129. Structure Abd

Question 1

What are the 3 arteries (and branches) flowing from the celiac trunk and what do they supply?

Answer 1

1. L Gastric a. = upper half of lesser curve stomach
2. Splenic a. (curvy/tortuous) = pancreas/spleen
   - branch: short gastric a. = upper half greater curve stomach
3. Common Hepatic A.
   - R Gastric a. = lower half lesser curve stomach
   - R+L Gastroepiploic a. = lower half greater curve stomach
   - Supraduodenal/Gastroduodenal = upper half duodenum
   - Hepatic A. Proper: Cystic A. (gallbladder), L/R Hepatic A. (Liver)
   - superior pancreaticoduodenal a. (anastamose with SMA)

Question 2

What are the 4 branches of the SMA and what do they supply?

Answer 2

1. Ileocolic: terminal ileum, cecum, part ascending colon
2. R. Colic: ascending colon
3. Middle Colic: transverse colon
4. Many Intestinal Branches (small intestine)

Question 3

What are the 3 branches of the IMA and what do they supply?

What are 3 features shared by parts of IMA and SMA?

Answer 3

1. L Colic: Descending Colon
2. Sigmoid Branches: Sigmoid Colon
3. Superior Rectal: continuation of IMA to rectum

Arcades: looping anastamoses
Vasa Recta: straight arteries to wall of intestines
Marginal Artery: follow contours of colon

Question 4

Describe the pathophysiology of Left Renal Vein Compression

Answer 4

• L Renal Vein needs to pass over aorta to get to IVC
• SMA branch off aorta passes over L renal vein as it goes over aorta (artery sandwich)
• L gonadal vein goes to left renal vein to avoid having to cross over itself (R gonadal vein to IVC)

SMA = compress L renal vein = impair L gonadal vein = L testicular varices (dilated veins)

Question 5

Describe the difference between parasymp and symp innervation of GI tract

Answer 5

Parasymp: Vagus N. (foregut and midgut); pelvic splanchnics (S2-S4) to hindgut, short postsynaptics on wall of intestines

• Myenteric (Auerbach’s) Plexus: b/w smooth muscle laters of GI (longitudinal/circular) for contraciton
• Submucosal (Meissner’s) Plexus: submucosal for gland secretion, MM inervation

Symp: for artery contractions
Thoracolumbar splanchnics to autonomic (enteric) plexus via collageral ganglia on aorta (follow artery to target organ)

Visceral Sensory nerves follow both symps and parasymps

Question 6

What visceral sensory spinal cord segments supply the following:
heart
pancreas
stomach/liver/spleen
Small intestine
appendix
R colic flexure
L colic flexure
Upper sigmoid colon

Answer 6

heart - T1 (shoulder, arm)
pancreas (under diaphragm - C3-5: shoulder)
stomach/liver/spleen - T7-9
small intestine - T9-10
appendix - T10 (umbilicus)
R colic flexure - T12
L colic flexure - L1
Upper Sigmoid Colon - L2

Question 7

View of liver from below:

What structures make up the R. bar, L. Bar, and cross-bar

Answer 7

R. Bar: adult structures (gallbladder - ant; IVC - post)

L. Bar: embryonic structures (ligamentum teres - ant; ligamentum venosum - post)

Cross bar: portal triad - bile duct, PV, HA

Question 8

What veins are collected by the PV? Where are 3 key sites of PV anastamoses and signs of PHTN?

Answer 8

PV drains: L gastric vein, SMV, IMV

1. Esophageal Varices: L gastric V = Esophageal Vein - Azygous vein
2. Caput Medusa: SMV = superficial epigastric v.
3. Hemorrhoids: IMV = internal iliac vein

Question 9

How does the pancreas develop?
How does this relate to Anular pancreas?
What is the most common pancreatic congenital defect?

Answer 9

Ventral bud: swings around duodenum to join dorsal bud, its main pancreatic duct joint common bile duct, HEAD of pancreas

Dorsal bud: minor (accessory) pancreatic duct, BODY and TAIL of pancreas

Anular pancreas: ventral bud wraps around and constricts duodenum

Most common: failure of fusion of both buds (accessory duct becomes main duct)

Question 10

Gallbladder:

• describe the flow of bile from gallbladder to small intestine
• what four structures does this touch? how is this clinically relevant?

Answer 10

GB - cystic duct + common hepatic duct - common bile duct + main pancreatic duct - sphincter of oddi - major duodenal papillae

1. Liver
2. Duodenum
3. Transverse Colon
4. Anterior Abd Wall
   infected gallbladder can sent gallstone fistulas and pain to these organs