GI/Liver: Anatomy Flashcards
1
Q
Name four functions of the abdominal wall.
A
- Protect abdominal viscera (organs).
- Increase intra-abdominal pressure (e.g. for defecation).
- Maintain posture.
- Movement of the trunk.
2
Q
What lines the internal aspect of the abdominal wall?
A
The parietal peritoneum.
3
Q
Name the five palpable bony landmarks that define the boundaries of the abdominal cavity.
A
- Xiphisternum.
- Costal margin.
- Iliac crests.
- ASIS (anterior superior iliac spine).
- Pubic tubercles.
4
Q
What are the iliac crests and where are they palpable?
A
Most superior aspect of the pelvis, palpable on the back.
5
Q
What is the ASIS (anterior superior iliac spine)?
A
Prominent part of the pelvis that protrudes anteriorly above the hips.
6
Q
What does the horizontal line that divides the upper and lower quadrants of the abdomen run through?
A
The umbilicus.
7
Q
At what vertebral level is the inter-tubercular line that helps divide the 9 regions of the abdomen?
A
L5.
7
Q
What 4 lines divide the abdomen into the 9 regions?
A
Left and right mid-clavicular lines.
Subcostal line.
Inter-tubercular line.
8
Q
What are the 9 regions of the abdomen?
A
Central:
Epigastrium.
Umbilical.
Suprapubic (AKA hypogastric region).
Right and left:
Hypochondrium.
Flank (AKA lumbar regions)
Iliac fossa
9
Q
What are the four pairs of muscles comprising the anterolateral abdominal wall?
A
External oblique.
Internal oblique.
Transversus abdominis
Rectus abdominis.
10
Q
What is the name of the fibrous envelope surrounding the rectus abdominis muscles?
A
The rectus sheath.
11
Q
What three structures do the rectus abdominis muscles attach to?
A
- Sternum.
- Costal margin.
- Pubis.
12
Q
What muscles are referred to by the term “six pack”? Why?
A
Rectus abdominis; on either side of the midline. Segmented by horizontal tendinous intersections, muscle bulges on either side of these when they hypertrophy with exercise.
13
Q
What skeletal movement does contraction of the rectus abdominis achieve?
A
Flexing of the spine, bringing the thorax closer to the pelvis.
13
Q
List the muscles of the abdominal wall which are lateral to the rectus abdominis in order of most superficial to most deep.
A
- External oblique
- Internal oblique
- Transversus abdominis.
14
Q
What happens when the external obliques, internal obliques, and transversus abdominis are contracted together?
A
Intra-abdominal pressure is increased.
15
Q
What movement are the obliques involved in?
A
Lateral flexion of lumbar spine and rotation of the torso.
16
Q
What is an aponeurosis?
A
Tendon of a flat muscle.
16
Q
What is the linea alba?
A
The area of dense fibrous tissue in the midline where the aponeuroses of the abdominal muscles (obliques and transversus abdominis) fuse together. Encase the rectus abdominis and form the rectus sheath.
17
Q
The aponeuroses of which muscles of the abdominal wall splits into anterior/posterior to form the innermost layer of the rectus sheath?
A
The internal obliques.
18
Q
What tissue lies deep to the transversus abdominis?
A
Transversalis fascia.
19
Q
Which spinal nerves innervate the abdominal wall?
A
Thoraco-abdominal nerves (T7-T11)
Subcostal nerve (T12)
Iliohypogastric and ilioinguinal nerves (branches of L1)
20
Q
What is the inguinal canal?
A
An oblique passageway through the anterior abdominal wall.
21
Q
On average in adults how long is the inguinal canal?
A
5cm.
22
Between what two structures does the inguinal canal run?
Deep inguinal ring and the superficial inguinal ring.
23
What is the function of peritoneal fluid?
To allow the visceral and parietal perineums to slide freely along each other.
24
What does intraperitoneal viscera refer to?
Organs in the abdominal cavity which are almost completely covered by peritoneum e.g. the stomach.
24
What does retroperitoneal refer to?
Structures in the abdominal cavity which are only covered by peritoneum on their anterior surface e.g. the pancreas.
25
What and where is the greater omentum?
