GI class 2 - dry lab Flashcards
the peritoneum is a transparent serous membrane that covers body wall and organs
although it is one continous layer, it is often described differently, depending on whether it lines the body wall or covers the organs
what are the 2 subdivisions?
it can also form folds, such as mesenteries and omenta, as well as ligaments, which may be vascular or avascular
parietal
visceral
define the term peritoneal cavity?
the potential space between the parietal and visceral peritoneum
The peritoneal cavity is a true space between the parietal peritoneum (the peritoneum that surrounds the abdominal wall) and visceral peritoneum (the peritoneum that surrounds the internal organs)
the 2 major divisions of the peritoneal cavity are termed sacs
which are these?
- greater sac
- lesser sac
through which passage do the two sacs communicate?
epiploic foramen
where is the epiploic foramen?
posterior to the free edge of the lesser omentum
organs can be described depending upon how they are peritonised
organs completley surrounded by visceral peritoneum are _____________
or only covered on their anterior surface and therefore firmly attached to the posterior wall are ____________
intraperitoneal
retroperitoneal
what are some retroperitoneal organs?
Main ones: ascending colon, descending colon, kidneys, pancreas
S = Suprarenal (adrenal) Glands
A = Aorta/IVC
D = Duodenum (except the proximal 2cm, the duodenal cap)
P = Pancreas (except the tail)
U = Ureters
C = Colon (ascending and descending parts)
K = Kidneys
E = (O)esophagus
R = Rectum
what are some intraperitoneal organs?
main ones: stomach, liver, spleen, transverse colon
The intraperitoneal organs are the stomach, spleen, liver, bulb of the duodenum (1st part), jejunum, ileum, transverse colon, and sigmoid colon
what is present in the peritoneal cavity?
peritoneal fluid (50ml)
what is extraperitoneal?
the term extraperitoneal is used to describe the structures in the abdomino-pelvic cavity which are not covered in peritoneum
retroperitoneal structures may only be partially peritonised
what layer of peritoneum is more sensitive to pressure, pain, heat and cold?
parietal peritoneum
has more somatic nerve innervation
A
lesser omentum
B
greater sac
C
epiploic foramen
D
lesser sac
E
greater omentum
what is the attachment of the greater omentum?
greater curvature of the stomach to posterior abdominal wall
what is the attachment of the lesser omentum
liver to lesser curvature of the stomach and first part of the duodenum
the greater omentum is often referred to by surgeons as the abdominal policemen, explain this
the lower margin and the left and right margins are free, and it moves about the abdominal cavity in response to peristaltic movements
in infection, especially appendicitis, inflammatory exudate causes the omentum to adhere to the site of infection, and wrap itself around the infected organ
this localises the infection to a small area of the cavity, protecting against serious diffuse peritonitis
what is peritoneal pain?
pain form the partietal peritoneum lining the abdominal wall is innervated by the lower 6 thoracic nerves and L1, thus pain here is somatic and can be precisely localised. it is extremely sensitive to streching, made use of in clinical diagnosis - rebound tenderness
the visceral peritoneum is innervated by autonomic nerves. pain is often referred, and is dull and poorly localised. becuase the GI tract is a midline structure receiving bilateral nerve supply, pain is referred to the midline
what are some wall msucles of the posterior abdominal wall?
psoas major
iliacus
quadratus lumborum
what are some organs of the posterior abdominal wall
kidneys
ureter
supradrenal gland
what are some main vessels of the posterior abdominal wall?
IVC
aorta
what are some main nerves of the posterior abdominal wall?
femoral nerve
obturator
(2 main branches of the lumbar plexus)
what are the 3 main openings in the diaphragm and what vertebral levels do they occur at?
caval hiatus - T8
oesophageal hiatus - T10
aortic hiatus - T12
what are the 3 main branches of the abdominal aorta which supplies blood to the gut tube within the abdominopelvic cavity?
coeliac artery
superior mesenteric artery
inferior mesenteric artery
at what vertebral level does the abdominal aorta divide into 2 common iliac arteries?
L4
how is the IVC formed in the abdomen?
formed by the union of the right and left common iliac veins
a
left gastric artery
b
splenich artery
c
proper hepatic artery
d
superior mesenteric artery
e
inferior mesenteric artery
a
hepatic portal vein
b
splenic vein
c
superior mesenteric vein
d
inferior mesenteric vein
what 3 main branches supply the gut tube? and what levels do these 3 midline branches occur?
coeliac artery - T12
superior mesenteric artery - L1
inferior mesenteric artery - L3
what are foregut strucutres?
abdominal part of oesophagus
stomach
proximal duodenum
what are midgut structures?
distal duodenum
jejunum
ileum
caecum
ascending colon]proximal 2/3 of transverse colon
what are hindgut strucutres?
