GI

Question 1

What separates the abdominal cavity from the thorax

Answer 1

Diaphragm

Question 2

Contents of the abdominal cavity

Answer 2

Organs of the gastrointestinal tract (stomach, small and large intestine) the heptobiliary system ( liver and gall bladder) the urinary system ( kidneys and hreters) and the endocrine system (pancreas and adrenal glands). The abdomen also carnations the spleen( a haematopeitc and lymphoid organ) and the great vessels and their branches).

Question 3

Components of the anterior, lateral and posterior walls of the abdomen

Answer 3

Skin, subcutaneous tissue and muscles and their associated aponeuroses ( flat tendons). 5 lumbar vertebrae

Question 4

Functions of the abdominal wall

Answer 4

Protect the abdominal viscera, increase the intro-abdominal pressure (e.g. for defecation and childbirth) maintain posture and move the trunk

Question 5

What lines the internal aspect of the abdominal wall

Answer 5

Serous membrane called parietal peritoneum

Question 6

What are the four quadrants of the abdominal wall

Answer 6

Right upper and lower and left upper and lower quadrants.
Split into quadrants by two invisible lines. A vertical line that runs through the lower sternum, umbilicus and the pubic symphysis
A horizontal line that runs across the abdomen through the umbilicus

Question 7

Name the nine regions of the anterior abdominal wall ( in order going from right to left starting on the top row)

Answer 7

Right hypochondrium, epigastrium, left hypochondrium
Right flank, umbilical region, left flank
Right iliac fossa, suprapubic region, left iliac fossa

Question 8

What are the lines that separate the anterior abdominal wall into nine regions

Answer 8

Midclavicular lines ( extend vertically from the midclavicular point to the mid-inguinal point.
Subcostal line ( horizontal line drawn through the inferior most parts of the right and left costal margins
Intertubercular line - a horizontal line drawn through the tubercles if the right and left iliac crests and the body of L5.

Question 9

What is the transpyloric plane

Answer 9

A horizontal plane that passes through the tips of the right and left ninth costal cartilages. It lies halfway between the superior border of the manubrium and the pubic symphysis. It transects the pylorus of the stomach, the gallbladder , the pancreas and the hila of the kidneys

Question 10

Transumbilical plane

Answer 10

An unreliable landmark as its position varies depending on the amount of subcutaneous fat present. In a slender individual it lies approx at the level of L3.

Question 11

Intercristal plane

Answer 11

Horizontal line drawn between the highest points of the right and left iliac crests. It cannot be palpated from the anterior aspect of the abdominal wall. It is used to guide procedures on the back

Question 12

McBurney’s point

Answer 12

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

Question 13

What four pairs of t muscles make up the anterolateral abdominal wall

Answer 13

External oblique, internal oblique, transversus abdominis, Rectum abdominis

Question 14

Which direction are the anterolateral abdominal wall muscles fibres orientated

Answer 14

External oblique - diagonally
Internal oblique - diagonally
Transversus abdominis - horizontally
Rectum abdominis - straight

Question 15

What is an aponeurosis

Answer 15

A flat tendon

Question 16

Linea alba

Answer 16

a tendinous, fibrous raphe that runs vertically down the midline of the abdomen. It extends between the inferior limit of the sternum and the pubis, separating the rectus abdominis muscles.

Question 17

What does the rictus a domino’s lie within ?

Answer 17

Recuts sheath

Question 18

Anterior and posterior walls of the recurs sheath are formed by

Answer 18

the aponeuroses of the 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 rictus sheath.
The posterior layer of the IO aponeurosis and the transversus abdominis aponeurosis form the posterior wall of the recuts sheath.

Question 19

What lies deep to the transversus abdominis

Answer 19

The transversal is fascia.
Deep to this lies the parietal peritoneum

Question 20

Ingiunal ligament

Answer 20

Formed where the most inferior part of the external oblique aponeurosis is attached to the anterior superior iliac spine laterally and the pubic tubercle medially
( above it is the inguinal canal)

Question 21

Vessels of the anterior abdominal wall

Answer 21

Musculophrenic artery - a branch of the internal thoracic
Superior epigastric artery - is the continuation of the internal thoracic artery. It descends in the recuts sheath.
Inferior epigastric artery - a branch of the external iliac artery. It ascends in the recuts sheath and anastomosis with the superior epigastric.
These vessels are accompanied by deep veins. An extensive network of superficial veins is found in the anterolateral abdominal wall.

