The intestines

Question 1

Location of the foregut

Answer 1

Ends after entry of common bile duct into duodenum

Question 2

Location of the midgut

Answer 2

Ends 2/3 of the way along transverse colon

Question 3

Location of the hindgut

Answer 3

Ends halfway down the anal canal

Question 4

Midgut mesentery

Answer 4

The mesentery attaches to posterior abdominal wall
Supplied by superior mesenteric artery
From DJF to ICJ, 15 cm long

Question 5

Small intestine

Answer 5

6m
Duodenum (1st part intraperitoneal)
Jejunum (intraperitoneal)
Ileum (intraperitoneal)
From pyloric sphincter to ileocaecal junction
Peristalsis and segmentation

Question 6

The duodenum

Answer 6

In umbilical region from transpyloric plane

Ascending segment, smooth mucosal wall
Descending segment, pancreatic bile duct
Horizontal, behind superior mesenteric artery
Ascending, DJF held up by suspensory ligament of Treitz

Plicae circulars only found in 2, 3 ,4
Brunners glands found here neutralize stomach acid

Question 7

Suspensary ligament of Treitz

Answer 7

Holds up DJF from right crus of diaphragm

Question 8

Parts and relations of the duodenum

Answer 8

R kidney behind descending duodenum
Pancreas wrapped in curvature of duodenum
Superior mesenteric artery comes over duodenum
Aorta and VC behind duodenum and pancreas

Question 9

Openings into duodenum

Answer 9

Accessory duct leads into minor papilla

Common bile duct and main pancreatic duct leads into major papilla/ampulla of Vater

Question 10

Jejunal mucosal layers

Answer 10

Plicae circularis, mucosa
Submucosa
Muscularis externa (circular, longitudinal)
Serosa

Long vasa recta, no anastomoses
Simple arterial arcades
V little fat

Question 11

Ileal mucosal layers

Answer 11

No plicae circularis, Peters patches instead
Submucosa
Muscularis externa (circular, longitudinal)
Serosa

Short vasa recta
Complex arterial arcades, many anastomoses
Fat filled mesentery

Question 12

Lymphatics of the intestines

Answer 12

Mesenteric nodes, joins pre aortic nodes (coeliac, superior, inferior mesenteric)
Join cistern chili via para aortic, enters thoracic duct and L jugular, subclavian

Question 13

Features of the large intestine

Answer 13

Teniae coli
Haustra
Epiploic appendages

Question 14

Teniae coli

Answer 14

3 longitudinal strips of muscle
Thickening of longitudinal muscle of musclaris externa
Maintain muscle tone, cause haustra

Question 15

Haustra

Answer 15

Saclike divisions

Question 16

Epiploic appendages

Answer 16

Mental appendices
Fat filled pouches
Extensions of peritoneum

Question 17

Large intestine function

Answer 17

Absorption of water and electrolytes
Mass peristaltic movements => rectum
Residue moves through colon in 12-24

Question 18

Caecum and ascending colon

Answer 18

Blind end of caecum into appendix
Expanded plicae circularis, forms ileocaecal valve
Retroperitoneal caecum, intraperitoneal appendix

Question 19

The appendix

Answer 19

Has its own mesentery
Can be in variable locations
Opening associated with teniae coli

Question 20

Appendicitis

Answer 20

Pain initially in umbilical region

When infection moves to parietal peritoneum, pain moves to R iliac

Question 21

Colon and colic flexures

Answer 21

R colic/hepatic flexure and L colic/splenic flexure
Transverse and sigmoid colon, intraperitoenal
Ascending, descending colon, retroperitonela

Question 22

Mesenteric vessels, superior mesenteric

Answer 22

Jejunal ileal
Ileocolic, appendicular
R colic
Middle colic

At L1

Veins match mesenteric arteries

Question 23

Mesenteric vessels, inferior mesenteric

Answer 23

L colic
Sigmoidal
Superior rectal

At L3
Veins match mesenteric arteries

Question 24

Sympathetic innervation of foregut, midgut, hindgut

• Roots
• Preganglionic nerve
• Sympathetic ganglion

Answer 24

Foregut

• T5-T9
• Greater splanchnic nerve => celiac sympathetic ganglia

Midgut

• T10-T12
• Lesser and least splanchnic nerve => superior mesenteric ganglia

Hindgut

• T12-L2
• Lumbar splanchnic nerve => inferior mesenteric ganglia

Question 25

Specific areas of innervation of the bowels

Answer 25

Duodenum T8
Jejunum T9
Ilium T10
Asc colon T11
Desc colon T12
Rectum and anus L1-2

Question 26

Referred abdominal pain

Answer 26

Foregut, epigastric, ventral and dorsal
Midgut, umbilical
Hindgut, superopubic

Due to visceral pain being referred via sympathetic nerves

Question 27

Parasympathetic innervation of the foregut, midgut, hindgut

• Preganglionic nerves
• Parasympathetic ganglion

Answer 27

Foregut
-Vagus => Intrinsic ganglia

Midgut
-Vagus => Intrinsic ganglia

Hindgut
-Pelvic splanchnic (S2-4) => Intrinsic ganglia