1. Layout and regional specialisations of alimentary system

Question 1

What structures make up the foregut?

Answer 1

Pharynx
Lower oesophagus
Proximal duodenum
Liver
Gallbladder
Pancreas
Spleen

Question 2

At what vertebral level do the foregut structures lie?

Answer 2

T12/L1

Question 3

What is the main arterial blood supply of the foregut?

Answer 3

Coeliac artery

Question 4

What nerve innervates the foregut?

Answer 4

Vagus nerve (CN X)

Question 5

What comprises the midgut?

Answer 5

From the distal duodenum to 2/3 of the transverse colon

includes jejunum, ileum, stomach, caecum, ascending colon, appendix

Question 6

What main artery supplies the midgut?

Answer 6

Superior mesenteric artery

Question 7

What is the main innervation of the midgut?

Answer 7

Vagus nerve (CN X)

Question 8

What does the hindgut consist of?

Answer 8

Distal 1/3 of transverse colon to rectum

including descending and sigmoid colon

Question 9

What innervates the hindgut?

Answer 9

Pelvic nerves

Question 10

What is the main arterial supply of the hindgut?

Answer 10

Inferior mesenteric artery

Question 11

Where is the watershed region between the superior mesenteric artery and the inferior mesenteric artery?

Answer 11

The splenic flexure

Question 12

What is the main blood supply of the pancreas? What are the areas of the pancreas that this artery supplies?

Answer 12

Splenic artery (branch of the coeliac trunk)
The neck, body and tail

Question 13

What is the arterial supply of the head of the pancreas?

Answer 13

The superior and inferior pancreatoduodenal arteries

Question 14

What is the venous drainage of the pancreas?

Answer 14

The splenic vein

Question 15

Name the 3 types of salivary glands, which are the largest?

Answer 15

Submandibular
Sublingual
Parotid (2) - largest

Question 16

List the layers of the GI tract from innermost to outermost layers.

Answer 16

Mucosa
Submucosa
Muscularis propria
Serosa/adventitia

Question 17

From inner to outer, describe the structural organisation of GI mucosa

Answer 17

Epithelium
Lamina propria
Muscularis mucosae

Question 18

What plexus is present in the submucosa and what is it responsible for?

Answer 18

Meissner’s (submucosal) plexus
Senses gut environment, controls glandular secretions, regulates local blood flow, alters water and electrolyte balance
Innervates epithelium and muscularis mucosae

Question 19

From innermost to outermost, describe the layers of the muscularis propria, and the types of contraction of the muscles involved.

Answer 19

Circular muscle - constriction
Auerbach’s plexus (myenteric plexus)
Longitudinal muscle - shortening of gut

Question 20

What does saliva consist of and what are the functions of its components?

Answer 20

Mucus - lubrication
Amylase - digests starch
Bicarbonate - neutralises acid
Thiocyanate, lysozyme - bactericidal agent

Question 21

How much saliva do we produce a day?

Answer 21

500ml (0.5L)

Question 22

List the layers of muscle in the stomach, from outer to innermost.

Answer 22

Longitudinal
Circular
Oblique

Question 23

List the 3 duodenal fissures from proximal to distal.

Answer 23

Superior duodenal fissure
Inferior duodenal fissure
Duodenojejunal fissure

Question 24

Name the 4 parts of the duodenum

Answer 24

1st part - (superior duodenum)
2nd part of duodenum - descending part
3rd part of duodenum - horizontal part
4th part of duodenum - ascending part

Question 25

Where does pancreatic secretions and bile enter the alimentary system?

Answer 25

Through the Ampula of Vater (major duodenal papilla) and the minor duodenal papilla

Question 26

What glands are present in the submucosa of the duodenum and what do they secrete?

Answer 26

Brunner's glands - secrete bicarbonate

Question 27

What structures are present in the ileum?

Answer 27

Peyer's patches - lymph follicles

Question 28

What are the two systems which make up the exocrine pancreas?

Answer 28

Acinar cells (enzymatic) and the duct system (aqueous/bicarbonate)