Unit 9; GIT revision 1+2 Flashcards
1
Q
What is the order of the different sections of the pylorus?
A
The pyloric antrum
The pyloric canal
The pyloric orifice/sphincter/constriction
2
Q
What is the difference between the pyloric orifice/sphincter/constriction?
A
The pyloric orifice - opening of stomach into duo
sphincter - circular muscles that controls the opening and closing
constriction - surface landmark to mark the end of pylorus (as if looking at it from the outside)
3
Q
Describe the relationship of the kidenys to the pancreas?
A
Lateral and posterior to the pancreas
4
Q
Describe the relationship of the superior mesenteric vessels to the pancreas and duodenum
A
Originate at L1 level and travel posterior to the neck of the pancreas
Then travel anterior to the ucinate process of the pancreas and the transverse (3rd) section of the duodenum.
5
Q
What are the four sections of the duodenum called?
A
Superior
Descending
Inferior
Ascending
6
Q
What is the relationship between the left colic lecture and the spleen?
A
The spleen is posterior to the flexure
7
Q
What is the relationship between the right colic flexure and the liver?
A
Part of the right lobe of the liver is anterior to the flexure
8
Q
What is the difference between the pyloric antrum and the pyloric canal?
A
The pyloric antrum opens into the stomach
The pyloric canal opens into the duodenum.
9
Q
What is the pectinate line?
A
Imaginary line, unification of the anal valves
10
Q
What is the significance of the pectinate line?
A
Marks the end of the hindgut
Marks the change in embryological origin, hence above and below the line have different lymphatics, vasculature and neurological supply.
11
Q
What is the vascular supply above and below the pectinate line?
A
Above - superior rectal artery/vein (portal drainage)
Below - inferior rectal artery/vein (systemic drainage)
12
Q
What is the nervous supply above and below the pectinate line?
A
Above - inferior hypogastric plexus (autonomic)
Below - inferior rectal nerves (somatic)
13
Q
What is the embryological origin above and below the pectinate line?
A
Above - endoderm
Below - ectoderm
14
Q
What is the lymphatic drainage above and below the pectinate line?
A
Above - internal iliac nodes
Below - superficial inguinal lymph nodes
15
Q
What is the epithelium like above and below the pectinate line?
A
Above - simple columnar epithelium
Below - strat squamous epithelium.
16
Q
What level is the transpyloric plane?
A
L1
17
Q
A
Spleen
Liver
Stomach
IVC
Aorta
18
Q
A
Spleen
Left kidney
Lover
Gall bladder
19
Q
A
Duodenum
Pancreas
Portal vein
IVC
20
Q
Transpyloric plane
A
Sma
Duodenum
Transverse colon
Liver
Right kidney
21
Q
Subcostal plane l3
A
Aorta
Descending colon
Ileum
Ascending colon
Right kidney
22
Q
At level of pubic symphysis
A
Pubic symphysis
Acetabulum
Bladder
Rectum
Puborectalis
23
Q
A
Coeliac trunk
Sma
Liver
Stomach
Transverse colon
24
Q
A
Ascending colon
Right splenic flexure
Duodenum
Stomach
Jejunum
Descending colon
Rectum
25
What features should be visible on a transverse ultrasound of the aorta?
Vertebral colum - disk or intervertebral disk, vertebrae has a greater acoustic shadow
Aorta superior and to the left (of patient)
IVC superior and to the right (of patient)
26
What faetures should be visible on an longitudinal view of the aorta?
Long aortic vessel as travels up/down thorax
May be able to see site of SMA/coeliac trunk
Should be able to follow up to diaphragm and disappearing behind the heart.
Liver may also be present in cranial section
27
What features should be visible on a longitudinal view of the IVC?
Slide to left should reveal aorta instead
On IVC view should be able to follow up to point of entry into the right atrium, should see pulsing near this point from the heart beat.
Liver may be seen in the cranial section
28
What is the first branch of the abdominal aorta?
The inferior phrenic arteries (paired)
29
What are the features of the oesophagus on cross sectional anatomy?
Look for a level T10
Join with the stomach roughly at level T11
Is anterior to the aorta
30
What are the features of the duodenum on cross sectional antomomy, related to its shape?
Duodenum is C-shaped curve around the head of the pancreas.
Roughlty at L1 transpyloric plane superior section should be identified, then scroll down and follow through descending section.
Then at L3 should see inferior section
Then scroll back up to see ascending section
Hence at some cross sections may be two parts of duodenum present, the ascending and the descending
31
How to distinguish between the transverse colon and the ascending colon/descending colon on cross sectional anatomy?