Question 22

Innervation if the anterior abdominal wall

Answer 22

Thoracic-abdominal nerves t7-t11. The continuation of the intercostal nerves t7-t11. These somatic nerves contain sensory and motor fibres.
5e subcostal nerve - this originates from the t12 spinal nerve ( runs along inferior boarder of the 12th rib)
Iliohypogastric and iliolingual nerves - both are branches if the L1 spinal nerve

Question 23

Inguinal canal

Answer 23

Oblique passageway through the muscles of the anterior abdominal wall and lies superior to the medial half of the inguinal ligament. It passes through each layer of the abdominal wall as it travels medially and inferiorly. The canal is about 5 cm long in adult. It extends from the deep inguinal ring laterally ( an aperture in the transversalis fascia ) to the superficial inguinal ring medially ( an aperture in the external oblique aponeurosis)

Question 24

Anterior boarder of the inguinal canal

Answer 24

External oblique aponeurosis
Laterally only : internal oblique aponeurosis

Question 25

Posterior boarder of the inguinal canal

Answer 25

Transversalis fascia
Medially only : dial fibres of the aponeuroses of the internal oblique and transversus abdominis ( together known as the conjoint tendon )

Question 26

Roof of the inguinal canal

Answer 26

Transversalis fascia
Arching fibres if the internal oblique and transversus abdominis

Question 27

Floor of the inguinal canal

Answer 27

Inguinal ligament ( the lower boarder it the external oblique aponeurosis)

Question 28

What is peritoneum

Answer 28

A serous membrane that lines the abdominal wall and covers the viscera within it

Question 29

Parietal peritoneum

Answer 29

Lines the abdominal wall
It can be seen with the naked eye and is innervated by the somatic nerves that supply the overlying muscles and skin if the abdominal wall.
Pain from the parietal peritoneum is usually sharp, severe and well localised to the abdominal wall

Question 30

Visceral peritoneum

Answer 30

Covers the abdominal viscera.
Adhered to the surface of the viscera and cannot be seen with the naked eye.

Question 31

Innervation if the visceral peritoneum

Answer 31

Visceral sensory nerves. These nerves convey painful sensation ps back to the cns along the path of the sympathetic nerves that Innervation the organ / structure it covers. Pain from the visceral peritoneum can be severe. It is usually dull and diffuse ( cannot be pinpointed to a specific location)
‘Painful’ sensations may be perceived as nausea or distension.

Question 32

Peritoneal cavity

Answer 32

Lies between the parietal and visceral peritoneum. In a health abdomen, a thin film of peritoneal fluid lies in the cavity. It allows the viscera to slide freely alongside each other.

Question 33

What does intraperitoneal mean

Answer 33

Almost completely covered by peritoneum e.g. the stomach

Question 34

What does retroperitoneal mean

Answer 34

Posterior to the peritoneum, hence only covered by peritoneum on their anterior surface e.g. pancreas and abdominal aorta
( secondary retroperitoneal - organs were intraperitoneal in early development but came to be stuck down into the posterior abdominal wall)

Question 35

Mesenteries

Answer 35

Folds of peritoneum that contain fat and suspend the small intestine and parts of the large intestine from 5e posterior abdominal wall. Arteries that supply the intestine ( from the abdominal aorta) and veins that drain the gut ( tributaries of the portal venous system) are embedded in the mesenteries.

Question 36

Greater and lesser omentum

Answer 36

Folds if peritoneum that are usually fatty and connect the stomach to other organs.
Greater omentum hangs from the greater curvature if the stomach and lies superficial to the small intestine.
The lesser omentum connects the stomach and duodenum to the liver. The hepatic artery, the hepatic portal vein and the bile duct ( the ‘portal triad’) are embedded within its free edge.

Question 37

Ligaments of the abdomen

Answer 37

Folds of peritoneum that connect organs to each other it to the abdominal wall.
Falciform ligament - connects the anterior surface of the liver to the anterior abdominal wall
Coronary and triangular ligaments - copnnect the superior surface of the liver to the diaphragm.

Question 38

Peritoneal folds

Answer 38

Raised from the internal aspect of the lower abdominal wall and are created by the structures they overlie, like carpet running over a cable. Sometimes they are difficult to see.

