8. Gallbladder and Colon Flashcards
primary fx of the gallbladder is
to concentrate and store bile which is produced by the liver.
the stored bile is then released from the gallbladder in response to
cholecystokinin
anterior and superior to the gallbladder
inferior border of the liver and the anterior abdominal wall.
posterior to the gallbladder
transverse colon and the proximal duodenum.
inferior to the gallbladder
biliary tree and remaining parts of the duodenum.
The gallbladder has a storage capacity of
30-50 mL
gallbladder parts
fundus
body
neck
the rounded, distal portion of the gallbladder. It projects into the inferior surface of the liver in the mid-clavicular line
fundus
largest part of the gallbladder. It lies adjacent to the posteroinferior aspect of the liver, transverse colon and superior part of the duodenum.
body
the gallbladder tapers to become continuous with the cystic duct, leading into the biliary tree.
neck
contains a mucosal fold, known as Hartmann’s Pouch. This is a common location for gallstones to become lodged, causing cholestasis.
neck of the gallbladder
is a series of gastrointestinal ducts allowing newly synthesised bile from the liver to be concentrated and stored in the gallbladder (prior to release into the duodenum).
biliary tree
common hepatic duct runs along the
hepatic vein
arterial supply of the gallbladder
cystic artery (b. of right hepatic artery)
venous drainage of the gallbladder
Neck: cystic veins -> portal vein
Fundus , body: hepatic sinusoids
innervation of the gallbladder
- coeliac plexus carries sympathetic and sensory fibres
* vagus nerve delivers parasympathetic innervation.
lymph drainage of the gallbladder
Neck: cystic lymph nodes -> hepatic LN -> celiac LN
uncomplicated gallstones
cholelithiasis
typically right upper quadrant pain following a fatty meal as gallstones obstruct the cystic duct during contraction of the gallbladder. Not associated with systemic upset
biliary colic
inflammation of the gallbladder. Pain is often associated with nausea, vomiting or fever
cholecystitis
gallstone within the common bile duct. Often causes deranged liver function tests.
choledocholithiasis
infection of the common bile duct often secondary to choledocholithiasis. Typically presents with right upper quadrant pain, fever and jaundice (Charcot’s Triad)
cholangtis
Charcot’s triad
right upper quadrant pain, fever and jaundice
surgical removal of the gallbladder
cholecystectomy
triangle of Calot boundaries
- liver -superior
- cystic duct - inferior
- common hepatic duct - medial
cystic artery originates from
right hepatic artery
common site of impacted gallstone
(+) referred pain in the epigastric region
hepatopancreatic ampulla
stimulation of visceral pain fibers that innervate GIT structure results in dull, aching, poorly localized pain
that is referred over ___-
T5 to L1 dermatome
Valve of houston is associated with what organ
rectum
Anatomically, the colon can be divided into four parts
ascending, transverse, descending and sigmoid.
the colon averages ___ cm in length
150 cm
marks the start of the transverse colon.
right colic flexure/ right hepatic flexure
at the left colic flexure/splenic flexure the colon is attached to the diaphragm by this ligament
phrenicolic ligament
is the least fixed part of the colon, and is variable in position (it can dip into the pelvis in tall, thin individuals).
transverse colon
unlike the ascending and descending colon, the transverse colon is
intraperitoneal
transverse colon is enclosed by
transvese mesocolon
left colic flexure is the start of
descending colon
sigmoid colon ave length
40 cm
sigmoid colon is located in this area of the abdomen
LLQ
sigmoid colon extends from
left iliac fossa to S3
The sigmoid colon is attached to the posterior pelvic wall by
a mesentery - sigmoid mesocolon
are two spaces between the ascending/descending colon and the posterolateral abdominal wall.
paracolic gutters
These structures are clinically important, as they allow material that has been released from inflamed or infected abdominal organs to accumulate elsewhere in the abdomen.
paracolic gutters
small pouches of peritoneum, filled with fat,
attached to the surface of the large intestine
omental appendices
Running longitudinally along the surface of the large bowel are three strips of muscle, known as the
taenia coli (mesocolic, free and omental coli.)
