Week 2 GI workbook part 1 Flashcards
1
Q
where does the foregut run from and to?
A
esophagus to the duodenum
2
Q
where does the midgut run from and to?
A
runs from the liver bud to the junction between the right two thirds and left third of the transverse colon
3
Q
where does the hindgut run to and from?
A
left third of transverse colon to the cloacal membrane .
4
Q
what does the small intestine include?
A
duodenum, jejunum, ileum
5
Q
what does the large intestine include?
A
caecum, appendix and the colon (ascending, transverse, descending, sigmoid)
6
Q
how long is the muscular tube of the oesophagus?
A
25cm long
7
Q
how long is the abdominal part of the oesophagus?
A
1.25cm
8
Q
what are the three constrictions of the oesophagus?
A
cervical, thoracic and diaphragmatic
9
Q
in which mediasteinum is the oesophagus located?
A
superior mediasteinum
10
Q
what is the vertebral level of the oesophageal opening?
A
T10
11
Q
what are the structures that pass through the diaphragm at the oesophageal opening?
A
Oesophagus
IVC
vagus nerves
descending aorta
12
Q
blood supply of the abdominal oesophagus?
A
left gastric artery (branch of the celiac trunk) and left inferior phrenic artery
13
Q
what is the venous drainage of the abdominal oesophagus?
A
mixed drainage via two roots;
to portal circulation via left gastric vein
to systemic circulation via azygous vein
forms a portosystemic anastomosis
14
Q
what is the lymphatic drainage of the abdominal oesophagus?
A
The lymphatic drainage of the oesophagus is divided into thirds:
Superior third – deep cervical lymph nodes.
Middle third – superior and posterior mediastinal nodes.
Lower third – left gastric and celiac nodes.
15
Q
what occurs to portosystemic anastomoses in portal hypertension?
A
the anastomoses open and forms venous dilatations called oesophageal varices, their rupture causes severe and dangerous haematemesis
16
Q
what is the stomach?
A
muscular bag forming the widest and most distensible part of the digestive tube.
17
Q
where does the lesser omentum extend from and to?
A
from lesser curvature to the liver
18
Q
where does the greater omentum spread from and to?
A
greater curvature to transverse colon
19
Q
What is the pyloric sphincter?
A
Movement of partially digested food (chyme) through the pyloric orifice is controlled by a valve, the pyloric sphincter.
20
Q
what is the pyloric orifice?
A
The distal opening of the stomach, into the small intestine, is called the pyloric orifice.
21
Q
what is the function of the pyloric sphincter?
A
The pyloric sphincter is formed by a thick circular layer of smooth muscle. Its activity is under autonomic nervous system control. Relaxation of the pyloric sphincter to allow emptying of the stomach contents into the duodenum occurs by action of the parasympathetic nervous system (Cranial nerve 10: Vagus nerve). Constriction of the pylorus and its sphincter is controlled by sympathetic innervation from the celiac ganglion (greater and lesser splanchnic nerves).
22
Q
what is pyloric stenosis?
A
narrowing of the opening from the stomach to the first part of the small intestine (pylorus)
symptoms include projectile vomiting without the presence of bile
23
Q
What are the gastric folds/rugae formed from?
A
The mucosa has a wrinkled aspect, consisting of ridges called gastric folds, or rugae. During distension of the organ, the gastric folds disappear. Along the lesser curvature of the stomach, a temporary, continuous furrow called gastric canal is formed between the gastric folds. This facilitates the passage of saliva and fluids during swallowing.
24
Q
In which parts of the stomach are gastric folds/rugae most apparent?
A
greater curvature
25
what are the three branches of the celiac trunk?
left gastric, splenic, common hepatic arteries , ,
26
where does the left gastric vein drain into?
hepatic portal vein
27
where does the right gastric vein drain into?
hepatic portal vein
28
where does the left gastriepiploic vein drain into?
first the splennic vein then the hepatic portal vein
29
where does the right gastroepiploic vein drain to?
superior mesenteric vein then to hepatic portal vein
30
where does all the lymph fluid from the greater and lesser curvatures of the stomach travel to?
