GASTROINTESTINAL SYSTEM Flashcards
1
Q
What are aponeuroses
A
Flat tendons
2
Q
How many lumbar vertebrae contribute to the posterior wall of the abdominal cavity
A
5
3
Q
The functions of the abdominal wall
A
- Protect the abdominal viscera
- Increase intra-abdominal pressure (e.g. for defecation and childbirth)
- Maintain posture and move the trunk
4
Q
Bony landmarks which define the boundaries of the abdominal cavity
A
- Xiphisternum
- Costal margin
- Iliac crests
- Anterior superior iliac spines (ASIS)
- Pubic tubercles
- Pubic symphysis (a fibrocartilaginous joint)
5
Q
What are the 4 quadrants of the anterior abdominal wall
A
right upper and lower quadrants
left upper and lower quadrants
6
Q
Which lines form the 4 quadrants of the anterior abdominal wall
A
A vertical line that runs down the midline through the lower sternum, umbilicus, and the pubic symphysis
A horizontal line that runs across the abdomen through the umbilicus
7
Q
What are the 9 regions of the abdominal wall
A
The central regions, from superior to inferior, are the epigastrium, the umbilical region and the hypogastric (suprapubic) region
On the right, the regions from superior to inferior are the right hypochondrium, the right lumbar region and the right iliac fossa (region)
On the left, the regions from superior to inferior are the left hypochondrium, the left lumbar region and the left iliac fossa (region)
8
Q
Which lines form the 9 regions of the anterior abdominal wall
A
Right and left mid-clavicular lines, down to the mid-inguinal point (halfway between the anterior
superior iliac spine and the pubic tubercle)
The subcostal line - a horizontal line drawn through the inferior-most parts of the right and left costal margins (through the 10th costal cartilage)
The intertubercular line - a horizontal line drawn through the tubercles of the right and left iliac crests and the body of L5
9
Q
Transpyloric plane
A
Horizontal line that passes through the tips of the right and left ninth costal cartilages.
It transects the pylorus of the stomach, the gallbladder, the pancreas and the hila of the kidneys
10
Q
Transumbilical plane
A
Horizontal line through the umbilicus approximately at the level of L3, but varies due to subcutaneous fat
11
Q
Intercristal plane
A
horizontal line drawn between the highest points of the right and left iliac crests
12
Q
McBurney’s point
A
The surface marking of the base of the appendix. It lies two thirds of the way along a line drawn from the umbilicus to the right anterior superior iliac spine
13
Q
How is the rectus abdominis orientated and what is it attached to
A
Left and right, lie either side of the midline
Superiorly attached to the sternum and costal margin
Inferiorly attached to the pubis
Surrounded by an aponeurotic rectus sheath
14
Q
Which 3 muscles are lateral to the rectus abdominis and what directions are their fibres
A
- External oblique (EO) is most superficial. The fibres of EO run medially and inferiorly, towards the midline.
- Internal oblique (IO) lies deep to EO. The fibres of IO are orientated perpendicular to those of EO (they run medially and superiorly).
- Transversus abdominis lies deep to internal oblique. Its fibres are orientated horizontally.
15
Q
Where do the fibres of the aponeuroses fuse with the aponeuroses of the other side. What is this structure called
A
Forms a tough midline raphe (seam) called the linea alba (‘white line’)
16
Q
Where do the rectus abdominis muscles lie
A
Either side of the linea alba, comprised of muscle segments interspersed with horizontal tendinous bands
17
Q
What are the anterior and posterior walls of the rectus sheath formed from
A
The aponeuroses of EO, IO and transversus abdominis.
- As it approaches the midline, the aponeurosis of IO splits into anterior and posterior layers.
- The EO aponeurosis and the anterior layer of the IO aponeurosis form the
anterior wall of the rectus sheath.
- The posterior layer of the IO aponeurosis and the transversus abdominis aponeurosis form the posterior wall of the rectus sheath.
18
Q
What lies deep to transversus abdominis
A
The transversalis fascia, deep to the fascia lies
the parietal peritoneum
19
Q
What is the the most inferior part of the external oblique aponeurosis attached to and what does this form
A
Anterior superior iliac spine laterally
Pubic tubercle medially
This forms the inguinal ligament. Just above the inguinal ligament is the inguinal canal.
