GI class 3 - wet lab Flashcards
how long is the oesophagus?
25cm
extends from pharynx to stomach
what are the three constrictions of the oesophagus?
cervical
thoracic
diaphragmatic
what is the vertebral level of the oesophageal opening (hiatus) in the diaphragm?
T10
list the structures that traverse (go through) the oesophageal opening
oesophagus
right and left vagus nerves
oesophageal branches of the left gastric artery/vein
left inferior phrenic vessels
lymphatics
what is the blood supply of the abdominal part of the oesophagus?
branches of the left gastric artery
what is the venous drainage of the abdominal part of the oesophagus?
gastric vein (to portal circulation)
azygous vein (to systemic circulation)
what is the lymphatic drainage of the abdominal part of the oesophagus?
left gastric nodes
left and right paracardinal nodes
what are oesophageal varices?
the lower end of the oesophagus is one of the important sites for portosystemic anastomoses
in portal hypertension, the anastomoses open and forms venous dilations called oesophageal varices
their rupture causes severe and dangerous haematemesis (vomiting of blood)
the stomach is a muscular bag forming the widest and most distensible part of the digestive tube
it has how many orifices or openings, curvatures and surfaces?
2 orifices or openings
2 curvatures
2 surfaces
what are the 2 orifices of the stomach
cardiac
pyloric
what are the 2 curvatures of the stomach?
greater
lesser
what are the 2 surfaces of the stomach
anterior
posterior
a
fundus
b
body
c
oesophagus
d
antrum
e
cardia
f
pylorus
g
duodenum
what is the pyloric sphincter?
a band of smooth msucle at the junction between the pylorus of the stomach and the duodenum of the small intestine
what is the function of the pyloric sphincter
controls flow of partially digested food from the stomach to the small intestine
the pyloric sphincted is formed from the thickening of which layer of gut tube?
muscularis externa - circular layer
some children are born with congenita ____________
pyloric stenosis
the lesser omentum extends from _______ curvature to _____________
lesser curvature
to the liver
the greater curvature extends from the _______ curvature to the ________
posterior abdominal wall
but along the way it attaches to transverse colon, spleen and diaphragm
what is the epiploic foramen?
it is the passage of communication between the greater and lesser sac
what are the gastric folds/rugae formed from?
coiled sections of tissue/gastric mucosa
exist in the mucosal and submucosal layers of the stomach
folds in the stomach lining
in which portions of the atomach are the gastric rugae most apparent?
greater curvature
pyloric
which sphincter contorls the discharge of food form the stomach to the duodenum?
pyloric sphincter
sotmach lies on several structures in the abdominal cavity
these structures form the stomach bed (posterior wall of the omental bursa or lesser sac)
they are:
- left dome of the diaphragm
- pancreas
- spleen
- left suprarenal gland
- part of the kidney (left)
- colon
- splenich artery
a
right gastric artery
b
left gastric artery
c
splenic artery
d
right gastroepoploic artery
e
left gastroepiploic artery
what is the venous drainage of the stomach?
via the portal system
portal vein, superior mesenteric vein, inferior mesenteric vein and splenic vein
the complex arrangement of the arterial supply to the stomach means that the lymphatic drinage is also complex
the sotmach is drained by what four groups of lymph nodes?
all the 4 primary nodes that drain the stomach eventually drain into which group of lymph nodes?
coeliac/gastric and gastric omental
gastric carcinoma (cancer) is common and occurs where?
along the greater curvature
on this account the lymphatic drainage of the stomach assumes importance
what is the nerve supply of the sotmach controlling motility?
vagus nerve
what is the effect of increased vagal stimulation on:
the pylorus
gastric secretion
causes it to relax
increases it
what does the arrangement of vagal branches of the sotmach allow for?
highly selective vagotomy to be used to treat over-active gastric acid secretion
this denervates (loss of nerve supply) the fundus and the body, decreasing secretion, while the supply to the antrum remains so preserving essential gastric motiliy
where does the small intestine extend form and to?
pylorus of the stomach to the ileocecal junction
what are the three parts of the small intestine?
