of the Celiac Trunk?
- Left Gastric Artery
- Splenic Artery
- Common Hepatic Artery
What branches come off of the Splenic Artery?
- Short Gastric Arteries
- Left Gastro-Omental Artery
- Greater Pancreatic Artery
- Dorsal Pancreatic Artery
(GPA and DPA anastomose to create the Inferior Pancreatic Artery)
What branches come off of the Common Hepatic Artery?
- Right Gastric Artery
- Gastroduodenal Artery
- Proper Hepatic Artery (??)
What branches come off of the Gastroduodenal Artery?
- Right Gastro-Omental Artery
- **Superior Pancreaticoduodenal Artery (sometimes)
OR
Posterior and Anterior Superior Pancreaticoduodenal Artery
1st Part of the Small Intestine
Duodenum
Duodenum
G-shaped with 4 parts:
- Superior (Pyloric Orifice to Neck of Gallbladder)
- Descending (Neck of Gallbladder to L3)
- Inferior (transversally crosses Aorta, IVC, and Vertebral Column)
- Ascending (L2 to Duodenojejunal Flexure
Major Duodenal Papilla
- Separation between Foregut and Midgut located between
- Entrance for Bile and Pancreatic Ducts
- Located in Descending Duodenum
Ligament of Treitz
Holds up the Ascending Duodenum
Superior Mesenteric Vein and Artery sit on top of what part of the Duodenum?
Third Part AKA Inferior Duodenum
Blood Supply to the Duodenum branches off of these major Arteries:
- Gastroduodenal Artery or Superior Pancreaticoduodenal Artery**
- Inferior Pancreaticoduodenal
- SMA (First Jejunal Branch)
Where do the Anterior and Posterior SUPERIOR Pancreaticoduodenal Arteries branch off of?
Gastroduodenal Artery
OR
Superior Pancreaticoduodenal Artery** (if it even exists)
Where do the Anterior and Posterior INFERIOR Pancreaticoduodenal Arteries branch off of?
Inferior Pancreaticoduodenal Artery
What branches off of the Superior Mesenteric Artery
- Inferior Pancreaticoduodenal Artery
- Ileocolic Artery
- Jejunal Arteries
- Ileal Arteries
What organs do the Pancreaticoduodenal Arteries supply with blood?
Pancreas and the Duodenum in the “C-shape” created by the Duodenum
Jejunum
Proximal 2/5 of the Small Intestine located in the Left Upper Quadrant
Ileum
- Distal 3/5 of Small Intestine (largest)
- Right Lower Quadrant
- Ends at the Ileocecal Valve where it joins with the Cecum (Large Intestine)
Ileocecal Valve
A sphincter that regulates chyme flow between Ileum and the Cecum
Blood Supply to the Jejunum and Ileum is supplied by what Unpaired Branch of the Abdominal Aorta?
Superior Mesenteric Artery
Name the arteries that provide the Jejunum and Ileum with blood
- Jejunal Arteries
- Ileal Branches
- Ileocolic Branch (provides Ileum and part of the Colon)
Mesentery anchors Small Intestine to…
Itself and to the posterior body wall
Arterial Arcades
Rounded bits of the Jejunal and Ileal arteries that allow you to differentiate Jejunum from the Ileum
Jejunal Arterial Arcades
- Small and not very extensive in the Mesentery
2. Give off Long Vasa Recta
Ileal Arterial Arcades
- Large and wide, take up a majority of the Mesentery
2. Give off very Short Vasa Recta
Vasa Recta
Straight, finger-like arteries that branch off of Arcades
Large Intestine consists of
- Cecum
- Appendix
- Colon
- Rectum
- Anal Canal
Cecum
- First part of the Large Intestine
- Largest segment of the Large Intestine
- Appendix comes off of the Cecum
Appendix branches off of the
Cecum segment of the Large Intestine
Parts of the Colon
- Ascending Colon
- Transverse Colon
- Descending Colon
- Sigmoid Colon (squiggle)
Water and Nutrients are absorbed in…
Small and Large Intestines
General Characteristics of the Large Intestine
- Large Diameter
- Omental Appendices (fat accumulations)
- Taniea Coli (longitudinal muscle)
- Haustra (pockets formed by Taniea Coli)
Taniea Coli
Longitudinal muscle that runs down the center for the entire length of the large intestine to squish it like an accordion
Haustra
Pockets formed by the Taniea Coli squishing the large intestine where nutrients and water can be absorbed from fecal matter
Omental Appendices
Pockets of peritoneum that contain adipose tissue in the large intestine
Hepatic Flexure/Right Colic Flexure
Right side where Large Intestine “turns the corner” right below the Liver; lower than left
Splenic Flexure/Left Colic Flexure
Left side where Large Intestine “turns the corner” right below the Spleen; higher than right
Cecum
- First part of Large Intestine
- Sits in Right Iliac Fossa (hip)
- Supplied by Anterior and Posterior Cecal Arteries (from Ileocolic Artery branched from SMA)
Appendix
- Narrow, hollow tube that originates on the Cecum near the start of the Taniea Coli
- Contains aggregations of lymphoid tissue
- Supplied by Appendicular Artery (from Iliocolic Artery branched from the SMA)
3 Main branches that go from Superior Mesenteric Artery to the Large Intestine
- Ileocolic Artery
- Right Colic Artery
- Middle Colic Artery
2 Main Branches that go from Inferior Mesenteric Artery to the Large Intestine
- Left Colic Artery
- Sigmoidal Arteries
- Superior Rectal Artery
What does the Ileocolic Artery branch into?
