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Question 1

What is a bolus?

Answer 1

A mass of chewed food

Question 2

Which parts of the esophagus are voluntary and involuntary?

Answer 2

Upper 1/3: Voluntary (also contains skeletal muscle)Lower 2/:3: Involuntary, purely peristalsis (smooth muscle)

Question 3

What is Barett’s esophagus? What is the epithelial change?

Answer 3

A pre-malignant shift from stratified squamous epithelia to simple columnar due to constant acid reflux (GERD)

Question 4

What’s achalasia?

Answer 4

A condition where muscles of the lower part of the esophagus fail to relax (LES doesn’t close), preventing food from passaging into the stomach and leading to a to a backup of food within oesophagus

Question 5

Name 3 causes of Barett’s esophagus?

Answer 5

1. LES isn’t working 2. Dysphagia and achalasia3. Esophageal varices or hernia

Question 6

Name the 7 accessory digestive organs

Answer 6

Teeth, tongue, gall bladder, salivary glands (parotid, submandibular, sublingual), spleen, liver and pancreas

Question 7

What hormone stimulates the contraction of the gall bladder? What secretes and stimulates this hormone?

Answer 7

Cholecystokinin is stimulated by the introduction of HCl, amino acids or fatty acids in the stomach or duodenum and is secreted from enterocytes in the duodenum - it then triggers contraction of the gall bladder so bile is released into the duodenum via the cystic duct

Question 8

What cell lines the ducts of the biliary tract and what is its role?

Answer 8

Cholangiocytes which modify the bile

Question 9

Which neural systems play a part in controlling the GI tract?

Answer 9

Somatic motor system for ingestion and excretion, Autonomic NS for everything else with the Parasympathetic system being the most significant

Question 10

Name the possible epithelia that line the GI tract their locations and function

Answer 10

Simple columnar - intestine Glandular epithelia - stomach *Both aid in secretion and absorption Stratified squamous non keratinized - mouth and rectumProvides moisture and protection

Question 11

Which nervous system is in the submucosa? What is it derived from? Name 3 things that it controls.

Answer 11

Submucosal Nerve plexus/Messner plexus: derived from myenteric nerve plexus Controls:1. Glandular secretions2. Regulates local blood flow3. Alters electrolyte and water transport

Question 12

What separates the circular and longitudinal layers of muscle? What is it derived from and what does it control?

Answer 12

The Myenteric or Auerbach’s plexus; Derived from plexus of parasympathetic nerves around SMA Controls GI tract motility/peristalsis

Question 13

Which areas are covered primarily with serosa and others with adventitia? Why?

Answer 13

Intraperitoneal regions are covered with serosa (visceral peritoneum): it secretes fluid that lubricates the outside of the GI tractRetroperitoneal regions requiring anchoring are covered with adventitia

Question 14

Which specific organs/regions are surrounded by adventitia?

Answer 14

Oral cavity, thoracic esophagus, ascending colon, descending colon, rectum

Question 15

What are the boundaries of the abdomen?

Answer 15

Superior: diaphragm Inferior: Pelvic inletLateral: serous membranes

Question 16

What are the 4 quadrants of the stomach? Which significant abdominal organs lie in each quadrant?

Answer 16

R Upper: Liver, gallbladderR Lower: AppendixL Upper: Stomach, spleenL Lower: descending colon, sigmoid colon

Question 17

Where is McBurney’s point and what is its significance in appendicitis?

Answer 17

Location: 1/3 along a line from the R ASIS to the umbilicus Significance: In appendicitis the nervous system is first stimulated by irritation in the visceral layer - so it localizes the pain as coming from where the organ was embryonically derived. As the condition worsens the parietal layer also becomes irritated. At this point, the brain is now able to localize the pain as closer to the appendix’s adult position. Therefore, as the condition worsens the pain will travel towards McBurney’s point

Question 18

What is the mesentery and what is its significance?

Answer 18

Double layer of the peritoneum: allows for blood, nerves and lymphatic access to the organs since vessels cannot directly penetrate the peritoneum

Question 19

List the 3 types of mesentery

Answer 19

1. Mesentery proper 2. Trasverse mesocolon mesentery 3. Sigmoid mesocolon mesentery

Question 20

What is the parietal cavity and what is its significance?

Answer 20

Between parietal and visceral peritoneum: contains fluid that lubricates the GI tract allowing for movement during digestionInflammation and infection can lead to increased production of fluid that puts pressure on the organs

Question 21

What does intraperitoneal and retroperitoneal mean?

Which important organs/structures are in which regions? (and which structures are ‘in-between’?)

Answer 21

Intraperitoneal: Completely surrounded by visceral peritoneum, suspended by mesenteries -Stomach, spleen, jejunum, ileum, caecum, appendix, transverse colon, sigmoid colonRetroperitoneal: behind the peritoneum, not suspended by mesenteries -kidney, adrenal glands, ureters, IVC, abdominal aorta “Inbetween”/somewhat covered by visceral peritoneum: duodenum, ascending colon, descending colon, pancreas

Question 22

What is Peritonitis and what does it commonly result from?