duodenum
jejunum
ileum
which part of the small intestine receives the opening of the bile and pancreatic duct?
duodenum
2nd part
where is the foregut/midgut boundary in the small intestine?
at the opening of the bile duct
how are the different parts of the small intestine peritonised?
duodenum - first part is intraperitoneal but the rest retroperitoneal
jejunum - intraperitoneal
ileum - intraperitoneal
which part of the small intestine is the shortest, widest and most fixed part?
duodenum
distinguishing characteristics between jejunum and ileum:
colour
jejunum - deeper red
ileum - paler pink
distinguishing characteristics between jejunum and ileum:
wall
jejunum - thick and heavy
ileum - thin and light
distinguishing characteristics between jejunum and ileum:
vascularity
jejunum - greater
ileum - less
distinguishing characteristics between jejunum and ileum:
vasa recta
(straight arteries coming off from arcades in the mesentery of the jejunum and ileum, and heading toward the intestines. The arcades are anastomoses of the jejunal and ileal arteries, branches of superior mesenteric artery)
jejunum - long
ileum - short
distinguishing characteristics between jejunum and ileum:
arcades
(vasa recta are straight arteries coming off from arcades in the mesentery of the jejunum and ileum, and heading toward the intestines. The arcades are anastomoses of the jejunal and ileal arteries, branches of superior mesenteric artery)
jejunum - a few large loops
ileum - many short loops
distinguishing characteristics between jejunum and ileum:
fat in mesentery
jejunum - less
ileum - more
distinguishing characteristics between jejunum and ileum:
circular folds
jejunum - large, tall and closely packed
ileum - low and sparce, absent in distal part
distinguishing characteristics between jejunum and ileum:
peyers patches
(small masses of lymphatic tissue found throughout the ileum region of the small intestine. Also known as aggregated lymphoid nodules, they form an important part of the immune system by monitoring intestinal bacteria populations and preventing the growth of pathogenic bacteria in the intestines)
jejunum - less
ileum - more
what is the order of the small intestine parts?
is there a step-transition form the jejunum to the ileum?
no
rather the morphology gradually alters, but either end is quite different
arterial arcades (arterial loops or arches) of jejunum and ileum
in which part do the arterial arcades have many loop?
ileum
which part of the autonomic nervous system (sympathetic or parasympathetic) stimuations reduces teh secretion and motility of the intestine and also actsas a vasoconstrictor?
sympathetic
what features allow the large intestine to be distinguished from the small intestine?
omental appendices
haustra or sacculations
teniae coli
retroperitoneal or intraperitoneal?
caecum
retroperitoneal
retroperitoneal or intraperitoneal?
ascending colon
retroperitoneal
retroperitoneal or intraperitoneal?
transverse
colon
intraperitoneal
retroperitoneal or intraperitoneal?
descending colon
retroperitoneal
retroperitoneal or intraperitoneal?
sigmoid colon
intraperitoneal
what are the 2 flexures of the colon called?
what is the midgut/hindgut boundary?
2/3 along transverse colon
in which abdominal region is the caecum and appendix located?
right iliac
what two structures open into the cavity of the caecum?
ileum
appendix
is the base of the appendix consistently located?
yes
but the tail is quite variable
what is McBurneys point and why is it useful clinically?
its the point of maximum tenderness of the appendix
where does the rectum pierce the pelvic floor?
ano-rectal junction
becomes anal canal which is located in the perineum (the area between the anus and the scrotum or vulva)
what is the arterial supply of the rectum and anal canal:
superior 1/3
middle 1/3
inferior 1/3
superior 1/3 - superior rectal artery
middle 1/3 - middle rectal artery
inferior 1/3 - inferior rectal artery
what is the venous drainage of the rectum and anal canal:
superior 1/3
middle 1/3
inferior 1/3
superior 1/3 - superior rectal vein
middle 1/3 - middle rectal vein
inferior 1/3 - inferior rectal vein
what is the peritonisation of the rectum and anal canal:
superior 1/3
middle 1/3
inferior 1/3
superior 1/3 - intraperitoneal
middle 1/3 - retroperitoneal
inferior 1/3 - none
what is the role of the pelvic floor in maintaining faecal continence?
