GI Flashcards
what is the blood supply for the lesser curvature of the stomach?
left + right gastric branch of the hepatic artery
what is the blood supply of the greater curvature of the stomach?
short gastric arteries
left and right gastro-omental arteries
which ligament does the lesser curvature of the stomach give attachment to?
hepatogastric ligament
name the four sections of the stomach
fundus, body, pylorus, cardia
what level is the cardia?
T11
what does the pylorus connect to?
duodenum
Where is the angular notch?
where does the Inferior Oesophageal Sphincter pass through and at what level?
Oesphageal Hiatus - T10
what is the pyloric sphincter made of?
smooth muscle
Where does the greater omentum hang from and join to?
From the greater curvature and folds up to join to the transverse colon
Why does the greater omentum contribute largely towards gastrointestinal immunity?
contains lots of lymph nodes
Where does the lesser omentum originate from and join to?
Lesser curvature and joins to the liver
Via what does the greater and lesser sac communicate through?
Epiploic foraman
Where does the coeliac plexus arise from?
2nd branch of abdominal aorta
What does the splenic artery supply?
spleen
What are the three main branches of the abdominal aortus?
Left gastric, Splenic and Common hepatic
What does the splenic artery branch into and what do those branches supply?
body + tail of pancreas via pancreatic branches
fundus via short gastrics
greater curvature of stomach via left gastric-omentum
Which ligament is the splenic artery contained within?
splenorenal ligament
Describe the general route the splenic branch takes towards the spleen
posterior of stomach, across superior border of pancreas
Why is the splenic branch easily identifiable compared to the other branches?
Has a tortuous appearance
What does the Left gastric artery supply?
Stomach + oesophagus
What does the left gastric artery anastomose with?
Right gastric artery
What are the two main branches of the common hepatic artery?
Proper hepatic & gastroduodenal
What does the proper hepatic ascend through?
Lesser omentum
Proper hepatic artery gives rise to:
R. Gastric
Right and Left hepatic
Cystic
What does the gastroduodenal supply?
Stomach + small intestine
Gastroduodenal gives rise to:
R. Gastroepiploic
Super prancreacticoduodenal
What does the cystic artery supply?
Gallbladder
What does the pancreaticoduondenal supply?
Head of pancreas
What’s the start and end of the duodenum?
pylorus of the stomach -> duodenojejunal flexure
Name the 4 parts of the duodenum
Superior, Descending, Inferior, Ascending
Via what ligament is the superior part of the duodenum connected to the liver?
Hepatoduodenal ligament
What spinal level is the Superior part of the duodenum at?
L1
What spinal level is the descending part of the duodenum at?
L1 - L3
Which part of the duodenum is the most common site of duodenal ulceration?
Superior
What covers the superior part of the duodenum?
Initial 3cm is covered anteriorly + posteriorly by visceral peritoneum
Rest is only covered anteriorly
What’s posterior and anterior of the descending part of the duodenum?
posteriorly to transverse colon
anteriorly to right kidney
Where does bile and pancreatic secretion enter the duodenum and where from?
Enters descending part of duodenum through major duodenal papilla from the Ampulla of Vater
Describe the structures around the inferior part of the duodenum
sits posterior to super mesenteric artery and vein
inferior to pancreas
describe the general route of the inferior part of the duodenum
Travels laterally to the left, crosses over inf. vena cava & aorta
What spinal level is the inferior part of the duodenum at?
L3
What spinal level is the ascending part of the duodenum at?
L3 - L2
What is the junction called between the duodenum and then jejenum?
duodenojejenum flexure
@ the junction between the duodenum and the jejenum, what muscle is present and what is its function?
Suspensory Muscle of Duodenum
contraction widens the angle of the flexure + aids movement of the contents into the jejenum
Where does the ileum end?
Ileocaecal junction
How can you differentiate between the jejenum and the ileum?
