Abdomen, GI tract Flashcards
What is the function of the splanchnic nerves?
They provide sympathetic innervation to the foregut, midgut and hindgut.
What 2 vertical lines divide the abdomen into it’s 9 nine regions?
Mid-clavicular lines that extend to the mid-inguinal point.
What 2 horizontal lines divide the abdomen into it’s 9 nine regions?
Upper - Subcostal: joins lower costal margins.
Lower - Intertubercular: connects the iliac crests.
How would you draw the transpyloric plane?
Also known as plane of Addison.
Half way between the suprasternal notch and the pubic symphysis.
midway between the xiphisternum and the umbilicus.
Through the 9th costal cartilages, at level of L1
What vertebral level is the transpyloric plane found?
Also known as plane of Addison.
L1
Name 5 structures found on the transpyloric plane
Also known as plane of Addison.
- Pylorus of stomach.
- Fundus of gall bladder.
- Pancreas.
- Hilum of Kidneys.
- Duodenojejunal flexure.
How would you draw the transtubercular plane?
pass through the iliac tubercles, small elevations found in the iliac crest of the iliac bone.
What vertebral level is the transtubercular plane found at?
L4. (Same level as the bifurcation of the abdominal aorta).
What is the intercristal plane?
It joins the highest points of the pelvis at the back.
What vertebral level is the intercristal plane found at? Why is this important?
Between the L4 and L5 vertebrae. This is important for lumbar punctures and epidurals.
What is McBurney’s point?
2/3 of the way along a line extending from the umbilicus to the right anterior superior iliac spine.
What is the significance of McBurney’s point?
Marks the base of the appendix and can act as a guide for the location of the caecum.
Name the 3 flat muscles of the Abdominal wall.
- External Oblique.
- Internal Oblique.
- Transversus Abdominis.
In what direction do the fibres of the flat muscles run in?
- External oblique - inferiorly and medially (down and in).
- Internal oblique - superiorly and medially (up and in).
- Transversus abdominis - transversely.
What is the origin of external oblique?
Lower 8 ribs and thoraco-lumbar fascia.
What is the insertion of external oblique?
Pubic crest, pubic tubercle, iliac crest and linea alba.
What is the origin of internal oblique?
Thoraco-lumbar fascia, iliac crest, lateral 1/2 of the inguinal ligament.
What is the insertion of internal oblique?
Linea alba, pubic tubercle.
Name 5 structures contained within the rectus sheath.
- Rectus Abdominis.
- Sup and inf epigastric arteries.
- Sup and inf epigastric veins.
- Nerves.
- Lymphatics.
What is the inferior epigastric artery a branch of?
The external iliac artery.
What is the internal thoracic artery a branch of? And what does it supply?
It is a branch of the subclavian artery and it supplies the anterior chest and abdominal wall and also the breasts.
What are the dermatomes of the abdominal wall?
T7 to L1.
What is the epithelium lining of the abdominal cavity?
Simple squamous epithelium.
What is the peritoneal cavity?
What is it filled with?
A potential space between the visceral and parietal peritoneum. It is filled with peritoneal fluid.
which consists of water, electrolytes, leukocytes and antibodies. This fluid acts as a lubricant, enabling free movement of the abdominal viscera, and the antibodies in the fluid fight infection.
What is a retroperitoneal organ
An organ that only has it’s anterior surface covered by peritoneum. These organs lie behind the peritoneum.
Name 6 retroperitoneal organs.
Duodenum, ascending colon, descending colon, pancreas, oesophagus, kidneys. (DADPOK).
What is an intraperitoneal organ
An organ fully covered in visceral peritoneum. It is suspended in the peritoneal cavity.
Name 6 intraperitoneal organs.
Sigmoid colon, appendix, liver, transverse colon, stomach, small intestine. (SALTSS).
What connects the lesser sac to the greater sac?
The epiploic foramen.
What does the lesser omentum attach to?
It extends from the liver and attaches to the lesser curvature of the stomach and the first part of the duodenum.