20
Q
Which arteries supply the anterolateral abdominal wall
A
- musculophrenic artery, a branch of the internal thoracic
- superior epigastric artery, which is the continuation of the internal thoracic artery. It descends in the rectus sheath
- inferior epigastric artery, a branch of the external iliac artery. It ascends in the rectus sheath and anastomoses with the superior epigastric
21
Q
Which nerves innervate the muscles and skin of the anterolateral abdominal wall
A
- Thoraco-abdominal nerves T7 – T11. These are the continuation of the intercostal nerves T7 – T11. These somatic nerves contain sensory and motor
fibres. - The subcostal nerve – this originates from the T12 spinal nerve (so called because it runs along the inferior border of the 12th rib).
- Iliohypogastric and ilioinguinal nerves – both are branches of the L1 spinal nerve.
22
Q
What does the parietal peritoneum line
A
Abdominal wall
23
Q
What type of nerves innervate the parietal peritoneum, what do they effect and how is pain characterised
A
Somatic nerves
Supply the overlying muscles and skin of the abdominal wall.
Pain from the parietal peritoneum is usually sharp, severe, and well localised to the abdominal wall.
23
Q
What does the visceral peritoneum cover
A
Abdominal viscera
24
What type of nerves innervate the visceral peritoneum, what do they effect and how is pain characterised
Visceral sensory nerves
convey ‘painful’ sensations back to the CNS along the path of the sympathetic nerves that innervate the organ / structure it covers
25
What lies between the parietal and visceral peritoneum, what does it contain and why
Peritoneal cavity
Contains a thin film of peritoneal fluid which allows the viscera to slide freely alongside each other
26
Intraperitoneal viscera
Almost completely covered by peritoneum e.g. the stomach
27
Retroperitoneal viscera
Posterior to the peritoneum, hence only covered by
peritoneum on their anterior surface e.g. the pancreas and abdominal aorta
28
secondarily retroperitoneal
These organs were intraperitoneal in early development but came to be ‘stuck down’ onto the posterior abdominal wall
29
Mesenteries
Folds of peritoneum that contain fat and suspend the small intestine and parts of the large intestine from the posterior abdominal wall
30
Omenta
Folds of peritoneum that are usually fatty and connect the stomach to other organs
31
Greater omentum
Hangs from the greater curvature of the stomach and lies superficial to the small intestine
32
Lesser omentum and what is embedded within it
Connects the stomach and duodenum (the first part of the small intestine) to the liver
The hepatic artery, the hepatic portal vein, and the bile duct (the ‘portal triad’) are embedded within its free edge
33
Peritoneum ligaments
Folds of peritoneum that connect organs to each other or to the abdominal wall
34
Falciform ligament
Connects the anterior surface of the liver to the anterior
abdominal wall
35
Coronary and triangular ligaments
Connect the superior surface of the liver to the diaphragm
36
Peritoneal folds
Raised from internal aspect of the lower abdominal wall and are created by the structures they overlie, like carpet running over a cable
37
Median umbilical fold
Lies in the midline and represents the remnant of the urachus, an embryological structure that connected the bladder to the umbilicus
38
Medial umbilical folds
Lateral to the median umbilical fold
These represent the remnants of the paired umbilical arteries, which returned venous blood to the placenta in foetal life
39
Lateral umbilical folds
Lateral to the medial umbilical folds
40
Which arteries lie deep to the Lateral umbilical folds and what do they supply
Inferior epigastric arteries
Supply the anterior abdominal wall
41
What 2 regions of unequal size is the peritoneal cavity divided into
Smaller lesser sac
Larger greater sac
42
How do the greater and lesser sacs communicate with each other
Via a passageway that lies posterior to the free edge of the lesser omentum, the epiploic foramen (also called the omental foramen)
43
Where does the gastrointestinal system develop
Embryonic gut tube which lies in the midline of the abdominal cavity
44
What suspends the embryonic gut tube from the posterior abdominal wall
Dorsal mesentery
45
What does the ventral mesentery connect
Connects the stomach to the anterior abdominal wall
46
As the liver grows within the ventral mesentery, what does the ventral mesentery form
anterior - falciform ligament
posterior - lesser omentum
47
What is growth, migration, and rotation of organs responsible for developing
Lesser sac and results in some organs being ‘pushed’ onto the posterior abdominal wall and becoming retroperitoneal.