Transverse more anterior
32
How can knowing the level of the kidneys help to identify vasculature on a cross sectional image?
Left kidney is T11 to L2
Right kidney is T12 to L3
Variation within these structures
If more left kidney more likely to be coeliac trunk - also accompanied by more dominant spleen.
If right kidney present more likely to be SMA
33
How to identify the left colic flexure on cross sectional anatomy?
Located between stomach and spleen.
34
Draw a diagram to represent the innervation of the GIT
35
Describe the sensory innervation of the abdomen
Skin is innervated by the dermatome regions
Internal organs refer pain to these dermatome regions on the skin
36
Where does the stomach refer pain to?
T8 on the left anterior
Between should blades posteriorly
37
Where does the liver and gallbladder refer pain to?
T6-T9 anteriorly, and lower right back for liver
Gallbladder T6-T9 anteriorly, also radiates superiormedially on the back (below scapula)
38
Where does the small intestine refer pain to?
Midline (umbilicus region) at T8- T10
39
Where does the large intestine refer pain to?
Cecum and As - T10
transverse T11
Desceding proximal T12-L1
Descending diatal _ L2(3)
Sigmoid S2
Rectum S4
40
Where does the kidney refer pain to?
T10-L1
Inguinal region - anteriorly
Superiormeridaly from illiac crest posteriorly
41
Where does the testes refer pain to?
T10-L1
INguinal region
42
Where does the urinary bladder refer pain to?
T11 to L1
Midline
43
Describe the embryological development of the foregut? (up until greater omemntum development)
Starts as a long tube
Grows and rotates on long axis, lengthens on a double curvature
Anchored to the abdominal wall by the ventral and dorsal mesogastrium
The liver develops in the ventral mesogastrium
The spleen develops in the dorsal mesogastrium
Mesogastrum rotates with the tube (ventral to right) (dorsal to left)
The liver grows so much that part of the ventral mesogastrum is obliterated with the abdominal wall forming the bare area of the liver.
At this point in time, the lesser sack and the epiploic foramen have developed and the greater omentum is preparing to develop
44
Describe the embryological development of the greater and lesser omentum?
Lesser omentum - from ventral mesogastrum
Greater omentum - from dorsal mesogastrum
The greater omentum grows downwards from the greater curvature of the stomach, is a folded structure.
Grows over the transverse colon in a double layer
Eventually these two layers fuse (creating the four layers found in mature adults)
The greater omentum will also fuse with the transverse mesocolon
45
What is the gastrocolic ligament?
Part of the greater omentum
Links to greater curvature of the stomach to the transverse colon
46
Desrcibe the development of the midgut
W5: Grows ventrally herniating into the umbilical cord, cranial section will become the proximal midgut and the caudal section the distal midgut
W6: Rotates 90 degrees anticlockwise around the SMA, the previous cranial section now on the left becomes convoluted, the previous caudal section grows a cecal bud.
W10: Rotates another 180 degrees anticlockwise and descends back into the abdomen, the colon now borders the small intestine.
M4/5: Ileocecal junction has descended into iliac fossa, some components of the GIT in the correct antomical position fuse to the abdominal wall becoming retroperitoneal.
47
Where does blood supply to the liver come from?
80% hepatic portal vein
20% proper hepatic artery
48
What vessels combine to form the hepatic portal vein?
The IMV merges with the splenic vein
The splenic vein merges with the SMV to form the hepatic portal vein
49
What is the venous drainage of the liver?
THe left, intermediate and right hepatic veins
Drain directly into the IVC.
50
What is the difference between the functional and anatomical divisions of the liver?
Anatomical - left, right, caudate and quadrate lobe
Functional - lobes by blood supply, 8 lobes
51
What is the peritoneum?
A single layer of flattened mesothelial cells
52
What is a sub-peritoneal structure?
Pelvic organs
Sit inferior to the peritoneum
53
What are the different retroperitoneal structures?
Supraarenal glands
Aorta/IVC
Duodenum
Pancreas
Ureter
Colon (ascending and descending only)
Kidney
Eosophagus
Rectum
54
Define greater omentum
A double layer of peritoneum between the greater curvature ot the stomach and the transverse colon
55
Define lesser sac
A potential space that is primarly located posterior to the stomach
56
Define lesser omentum
Double layer of peritoneum between lesser curvature of stomach/proximal duodenum and liver
57
What are the different types of peritoneal reflections?
Omenta
Mesenteries
Ligaments
58
Define peritoneal omenta?