Fatty fold of peritoneum hanging from the greater curvature of the stomach and rests on top of the small intestine. The transverse colon is embedded in the greater omentum.
26
What and where is the lesser omentum?
Fatty fold of peritoneum hanging from the lesser curvature of the stomach and connects the stomach and duodenum to the liver.
27
What three structures are embedded in the lesser omentum? What term refers to these three structures together?
Hepatic artery, hepatic portal vein, and bile duct.
"The portal triad"
28
What are mesenteries?
Folds of peritoneum that suspend the small intestine and parts of the large intestine from the posterior abdominal wall.
29
What vessels are embedded in the mesenteries?
Arteries that supply the intestines (branches of the abdominal aorta).
Veins that drain the gut (tributaries of the portal venous system).
30
What abdominal organs develop from the foregut?
Liver, gallbladder, and pancreas, distal oesophagus, stomach, and first half of the duodenum.
31
What artery branching from the abdominal aorta supplies all organs which derive from the foregut?
The coeliac trunk.
32
What section of the GI tract does the midgut give rise to?
Second half of duodenum, small intestine, and large intestine - ending 2/3 of the way along the transverse colon.
33
What artery branching from the abdominal aorta supplies all organs which derive from the midgut?
Superior mesenteric artery.
34
What section of the GI tract does the hindgut give rise to?
Distal third of the transverse colon, descending colon, sigmoid colon, rectum, upper part of the anal canal.
35
What artery branching from the abdominal aorta supplies all organs which derive from the hindgut?
Inferior mesenteric artery.
36
Where does the nutrient-dense venous blood drained from the gut go?
To the liver via the portal vein.
37
Where is bile made?
In the liver.
38
Where is bile stored?
In the gallbladder.
39
Where and how does bile enter the gut?
Enters the duodenum, via the biliary tree.
40
What is the main function of bile?
To break down lipids so they can be absorbed by the small intestine.
41
What are four different terms for folds of peritoneum?
Ligaments, folds, omenta, and mesenteries.
42
What is the difference between intraperitoneal and retroperitoneal viscera?
Intraperitoneal = viscera which are completely surrounded by peritoneum, connected to abdominal wall by mesenteries so are more mobile.
Retroperitoneal = viscera only covered on anterior surface, no mesenteries so are less mobile.
43
Which 10 viscera are retroperitoneal?
Suprarenal (adrenal) glands
Aorta & IVC
Duodenum (2nd & 3rd segments)
Pancreas
Ureters
Colon (ascending & descending)
Kidneys
oEsophagus
Rectum
44
What type of nerves innervate the parietal peritoneum? Describe parietal peritoneum pain.
Same somatic nerves that supply overlying muscles and skin.
Pain is sharp, severe, well localised to abdominal wall.
45
What type of nerves innervate the visceral peritoneum? Describe visceral peritoneum pain.
Visceral sensory nerves.
Pain is dull, severe, poorly localised/diffuse.
46
Where is visceral pain from the different parts of the gut (foregut/midgut/hindgut) felt in the 9 regions?
Foregut = epigastrium.
Midgut = umbilicus.
Hindgut = suprapubic.
47
In which quadrant does the stomach mainly lie?
LUQ
48
Where does the foregut end and the midgut start?
Half-way along the duodenum.
49
What is the oesophageal hiatus and at what vertebral level is it?
Where the oesophagus passes through the diaphragm, at the level of T10. Additional muscle surrounding the hiatus functions as a sphincter preventing reflux of stomach contents.
50
How long is the abdominal segment of the oesophagus (after passing through the diaphragm)?
Less than 2cm long.
51
What artery supplies the distal oesophagus?
The left gastric artery.
52
Is venous drainage from the oesophagus systemic or portal?
Both! Systemic via oesophageal veins draining into the azygos vein, and portal via the left gastric veins.
53
Describe the four parts of the stomach.
The cardia; continuous with the oesophagus.
The fundus; most superior part of the stomach.
The body; largest part.
The pyloric antrum tapering towards the pyloric canal (containing the pyloric sphincter).
54
Is the lesser curvature of the stomach the left or right border?
The right border.
55
What does the fundus usually contain?
Gas!
56
What forms the pyloric sphincter?