48
What does the oesophagus pass through within the diaphragm and at what level is this
Oesophageal hiatus at T10
49
How is the reflux of stomach contents into the oesophagus prevented
Muscle around the hiatus functions as a sphincter
50
The branches of what artery supplies the distal oesophagus
Left gastric artery
51
What drains the distal oesophagus
Systemic system of veins (via oesophageal veins that drain into the azygos vein)
Portal venous system (via the left gastric veins)
52
How and what does the stomach break down food into
Chemically and mechanically breaks down food into chyme
53
Which region of the stomach is continuous with the site of at which the oesophagus enters the stomach
Cardia
54
What is the most superior part of the stomach and what does it contain
Fundus
Lies superior to the level of entry of the oesophagus and is usually filled with gas
55
What is the largest part of the stomach
The body
56
What are the regions of the pyloric part which is distal to the body
The pyloric antrum is wide and tapers towards the pyloric canal, which is narrow and contains the pyloric sphincter
57
What is the pyloric sphincter and what is its function
Circular smooth muscle
Regulates the passage of chyme into the duodenum
58
What are the left and right borders of the stomach
The right border of the stomach is the lesser curvature. The longer left border is the greater curvature
59
What are the anatomical relations of the anterior surface of the stomach
Related to the anterior abdominal wall, diaphragm, and left lobe of the liver
60
What does the posterior surface of the stomach form
The anterior wall of the lesser sac
61
Which regions of the anterior abdominal wall does the stomach lie
Epigastric and umbilical regions
62
What lies posterior to the stomach
Lesser sac, pancreas, left kidney, left adrenal gland, spleen, splenic artery, transverse mesocolon
63
What connects the lesser curvature of the stomach to the liver
Lesser omentum
64
What does the free edge of the lesser omentum contain
Hepatic artery, hepatic portal vein and the bile duct
65
Where is the entrance to the lesser sac in relation to the free edge of the lesser omentum
Posterior to the lesser omentum
66
What hangs from the greater curvature of the stomach
The greater omentum
67
Where are the arteries which supply the stomach branched from
The coeliac trunk
68
What does the foregut comprise of
The stomach, the first half of the duodenum, the liver, gallbladder, and pancreas
69
Where does the spleen develop and what is it supplied by
develops in the dorsal mesentery, and is supplied by the splenic artery, a branch from the coeliac trunk, but it is mesodermal in origin
70
What branches arises from the division of the coeliac trunk
Left gastric artery
Common hepatic artery
Splenic artery
71
Which arteries run along the lesser curvature of the stomach
The left and right gastric arteries and anastomose with each other
The left gastric artery arises from the coeliac trunk
The right gastric artery usually arises from the common hepatic artery
72
Which arteries run along the greater curvature of the stomach
The left and right gastro-omental (gastroepiploic) arteries and anastomose with each other
The left gastro-omental artery arises from the splenic artery
The right gastro-omental artery arises from the gastroduodenal artery, a branch of the common hepatic artery
73
What do the right and left gastric veins and right and left gastro-omental veins drain into
Hepatic portal vein
74
Where does the hepatic portal vein carry blood to
Carries nutrient-rich venous blood from the GI tract to the liver
75
Which nerve conveys parasympathetic fibres to the stomach
Vagus nerve
76
Parasympathetic stimulation of the stomach
Promotes peristalsis and gastric secretion
77
How are parasympathetic fibres conveyed to the stomach
Via the greater splanchnic nerve
Formed of preganglionic sympathetic fibres that leave spinal cord segments T5-T9 and pass through the sympathetic trunk without synapsing. The fibres synapse in prevertebral ganglia around the coeliac trunk. The postganglionic fibres travel to the stomach and inhibit peristalsis and secretion.
