Anatomy of the GI tract Flashcards
where do the rectus abdominis muscles lie
either side of the midline
which direction do ext obliques run
downwards and inwards
which direction do int obliques run
upwards and inwards
which direction does transverse abdominis run
transversely
what forms the sheath for rectus abdominis
as ext/int obliques and transverse abs (3 muscle layers) pass forwards the muscles become aponeurotic (these aponeuroses form sheath for rectus abdominis)
where does the aponeurosis of the external oblique attach
ASIS laterally
pubic tubercle medially
thesis the inguinal ligament
where does the costal margin run from
7th-10th ribs
what are the 3 central abdominal regions from sup to inf
epigastric
umbilical
suprapubic/hypogastric
what are the 3 lateral abdominal regions
hypochondriac
flank/loin/lumbar
iliac region
what lies on the transpyloric plane of addison
gall bladder
pancreas
pylorus
duodeno-jejunal flexure
where does the transpyloric plane run
horizontally across epigastrium - releases costal margin @ lateral part of rectus abs (
what is the sub-costal plane
lies at lowest points of costal margin (10th)
what is the usual site of the base of the appendix
mcburney;s point
where does McBurney’s point lie
2/3 of way along a line joining umbilicus to right ASIC
at what vertebra does the umbilicus usually lie
l3
what plane marks the bifurcation of abdominal aorta
l4 - inter tubercular plane
what is the inter tubercular plane
tubercles of iliac crest
where does the greater splanchnic nerve arise from
t5-9
what is the innervation of foregut
greater splanchnic nerve
where is greater splanchnic nerve pain felt
anteriorly in midline - epigastrium
what is the innervation of midgut
lesser splanchnic nerve
where does the lesser splanchnic nerve arise from
t10-11
what is the innervation of the hindgut
least splanchnic nerve
where does the least splanchnic nerve arise from
t12
what does the peritoneum covering the inside of the abdominal wall have the same sensory nerve supply as
the skin overlying the same area
if c3/4/5 affected (diaphragm) where may pain be felt?
shoulder
what is the sensory innervation of the kidney and gonads
sympathetic plexus (t10,11,12)
what is the upper extent of the abdominal cavity
under surface of diaphragm
reaches 5th intercostal space
what are the dermatomes of the abdomen like
correspond to relative vertebra
where is foregut, midgut and hindgut pain felt
epigastrium
umbilicus
suprapubis
what kind of epithelium is the abdominal cavity lined by
simple squamous
what is ascites
accumulation of protein-containing fluid within abdomen
what is the line alba
fibrous structure at midline of abdomen - runs from xiphoid process
what is the midline median umbilical ligament a remnant of
allantois which helped embryo to exchange gases and handle liquid waste
what is the deep inguinal ring
entrance to inguinal canal
what is the falciform ligament
separates l and r lobe of liver
attaches liver to anterior body wall
what is the double layer of peritoneum that attaches liver to diaphragmatic undersurface called
left triangular ligament
is the left lobe of the liver above or below the costal margin
above
where does the lesser momentum run from
liver to lesser curvature of stomach
what is the porta hepatis aka
hilum of the liver
what runs through the portal hepatis
all neuromuscular structures minus hepatic veins (and hepatic ducts also run through)
where does portal vein carry blood from and to
from GI tract, gallbladder, pancreas, spleen
to liver
what is the epiploic foramen aka
foramen of winslow
where is the epiploic foramen
passage of communication btwn g and l sac
what is attached to the deep surface of the greater omentum
transverse colon
do fixed organs produce pain on movmeent
no, only mobile parts eg ileum or appendix will move with movement of body n breathing
what is a supine position
patient laying face upwards
with patient supine, where might fluid collect in the abdomen
posterior the liver
which parts of the bowel have a mesentery
1st cm of duodenum
all jejunum/ileum
transverse n sigmoid colon
appendix
what structures form portal triad
hepatic portal vein
bile duct
hepatic artery
what can lead to a peptic ulcer
stomach = harsh acidic env
may lead to destruction of mucosa
what is the origin of the hepatic artery
common hepatic artery
what does the gasproduodenal artery supply
blood directly to the pylorus and proximal duodenum
what kind of muscle is the pylori sphincter
smooth
what are the diff stomach parts
cardia fundus body antrum pylorus
where does blood from the caudate lobe directly drain
into the IVC
where do veins in the lower third of the oesophagus usually drain into
portal vein (may also join with veins in the chest that drain into SVC)
in bowel disease, portal, the liver’s portal channels become smaller until insufficient - venous blood will then flow up veins of oesophagus and into SVC: porto-systemic shunt which can lead to oesophageal varicose veins
why might some babies in the first 6w projectile vomit and what symptoms do they have
over developed pyloric sphincter
stomach cannot empty into duodenum
after feeding, food is forced out the mouth
bc child is not getting nutrition - hungry and eager to feed
what is a common site of peptic ulcer
post wall of first part of duodenum
which structures pass through the diaphragm alongside the oesophagus
vagal trunks
inferior oesophageal artery and vein
where does the stomach receive its sympathetic and parasympathetic nerve supply
sympathetic - greater splanchnic (t5-9)
parasympathetic: vagus
what lies in front of the stomach
left liver lobe
ant abdominal wall
what lies behind stomach
lesser sac