- Middle Colic Artery
- Right Colic Artery
- Anterior Cecal Artery
- Posterior Cecal Artery
- Appendicular Artery
Blood Supply for the Cecum and the Ascending Colon
- Colic Branch (from Ileocolic Artery)
- Anterior and Posterior Cecal Arteries (from Ileocolic Artery)
- Right Colic Artery (from SMA)
Blood Supply for the Transverse Colon
- Right Colic (from SMA)
- Middle Colic (from SMA)
- Left Colic (from IMA)
Blood Supply to the Descending Colon
Left Colic Artery (from IMA)
Blood Supply to the Sigmoid Colon
Sigmoidal Arteries (from IMA)
Superior Mesenteric Artery provides blood to what parts of the Large Intestine?
- Cecum
- Ascending Colon
- Proximal 2/3 of Transverse Colon
What parts of the Large Intestine are NOT suspended by Mesentery?
- Ascending Colon
2. Descending Colon
Right and Left Paracolic Gutters
- Immediately Lateral to Ascending (Right) and Descending (Left) Colon
- Depression that provide a passageway for materials to pass behind the Peritoneum and go from one region to another within the abdomen
- Can provide a relatively blood-free mobilization of the
Ascending and Descending Colon by cutting the Peritoneum along these lateral Paracolic gutters since vessels and lymphatics are medial and posteromedial
Rectosigmoidal Junction
- Located around S3 Vertebrate
2. Where the Sigmoid Colon becomes the Rectum
Rectum and the Anal Canal
- Retroperitoneal (both)
2. Not suspended by Mesentery
Blood Supply to the Rectum and Anal Canal
- Superior Rectal Artery (from IMA)
- Middle Rectal Artery (from Internal Iliac)
- Inferior Rectal Artery (from Internal Iliac)
Pre-Aortic Nodes
Drain the Abdominal GI tract and sit on the anterior aspect of the Aorta
Celiac Pre-Aortic Nodes
Provide Lymphatic Drainage of the Foregut Structures
Superior Mesenteric Pre-Aortic Nodes
Provide Lymphatic Drainage of the Midgut Structures
Inferior Mesenteric Pre-Aortic Nodes
Provide Lymphatic Drainage of the Hindgut Structures
Enteric Nervous System
The Intrinsic Nervous System of the digestive tract located inside its walls that regulates digestion
What are the 2 Major Plexuses that run the Enteric Nervous System
- Myenteric Plexus
2. Submucosal Plexus
Myenteric Plexus
- Plexus of nerves found in the muscular layer of the entire Gut Tube
- Regulates contraction of muscle and movement of things through digestive tract
Submucosal Plexus
- Controls glandular secretion
What is the main branch of the Autonomic Nervous System that encourages digestion?
Parasympathetic Nervous System (Rest and Digest)
Sympathetic Innervation of the Foregut and Midgut
Thoracic Splanchnic Nerves (Greater, Lesser, and Least)
Parasympathetic Innervation of the Foregut and Midgut
Vagus Nerve (AKA Cranial Nerve 10)
Sympathetic Innervation of the Hindgut
- Lumbar Splanchnics
2. Sacral Splanchnics
Parasympathetic Innervation of the Hindgut
Pelvic Splanchnics
Greater Thoracic Splanchnic travels to
Celiac Ganglian (near Celiac Trunk)
Lesser Thoracic Splanchnic travels to
Aorticorenal Ganglion (near Celiac Trunk)
Least Thoracic Splanchnic travels to
Renal Plexus (near Celiac Trunk)
Lumbar Splanchnic travels to
Prevertebral Plexus (near IMA)
Sacral Splanchnic travels to
Inferior Hyopgastric Plexus (extension of the Prevertebral Plexus in the pelvis also near the IMA)
Anterior and Posterior Vagal Trunks
- Provide parasympathetic Innervation to Foregut and Midgut
- Enters Abdomen with Esophagus at T10
- Sneds branches to abdominal pre-vertebral plexuses
Pelvic Splanchnic
- Provides PARASYMPATHETIC innervation to the Hundgut
- Arises from S2-S4
- Enters inferior hypogastric plexus in the pelvis and moves upward into the inferior mesenteric part of pre-vertebral plexus
Plexus vs, Ganglion
Plexus can carry Sympathetic AND Parasympathetic
Ganglion can carry Sympathetic OR Parasympathetic