Circular smooth muscle.
57
What are rugae?
Folds of mucosa which line the stomach, allow for stretching to accommodate expansion with food/fluid.
58
What does the posterior surface of the stomach rest against?
The pancreas.
59
How is the stomach connected structurally to the liver?
By the lesser omentum.
60
What three arteries does the coeliac trunk divide into?
Left gastric artery, common hepatic artery, and the splenic artery.
61
What do the right and left gastric and gastro-omental veins drain into?
The hepatic portal vein.
62
Which nerve provides parasympathetic innervation to the stomach?
The vagus nerve.
63
Which nerve provides sympathetic innervation to the stomach?
The greater splanchnic nerve.
64
What is the major duodenal papilla and where is it?
The opening of the bile duct and the main pancreatic duct into the duodenum. Approx halfway along the internal wall of the duodenum.
65
What is the distinction between the blood supply to the first and second halves of the duodenum?
First half = coeliac trunk (foregut)
Second half = superior mesenteric artery (midgut)
66
What does the duodenum curve around?
The head of the pancreas.
67
Name two anatomical differences between the jejunum and the ileum.
Plicae are more pronounced and numerous in the jejunum.
Internal ileum has Peyer's patches - large submucosal lymph nodules.
68
What are folds of mucosa in the small intestine called?
Plicae circulares.
69
What is the ileocaecal junction? In which of the 9 regions is this located?
Where the terminal ileum is continuous with the caecum - first part of the large intestine. Right iliac fossa.
70
What is the main function of the large intestine?
To reabsorb water from faecal material to form semi-solid faeces.
71
What are the taeniae coli?
Three bands of muscle that form the outer longitudinal muscle layer of the large colon.
72
The inner circular layer of the large intestine forms bulges - what are these called?
Haustra (or haustrations).
73
Where would you find epiploic appendages and what are they?
On the outside of the large intestine, they are fatty tags.
74
What does the appendix contain?
Lymphoid tissue.
75
What is the mesoappendix?
Small mesentery connecting the appendix to the caecum.
76
What is the bend between the ascending and transverse colon called?
Hepatic flexure (or right colic flexure)
77
What is the bend between the transverse and descending colon called?
Splenic flexure (or left colic flexure)
78
Is the large colon retroperitoneal or intraperitoneal?
Depends which part! The ascending and descending colon, rectum and anal canal are all retroperitoneal. The transverse and sigmoid are intraperitoneal.
79
What is the transverse mesocolon?
The mesentery for the transverse colon, suspends it from the posterior abdominal wall.
80
Where is the rectosigmoid junction?
The 90 degree bend in the sigmoid colon when it approaches the midline and then becomes continuous with the rectum.
81
Is the rectum in the abdomen?
No, it is in the pelvis.
82
What is the main function of the rectum?
To store faeces until it is convenient to defecate.
83
Where would you find the inferior mesenteric vein?
Left side of the abdomen.
84
What does the inferior mesenteric vein drain into?
The splenic vein.
85
What does the superior mesenteric vein unite with to form the hepatic portal vein?
The splenic vein.
86
Is venous drainage from the rectum systemic or portal?
Both!
Systemic via internal iliac veins.
Portal via inferior mesenteric vein.
87
Which nerve provides parasympathetic stimulation to the foregut and midgut?
The vagus nerve.
88
Which nerve provides parasympathetic stimulation to the hindgut?
The pelvic splanchnic nerves.
89
Where are the cell bodies of the preganglionic parasymapthetic neurons that form the pelvic splanchnic nerve?
S2-S4
90
Which vertebra does the greater splanchnic nerve fibres come from and what does it innvervate?
T5-T9
The foregut.
91
Which vertebra does the lesser splanchnic nerve fibres come from and what does it innvervate?
T10-T11
The midgut.
92
Which vertebra does the least splanchnic nerve fibres come from and what does it innvervate?
T12
The hindgut.
93
Do visceral sensory fibres that convey pain generally travel with sympathetic or parasympathetic nerves?
Sympathetic nerves.
94
Which parts of the abdominal wall have somatic sensory fibres from dermatomes T5-T9?
Upper abdomen and epigastrium.
95
Which dermatome is the suprapubic region?