Answer 22

Inflammation and infection of the peritoneum, commonly the result of: burst appendix, penetrating wound, perforated duodenal ulcer

Question 23

What landmarks mark the beginning of the abdominal aorta?

Answer 23

Aortic hiatus of the diaphragm, T12

Question 24

What are the 3 major trunks/arteries that branch off the abdominal aorta that supply the gut? List them in order of superior-inferior

Answer 24

1. Celiac Trunk: foregut2. Superior mesenteric artery: midgut3. Inferior mesenteric artery: hindgut

Question 25

What are the 3 major branches of the Celiac Trunk? Which branches go left and right, and what do they collectively supply (7)?

Answer 25

1. L gastric artery 2. Splenic artery (goes L) 3. Common hepatic artery (goes R)Collectively: supplies the stomach, spleen, liver, gall bladder, abdominal esophagus, pancreas and duodenum

Question 26

What does the L gastric artery give rise to and anastomose with?

Answer 26

Gives rise to oesophageal branches, then continues anteriorly along lesser curvature of stomach and anastomoses with the R gastric artery

Question 27

What is the splenic artery’s pathway and what structure contains the vessel during its course?

Answer 27

Travels L towards spleen, posterior to the stomach within the splenorenal ligament. Has a tortuous appearance

Question 28

In addition to supplying the spleen what are 3 other important vessels the splenic artery gives rise to? What do they supply?

Answer 28

1. L gastroepiploic: greater curvature of stomach 2. Short gastrics: fundus of stomach 3. Pancreatic branches: body and tail of pancreas

Question 29

Why is the common hepatic artery so essential and what are its 2 terminal branches?

Answer 29

It is the sole arterial supply to the liver, gives rise to the proper hepatic and gastroduodenal arteries

Question 30

Where does the proper hepatic artery travel through? What 3 branches does it give off and what do they supply?

Answer 30

Ascends through the lesser omentum towards the liver:1. R gastric: pylorus and lesser curvature of stomach 2. R and L hepatic: respective lobes of liver3. Cystic: gall bladder

Question 31

Where does the gastroduodenal artery travel through? What are its 2 branches and what do they mainly supply?

Answer 31

Posterior to the superior portion of the duodenum:1. R gastroepiploic: greater curvature of stomach and greater omentum 2. Superior pancreaticoduodenal: head of pancreas

Question 32

What are the borders and contents of the triangle of calot? Which surgery requires knowledge of this landmark?

Answer 32

Borders: Superior - liverMedial - common hepatic duct Lateral - cystic duct Contents: Cystic artery, R hepatic artery, accessory ducts Important in a cholecystectomy: removal of gall bladder

Question 33

What organs are supplied by the superior mesenteric artery? Which vertebral level does this vessel begin at?

Answer 33

L1: Distal duodenum, jejunum, ileum, colon -> splenic flexure

Question 34

Name the 5 major arterial branches that come off the SMA

Answer 34

1. Jejunal branches2. Ileal branches 3. Ileocolic branch: terminal part of ileum and first part of ascending colon4. R and middle colic artery

Question 35

Describe the structure that provides anastomoses between the arterial branches of the SMA and IMA, where is it located?

Answer 35

Anastomoses is provided by the ‘marginal artery of drummond’, found along the mesenteric border of the large intestine (a continuous arterial circle along the inner border of the colon)

Question 36

What structures does the Inferior mesenteric artery supply? Which vertebral level does this vessel begin at?

Answer 36

L3: Colon (past splenic fixure); descending colon, sigmoid colon, superior rectum

Question 37

Name the 3 major arterial branches that come off the IMA

Answer 37

1. L colic artery2. Sigmoidal arteries 3. Superior rectal artery; (rectum and upper half of anal canal)

Question 38

List the 3 major veins that drain the gut (and which structures they drain), where does the entire venous drainage then lead to?

Answer 38

1. SMV: bulk of SI2. IMV: distal colon3. Splenic vein All drain into the liver via the portal vein (where the blood is detoxified and metabolized). Blood is then returned to the heart via the IVC

Question 39

What is chyle and when might it have a ‘milky appearance’?

Answer 39

Chyle is GI lymphatic drainage which can appear milky after there has been absorption of fatty material

Question 40

Which artery is likely to be affected in a duodenal ulcer and why?

Answer 40

Duodenal ulcers erode posteriorly, directly making contact with the gastroduodenal artery - causing it to bleed

Question 41

Where are the ‘paracolic gutters’ and what is their significance?

Answer 41

Paracolic gutters are depressions formed between lateral margins of the intestine and posterolateral abdominal walls. Infection/pus/fluid can easily spread around regions of the peritoneal cavities via the gutters in the direction of gravity. An accumulation of fluid may require drainage

Question 42

GALT (gut associated lymphoid tissue) is generally diffusely situated, name three areas in the GIT where GALT is nodular

Answer 42

1. Peyer’s patches in the ileum2. Tonsils3. Appendix