Lymph fluid drains into the gastric and gastro-omental lymph nodes found at the curvatures.
Efferent lymphatic vessels from these nodes connect to the coeliac lymph nodes, located on the posterior abdominal wall.
31
what lymph nodes drain the cardia of the stomach?
The cardia of the stomach is drained by the juxtacardial lymph nodes,
32
what lymph nodes drain the fundus of the stomach?
the fundus by the short gastric nodes
33
what lymph nodes drain the pyloric part of the stomach?
pyloric part by the pyloric lymph nodes (suprapyloric, retropyloric, subpyloric nodes).
34
where do all the respective lymph nodes of the stomach drain to?
Subsequently, lymph from these nodes empties into the celiac lymph nodes (located around the celiac trunk), which then flows through the intestinal lymphatic trunk into the thoracic duct via the cisterna chyli.
35
where does the parasympathetic nerve supply of the stomach come from?
Parasympathetic nerve supply arises from the anterior and posterior vagal trunks, derived from the vagus nerve.
36
where does the sympathetic nerve supply of the stomach come from?
Sympathetic nerve supply arises from the T6-T9 spinal cord segments and passes to the coeliac plexus via the greater splanchnic nerve. It also carries some pain transmitting fibres.
37
what is the effect of increased vagal stimulation on the pylorus and gastric secretion?
Vagus nerve stimulation significantly accelerated gastric emptying by promoting the relaxation of the pyloric sphincter
38
what procedure is used to treat over-active acid secretion?
vagotomy
39
what does a vagotomy do?
denervates the fundus and body, decreasing secretion while the supply to the antrum remains so preserving essential gastric motility
40
what is the duodenum?
The duodenum is the C shaped structure which continues from the pyloric sphincter of the stomach. The duodenum is the first part of the small intestine. It runs from the pylorus of the stomach to the duodenojejunal junction
41
how many parts does the duodenum have?
superior, descending, inferior and ascending
42
What organ sits within the C shape of the duodenum?
head of the pancreas
43
How is the duodenum peritonised?
Initial 3cm of the superior duodenum is covered anteriorly and posteriorly by visceral peritoneum, with the remainder retroperitoneal (only covered anteriorly)
44
There is a small opening in the duodenum where pancreatic and bile fluids enter the gut tube. What is this opening called?
major duodenal papilla (papilla of Vater)
45
What two structures come together at this opening (papilla of Vater)?
common bile duct
pancreatic duct
46
What is the sphincter that controls the opening (papilla of vater) called?
sphincter of oddi
47
describe the first section of the duodenum?
D1 – Superior (Spinal level L1)
The first section of the duodenum is known as ‘the cap’. It ascends upwards from the pylorus of the stomach, and is connected to the liver by the hepatoduodenal ligament. This area is most common site of duodenal ulceration.
The initial 3cm of the superior duodenum is covered anteriorly and posteriorly by visceral peritoneum, with the remainder retroperitoneal (only covered anteriorly).
48
describe the second portion of the duodenum?
D2 – Descending (L1-L3)
The descending portion curves inferiorly around the head of the pancreas. It lies posteriorly to the transverse colon, and anterior to the right kidney.
Internally, the descending duodenum is marked by the major duodenal papilla – the opening at which bile and pancreatic secretions to enter from the ampulla of Vater (hepatopancreatic ampulla).
49
describe the third portion of the duodenum?
D3 – Inferior (L3)
The inferior duodenum travels laterally to the left, crossing over the inferior vena cava and aorta. It is located inferiorly to the pancreas, and posteriorly to the superior mesenteric artery and vein
50
describe the fourth portion of the duodenum?
D4 – Ascending (L3-L2)
After the duodenum crosses the aorta, it ascends and curves anteriorly to join the jejunum at a sharp turn known as the duodenojejunal flexure.
Located at the duodenojejunal junction is a slip of muscle called the suspensory muscle of the duodenum. Contraction of this muscle widens the angle of the flexure, and aids movement of the intestinal contents into the jejunum.
51
what is the minor papillae?
opening for the accessory pancreatic duct. It consists of: the accessory pancreatic duct; pancreatic tissue of the dorsal pancreas, which penetrate the muscularis propria of the duodenum; and the surrounding fibrous connective tissue.