They’re macroscopically different
State the function of the ileocaecal valve
To prevent reflux of material back into the ileum
Describe the general route of the duodenal vein system
Veins follow the major arteries and drain into the hepatic portal vein
Describe the general route of lymph in the duodenum
Lymph drains into the pacreaticoduodenal + superior mesenteric nodes
What artery supplies the dueodenal proximal to the major duodenal papilla?
Gastroduodenal artery
What artery supplies the duodenum distal of the major duodenal papilla?
Inferior pancreaticoduodenal artery
Describe the lymphatic drainage of the jejunum and the ileum
Lymph drains into the superior mesenteric nodes
What’s the vein for the ileum and the jejunum?
Superior mesenteric vein
Which artery supplies the jejunum and the ileum?
Superior Mesenteric artery
Where does the superior mesenteric artery branch off?
Branches off abdominal aorta just inferior the coeliac trunk, Level L1-2
Name the loops/arches that the jejunal arteries form
Arterial arcades
What’s the clinical important of arterial arches?
Able to function despite damage because of the loops/arches
What arteries branch off the arterial arcades?
Straight arteries (Vasa recta)
Name the 4 sections of the Large Intestine
Ascending Colon
Transverse Colon
Descending Colon
Sigmoid Colon
State the beginning and end points of the Ascending Colon
Cecum -> Hepatic flexure (right colic flexure)
State the beginning and end points of the transverse colon
Hepatic Flexure (right colic flexure) -> Splenic Flexure (Left colic flexure)
What is the transverse colon enclosed by?
Transverse mesocolon
Which ligament attaches the transverse colon to the diaphragm?
Phrenicocolic ligament
Which sections of the colon lay intraperitoneally?
AC + DC
State the beginning and end points of the Descending Colon
Splenic Flexure -> Sigmoid Flexure
What’s posterior to the Descending Colon?
Left kidney
State the beginning and end points of the Sigmoid Colon
Left iliac fossa -> S3 vertebra
What attaches the sigmoid colon to the posterior pelvis?
Sigmoid mesocolon
What does the Sigmoid Colon’s long length enable?
Mobility
What sections of the Colon were derived from the midgut?
Ascending Colon + initial 2/3rds of Transverse Colon
What sections of the Colon were derived from the hindgut?
Descending Colon, distal 1/3rd of the Transverse Colon and Sigmoid Colon
What arteries supply the midgut derived structures?
Superior Mesenteric Artery
What artery supplies the Hindgut-derived structures?
Inferior Mesenteric Artery
What arteries supply the transverse colon and where did they branch from?
R. Colic artery & M. Colic artery -> SMA
L. Colic = IMA
What is the arterial supply for the Sigmoid Colon?
Sigmoid arteries
Where does lymph from the Ascending and Transverse Colon drain into?
Superior Mesenteric Nodes
Where does the lymph from the Descending and Sigmoid Colon drain into?
Inferior Mesenteric Artery
Describe the route of lymph drainage after it’s collected into the superior and inferior mesenteric lymph nodes
- > Intestinal Lymph Trunks - > Cisterna Chyli - > Thoracic Duct
Describe the venous drainage of the Ascending Colon
Ileocolic vein + Right colic vein -> SMA -> hepatic portal vein
Describe the venous drainage of the Transverse Colon
Middle Colic Vein -> SMA -> hepatic portal vein
Describe the venous drainage of the Descending Colon
Left Colic Vein -> IMA -> hepatic portal vein
Describe the venous drainage of the Sigmoid Colon
Sigmoid Veins -> IMA -> hepatic portal vein
State the innervation of midgut-derived structures
Sympathetic, Parasympathetic + Sensory innervation via nerves from the Superior Mesenteric Plexus
State the innervation of hindgut-derived structures
Sympathetic, Parasympathetic + Sensory innervation via nerves from Inferior Mesenteric Plexus
Para –> Pelvic Splanchnic
Symp –> Lumbar Splanchnic
Name the lateral border of the rectus abdominis
Linea Semilunaris
Describe the path of the lateral border of the Rectus Abdominis
Curved line from 9th rib to pubic tubercle
Name the line that splits the rectus abdominis in two
Linea Alba
What are the 2 horizontal planes of the abdomen?