T12
96
Where might the liver be palpable?
Below the right costal margin during inspiration (when the diaphragm moves liver inferiorly).
97
Are all products of digestion transported to the liver via the hepatic portal vein?
No, lipids are not.
98
What are the two surfaces of the liver?
Diaphragmatic surface and visceral surface.
99
Which three regions of the liver are not covered by peritoneum?
The diaphragmatic surface where the liver is in direct contact with the diaphragm (the "bare area").
The region where the gallbladder is in direct contact with the liver.
The porta hepatis (where hepatic blood vessels and biliary ducts enter/exit liver).
100
What separates the two anatomical lobes of the liver?
The falciform ligament.
101
What is the function of the falciform ligament?
Connects the anterior surface of the liver to the internal aspect of the anterior abdominal wall.
102
What are the two accessory lobes of the liver and where are they visible?
Caudate and quadrate lobes.
Visible on the posterior surface.
103
How is the liver separated into eight functional segments?
Each segment is served by its own branch of the portal triad (hepatic artery, portal vein, and hepatic duct).
104
What connects the liver to the diaphragm?
The coronary and triangular ligaments.
105
What recesses near the liver provide potential space for fluid to gather e.g. in internal bleeding?
Hepatorenal recess and subphrenic recesses (either side of falciform ligament).
106
What and where is the ligamentum teres?
Remanent of the umbilical vein, in the free edge of the falciform ligament.
107
What is the name for the remanent of the ductus venosus, and where is it?
Ligamentum venosum, on the posterior surface of the liver in the groove between the caudate lobe and left lobe.
108
Where do the right and left hepatic arteries enter the liver?
At the porta hepatis, inferior posterior surface of the liver.
109
How many hepatic veins unite with the inferior vena cava as it passes posterior to the liver? Are these visible externally to the liver?
2 or 3.
Not visible externally.
110
What nerve plexus supplies the liver, and what fibres form this plexus?
Hepatic plexus. Formed of parasympathetic fibres (from the vagus nerve), and sympathetic fibres.
111
Where is pain in the liver referred to and by what nerves?
To the epigastric region (because the liver is a foregut derivative), via the greater splanchnic nerves.
112
Where is the gallbladder in relation to the liver?
Posterior inferior surface of the liver, close to the duodenum.
113
What are the three parts of the gallbladder?
Fundus, body, neck.
114
The left and right hepatic ducts converge to form the common hepatic duct. What does this duct then converge with, and what is the duct then called distal to this point of convergence?
Common hepatic duct converges with the cystic duct from the gallbladder. This then becomes the common bile duct, which then descends posteriorly to the duodenum and pancreas to enter the duodenum.
115
How does bile enter the gallbladder for storage when not required for digestion?
From the common hepatic duct, enters the cystic duct and then into the gallbladder.
116
What vessels supply and drain the gallbladder?
Cystic artery (typically from right hepatic artery), and cystic veins (either join hepatic portal vein or enter liver directly).
117
What are the four parts of the duodenum?
First = superior
Second = descending
Third = inferior
Fourth = ascending
118
What important artery is passes anterior to the inferior/third part of the duodenum?
Superior mesenteric artery.
119
At what vertebral level does the pancreas lie?
L1
120
What is the uncinate process?
The hook-like projection of the head of the pancreas.
121
What does the tail of the spleen extend up to?
The hilum of the spleen.
122
What do the common bile duct and main pancreatic duct merge into before entering the major duodenal papilla?
The hepatopancreatic ampulla.
123
What is the name for the smooth muscle that surrounds the hepatopancreatic ampulla? What is the main function of this sphincter?
The hepatopancreatic sphincter (the sphincter of Oddi).
Prevents reflux of duodenal contents into the common bile duct and main pancreatic duct.
124
Where does the accessory pancreatic duct lead to?
The minor duodenal papilla (proximal to the major duodenal papilla), where it empties pancreatic juice into the duodenum.
125
When and where is the spleen palpable?
If it is a healthy normal sized spleen, it should not be palpable! Only palpable when enlarged to three times its normal size below the left costal margin.
126
Which borders of the spleen are notched as opposed to smooth?
The anterior and superior borders are notched.