52
what are distinguishing characteristics of the jejunum?
red, thick intesinal wall, more vascular, longer vasa recta (stright arteries), less arcade, less fat in mesentery, large tall closely packed circular folds, small amount lymphoid tissue
53
what are distinguishing characteristics of the ileum?
paler pink
thin intestinal wall
less vascularity
shorter vasa recta
many short loops arcades
more fat in mesentery
less circular folds
numerous peyers patched lymphoid tissue
54
Which major blood vessel supplies the jejunum and ileum?
superior mesenteric artery
55
Where do the veins surrounding the jejunum and ileum drain to?
superior mesenteric vein
56
Which set of lymph nodes does lymph drain to from here?
superior mesenteric nodes
57
Which part of the autonomic nervous system (sympathetic or parasympathetic) stimulations reduces the secretion and motility of the intestine and also acts as vasoconstrictor?
The sympathetic nervous system exerts a predominantly inhibitory effect upon GI muscle and provides a tonic inhibitory influence over mucosal secretion while, at the same time, regulates GI blood flow via neurally mediated vasoconstriction.
The nerve supply comes from the superior mesenteric plexus therefore pain generally goes to the umbilical region.
58
The large intestine can be distinguished from the small intestine by 3 features, what are they?
teniae coli
haustra
omental appendices
59
How is the large intestine peritonised?
Anatomically, the colon can be divided into four parts – ascending, transverse, descending and sigmoid.
60
what are the different parts of the large intestine?
Caecum
Ascending Colon
Transverse Colon
Descending Colon
Sigmoid Colon
61
In which of the 9 abdominal region is the caecum and appendix located?
right inguinal region
62
What two structures open into the caecum?
base of the appendix and terminal ileum
63
What is McBurney’s point and why is it clinically useful?
the point on the lower right quadrant of the abdomen at which tenderness is maximal in cases of acute appendicitis.
64
Arterial Supply -Major branch(s) of ascending colon?
two branches of the superior mesenteric artery; the ileocolic and right colic arteries.
The ileocolic artery gives rise to colic, anterior cecal and posterior cecal branches – all of which supply the ascending colon.
65
Venous Drainage – Major vessel branch of the ascending colon?
ileocolic and right colic veins, which empty into the superior mesenteric vein.
66
how is the ascending colon lymphatically drained?
superior mesenteric nodes.
67
Arterial Supply -Major branch(s) transverse colon
The transverse colon is derived from both the midgut and hindgut, and so it is supplied by branches of the superior mesenteric artery and inferior mesenteric artery:
Right colic artery (from the superior mesenteric artery)
Middle colic artery (from the superior mesenteric artery)
Left colic artery (from the inferior mesenteric artery)
68
Venous Drainage – Major vessel transverse colon
middle colic vein, which empties into the superior mesenteric vein.
69
how is the transverse colon lymphatically drained?
superior mesenteric nodes.
70
Arterial Supply -Major branch(s) descending colon?
The descending colon is supplied by a single branch of the inferior mesenteric artery; the left colic artery
71
Venous Drainage – Major vessel descending colon?
left colic vein, which drains into the inferior mesenteric vein.
72
how is the descending colon lymphatically drained?
inferior mesenteric nodes
73
Arterial Supply -Major branch(s) of the sigmoid colon?
The sigmoid colon receives arterial supply via the sigmoid arteries (branches of the inferior mesenteric artery).
74
Venous Drainage – Major vessel sigmoid colon?
drained by the sigmoid veins into the inferior mesenteric vein.
75
lymphatic drainage of sigmoid colon?
inferior mesenteric nodes.
76
The superior mesenteric and inferior mesenteric veins ultimately empty into?
hepatic portal vein. This allows toxins absorbed from the colon to be processed by the liver for detoxification
77
where do most of the lymph from the superior mesenteric and inferior mesenteric nodes drain into?
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.
78
what is the arterial supply of the superior 1/3 of the rectum?
superior rectal artery (branch of the inferior mesenteric artery)
79
what is the venous drainage of the superior 1/3 of the rectum?
superior rectal vein
80
what is the lymphatic drainage of the superior 1/3 of the rectum?