78
What are the 3 regions of the small intestines
Duodenum, jejunum, and ileum
79
Which region of the stomach is the duodenum continuous with
Pylorus of the stomach
80
What shape is the duodenum and why
C-shaped around the head of the pancreas
Most of the length of the duodenum is retroperitoneal
81
What is the major duodenal papilla and where is it located
Opening of the bile duct and the main pancreatic duct into the duodenum
Bile and pancreatic juice enters the duodenum here
Approximately halfway along the internal wall of the duodenum
82
What supplies the first half of the duodenum and why
Arterial branches from the coeliac trunk as the first half develops from the embryological foregut
83
What supplies the second half of the duodenum and why
Branches from the superior mesenteric artery as the second half develops from the embryological midgut
84
What suspends the jejunum and ileum from the posterior abdominal wall
The mesentery of the small intestine
85
What does the midgut comprise of
Second half of the duodenum, jejunum, ileum, cecum, appendix, ascending colon and the first 2/3's of the transverse colon
86
How is the jejunum and ileum specialised for nutrient absorption
Vast surface area: the small intestine is long, the mucosa is folded (plicae circulares), the mucosal folds bear villi and there are microvilli on the luminal surface of each epithelial cell
87
What are the internal differences of the jejunum and ileum
The plicae are more pronounced in the jejunum
The internal ileum is characterised by Peyer’s patches, which are large submucosal lymph nodules
88
What is Meckel’s diverticulum
A blind-ended diverticulum approximately one meter from the ileum's termination
The embryological remnant of the connection that was present between the midgut loop to the yolk sac. If it becomes inflamed, it may mimic an appendicitis (inflammation of the appendix)
89
What is the caecum, what is it continuous with and how are they connected
Distended, blind-ended ‘pouch’ which is covered by peritoneum but doesn't have a mesentery
Continuous with the terminal ileum via the ileocaecal junction in the right iliac fossa
90
What is the function of the large intestine
Reabsorbs water from faecal material to form semi-solid faeces
91
What is the large intestine composed of
Caecum, appendix, ascending colon, transverse colon, descending colon, sigmoid colon, rectum, and anal canal
92
What is the taeniae coli
The outer longitudinal smooth muscle layer organised into 3 bands
93
What are the bands of the taeniae coli
mesocolic, free and omental coli
94
What is a haustra (or haustrations)
Bulges or sacculations due to contraction of the inner circular muscle layer of the taeniae coli
95
What are epiploic appendages (appendices epiploicae)
Fatty tags in the large intestines which mark the point at which blood vessels penetrate the intestinal wall
96
What is the appendix
Small diverticulum that arises from the caecum and contains lymphoid tissue
97
How is the appendix attached to the cecum
By a small mesentery, the mesoappendix
98
What is the 90° turn left of the ascending colon in the right upper quadrant, becoming continuous with the transverse colon
Hepatic flexure (sometimes called the right colic flexure)
99
Where does the ascending colon lie
Runs vertically on the right side of the posterior abdominal wall in the right paracolic gutter
100
Is the ascending colon retroperitoneal or intraperitoneal
It is retroperitoneal (it is an example of a secondarily retroperitoneal organ)
101
Mesocolon
The part of the mesentery that attaches the colon to the abdominal wall
102
What is the 90° turn inferiorly of the transverse colon in the left upper quadrant, becoming continuous with the descending colon
Splenic flexure (sometimes called the left colic flexure)
103
How is the splenic flexure tethered to the diaphragm
By the phrenicocolic ligament
104
What does the hindgut compose of
Distal third of the transverse colon, descending colon, sigmoid colon and proximal third of the rectum
105
Where does the transverse colon lie
Runs vertically on the left side of the posterior abdominal wall in the left paracolic gutter
106
Is the descending colon retroperitoneal or intraperitoneal
It is retroperitoneal (also secondarily retroperitoneal)
107
Is the transverse colon retroperitoneal or intraperitoneal
Intraperitoneal
108
What is the 90° turn inferiorly into the pelvis of the sigmoid colon
Rectosigmoid junction
109
Which mesentery connects the sigmoid colon to the pelvic wall
Sigmoid mesocolon, and so is intraperitoneal
110
Function of the rectum
Stores feaces until it is convenient to defecate
111
Which arteries supply the gastrointestinal tract and which regions do they supply
Coeliac trunk - Foregut
Superior mesenteric artery - Midgut
Inferior mesenteric artery - Hindgut
112
At what level does the coeliac trunk leave the abdominal aorta
T12
113
At what level does the superior mesenteric artery leave the abdominal aorta
L1
114
At what level does the inferior mesenteric artery leave the abdominal aorta
L3
115
What are the major branches of the superior mesenteric artery
Jejunal branches – several branches to the jejunum
Ileal branches – several branches to the ileum
Ileocolic artery – supplies the caecum, appendix, and ascending colon
Right colic artery – supplies the ascending colon
Middle colic artery – supplies the transverse colon
116
What are the jejunal and ileal branches embedded in
The mesentery of the small intestine
117
What forms when the jejunal and ileal branches anastomose
‘Loops’ of arteries called arcades. From these arcades run the vasa recta (‘straight’ vessels), which supply the intestinal wall.