Question 39

Median umbilical fold

Answer 39

Lies in the midline and represents the remnant of the urachus, an embryological structure that connects the bladder to the umbilicus.

Question 40

Medial umbilical fold

Answer 40

Lateral to the median. They represent the remnants of the paired umbilical arteries, which returned venous blood to the placenta in foetal life

Question 41

Lateral umbilical folds

Answer 41

Lateral to the medial umbilical folds. The inferior epigastric arteries lie deep to these peritoneal folds. They supply the anterior abdominal wall.

Question 42

The smaller lessersac

Answer 42

Also called mental bursa - a space that lies posterior to the stomach and anterior to the pancreas

Question 43

The greater sac

Answer 43

Remaining part of the peritoneal cavity that is not the lesser sac

Question 44

Communication between greater and lesser sacs

Answer 44

Via a passageway that lies posterior to the free edge of the lesser omentum, the epiploic foramen.( also called mental foramen )

Question 45

What level does the oesophagus pass through the oesophageal hiatus in the diaphragm

Answer 45

T10

Question 46

Muscles around the oesophageal hiatus

Answer 46

Functions as a sphincter that prevents reflux of stomach contents into the oesophagus. The abdominal section of the oesophagus is less than 2 cm long.

Question 47

Supply of the distal oesophagus

Answer 47

Branches of from the left gastric artery. It’s venous drainage is towards both the systemic system of veins ( via oesophageal veins that drain into the azygous vein) and to the portal venous system ( via the left gastric veins. The distal oesophagus is therefore a site if portosystemic anastomoses, which are clinically important .

Question 48

Four parts of the stomach

Answer 48

Cardia, body, fungus and pyloric part

Question 49

Most superior part of the stomach

Answer 49

Fund us. It lies superior to the level of entry of the oesophagus and is usually filled with gas.

Question 50

Largest part of the stomach the body

Question 51

Pyloric part of the stomach

Answer 51

Distal to the body. The pyloric antrum is wide and tapers towards the pyloric canal, which is narrow and contains the pyloric sphincter.

Question 52

Relative locations of the stomach and lesser sac

Answer 52

It’s posterior surface forms the anterior wall of the lesser sac. The lesser sac and the structures that form it’s posterior wall lie posterior to the stomach : these include the pancreas, left kidney and spleen.

Question 53

Blood supply of the stomach

Answer 53

Supplied by arteries that branch from the coeliac trunk. This is one of the three large unpaired vessels that leave the anterior aspect of the abdominal aorta ( at the level of T12) to supply the abdominal viscera that are derived from the embryological foregut. The spleen develops in the dorsal mess trey and is supplied by the coeliac trunk, but it is mesodermal in origin.

Question 54

The foregut comprises of the

Answer 54

Stomach, first half of the duodenum, the liver, gall bladder and pancreas.

Question 55

The coeliac trunk

Answer 55

only a short stump, it divides into three branches close to the aorta. These are the left gastric artery, the common hepatic artery, and the splenic artery. The left gastric is a much smaller calibre vessel than the common hepatic and splenic artery.

Question 56

The left and right gastric arteries

Answer 56

Run along the lesser curvature of the stomach and anastomose with each other
The left gastric artery arises from the coeliac trunk
The right gastric artery may arise from either the common hepatic artery of the hepatic artery proper.

Question 57

The left and right gastric-omental (gastroepiploic) arteries

Answer 57

run along the greater curvature of the stomach and anastomose with each other.
The left gastro-omental artery anastomose with each other.
The right gastro-omental artery arises from the gastroduodenal artery, a branch of the common hepatic artery.

Question 58

Right and left gastric veins and right and left gastro-omental veins

Answer 58

Drain into the hepatic portal vein ( HPV). This is a large vein that carries nutrient rich venous blood from the gi tract to the liver.

Question 59

Innervation of the stomach

Answer 59

The vagus nerve conveys parasympathetic fibres to the stomach. Parasympathetic stimulation promotes peristalsis and gastric secretion.
Sympathetic fibres are converts to the stomach via the greater splanchnic nerve. The greater splanchnic nerve is 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 post ganglion is fibres travel to the stomach and inhibit peristalsis and secretion.