Ascending colon and proximal 2/3 of the transverse colon
–derived from the
midgut
Distal 1/3 of the transverse colon, descending colon and sigmoid colon
hindgut
midgut-derived structures are supplied by the
superior mesenteric artery
hindgut-derived structures
are supplied by the
inferior mesenteric artery
ascending colon receives arterial supply from
branches of the superior mesenteric artery; the ileocolic and right colic arteries.
ileocolic artery gives rise to colic, anterior cecal and posterior cecal branches – all of which supply the ascending colon.
transverse colon is derived from
both midgut and hindgut
transverse colon is derived from both the midgut and hindgut, and so it’s arterial supply are
- Right colic artery (from the superior mesenteric artery)
- Middle colic artery (from the superior mesenteric artery)
- Left colic artery (from the inferior mesenteric artery)
arterial supply of the descending colon
the left colic artery (b. of inferior mesenteric artery )
The sigmoid colon receives arterial supply via
sigmoid arteries (branches of the inferior mesenteric artery).
is a clinically important vessel that provides collateral supply to the colon – thereby maintaining arterial supply in the case of occlusion or stenosis of one of the major vessels.
Marginal Artery of Drummond
As the terminal vessels of the superior mesenteric and inferior mesenteric artery approach the colon, they split into many branches, which anastomose with each other. These anastomoses form a continuous arterial channel which extends the length of the colon called
marginal artery
Long, straight arterial branches arise from the marginal artery to supply the colon,called
vasa recta
venous drainage of the ascending colon
ileocolic and right colic veins–> superior mesenteric vein.
venous drainage of the transverse colon
middle colic vein, –> superior mesenteric vein.
venous drainage of the descending colon
left colic vein–> inferior mesenteric vein.
venous drainage of the sigmoid colon
drained by the sigmoid veins into the inferior mesenteric vein.
The superior mesenteric and inferior mesenteric veins ultimately empty into the
hepatic portal vein
Midgut-derived structures (ascending colon and proximal 2/3 of the transverse colon) receive their sympathetic, parasympathetic and sensory supply via
nerves from the superior mesenteric plexus.
Hindgut-derived structures (distal 1/3 of the transverse colon, descending colon and sigmoid colon) receive their sympathetic, parasympathetic and sensory supply via nerves from the
inferior mesenteric plexus
•Parasympathetic innervation via the pelvic splanchnic nerves
•Sympathetic innervation via the lumbar splanchnic nerves.
The lymphatic drainage of the ascending and transverse colon is into the
superior mesenteric nodes
Lymphatic: The descending colon and sigmoid drain into the
inferior mesenteric nodes.
Most of the lymph from the superior mesenteric and inferior mesenteric nodes passes into the intestinal lymph trunks, and on to the cisterna chyli – where it ultimately empties into the
thoracic duct
sacculations of the large intestine
haustra
fatty tags of the large intestine
appendices epiploicae
transverse colon
caliber
38 cm
sigmoid colon
caliber
25-38 cm
caliber
descending colon
25 cm
rectum
caliber
13 cm
ascending colon caliber
13 cm
anal colon
caliber
4 cm
blood supple of the cecum
SMA-> ileocolic a. -> anterior/posterior cecal a.
venous drainage of cecum
anteiror/posterior cecal v. -> ileocolic v. -> SMV
The appendix originates from the
posteromedial aspect of the cecum
appendix is supported by
mesoappendix, a fold of mesentery which suspends the appendix from the terminal ileum.
position of the free-end of the appendix is highly variable and can be categorised into seven main locations depending on its relationship to the ileum, caecum or pelvis
Pre-ileal – anterior to the terminal ileum – 1 or 2 o’clock.
Post-ileal – posterior to the terminal ileum – 1 or 2 o’clock.
Sub-ileal – parallel with the terminal ileum – 3 o’clock.
Pelvic – descending over the pelvic brim – 5 o’clock.
Subcecal – below the cecum – 6 o’clock.
Paracecal – alongside the lateral border of the cecum – 10 o’clock.
Retrocecal – behind the cecum – 11 o’clock.
the most common position of the appendix
retrocecal
The appendix is derived from the embryologic
midgut
the vascular supply of the appendix
SMA -> ileocolic a -> appendicular artery
the venous drainage of the appendix
appendicular vein
lymphatic drainage of the appendix
ileocolic lymph nodes (which surround the ileocolic artery).
etiology of appendicitis
In the young –increase in lymphoid tissue size, which occludes the lumen.
From 30 years old onwards – blocked due a faecolith.
this nerve maybe injured in appendectomy
iliohypogastric nerve -> weakening of anterior abdominal wall
- the sigmoid colon twists around the sigmoid mesocolon and may become obstructed
- patient experience left sided colicky pain, abdominal distention, hematochezia (compromise of sigmoid arteries)
sigmoid volvulus
refers to a diverticula that are not inflamed
diverticulosus
- inflamed diverticula, contents may irritate the parietal peritoneum, resulting in pain that is localized to the LLQ
- may have hematochezia
diverticulitis