118
What are the major branches of the inferior mesenteric artery
Left colic artery – supplies the transverse colon and the descending colon
Sigmoid branches – supply the sigmoid colon
Superior rectal artery – the terminal branch of the IMA, which supplies the upper rectum
119
What is the marginal artery
The anastomose of the branches of the middle colic artery and left colic artery, along the distal third of the transverse colon and the splenic flexure
120
What is the function of the inferior mesenteric vein and where does it lie
Drains the hindgut.
Ascends on the left side of the abdomen and typically drains into the splenic vein from the spleen
121
What is the function of the superior mesenteric vein and where does it lie
Drains the midgut.
Ascends and unites with the splenic vein close to the liver (posterior to the neck of the pancreas) to form the hepatic portal vein
122
Function of the hepatic portal vein
Supplies the liver with nutrient rich blood from the gut, as the splenic, superior mesenteric and inferior mesenteric veins join together.
123
Function of the small hepatic veins and what do they form
Carries blood which has had its nutrients removed from the liver.
They unite within the liver to form 2 or 3 large hepatic veins that enter the inferior vena cava
124
What innervates the foregut and midgut
Parasympathetic fibres from the vagus nerve
125
What innervates the hindgut
Parasympathetic fibres via the pelvic splanchnic nerves
126
What are the pelvic splanchnic nerves formed from
The axons of parasympathetic neurons that lie in the sacral spinal cord
The cell bodies of preganglionic parasympathetic neurons lie in S2 – S4
The axons of these neurons leave the spinal cord and form the pelvic splanchnic nerves
The preganglionic axons synapse with a second neuron in a ganglion. The parasympathetic ganglia are located very close to, or even within, the walls of the viscera
127
What fibres pass through the sympathetic trunk (without synapsing) via the greater, lesser, and least splanchnic nerves
Preganglionic sympathetic fibres from T5 – T12
128
Which fibres do the greater, lesser, and least splanchnic nerves carry and what do they innervate
The greater splanchnic carries fibres from T5 – T9 and innervates the foregut.
The lesser splanchnic carries fibres from T10 – T11 and innervates the midgut.
The least splanchnic carries fibres from T12 and innervates the hindgut.
129
How do parasympathetic fibres innervate the midgut and hindgut
Stimulate peristalsis and secretions
130
The preganglionic fibres in splanchnic nerves synapse within ganglia that lie where
In the abdomen, clustered around the aorta and the coeliac trunk, SMA and IMA
131
What do the postganglionic sympathetic fibres of the splanchnic nerves form and how do they innervate the gut
Form visceral nerves that innervate the gut
They inhibit peristalsis and secretions
132
How do visceral sensory fibres from the gut travel to the CNS
Alongside the sympathetic fibres that innervate that part of the gut
133
Painful sensations from the gut enter what spinal chord segments
Foregut enter spinal cord segments T5 - T9
Midgut enter spinal cord segments T10 – T11
Hindgut enter spinal cord segment T12
134
T5-12 of the spinal cord also receive somatic sensory information, from which dermatomes
The region of the dermatome is consistent with the region of the spinal cord
T5 – T9 (upper abdomen and epigastrium)
T10 – T11 (the umbilical region)
T12 (the suprapubic region)
Epigastric pain suggests foregut pathology
Central abdominal / umbilical pain suggests midgut pathology
Lower abdominal / suprapubic pain suggests hindgut pathology.