Question 60

Three parts of the small intestine

Answer 60

Duodenum, jejunum and ileum

Question 61

The duodenum

Answer 61

Continuous with the pylorus of the stomach. It is short and curved into a c shape around the head of the pancreas. Most of the length of the duodenum is retroperitoneal. Approx halfway along the internal wall of the duodenum, is the major duodenal papilla. This is the opening of the bile duct and the main pancreatic duct into the duodenum.

Question 62

Embryological development of the duodenum

Answer 62

First half develops from the embryological foregut and is supplied by arterial branches from the coeliac trunk. The second half of the duodenum develops from the embryological midgut and is supplied by branches from the artery of the midgut - the superior mesenteric artery.

Question 63

Jejunum and ileum

Answer 63

The jejunum is continuous with the duodenum. Both the jejunum and the ileum are intraperitoneal and are ‘suspended’ from the posterior abdominal wall by the mesentery of the small intestine. Blood vessels that supply the small intestine ( from the superior mesenteric artery) are embedded within the mesenteric. The small intestine lies centrally in the abdomen, the jejunum lying in the left upper region and the ileum lying in the right lower region.

Question 64

Jejunum and ileum derived from what embryologically

Answer 64

Both the jejunum and ileum are derived from the embryological midgut .

Question 65

Components of the jejunum and ileum that make that adapted to nutrient absorption

Answer 65

The sites of nutrient absorption., so have a vast surface area: the small intestine is long, the mucosa is folded (plicae circulates), the mucosal folds bear villi and there are microvilli on the luminal surface of each epithelial cell.

Question 66

Differentiating between the ileum and the jejunum in a cadaver

Answer 66

Difficult based on their external appearances. There are some internal differences. The plicae are more pronounced in the jejunum. The internal ileum is characterised by peyer’s patches, which are large submucosal lymph nodes. The terminal ileum is continuous with the caecum - the first part of the large intestine at the ileocaecal junction inn the right iliac fossa.

Question 67

Meckel’s diverticulum

Answer 67

In some people, the ileum bears a blind-ended diverticulum approx one metre from its termination. It is the embryological remnant of the connection that was present between the midgut loop of the yolk sac. If it becomes inflamed, it may mimic an appendicitis.

Question 68

The large intestine

Answer 68

Reabsorbs water from faecal material to form semi-solid faeces. It lies peripherally in the abdomen and is composed of the caecum, appendix, ascending colon, transverse colon, descending colon, sigmoid colon, rectum, and anal canal. Some segments are retroperitoneal and some are intraperitoneal.

Question 69

Distinguishing the large intestine in a cadaver

Answer 69

Usually easy to distinguish. It is peripherally located, and larger calibre. The outer longitudinal muscle layer is organised into three bands - the taeniae coil. The inner circular muscle layer forms ‘bulges’ called Austria ( or haustrations). The large intestine bears fatty tags called epic logic appendages ( appendices apiploicae) that mark dthe point at which blood vessels penetrate the intestinal wall.

Question 70

Caecum

Answer 70

The first part of the large intestine. It is distended, blind-ended pouch. It is covered by peritoneum but does not have a mesentery.

Question 71

The appendix

Answer 71

A small diverticulum that arises from the caecum and contains lymphoid tissue. The surface marking of the base of the appendix is McBurney’s point. The appendix varies in length and the position of its tip of variable. It is connected to the caecum by a small mesentery, the mesoappendix.

Question 72

Ascending colon

Answer 72

Continuous with the caecum. It runs vertically on the right side of the posterior abdominal wall in the right parabolic gutter. It is retroperitoneal ( it is an example of a secondarily retroperitoneal organ). The ascending colon makes a 90 degree turn left on the right upper quadrant, becoming continuous with the transverse colon. The bend in the colon here is the hepatic felxure ( sometimes called the right colic flexure)

Question 73

Transverse colon

Answer 73

Continuous with ascending colon. Runs horizontally in upper abdomen but often hangs inferiorly. It is intraperitoneal and is suspended from the posterior abdominal wall by the transverse mesocolon. It makes a 90 degree turn inferiorly in the upper left quadrant, becoming continuous with the descending colon. The bend in the colon here is the splenic flexure ( sometimes called left colic flexure) . The splenic flexure is tethered to the diaphragm by the phrenicocolic ligament.