behind lesser sac is pancreas/diaphragm
what is a porto-systemic anastomosis
a vein which joins to the hepatic portal system to systemic system
what does the post wall of the duodenum lie in contact with
gastroduodenal artery
what differentiates duodenum from rest of small intestine
duodenum - it is retroperitoneal so fixed and constant
jejunum/ileum - attached to post abdominal wall by mesentery so relatively mobile
what are plaice circulares
mucosal folds
what are some adaptations for maximum absorption for the small intestine
- plicae circulares (mucosal folds)
- villi on mucosal folds
- microvilli on each individual epithelial cell
where are mucosal folds/plicae circulares most pronounced
jejunum
what is the ileum marked by
Peyer’s patches; large syubmucosal lymph nodules
what is mickel’s diverticulum
occasionally, ileum bears a blind-eded diverticulum 1m(?) from termination - an embryonic remnant of attachment of midgut loop to yolk sac
what are the arterial arcades
series of anastomosis arterial arches btwn arterial branches of jejunum and ileum
to the right of he sup mesenteric arteries are branches to the colon; name them (3)
ileo-colic
right colic
middle colic
what is the diff btwn jejunum n ileum in terms of arcades and vasa rectae
jejunum: fewer arcades
ileum: more arcades
jejunum: longer vasa rectae
ileum: fewer vasa rectae
what does the splenic vein form
portal vein
where does the large intestine form
ileo-caecal valve in right iliac fossa
what are the ascending and descending colon usually
retroperitoneal
where do the transverse and sigmoid colon usually lie
within a mesentery
what is the name of the 3 bands that the longutudinal muscular layer of stomach forms
taenia coli
what are appendices epiploica
pouches of peritoneum filled w fat
where blood vessels penetrate muscles of bowel wall to supply mucosa n sub mucosa
where does appendix arise from
base of caecum
does the caecum have mesentery
no not usually
does the inferior mesenteric artery arise from just above or below the bifurcation
above
what does the superior rectal artery supply
rectum and upper anal canal
whats the first pass effect
all drug dose absorbed from the GI tract is first delivered to the liver by the portal vein
a fraction of the drug can then be metabolized in the liver
overall concentration of the drug is reduced before it even reaches the systemic circulation
which vein drains blood from the colon and where does it flow to
inferior mesenteric vein drains into the splenic vein
where does lymph from small bowel drain
into the cisterna chyli (lol wtf, cba to google) and to the thoracic duct
which foodstuffs are absorbed through the lymphatic system
lipids
which part of the bowel is supplied by s2,3,4
hindgut
where does the liver develop in an embryo
ventral mesentery
what does the ventral mesentery become in an adult
lesser omentum
whats the bare area of the liver
triangular surface that has no peritoneal covering - direct contact with diaphragm
what is the blood supply of liver
hepatic portal vein
what can gall stones lead to
jaundice
what does the hepatic artery arise from
coeliac trunk
what does the cystic duct join with to form the common bile duct
common hepatic duct
what is immediately behind the epiploic foramen (passage btwn greater and lesser sac)
aorta on the left
IVC on the right
what is the hepatic flexure
sharp bend btwn ascending and transverse colon
what is the blood supply to the hepatic flexure
superior mesenteric artery
what can cause gallstones
too much bilirubin
too much cholesterol
not enough bile salts
which artery is the cystic artery a branch of
usually right hepatic artery
which structures can be found in the portal hepatis (2)
macroscopically: portal vein, r and l hepatic artery, r and l hepatic duct
microscopically: lymphatic branches of vagus and greater splanchnic nerves
what is an embryological bypass for the liver
ductus arterioles - forms into ligamentum venosum
what is the surface marking of the funds of the gall bladder
tip of the 9th costal cartilage
midclavicular line crosses costal margin
where do the hepatic veins drain
directly into IVC
what happen sin spleen
old RBC are recycled
platelets and WBC are stored
where does the head of the pancreas lie
in the curve of the duodenum
hwhat are the 4 parts of the pancreas
uncinate process head neck body tail
what are the 4 parts of the duodenum
superior
ascending
horzintal
ascending
how does the first part of the duodenum appear on endoscopy
smooth walled - almost no mucosal folds
where does the spleen lie
btwn 9th and 11th ribs
- located in the left hypochondrium and partly in the epigastrium
- situated between the fundus of the stomach and the diaphragm.
what is pancreatitis
- blockage of pancreatic duct
- high pressure
- digestive enzymes leak out to the duct and start digesting the pancreas
can the spleen be palpated during normal abdominal examination
no
what structures might a tumour the head of the pancreas involve
hepatic portal vein
bile duct
pancreatic duct
what structures join to forrm the common bile ducft
common hepatic duct
cystic duct
what is the path of the common bile duct
runs in the free edge of the lesser momentum, behind 1st part of duodenum
- onto post pancreas - enters pancreas to run alongside the pancreatic duct before opening into the duodenum
where is the sphincter of Oddi located
on medial wall of the duodenum btwn 2nd and 33rd parts
which artery lies behind 1st part of duodenum
gastroduodenala rtery
what lies btwn pancreas and stomach
lesser sac
how many pancreatic ducts are there and what is the embryological significance
2
- 1 from the ventral pancreatic bud
- 1 from the dorsal pancratic bud