135
Where does the liver lie
Upper right quadrant and epigastric region
Predominantly in the right hypochondrium and epigastric areas, and extends into the left hypochondrium
136
Which products of digestion from the gut are transported to the liver and how
All products, except lipids, via the hepatic portal vein
137
What is the function of bile and where is it stored
Produced in the liver and is transported to the gallbladder for storage
Bile emulsifies lipids in the chyme entering the duodenum from the stomach
138
What are the 2 surfaces of the liver
Diaphragmatic surface - Lies anterosuperior and is related to the inferior surface of the diaphragm.
Visceral surface - Lies posteroinferior and is related to other organs.
139
Which regions of the liver are not covered by visceral peritoneumeum
-Bare area of the liver – A region on the posterior surface that lies in contact with the diaphragm
-The region where the gallbladder lies in contact with the liver
-Region of the porta hepatis – where hepatic blood vessels and ducts of the biliary system enter and exit the liver (the equivalent of the hilum of the lung)
140
What is the falciform ligament
A ligament which separates the small left lobe and the large right lobe
It connects the anterior surface of the liver to the internal aspect of the anterior abdominal wall
141
What are the accessory lobes of the liver and where are they located
The caudate and quadrate lobes, located on the posteroinferior surface
These lobes do not represent the internal, functional organisation of the liver
142
How many functional segments are in the liver
8 functional segments
Each segment is served by its own branch of the hepatic artery and portal vein, and by its own hepatic duct
143
What arteries supply the liver and how do these arteries arise
The right and left hepatic arteries
The common hepatic artery, which arises from the coeliac trunk, becomes the hepatic artery proper after the gastroduodenal artery branches off.
The hepatic artery proper bifurcates into right and left hepatic arteries, which enter the liver at the porta hepatis.
144
What is the liver connected to and how
-Diaphragm by the coronary and triangular ligaments
-Anterior abdominal wall by the falciform ligament
-Stomach and duodenum by the lesser omentum
145
Where does the liver grow from
A tissue bud that develops in the ventral mesentery – a peritoneal fold in the upper abdomen that connects the stomach to the anterior abdominal wall
146
What do the remains of the ventral mesentery form
The lesser omentum and the falciform ligament
147
What does the free edge of the falciform ligament contain
The round ligament of the liver (the ligamentum teres)
It is the remnant of the umbilical vein, which, in the foetus, carries oxygenated blood from the placenta to the foetus
148
What is the embryological remnant, the ligamentum venosum
It is the remains of the ductus venosus, which in foetal life diverts blood from the umbilical vein to the IVC, thus shunting oxygen-rich blood to the heart and bypassing the liver.
Lies on the posterior surface of the liver, in the groove between the caudate lobe and the left lobe of the liver.
149
What is the function of the gallbladder
Stores and concentrates bile
150
Where does the gallbladder lie and what are its 3 main parts
Lies on the posteroinferior (visceral) surface of the liver and lies close to the duodenum
Fundus, the body, and the neck
151
What is the body of the gallbladder
Main part of the gallbladder which sits in the gallbladder fossa on the visceral surface of the liver and tapers towards the neck
152
What is the neck of the gallbladder
Communicates with the cystic duct
153
What is the fungus of the gallbladder
The rounded end of the gallbladder, which typically extends to the inferior border of the liver
154
What is the surface marking of the fundus of the gallbladder
Tip of the 9th costal cartilage, at the point where the right midclavicular line intersects the right costal margin
155
What cells produce bile
Hepatocytes in the liver
156
How does bile reach the duodenum from the liver
First excreted into small channels called bile canaliculi, which drain into bile ducts of increasing which converge to form right and left hepatic ducts that exit the liver at the porta hepatis.