What is attached to the greater curvature of the stomach?
The greater omentum.
Describe the position and folding of the greater omentum in the peritoneal cavity.
It hangs down like an apron and then folds back on itself meaning there are 4 layers. The posterior 2 layers go on to enclose the transverse colon (transverse mesocolon) and then form the parietal peritoneum of the posterior abdominal wall.
What is it called when the peritoneal cavity becomes distended by fluid?
Ascites.
What embryological structure forms the ligamentum teres?
The umbilical vein.
What connects the jejunum to the posterior abdominal wall?
Small intestine mesentery.
What parts of the large intestine are intraperitoneal?
The transverse and sigmoid colon.
Define lesser sac.
The lesser sac lies posterior to the stomach and lesser omentum. It allows the stomach to move freely against the structures posterior and inferior to it.
It communicates with the greater sac through the epiploic foramen.
What structures lie posteriorly to the stomach?
Pancreas, diaphragm, splenic artery and vein.
Name the 4 main regions of the stomach.
- Cardia.
- Fundus.
- Body.
- Pylorus.
What are the folds of the internal stomach surface called?
Rugae.
Name the 2 sphincters of the stomach.
- Inferior oesophageal sphincter.
2. Pyloric sphincter.
What is the function of the pyloric sphincter?
Controls the exit of chyme from the stomach.
What vertebral level is the coeliac trunk found?
T12.
Where does the foregut begin and end?
The mouth to the 2nd part of the duodenum (major duodenal papilla).
What is the blood supply to the greater curvature of the stomach?
The short gastrics, and the right and left gastro-epiploic arteries
What is the blood supply to the lesser curvature of the stomach?
The lesser curvature of the stomach is supplied by the left and right gastric artery, which are branches of the celiac trunk and the common hepatic artery respectively.
What is the right gastro-epiploic artery a branch of?
It is the terminal branch of the gastroduodenal artery, this arises from the common hepatic artery which arises from the coeliac trunk.
What is the left gastro-epiploic artery a branch of?
The splenic artery which arises from the coeliac trunk.
What vein does venous blood from the GI tract, liver and spleen drain into?
The hepatic portal vein (goes to the liver).
What supplies sympathetic innervation to the stomach (foregut)?
The greater splanchnic nerve (T5-T9).
What supplies parasympathetic innervation to the stomach (foregut)?
The Vagus nerve Cn 10.
Is contraction of the stomach sphincters a sympathetic or parasympathetic action?
Sympathetic. (Parasympathetic = rest and digest).
At what vertebral level does the oesophagus pass through the stomach?
T10.
What structures pass through the diaphragm along side the oesophagus?
Vagus nerves and the oesophageal arteries and veins.
What does the left gastric artery supply?
The superior part of the lesser curvature of the stomach.
What is the principle function of the small intestine?
Digestion and absorption of food.
What are the folds of mucosa inside the small intestine called?
Plicae circulares.
What are Peyer’s patches?
Large, sub-mucosal, lymph nodules.
Where in the small intestine would you find Peyer’s patches?
Ileum.
Is the duodenum intraperitoneal or retroperitoneal?
1st and 4th parts are Intraperitoneal, 2nd and 3rd parts are Retroperitoneal.
Would you describe the jejunum and ileum as intraperitoneal or retroperitoneal?
Intraperitoneal.
Which has a thicker intestinal wall, the jejunum or the ileum?
Jejunum.
Describe 5 characteristics of the Jejunum.
- Thick intestinal walls.
- Longer vasa recta.
- Less arterial arcades.
- Pronounced plicae circulares.
- Red in colour
Describe 5 characteristics of the Ileum.
- Thin intestinal walls.
- Shorter vasa recta.
- More arterial arcades.
- Peyer’s patches.
- Pink in colour.
Where does the mid-gut begin and end?
3rd part of duodenum to 2/3 along the transverse colon.
What is the blood supply to the midgut?
Superior mesenteric artery (L1).
Name 3 major branches of the SMA.
- Ileo-colic.
- Right colic.