Question 74

Embryological origin of the transverse colon

Answer 74

Marks the transition pint of between the embryological midgut and the embryological hindgut. The proximal ( first) two thirds develop from the midgut whilst the distal third develops from the hind gut . This means that these two parts of the transverse colon are supplied by different blood vessels and nerves.

Question 75

Descending colon

Answer 75

Continuous with the transverse colon superiority and the sigmoid colon inferiorly. It runs vertically on the left side of the posterior abdominal wall in the left paracolic gutter. It is retroperitoneal ( also secondary retroperitoneal)

Question 76

Sigmoid colon

Answer 76

Lies in the left lower quadrant and is named because of its sinuous shape. It is continuous with the descending colon superiority and the rectum inferiorly. As the sigmoid approaches the midline, it makes a 90 degree turn inferiorly into the pelvis. This bend is the rectosigmoid junction. The sigmoid colon has a mesentery - the sigmoid mesocolon and is therefore intraperitoneal.

Question 77

Rectum and anal canal

Answer 77

Rectum lies in the pelvis and is retroperitoneal. It is continuous superiority with the rectosigmoid junction ( at the level of S3) and inferiorly with the anal canal.

Question 78

Three large unpaired arteries that leave the abdominal aorta to supply the go tract

Answer 78

Coeliac trunk
Superior mesenteric artery
Inferior mesenteric artery

Question 79

What structures does the coeliac trunk supply

Answer 79

Branches that supply the foregut x the oesophagus, stomach, first half of the duodenum, liver, gallbladder, bile ducts, pancreas and spleen.

Question 80

Superior mesenteric artery

Answer 80

Artery of the midgut. It leaves the aorta at the level of L1. Its branches supply the midgut structures : the second half of the duodenum, the small intestine, and the large intestine as far as ( and including) the first two thirds of the transverse colon. Branches also supply part of the pancreas

Question 81

Major branches of the sma

Answer 81

Jejunal branches - several branches to the jejunum
Ileal branches - several branches to the ileum
( jejunal and ileal branches are embedded in the mesentery of the small intestine. The anastomose with each other forming loops of arteries called arcades. From these run vasa recta which supply the intestinal wall)
Ileocolic artery - supplies the caecum, appendix, and ascending colon.
Right colic artery - supplies the ascending colon
Middle colic artery - supplies the transverse colon

Question 82

Inferior mesenteric artery

Answer 82

The artery of the hindgut. It leaves the aorta at the level of L3. It is a smaller calibre vessel than the coeliac trunk and SMA. Its branches supply the hind gut structures : the distal third of the transverse colon, the descending and sigmoid colon, the rectum and the upper part of the anal canal.

Question 83

Major branches of the IMA

Answer 83

Left colic artery - supplies the transverse colon and descending colon
Sigmoid branches - supply the sigmoid colon
Superior rectal artery - the terminal branch of the IMA, which supplies the rectum .

Question 84

The marginal artery

Answer 84

Branches of the middle colic ( from the sma ) and the left colic ( from the ima ) anastomose along the distal third of the transverse colon and the splenic flexure forming the marginal artery. Branches of the left colic and sigmoid arteries also anastomose.

Question 85

Blood supply of the rectum

Answer 85

Also supplies by middle and inferior recital arteries which branch from the internal iliac arteries in the pelvis. The middle and inferior rectal arteries anastomose with branches of the superior recital arteries

Question 86

Venous drainage of the small and large intestine

Answer 86

Venous drainage from the gut reaches the inferior vena cava and is returned to the heart. It contains absorbed nutrients it first enters the liver via the portal venous system before being returned to the heart via the ivc.

Question 87

Inferior mesenteric vein

Answer 87

Accompanies the ima and drains the hindgut. It ascends on the left side of the abdomen shod typically drains into the splenic vein from the spleen. Venous blood from the rectum drains into both the portal system and the systemic system.

Question 88

Superior mesenteric vein

Answer 88

Accompanies the sma and drains the midgut. The sma ascends and unites with the splenic veins close to the liver ( posterior to the neck of the pancreas ) to form the hepatic portal vein.

Question 89

The hepatic portal vein

Answer 89

Enters the liver. After the nutrients are removed from the blood, it enters small hepatic veins which unite within the liver to form two or three large hepatic veins that enter the IVC as it passes posterior to the liver ( hence the hepatic veins are within the liver and cannot be seen externally)