Double layer of peritoneum
Connets abdominal viscera to other viscera
59
Define peritoneal mesenteries
Double layer of visceral peritoneum
Connects abdomainl viscera to abdominal walls
60
Define peritoneal ligaments
Double layer of peritoneum
Connects viscera to viscer adn viscera to wall
61
What are the key stages in embryological development for the GIT?
Week 3: Gastrulation
Week 4: FOlding to form body cavities - gut tube is still straight
62
Explain the early embryological stages of the GIT.
Develops in three sections: Foregut, midgut and hindgut separated by arterial supply.
Tract is covered by peritoneum that attaches to the dorsal wall (and ventral in foregut) by mesogastrium
63
What structures does the dorsal mesogastrum become in the adult?
Mesenteries - any meso structures
For example: mesoappendix
64
What structures embryologically will have a dorsal mesogastrum attachement?
Any intraperitoneal structures
Appendix transverse and sigmoid colon
Note the cecum is intraperitoneal but lacks a mesentery
65
What is the significant of the liver developing in the ventral mesogastum?
Liver develops in the ventral mesogastrum of the foregut
Falciform ligament is part of the ventral mesogastrum that is ventral to the liver
Lesser omentum is dorsal to the liver, connects to the gut tube (will become stomach and proximal duodenum)
66
What is the significant of the spleen developing in the dorsal mesogastrum?
Splits the dorsal mesogastrum into the splenorenal ligament posteriorly (connects to kidney) and the gastrospenic ligament anteriorly (continuous with the greater omentum)
67
What three ligaments form the greater omentum?
Gastrophrenic
Gastrosplenic
Gastrocolic
68
Label the tree ligaments
Gastrophrenic
Gastrosplenic
Gastrocolic
69
What is the clinical importance of the free inferior margin of the lesser omentum?
Made of the hepatoduodenal ligament.
Contains the portal triad, and may be clamped during surgery (pringle manoeuvre)
70
What is the embryological timeline of gut development?
Week 5-8: foregut rotates and stomach forms
Week 5-8: midgut herniation and midgut rotation (90 degrees)
Week 10: midgut migrates back into abdominal cavity (as cavity grown in size), second midgut rotation occurs (180 degrees)
Week 20: retroperitoneal structure is in the correct anatomical position, gut tube fuses with the posterior abdominal wall.
71
What is the difference between primary and secondary retroperitoneal?
Embryological development terms
Primary - retroperitoneal throughout development
Secondary - was intra but has now fused with posterior abdominal wall to become retro.
72
Why does the midgut herniate out of the abdominal cavity during embryological development?
Growth of the liver in the foregut means there is not enough room for the midgut to grow within the cavity.
73
What are the results of midgut rotation in embryology?
Duodenojejunal flexure - just left of the median plane at L1
Terminal ileum and ileocecal junction - in the right iliac fossa
Mesentery has a braod attachment running obliquely in the infracolic compartment
74
What congenital abnormalities are associated with rotation of the midgut?
Malrotation - incorrect or no rotation of the midgut - spectrum of diseases
75
Why is understanding peritoneal cavity embryology important clinically?
FAST ultrasound scanning - to identify fluid accumulation - thinking about where fluid would sit when supine etc
Spread of infection - peritoneal borders can limit the area to where infection can spread.
76
Where may fluid accumulate in the perionteal space?
Rectovesical or rectouterine pouch - when standing
Hepatorenal space - when supine (lying down), between liver and kidney
77
What are the different potential spaces within the peritoneal cavity?
Right/left paracolic gutters
Infracolic compartment
Supracolic compartment
Lesser sac
78
Describe how infection might flow in the peritoneal cavity?
Tends to flow downwards towards the rectouterine or rectovesical pouches
May also flow between the supracolic and infracolic compartment by the right paracolic gutter
79
What ligament acts as a barrier to the spread of infection in the peritoneal cavity?
Phrenicocolic ligament - like a cap on the left paracolic gutter, prevents flow from the supracolic compartment
80
What are the different ligaments of the liver?
Coronary ligament (ANT and POST)
Falciform ligament
Round ligament (remenant of embryological umbilical vein)
Triangular ligaments (L+R)
Ligamentum venosusm (remnant of embryological ductus venosum)
81
What are portosystemic anastamoses?
A point of connection between portal and systemic venous circulation
82
What are the three different categories of portal hypertension?
Pre hepatic
INtra hepatic
Post hepatic
83
What are some examples of intra hepatic hypertension?
Cirrhosis of liver
Hepatitis
84
What is portal hypertension? What is the consequence?