Lymphatic drainage of the rectum is via the pararectal lymph nodes, which drain into the inferior mesenteric nodes.
81
how is the superior 1/3 of the rectum peritonised?
In the superior third of the rectum, the anterior surface and lateral sides are covered by peritoneum.
82
what is the arterial supply of the middle 1/3 part of the rectum?
middle rectal artery (branch of the internal iliac artery)
83
what is the venous drainage of the middle 1/3 of the rectum?
middle rectal vein
84
what is the lymphatic drainage of the middle 1/3 of the rectum?
Lymphatic drainage of the rectum is via the pararectal lymph nodes, which drain into the inferior mesenteric nodes.
85
how is the middle 1/3 of the rectum peritonised?
The middle third only has an anterior peritoneal covering,
86
what is the arterial supply of the inferior 1/3 part of the rectum?
inferior rectal artery (branch of the internal pudendal artery
87
what is the lymphatic drainage of the inferior 1/3 of the rectum?
Additionally, the lymph from the lower aspect of the rectum drains directly into the internal iliac lymph nodes.
88
what is the venous drainage of the inferior 1/3 of the rectum?
inferior rectal vein
89
how is the inferior 1/3 of the rectum peritonised?
lower 1/3 has no peritoneum associated with it.
90
what is the sensory and autonomic innervation of the rectum?
The rectum receives sensory and autonomic innervation. Sympathetic nervous supply to the rectum is from the lumbar splanchnic nerves and superior and inferior hypogastric plexuses. Parasympathetic supply is from S2-4 via the pelvic splanchnic nerves and inferior hypogastric plexuses. Visceral afferent (sensory) fibres follow the parasympathetic supply.
91
What is the role of the pelvic floor in maintaining faecal continence?
The rectum begins at the level of the S3 (as a continuation of the sigmoid colon). It is macroscopically distinct from the colon, with an absence of taenia coli, haustra, and omental appendices.
The course of the rectum is marked by two major flexures:
Sacral flexure – anteroposterior curve with concavity anteriorly (follows the curve of the sacrum and coccyx).
Anorectal flexure – anteroposterior curve with convexity anteriorly. This flexure is formed by the tone of the puborectalis muscle, and contributes significantly to faecal continence.
There are additionally three lateral flexures (superior, intermediate and inferior), which are formed by transverse folds of the internal rectum wall.
The final segment of the rectum, the ampulla, relaxes to accumulate and temporarily store faeces until defecation occurs. It is continuous with the anal canal; which passes through the pelvic floor to end as the anus.
92
What other structures are involved in faecal continence?
anorectal flexure and ampulla
93
What is the pectinate line?
The pectinate line (dentate line) is a line which divides the upper two-thirds and lower third of the anal canal.
94
what is the liver?
The liver is a large gland situated in the right upper quadrant of the abdominal cavity. In the living subject, the liver is reddish brown in colour, soft in consistency, and very friable.
95
what are the four lobes of the liver?
caudate lobe
quadrate lobe
left lobe
right lobe
96
which lobe cannot be seen from the front?
caudate lobe
97
what is the liver encapsulated with?
fibrous layer that is known as a capsule
98
describe the pain caused by an enlarged liver?
some conditions can cause the liver to expand within its fibrous layer
the fibrous layer iss innervated by branches of the lower intercostal nerves
the stretching of the fibrous layer results in a sharp and well localised pain known as liver capsule pain
99
what alternative pain can an enlarged liver cause?
an enlarged liver can also affect the diaphragm due to its close relation which can cause referred pain in the shoulder tip
100
What is meant by the term ‘bare area’ of the liver?
The bare area of the liver (nonperitoneal area) is a large triangular area on the diaphragmatic surface of the liver. It is the only part of the liver with no peritoneal covering, although it is still covered by Glisson's capsule. It is attached directly to the diaphragm by loose connective tissue
101
Round ligament of liver (also called as ligamentum teres) is the remnant of which embryological structure?
Falciform ligament - this sickle-shaped ligament attaches the anterior surface of the liver to the anterior abdominal wall. Its free edge contains the ligamentum teres, a remnant of the umbilical vein.