Transpyloric Plane
Intertubercular
Describe the location of the two horizontal planes of the abdomen
Transpyloric Plane - halfway between jugular notch and pubic symphysis ≈ L1
Intertubercular Plane - between superior aspects of L + R iliac crests
Name and describe the vertical plane of the abdomen
Mid-Clavicular Plane
middle of clavicle -> mid inguinal point
Describe the location of McBurney’s Point and its use clinically
1/3 of the distance between ASIS and umbilicus
can be used to split muscle fibres without cutting
What are the 4 main layers of the Anterior Abdominal Wall (interior to exterior)?
Parietal Peritoneum
Muscles + associated fascia
Superficial fascia
Skin
Describe how the superficial fascia differs above and below the umbilicus
Above : single layer of connective tissue
Below : Camper’s Fascia -> superficial fatty layer
Scarpa’s Fascia -> deep membranous layer
Deepest flat muscle
Function
Origin
Insertion
Innervation
Which direction do the fibres run?
Transversalis Abdominis
Compression of abdominal contents
Inguinal ligament, costal cartilages 7-12, iliac crest & throracolumbar fascia
Conjoint tendon, xiphoid process, linea alba & pubic crest
Thoracoabdominal Nerves (T7-T11), Subcostal nerve (T12), branches of lumbar plexus
Transversely
Middle flat muscle
Function
Origin
Insertion
Innervation
What direction do the fibres run?
Internal Oblique
Bilateral contraction compresses abdomen & Unilateral contraction rotates torso ipsilateraly
Inguinal ligament, iliac crest & lumbodorsal fascia
Ribs 10 - 12
Thoracoabdominal Nerves (T7 - T11), subcostal nerve (T12) & branches of lumbar plexus
Superomedially
Most Superficial Flat Muscle
Function
Origin
Insertion
Innervation
What direction do the fibres run?
External Oblique
Contralateral rotation of torso
Ribs 5 - 12
Iliac crest + pubic tubercle
Thoracoabdominal Nerves (T7 - T11) & Subcostal Nerves (T12)
Inferomedially
Deep Vertical Muscle
Function
Origin
Insertion
Innervation
Rectus Abdominis
Compresses abdomen & Stabilises pelvis whilst walking & Depresses Ribs
Crest of Pubis
Xiphoid proces, costal cartilages of ribs 5-7
Thoracoabdominal nerves (T7-T11)
Superficial Vertical Muscle
Function
Origin
Insertion
Innervation
Pyramidalis
Tenses the libea alba
Pubic crest
Linea alba
Subcostal Nerve (T12)
What forms the rectus sheath?
The aponeuroses of the 3 flat muscles
What does the rectus sheath enclose?
Rectus abdominis and Pyramidalis
What is the arcuate line?
The point where the rectus sheath ends
What is the role of folate, what substance does it require to function and what happens if either are deficient?
Used in the synthesis of nucleic acids & help to prevent against neural tube defects (spinabifida)
Requires B12
If deficient, anaemia (bc cell division is affected due to lack of intrinsic factor ∴ lack of RBCs)
Pancreas is made up of two types of glands, exocrine and endocrine.
what are the functions of each?
Exocrine - secretes digestive enzymes + sodium bicarbonate into duodenum
Endocrine - contains Islets of Langerhan and secrete hormones into bloodsteam
What does the delta-cell secrete and what is its role?
Somatastatin - inhibits glucagon and insulin
What is the space between hepatocytes called, what occurs in these spaces?
Space of Disse, lymphatic drainage
5 stages of embryology of midgut
elongation → herniaton → rotation → retraction → fixation
What connects the midgut to the yolk sac?
what is the blood supply?
vitelline duct
SMA