These converge to form the common hepatic duct
Common hepatic duct receives the cystic duct from the gallbladder, the duct is now called the bile duct which runs in the free edge of the lesser omentum
It lies posterior to the superior part of the duodenum and posterior to the
head of the pancreas
The bile duct enters the duodenum
157
How and when does bile enter the gallbladder from the liver
When bile is not needed for digestion, it enters the gallbladder via the cystic duct
158
Where is the spiral fold (spiral duct)
Lies at the junction between the gallbladder neck and the cystic duct
159
Which artery supplies the gallbladder
Cystic artery, which typically arises from the right hepatic artery
160
How is the gallbladder drained of blood
By cystic veins that pass directly into the liver or join the hepatic portal vein
161
Visceral afferents from the gallbladder return to the CNS via what type of fibres
Sympathetic fibres
162
Visceral pain from the gallbladder enters which spinal cord levels
T5 – T9
Therefore referred to (i.e. felt in) the epigastrium
163
Why might gallbladder pain also be referred to the right shoulder
If gallbladder pathology (e.g. inflammation) irritates the diaphragm
The diaphragm is innervated by the phrenic nerve which originates at spinal segments C3-5, which also receives somatic sensory information from the skin over the shoulder
164
If gallbladder pathology irritates the parietal peritoneum, where is pain felt
Pain is well localised to the right hypochondrium
The parietal peritoneum is innervated by somatic nerves
165
What is hepatomegaly and what causes it
Enlargement of the liver
Causes include hepatitis (inflammation of the liver from various causes), malignancy, and heart failure
When the liver is enlarged, its inferior border becomes palpable inferior to the right costal margin
166
Why do cancers often metastasise to the liver
Venous blood from the gut passes through the liver, bowel cancers often metastasize to the liver, via the portal vein
167
What is cirrhosis of the liver and what causes it
Scarring of the liver, where hepatocytes are destroyed and replaced with fibrous tissue
Can impair liver function and cause failure due to less hepatocytes
The liver becomes shrunken, hard, and nodular
Caused by chronic excess alcohol consumption, chronic infection with hepatitis B or C, or a build-up of fat in the liver
168
What is portal hypertension and what causes it
High blood pressure in the portal venous system
Caused when blood flow through the liver and portal vein is obstructed (e.g. in cirrhosis of the liver)
169
What are portosystemic anastomoses
Communications between veins draining to the systemic circulation and veins draining to the portal circulation
In the distal oesophagus, venous blood drains into both the systemic veins (via the azygos) and into the portal system (via the gastric veins)
170
If flow in the portal system is obstructed, where does the blood go
Pressure in the portal system increases and blood is diverted from the portal veins into the systemic veins
Systemic veins become distended and varicose (in the oesophagus these are called oesophageal varices) and prone to rupture, which can result in catastrophic bleeding
171
What are gallstones mostly composed of
cholesterol
172
Where are gallstones lily to be present if the patient is asymptomatic
Within the gallbladder
173
What is biliary colic
Severe pain when the gallbladder contracts with gallstones lodged within the cyst duct
174
What happens if a gallstone gets stuck in the biliary tree
Results in the accumulation of bile.
If it gets stuck in the cystic duct, flow of bile into the cystic duct and the gallbladder becomes inflamed (cholecystitis)
175
What is a cholecystectomy
Removal of the gallbladder
176
What are the 4 parts of the duodenum
The superior (first), descending (second), the inferior (third) and the ascending (fourth) parts
177
Where do the bile duct, gastroduodenal artery and the hepatic portal vein lie in relation to the pancreas
Posterior to the first part of the duodenum
178
Where does the superior mesenteric artery lie in relation to the pancreas
Anterior to the third (anterior) part
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Arterial branches that supply the duodenum are derived from what arteries
Gastroduodenal artery (from the common hepatic artery and hence the coeliac trunk)
Inferior pancreaticoduodenal arteries (from the superior mesenteric artery)
Veins follow the arteries and are tributaries of the hepatic portal vein
180
Where does the pancreas lie
Horizontally on the posterior abdominal wall at the level of L1, behind the stomach
Forms part of the posterior wall of the lesser sac
181
Is the pancreas intraperitoneal or retroperitoneal
Retroperitoneal
It does not have a capsule so in the cadaver its surface appears ‘bumpy’ rather than smooth
182
How does the pancreas develop
Forms from dorsal and ventral pancreatic buds which fuse
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What are the 4 parts of the pancreas
