Lecture 6 Flashcards
Which abdominal components are not contained within the abdominal cavity?
Oes and rectum
Which region is referred pain generally referred to?
Epigastric, umbilical, pubic regions
Quadrant system also used
What does the celiac trunk split into?
Left gastric, splenic, common hepatic
Is the celiac trunk short or long?
Short
Where does the celiac trunk come off the abdominal aorta?
At T12
Where does the superior mesenteric artery come off the abdominal aorta?
At L1
Where does the inferior mesenteric artery come off the abdominal aorta?
At L3
What is the arterial supply of the foregut?
Branches of celiac axis
What is the venous drainage of the foregut?
Portal vein
What is the nerve supply to the foregut?
Celiac plexus at T12
What are the lymphatics of the foregut?
Pre-aortic nodes at T12 (Celiac nodes)
Where is pain in the foregut referred to?
Epigastric region
What is the general region where the stomach is located?
Epigastric region to the left of the midline.
At which position is the fundus located?
Ribs 5/6
At which position does the oes enter the stomach?
Costal cartilage of ribs 7/8
At which position is the pylorus located?
L1 vertebral level on the transpyloric plane
What are the three muscle layers in the wall of the stomach?
- Outer longitudinal
- Middle circular
- Inner oblique
What is the special feature that the inner wall has?
Many rugae to increase surface area and expandability
Where on the stomach does the lesser omentum attach?
Lesser curvature
Describe the pyloric valve
Thickened region of muscle controlling flow of contents out of stomach
What is the arterial supply of the stomach ultimately from?
Coeliac trunk
What is the arterial supply of the lesser curvature?
Left gastric (coeliac trunk) Right gastric (common hepatic)
What is the arterial supply of the greater curvature?
Left gastro-omental (splenic)
Right gastro-omental (gastroduodenal
What is the arterial supply of the fundus?
Short gastric
What is the origin of the duodenum?
Immediately following pyloric region of the stomach
At which position is the first part of the duodenum found?
Transpyloric plane
What does the 2nd part of the duodenum wrap around?
Pancreas to the RHS of the midline
How does the biliary tree make its way through the pancreas and into duodenum?
Goes through head of pancreas and enters into 2nd part of duodenum
What is the pathway of the 3rd part of the duodenum?
Crosses back over IVC and aorta
What is the pathway of the 4th part of the duodenum?
Ascents to duodenojujenal flexure (LHS of midline)
Distinguish between the intra and retoperitoneal parts of the duodenum
1st part: intraperitoneal
2nd, 3rd, 4th: retroperitoneal
Where do the superior mesenteric artery and vein cross over the duodenum?
3rd part
What are other names for the 1st to 4th part of the duodenum?
1: superior
2: descending
3: inferior
4: ascending
What is the arterial supply of the duodenum?
Superior half: superior pancreatoduodenal branches (from gastroduodenal artery - coeliac origin)
Inferior half: inferior pancreatoduodenal branches (from superior mesenteric origin)
What is the nerve supply of the duodenum?
Superior: Celiac plexus at T12
Inferior: Superior mesenteric plexus at L1
What is the venous drainage of the duodenum?
Superior: Direct to portal vein
Inferior: SMV
What is the lymphatic drainage of the duodenum?
Superior: Pre-aortic coeliac nodes at T12
Inferior: Pre-aortic superior mesenteric nodes at L1
What is the ampulla of vater?
Union of common bile duct and main pancreatic duct
What is meant by an ampulla?
Swelling in the tube where 2 ducts meet
What is another name for ampulla of vater?
Hepatopancreatic ampulla
What is the major duodenal papilla? What is its purpose?
A mound that enters through wall of descending duodenum. Controls flow of bile (from liver) and pancreatic juice from pancreas into the duodenum via the sphincter of Oddi.
What enters through the minor duodenal papilla?
Accessory pancreatic duct
What is the arterial supply of the midgut?
Branches of SMA
What is the venous drainage of the midgut?
SMV
What is the nerve supply to the midgut?
Superior mesenteric plexus
What are the lymphatics of the midgut?
Pre-aortic nodes at L1 (superior mesenteric nodes)
Where is pain from the midgut referred to?
Umbilical region
Describe the structure of the small intestine?
Long, thin, muscular tube (6m long)
What is the function of the small intestine?
Bulk of digestion occurs here
What is the small intestine divided into?
Jejunum (proximal 2/5th)
Ileum (distal 3/5th)
What is the small intestine suspended from the body wall with?
Mesentery
Describe the mesentery of the small intestine. What does it allow?
Fan-shaped folds of peritonuem enclosing the gut tube. Allows ingress/egress of vessels, nerves, and lymphatics
Describe the main identifying difference between the jejunum and ileum.
Arterial arcade patterning
J: 1 or 2 arcade with long branches
I: More arcades with many short branches
What is the arterial supply of the small intestine?
Branches of SMA
- Jejunal arteries
- Ileal arteries
What is the ANS nerve supply of the small intestine?
Superior mesenteric plexus at L1
What is the venous drainage of the small intestine?
SMV
What is the lymphatic drainage of the small intestine?