distal 1/3 pf transverse colon
descending colon
sigmoid colon
rectum
artery supply foregut =
artery supply midgut =
artery supplying hindgut =
artery supply foregut = coeliac artery
artery supply midgut = superior mesenteric artery
artery supplying hindgut = inferior mesenteric artery
name additional foregut and midgut-derived organs which are not part of the gut tube?
pancreas
liver
spleen
gallbladder
what is the venous drainage of the GI tract?
blood from the abdominopelvic gastrointestinal tract drains via a portal system to the liver
what is a portal system?
any system of blood vessels which has a capillary network at each end
(the system of blood vessels consisting of the hepatic portal vein with its tributaries and branches)
the portal vein is formed by the union of which 2 major veins of the abdominal cavity?
superior mesenteric vein
splenic vein
blood from the gut tube superior to the diaphragm and inferior to the pelvic floor drains via the systemic venous system. this means that an anastomosis is present at these watersheds: porto-systemic (portocaval anastomoses)
list the 4 sites of portocaval anastomosis in the body?
in the distal oesophagus
superior part of the rectum
umbilicus
area of the liver
what is the clinical significance of these portocaval anastomoses?
in liver disease, e.g. hepatic cirrhosis, could cause back pressure leading to bleeding
can go to systemic blood
what is the sympathetic nerve supply to the abdominal viscera done by?
abdominopelvic splanchnic nerves (greater, lesser and least)
prevertebral sympathetic ganglia
abdominal aorta plexuses
what is the parasympathetic nerve supply yo the abdominal viscera done by?
anterior and posterior vagal trunks (vagus nerve - 10th cranial nerve)
pelvic splanchnic nerves (S2, S3 and S4)
does parasympathetic and sympathetic innervation increase or decrease GI secretion?
parasympathetic -
sympathetic -
does parasympathetic and sympathetic innervation increase or decrease GI secretion?
parasympathetic -
sympathetic -
does parasympathetic and sympathetic innervation increase or decrease GI secretion?
parasympathetic - increases
sympathetic - decreases
does parasympathetic and sympathetic innervation increase or decrease peristalsis or GI motility?
parasympathetic - increases
sympathetic - decreases
what is the effect of parasympathetic and sympathetic innervation on blood vessels?
parasympathetic - little effect
sympathetic - vasoconstriction
what is the effect of vagotomy on gastric secretion?
(a surgical operation in which one or more branches of the vagus nerve are cut, typically to reduce the rate of gastric secretion (e.g. in treating peptic ulcers))
reduces it
what is the functional difference between the greater, lesser and least splanchnic nerves (splanchnic means viscera) and the pelvic splanchnic nerves?
greater, lesser and least are sympathetic
pelvic are paradympathetic
what is the chief difference in the arrangement of ganglia in the sympathetic and parasympathetic nervous system?
sympathetic goes into sympathetic trunk
sympathetic is short pre-ganglionic and long post-ganglionic
parasympathetic is long pre-ganglionic and short post-ganglionic
different outflow regions
study the following image
although not part of the gastrointestinal system, we will consider these additional posterior abdominal wall organs
what am i and where am i found?
the kidney
posterior abdominal wall at the level of T12-L3
the right kidney lies slightly at a lower level than the left kidney
what is the reason for this?
due to the liver on the right side
what are the 3 main structure entering or leaving the hilum of the kidney?
renal vein
renal artery
pelvis of the ureter
what is the top one?
renal artery
what is the middle one?
renal vein
what is the bottom one?
pelvis of the ureter
what is the anterior-to-posterior arrangement of the structures entering and leaving the hilum of the kidney?
renal vein - renal artery - ureter
how are the kidneys peritonised?
retroperitoneal
what is the anatomical location of the suprarenl gland, and what type of gland is it?
found above the kidneys and are endocrine glands
what are ureters?
muscular ducts that carry urine from the kidneys to the urinary bladder
what is the term used to describe the expanded upper part of the ureter?
renal pelvis
the ureter is normally ocnstricted at 3 locations during its course from the kidneys to the urinary bladder, what are they?
- at the junction of the ureters and renal pelvis (pelviiureteric junction)
- as the ureters enter the pelvis and crosses over the common iliac artery bifurcation
- at the vesicoureteric junction as the ureter obliquely enter the bladder wall
(UVJ is the most distal portion of the ureter, at the point where it connects to the urinary bladder)
From website:
The ureter has a diameter of 3 mm 1 but there are three constrictions, which are the most common sites of renal calculus obstruction:
at the pelviureteric junction (PUJ) of the renal pelvis and the ureter
as the ureter enters the pelvis and crosses over the common iliac artery bifurcation
at the vesicoureteric junction (VUJ) as the ureter obliquely enters the bladder wall
are the ureters intraperiotoneal or retroperitoneal?
retroperitoneal