The head, the neck, the body, and the tail
184
What is the uncinate process
A hook-like projection of the head of the pancreas
185
Where does the tail of the duodenum extend to
The hilum of the spleen
186
How does the splenic artery and vein interact with the pancreas
Splenic artery runs towards the spleen embedded in the upper border of the pancreas
Splenic vein lies posterior to the pancreas
187
Function of the pancreas
Endocrine - Synthesizes and secretes insulin and glucagon
Exocrine - Produces pancreatic juice that contains digestive enzymes
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How is pancreatic juice transported to the duodenum
Via the main pancreatic duct which merges with the bile duct at the hepatopancreatic ampulla which opens into the second part of the duodenum at the major duodenal papilla
Via the accessory pancreatic duct, which empties pancreatic juice into the duodenum at the minor duodenal papilla, which lies just proximal to the major duodenal papilla
189
What is the sphincter of Oddi and what is it's function
The smooth muscle around the hepatopancreatic ampulla
Contraction of the sphincter prevents reflux of duodenal contents into the bile and main pancreatic ducts
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Where does the accessory pancreatic duct empty pancreatic juice in the duodenum
At the minor duodenal papilla
Lies just proximal to the major duodenal papilla
191
What blood vessels supply the pancreas
-The splenic artery runs along the upper border of the pancreas and gives rise to pancreatic arteries
-The superior pancreaticoduodenal arteries which arise from the gasproduodenal artery from the common hepatic artery and hence the coeliac trunk
-Inferior pancreaticoduodenal arteries derived from the superior mesenteric artery
192
Which veins drain the pancreas
Veins follow the arteries
The splenic vein drains the pancreas and unites with the superior mesenteric vein to form the hepatic portal vein posterior to the neck of the pancreas
193
What is the spleen and what are its functions
A haematopoietic and lymphoid organ.
It has several functions that include the breakdown of old red blood cells, the storage of red blood cells and platelets, and various immune responses, including production of IgG
194
What are the 2 surfaces of the spleen
The diaphragmatic surface
The visceral surface lies in contact with the stomach, left kidney and colon. The splenic vessels enter and exit the spleen at the hilum on the visceral surface
195
What are the 4 borders of the spleen
The anterior and superior borders are typically notched
The posterior and inferior borders are smooth
196
What vessel supplies the spleen
The splenic artery which runs along the superior border of the pancreas, embedded within it
The artery divides into approximately five branches at the hilum
197
How is the pancreas drained of blood
Via the splenic vein, which runs posterior to the pancreas
It unites with the superior mesenteric vein to form the hepatic portal vein
198
What is a duodenal ulcer and what can it result in
Sores, mostly found in the first half of the duodenum
May erode the duodenal wall and gastroduodenal artery, which lies posterior to the first part of the duodenum, resulting in severe intra-abdominal bleeding
199
What is pancreatitis
Inflammation of the pancreas which may be chronic or acute
Acute pancreatitis is a life- threatening condition
200
What are the main causes of pancreatitis
Excess alcohol intake
Impaction of the gallstone prevents pancreatic juice from leaving the pancreas and it starts to break down the pancreas - Autolysis
201
How can pancreatic cancer result in bile pigments in the blood and jaundice (yellowing of the skin)
When it affects the head of the pancreas, it can obstruct flow of bile in the bile duct
202
What is diabetes mellitus
When the insulin-producing cells (β cells) of the pancreas no longer produce insulin or not enough
High blood glucose levels
Some patients develop diabetes secondary to pancreatitis
203
What is splenomegaly and what can cause this
Enlargement of the spleen towards the midline, in the
direction of the right iliac fossa, because the phrenicocolic ligament prevents its direct descent towards the left iliac fossa
Infection (e.g. infectious mononucleosis, malaria), haematological malignancy (e.g. leukaemia) and portal hypertension
204
Why is the spleen prone to rupture or blunt abdominal trauma
Its soft and highly vascular
205
What is the long-term risk after a splenectomy
More prone to some bacterial infections
206
Which part of the nasal cavity contains olfactory receptors
Mucosa in the upper part of the nasal cavity
207
What form the olfactory nerves
The axons of these receptors
208
How are the left and right nasal cavities separated
Thin midline septum, formed of cartilage and bone
The oral cavity inferiorly by the hard palate
The brain superiorly by bone
209
What are paranasal sinuses
Cavities within the skull bones
210
What forms the midline nasal septum
Cartilage anteriorly and two thin plates of bone posteriorly