Pre-aortic superior mesenteric nodes at L1
What are the two flexures of the large intestine? Which is positioned lower?
Right colic/hepatic flexure (lower)
Left colic/splenic flexure
What are the functions of the large intestine?
- Absorb water and electrolytes
- Store undigested material until expelled by the body
What are the 4 general features of the large intestine?
Haustra
Appendices epiploicae
Teniae coli
Appendix
What are haustra?
Saculations of the wall of the large intestine
What are Appendices epiploicae?
Fatty tags that can get inflamed, which mimics appendicitis. None on small intestine.
What are teniae coli?
Longitudinal muscles collected into 3 bands, continuous with the smooth muscle of the small intestine
In what regions is the large intestine found?
In all regions except the umbilical
List where each of the components of the large intestine are found in the different regions of the abdomen
Caecum/appendix: Right groin
Ascending colon: Right flank
Hepatic flexure: Right hypochondrium (inferior to liver)
Transverse colon: Epigastric region
Splenic flexure: Left hypochondrium (anterior to spleen)
Descending colon: Left flank
Sigmoid colon: Left groin
What is the arterial supply of the caecum/appendix?
Caecal and appendicular arteries from the ileocolic artery
What is the arterial supply of the ascending colon?
Right colic artery
What is the arterial supply of the proximal 2/3 transverse colon?
Middle colic and marginal
Which branches that supply the large intestine are given off from the SMA?
Iliocolic artery
Right colic artery
Middle colic artery
Marginal artery
What is the arterial supply of the distal 1/3 of the transverse colon?
Marginal and left colic artery
Descending colon arterial supply
Left colic artery
Sigmoid colon arterial supply
Sigmoid artery
Branches of the IMA that supply the large intestine
Marginal
Left colic
Sigmoid
What is the marginal artery?
The anastamotic point between the superior and inferior mesenteric arteries
What portion of the colon often becomes muscularised?
Descending/sigmoid
What is the function of the rectum?
Final storage depot for digestive material
At which level does the sigmoid colon become the rectum?
At S3 vertebral level
Where does the rectum pierce the pelvic diaphragm?
AT the tip of coccyx
What does the rectum become after piercing the pelvic diaphragm?
Anal canal
Describe the relationship between the rectum and the peritoneum for each third.
Superior: Covered in visceral peritoneum on anterior and lateral sides
Middle: Peritoneum on anterior surface only
Inferior: Infraperitoneal
What is the arterial supply of the rectum?
Sup: Superior rectal branches of IMA
Mid: Middle rectal branch of internal iliac
Inferior: Inferior rectal branch of internal pudendal
Describe the venous drainage of the rectum
Superior rectal vein - IMV - portal vein
Mid. and inferior rectal vein - internal iliac - common iliac - IVC
What is portal-systemic anastomosis important in?
Cases of hypertension
What is the ANS nerve supply of the rectum?
Proximal 1/3: inferior mesenteric plexus
Distal 2/3: inferior hypogastric plexus
What are the lymphatics of the rectum?
Proximal 1/3: to pre-aortic nodes at L3
Distal 2/3: to internal iliac nodes
At what position is the portal vein formed?
At L1 transpyloric plane
What is the parasympathetic nerve supply to the gut?
Vagus nerve (CN X) Pelvic splanchnic nerves S2-4
What is the sympathetic nerve supply to the gut?
Thoracic, lumbar, and sacral splanchnic nerves from T5-L2 sympathetic ganglia
What does the autonomic nervous system control in the gut?
Viscera, glands, blood vessels
Smooth muscle
Non-conscious control
Motor and sensory
What do splanchnic nerves control?
They are specifically visceral so go straight to organs
State the plexus, sympathetic and parasympathetic supply to the foregut.
Coeliac plexus
Sym: Greater splanchnic T5-9
Para: Vagus [X]
State the plexus, sympathetic and parasympathetic supply to the midgut
Superior mesenteric plexus
Sym: Lesser splanchnic T10-T11
Para: Vagus [X]
State the plexus, sympathetic and parasympathetic supply to the hindgut
Inferior mesenteric/superior hypogastric plexus
Sym: Lumbar/sacral splanchnic L1-2/S2-4
Where is pain referred back to?
The origin spinal levels of the sympathetic supply via afferent fibres and then via the dorsal root (along with somatic afferents).
Is there a specific point of reference for the nerves in the gut? What is a consequence of this?
NO
Pain is spread around the corresponding dermatome
Where does pain in the foregut get referred to?
Epigastric region
Where does pain in the midgut get referred to?
Umbilical region
Where does pain in the hindgut get referred to?
Suprapubic region
What happens to the appendix during appendicitis?
Appendix becomes enflamed
Where does pain get referred to during appendicitis?
Afferent sympathetic fibres refer back to T10-11 dermatomes
What kind of pain is experienced during initial appendicitis? Where?
Broad diffuse pain experienced around umbilical region
What happens when the appendix becomes so enflamed that it is in contact and starts pressing on parietal peritoneum of body wall?
Somatic sensory supply is activated and pain is now felt as acute and localised to lower right quadrant.