levator ani is normally constricted to keep anal canal closed and defication/allow delay of emptying
The levator ani is a broad, thin muscle, situated on either side of the pelvis. It is formed from three muscle components: the pubococcygeus, the iliococcygeus, and the puborectalis. It is attached to the inner surface of each side of the lesser pelvis, and these unite to form the greater part of the pelvic floor
what other strucutres are involved in faecal continence?
internal sphincter
external sphincter
what is the significance of understanding the differences between visceral and somatic innervation of the anal canal?
for voluntary and unvoluntary control
the hepatoduodenal and hepatogastric ligaments are parts of what omentum?
the lesser omentum
what is the falciform ligament and what structures lie within its free border?
a ligament that attaches the liver to the front body wall
round ligament of the liver
what structure in the free edge of the falciform ligament is a remnant of an embryonic blood vessle? what is the name of this vessel in the embryo?
the ligamentum teres (round ligament)
remnanty of the umbilical vein
how many layers of the peritoneum are present in the greater omentum?
4
the greater omentum is often called the abdominal policeman
what functions of this strucutre lead to this term being used?
role in immunity and it can migrate to infected viscera or the site of surgical disturbance
what are paracolic gutters?
spaces between the colon and the abdominal wall
where are the paracolic gutters found in relation to the large intestine?
beside (lateral) ascending (caecum) and descending colon
what is the clinical significance of the paracolic gutters?
as if fluid accumulates in the peritoneal cavity it will gather hear due to gravity
list 3 abdominal viscera which lie in the free edge of a double layer of peritoneum described as a mesentery
sigmoid colon
transverse colon
appendix
what muscle type form the muscularis externa in oesophagus?
smooth msucle lower 1/3
skeletal muscle top 1/3
mixed in middle 1/3
what is the surface epitheliumo f the oesophagus?
stratified squamous
what type of muscle is the muscularis mucosae (interna)?
smooth muscle
what are the large folds present in the wall of the stomach?
rugae
what secretory cells are present in the gastric pits of the stomach?
cheif cells
parietal cells
mucous neck cells
what are the large folds that you see extending into the lumen of the small intestine called?
villi
when looking at one of these large folds, superimposed on each large fold are numberous finger like processes cut in different plnes - what are these processes called?
micro-villi
what is the surface epithelium in the small intesitne?
simple columnar
in the small intestine, what type of muscle is the muscularis mucosae?
smooth muscle
glands in the lamina propria do not extend down beyond the muscularis mucosae
where along the gut tibe do glands extend down beyond the muscularis mucosae into the submucosa?
oesophagus - mucous
duodenum - brinners
what appear to be spaces can be seen scattered between the cells of the surface epithelium, these are actially the contents of secretory cells
what are the cells called and what do they secrete
goblet cells and mucous
what type of cells are present in the surface epithelium
simple columnar
where are payers pathces mainly
submucos
mostly seen in the ileum
what is the predominant cell present in the surface epithelium of the colon
simple columnar absoprive cells/enterocytes
what is the change of epithelium seen i the recto-anal junction?
simple columnar to stratified squamous epithelium
what is the transpyloric plane?
an imaginary horozontal plane, located halfway between the suprasternal notch of the manubrium and the upper border of the symphysis pubis at the level of L1
how would you locate the transpyloric plane on a patient?
midway between xiphisternum and umbilicus
list structures present in the transpyloric plane
pylorus of the stomach
duodenum
neck of the pancreas
L1
fundus of gallbladder
images following a barium meal, barium meall follow-through and barium enema are shown
braium meal 1 - which organ is examined?
barium meal follow-through 2 - which organ is examined
barium enema 3 - which organ is examined
1 - stomach
2 - small intestine
3 - large intestine
image A
name 1, 2, 3 and 4
1 - liver
2 - right kidmey
3 - ileum
4 - transverse colon
image B
name 1, 2, 3 and 4
1 - spleen
2 - liver
3 - stomach
4 - aorta