- Middle colic.
What does the right colic artery supply?
The ascending colon.
What does the middle colic artery supply?
The transverse colon.
Into which vein does blood from the jejunum and ileum drain and what is the final destination of the blood?
Drains into the superior mesenteric vein.
This vein combines with the splenic vein to form the hepatic portal vein which then goes on to the liver.
What is the innervation of the small intestine?
Sympathetic: Lesser splanchnic (T10-11). Parasympathetic: Vagus. No somatic innervation.
Name 4 mechanisms that ensure a high surface area for absorption of nutrients in the intestine.
- Pliae circularis.
- Coiled length.
- Villi.
- Microvilli.
What is the main function of the large intestine?
Water absorption and the formation of faeces.
State whether the caecum is intraperitoneal or retroperitoneal and describe the blood supply and venous drainage.
- Intraperitoneal.
- Ileocolic artery.
- Ileocolic vein; drains into superior mesenteric vein.
State whether the ascending colon is intraperitoneal or retroperitoneal and describe the blood supply and venous drainage.
- Retroperitoneal.
- Ileocolic and right colic arteries.
- Ileocolic and right colic veins.
State whether the transverse colon is intraperitoneal or retroperitoneal and describe the blood supply and venous drainage.
- Intraperitoneal.
- Middle colic artery.
- Superior mesenteric vein.
State whether the descending colon is intraperitoneal or retroperitoneal and describe the blood supply and venous drainage.
- Retroperitoneal.
- Left colic and superior sigmoid arteries.
- Inferior mesenteric vein.
State whether the sigmoid colon is intraperitoneal or retroperitoneal and describe the blood supply and venous drainage.
- Intraperitoneal.
- Sigmoid arteries.
- Inferior mesenteric vein.
What vertebral level is the inferior mesenteric artery found at?
L3.
Name 3 characteristic features of the large intestine that allow it to be distinguished from other abdominal organs.
- Haustrations.
- Tenia coli.
- Appendices epiploicae.
What are appendices epiploicae?
Small pouches of peritoneum filled with fat. They mark where blood vessels enter the bowel to supply the mucosa.
What are tenia coli?
3 strips of longitudinally running muscle on the outer surface of the large intestine.
What are haustrations?
Sacculations produced from where the tenia coli contract to shorten the wall of the bowel.
Where does the hind gut begin and end?
Distal 1/3 of the transverse colon to the anal canal.
What is the innervation of the hind gut?
Sympathetic: least splanchnic nerve (T12). Parasympathetic: S2-4. No somatic innervation
What artery normally supplies the descending colon?
The left colic artery.
Name the intraperitoneal parts of the large intestine.
Caecum, transverse colon, sigmoid colon.
What are the 3 major branches of the Coeliac trunk?
The left gastric, the splenic and the common hepatic.
What does the left gastric artery supply
The lesser curvature of the stomach and lower oesophagus.
What branches does the splenic artery give off?
- The short gastric arteries.
- The pancreatic arteries.
- The left gastroepiploic artery.
- 5 branches just before it reaches the Spleen.
What do the short gastric arteries supply?
The greater curvature of the stomach.
What does the left gastroepiploic artery supply? What does anastomose with?
It supplies the greater curvature of the stomach. It anastomoses with the right gastroepiploic artery.
Name the 2 branches of the common hepatic artery.
- Proper hepatic artery.
2. Gastroduodenal artery
Name the 2 branches of the Gastroduodenal artery.
- Right gastroepiploic artery (supplies greater curvature of the stomach).
- Superior pancreaticoduodenal artery (supplies head of pancreas).
Name the 2 branches of the proper hepatic artery?
- Right hepatic artery.
- Left hepatic artery.
The cystic artery comes off the right hepatic artery
What does the right gastric artery supply
The lesser curvature of the stomach.
What is a branch of the right hepatic artery?
The cystic artery (supplies the gall bladder).
Name the 4 divisions of the Duodenum.
- Superior.
- Descending.
- Inferior.
- Ascending.