102
What is the porta hepatis?
The porta hepatis is the central intraperitoneal fissure of the liver (in the visceral surface) that separates the caudate and the quadrate lobes. It is the entrance and exit point for several important structures including the portal vein, the hepatic arteries, the hepatic ducts, the hepatic nervous plexus and the lymphatic vessels
103
name structures present in the porta hepatis
portal vein
common hepatic ducts
right and left hepatic arteries
hepatic nervous plexus
lymphatic vessels
104
What structures are in the portal triad?
Arteriole – a branch of the hepatic artery entering the liver
Venule – a branch of the hepatic portal vein entering the liver.
Bile duct – branch of the bile duct leaving the liver
105
Where does the central vein drain to?
Reunites with the hepatic vein
106
the extrahepatic biliary apparatus consists of what?
right and left hepatic ducts
common hepatic duct
gall bladder
common bile duct
cystic duct
107
Where is bile produced?
liver
108
Where is bile stored?
gall bladder
109
Where does bile enter the gut tube?
sphincter of oddi
110
What is the function of bile?
helps with digestion, fat absorption
111
when does biliary obstruction arise?
biliary obstruction arises when passage of bile into the duodenum is blocked completely or partially.
obstruction may be intrahepatic or extrahepatic
pancreatic cancer often presents late if it starts at the head of the pancreas it will cause biliary obstruction making symptoms more obvious allowing time for diagnosis
112
what is the pancreas?
The pancreas is a gland that partly exocrine and partly endocrine. The exocrine part secretes the digestive pancreatic juice; the endocrine part secretes hormones.
113
how is the pancreas related to the duodenum?
The main pancreatic duct carrying the pancreatic secretions joins with the bile duct to form the hepatopancreatic ampulla, which opens into the descending part of the duodenum.
114
How is the pancreas peritonised?
The anterior surface of the body of the pancreas is covered with peritoneum. The posterior surface of the body is devoid of peritoneum. It is in contact with the aorta, the superior mesenteric artery (SMA), the left suprarenal gland, the left kidney, and renal vessels
115
Which vein is formed posterior to the neck of the pancreas?
portal vein
116
Into which part of the duodenum does the pancreatic duct open?
major duodenal papilla
117
what is the arterial supply of the pancreas?
Similar to the duodenum, the pancreas has a dual blood supply from the coeliac trunk and the superior mesenteric artery.
118
what is the venous drainage of the pancreas?
drain into the splenic or superior mesenteric veins (into the portal system)
119
what is the nerve supply of the pancreas?
Both the coeliac plexus and the superior mesenteric plexus.
120
what is the lymphatic drainage of the pancreas?
Both to pre-aortic nodes at T12 and to Pre-aortic nodes at L1.
121
what can be done as conservative management for pancreatic cancer?
coeliac plexus nerve block
122
what is the spleen?
The spleen is the largest single mass of lymphoid tissue in the body. It acts as a filter for blood and plays an important role in the immune responses of the body. It is highly vascularised and if perforated will bleed heavily. Use these diagrams to understand where the spleen sits in the abdominal cavity.
123
How is the spleen peritonised?
The outer surface of the spleen can be anatomically divided into two:
Diaphragmatic surface – in contact with diaphragm and ribcage.
Visceral surface – in contact with the other abdominal viscera.
124
how would you describe anterior, superior, posteromedial and inferior borders.
It has anterior, superior, posteromedial and inferior borders. The posteromedial and inferior borders are smooth, whilst the anterior and superior borders contain notches.
125
In which region of the abdominal cavity is the spleen located?
left hypochondriac region
126
does spleen move with respiration?
yes and may be palpable only at the end of inspiration
127
name the structures in the hilum of spleen?
hepatic artery
portal vein (splenic vein, superior mesenteric vein, inferior mesenteric vein)
common bile duct
128
The tail of which organ is closely related to hilum of the spleen?
pancreatic tail
Surgeons must take care not to damage this when removing the spleen.
The spleen is prone to injury due to its location. Removal of the spleen (splenectomy) can save the patient’s life after injury.
129