High blood pressure in the portal vein - due to impeded blood flow into the liver
Causes increased tension in tributaries can lead to varicose veins
85
What are some prehepatic causes of portal hypertension?
Thrombosis in tributary into hepatic portal vein
Tumour in GIT pressing and occluding blood flow into the hepatic portal vein
86
What are some post hepatic causes of portal hypertension?
Slowed flow of blood from the liver into IVC
Thorax problem - heart failure
Thrombus in right, middle and left hepatic vein
87
What are the three main areas of porto-systemic anastomosis?
Round ligament - remenant of embryoligical umbilical vein
Oesophagus - left gastric (portal) and lower oesophageal branches (systemic)
Superior rectal vein (IMV) to middle rectal (anterior division of internal illiac)
88
POrtal hypertension causes problems at the portosystemic anastomosis.
What are the symptoms if blood volume increases in these areas?
Round ligament - recanalised, blood drain into towards the umbilicus, follows drainage of superficial veins, results in caput medusae and swollen abdomen.
Oesophagus - internal and external plexus, veins rupture cause to vomit or cough up blood, swallow blood causing black stools
Superior rectal veins - bleeding rectum
Often see enlarged spleen as increased blood in splenic vein.
Ascities - ECF leaves the portal vein as low solute concentration
Loss of liver function - jaundice, hyperglycemia, hepatic encephalopathy, coagulation problems
89
How many paracolic gutter are there?
Which should be described as open?
4
Lateral right paracolic - open
Medial right paracolic - open inferiorly, superiorly is blocked by the transverse mesocolon
Lateral left paracolic - open inferiorly, blocked superiorly by the phrenicocolic ligament
Medial left paracolic - open inferiorly, blocked superiorly by the transverse mesocolon.
90
Describe how the supracolic and infracolic compartments are seperated?
By the transverse mesocolon
91
How is the infracolic compartment further subdivided?
Into left and right by the root of the mesentery (SI)
92
When the patient is in the supine position where might fluid in the peritoneum accumulate?
The hepatorenal pouch
93
What is the subphrenic space?
A peritoneal space between the anterior liver and the diaphragm
Is separated into right and left by the falciform ligament
94
What is the subhepatic space?
Peritoneal space below the liver but above the transverse mesocolon
Includes the hepatorenal pouch
Part of supracolic compartment
95
When a patient is standing up where is fluid in the peritoneal cavity most likely to accumulate?
The rectovesical pouch (males
rectouterine/ uterinevesical pouch (females)
96
Draw a diagram to represent the potential flow of fluid in the peritoneal cavity
Green line represents the phrenicocolic ligament
97
Draw a diagram to show the tributaries into the hepatic portal vein.
98
Draw a diagram to represent the bilary tree and it’s sphincters?
99
What is the typical pattern of pain in appendicitis?
Early onset pain in umbilicus region - near T10, usually centralised as most intestines share this innervation
Later pain will local more towards the right illiac fossa due to inflammation of the parietal peritoneum and progression of inflammation in the appendix.
100
What is the link between understanding the autonomic innervation of the GIT and referred pain?
Referred pain typically occurs along the dermatomes that create the sympathetic splanchnic nerve supply each region, as sensory afferents travel with the splanchnic nerves and enter the cord at the same level.
Signals can get crossed
101
What is the sensory innervation of the GUT like?
Visceral afferents (sensory nerves of viscera) travel alongside the sympathetic nerves
102
Define dermatome
An area of skin provided with sensory innervation by a single spinal nerve root
103
Dermatome diagram
104
What is the mechanism behind referred pain?
Multiple primary sensory neurones converge on the single ascending tract, many originate from the same vertebral elvel.
The brain is unable to distinguish between nociceptive signals from the viscera and the somatic receptors.
Often organ pain is associated with regions of skin
105
If someone has epigastric pain, where might the pathology be located? Why?
Epigastric region contains the dermatomes T6-9
These dermatomes correspond with innervation to the foregut.
Organs corresponding to these dermatomes includes oesophagus, stomach, duodenum, pancreas, liver,spleen etc
106
Describe and explain the pain patterns in perforation of the duodenum?
Intial: Sharp pain in his right shoulder - air irritates the diaphragm, detected by phrenic nerve of route C3,4,5 corresponds to dermatomes on the shoulder
Then: severe acute abdominal pain in epigastric region -sensory afferents enter cord as T5-T9 level
Rebound tenderness - GI content in peritoneum results in peritonitis, removal of pressure when lifting hand causes pain