Is the duodenum retroperitoneal or intraperitoneal?
The duodenal cap is intraperitoneal but the rest of the duodenum is retroperitoneal.
What is the function of the spleen?
In an adult it functions mainly as a blood filter, removing old RBC’s from circulation.
Is the spleen intraperitoneal or retroperitoneal?
Intraperitoneal
What is the embryological significance of the major duodenal papilla?
It marks the junction between the foregut and the midgut.
What is the importance of the plicae circularis?
They increase the intestinal SA available for absorption.
What is the dermatome of the umbilicus?
T10.
What is the appendicular artery a branch of?
The ileocolic artery (branch of SMA).
what is the action of the rectus abdominus
flexes the spine
What is the level of the umbilicus (belly button)
L3-L4
Cells of Stomach what do chief cells secrete?
pepsinogen and gastric lipase
Cells of Stomach what do Parietal cells secrete?
Hcl and Intrinsic factor
Cells of Stomach what do G cells secrete?
gastrin, in the antrum of stomach
Cells of Stomach what do D cells secrete?
Somatostain, stops gastrin , common in antrum
Cells of Duodenum what do I cells secrete?
Chloecystokinin CCK, which stimulates gall bladder contraction
Cells of Duodenum what do S cells secrete?
secretin , which trigger HCO3- secretion
Cells of stomach what do Enterchromafin- like cells secrete?
Enterochromaffin- like cells (ECF) - Secrete Histamine (it’s a great mediator of Gastric Secretion)
Cells of stomach , what do foveolar cells secrete? where are they in the stomach
Foveolar cells - Secret Mucous (made of water and Glycoproteins). Found in the cardiac notch
Rectus Sheath: What are the anterior and posterior boarders ABOVE the arcuate line?
( The arcuate line occurs about half of the distance from the umbilicus to the pubic crest, but this varies from person to person.)
The anterior layer is derived from the external oblique aponeurosis and the anterior lamina of the internal oblique aponeurosis.
The posterior layer is made up of the posterior lamina of the internal oblique aponeurosis and the transversus abdominis aponeurosis.
Rectus Sheath: What are the anterior and posterior boarders BELOW the arcuate line?
( The arcuate line occurs about half of the distance from the umbilicus to the pubic crest, but this varies from person to person.)
Inferior to the arcuate line, the aponeuroses of the external oblique muscle, the internal oblique muscle, and the transversus abdominis muscle merge and pass superficial to the rectus abdominis muscle.
Therefore, inferior to the arcuate line, the rectus abdominis rests directly on the transversalis fascia.
What is the cotnents of the rectus sheath?
Inferior epigastric artery
Inferior and superior epigastric vein
The rectus abdominis muslce
lymphatics
What is the innervation of the kidneys?
The sympathetic plexus, T10-T12
What is the epithelial linig of the abdominal cavity
Simple squamous epithelium
What structure attaches the stomach to the liver?
The hepatogastric ligament extends between the liver and stomach. It consists of two layers that are continuous with the posterior leaf of the left triangular ligament and the right coronary ligament.
What artery is at risk if someone has peptic ulcers?
The gastroduodenal artery,
as it is by the first part of the duodenum, just after the pyloric sphincter which is prone to peptic ulceration
jejunum or ileum: where are plicae circulairs more pronounced?
jejunum
What lies between the pancreas and the stomach?
The lesser sac
What is the short gastric arteries a branch of?
Terminal splenic, and left gastro-epiploic
What is the structure of the muscle fibres in the upper and lower part of the oesophagus? what is the significance of this?
Upper portion of the oesophagus has voluntary (striated) fibres (1)
- Lower portion of the oesophagus has involuntary (smooth) fibres (1).
- (The middle third has a mixture of these).
What part of the embryo folds to form the epithelial lining of the GI tract?
Endoderm!
What are the parts of the bowel with mesentery ?
jejunum, ileum, transverse colon
and sigmoid colon
What are the parts of the bowel without mesentery ?
the duodenum,
caecum, ascending colon, descending colon and rectum.
